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. 2021 Sep 16;8:694679. doi: 10.3389/fnut.2021.694679

Comparative Quality Evaluation of Physicochemical, Technological, and Protein Profiling of Wheat, Rye, and Barley Cereals

Monika Rani 1, Gagandeep Singh 2, Raashid Ahmad Siddiqi 1, Balmeet Singh Gill 1, Dalbir Singh Sogi 1,*, Mohd Akbar Bhat 3
PMCID: PMC8481659  PMID: 34604274

Abstract

Agronomically important cereal crops wheat, barley, and rye of the Triticeace tribe under the genus Triticum were studied with special focus on their physical, proximal, and technological characteristics which are linked to their end product utilization. The physiochemical parameters showed variability among the three cereal grains. Lactic acid-solvent retention capacity (SRC) was found to be higher in wheat (95.86–111.92%) as compared to rye (53.78–67.97%) and barley (50.24–67.12%) cultivars, indicating higher gluten strength. Sucrose-SRC and sodium carbonate-SRC were higher in rye as compared to wheat and barley flours. The essential amino acid proportion in barley and rye cultivars was higher as compared to wheat cultivars. Barley and rye flours exhibited higher biological value (BV) owing to their higher lysine content. SDS-PAGE of wheat cultivars showed a high degree of polymorphism in the low molecular range of 27.03–45.24 kDa as compared to barley and rye cultivars. High molecular weight (HMW) proteins varied from 68.38 to 119.66 kDa (4–5 subunits) in wheat, 82.33 to 117.78 kDa (4 subunits) in rye, and 73.08 to 108.57 kDa (2–4 subunits) in barley. The comparative evaluation of barley and rye with wheat cultivars would help in the development of healthy food products.

Keywords: wheat, rye, barley, solvent retention capacity, SDS-PAGE, amino acids

Introduction

Wheat is the most utilized cereal for human consumption as compared to rye and barley. Clinical studies have shown that barley and rye play a significant role in reducing the risk of cardiovascular disease (CVD), lower postprandial body glycemic index, improve insulin responses in diabetics, lower serum cholesterol level, protect against obesity, and safeguard against the hormone-related risk of colon cancers (1, 2). The U.S. Food and Drug Administration (FDA) has declared barley as a functional food while the European Food Safety Authority (EFSA) has approved the health claim of rye for maintaining bowel function (3).

The rye grain contains a high amount of total dietary fiber, i.e., 19.9% of dry matter (including soluble dietary fiber, SDF, and insoluble-dietary fiber, IDF) as compared to 15.2% in barley and 13.5% in wheat grains (1). SDFs such as arabinoxylan and β-glucan cause an increase in the viscosity of intestinal contents, regulating slower absorption of sterol and glucose and ultimately maintaining glucose, cholesterol, and insulin levels. Similarly, IDFs like cellulose, lignin, and hemicelluloses owing to their high-water absorption ability increases the fecal volume which prevents short as well as long-term disease complications.

Barley and rye flour have been utilized for the production of different commercial food preparations such as breakfast cereals, barley flour tortillas, soft whole-grain rye bread, crisp bread, soups, porridge, and baby foods, etc. About 65% of wheat production is utilized as human food while its remaining 20 and 15% are used for animal feed and miscellaneous purposes, respectively (4, 5). In barley, about 68% is used for feed purposes, 24% for distillery and brewing industries, 6% for human food, and the remaining 2% for other purposes like bio-fuel generation (6). Similarly, in rye, about 42% is used for livestock feed, 31% for human food mainly as rye bread or other processed products, and 27% for other purposes (2). The primary reason for the disparity in the usage of these cereals for human consumption is apparently due to the remarkable visco-elastic nature of wheat dough. This is one of the reasons why wheat is used in conjunction with many rye and barley products for achieving desired dough properties. Therefore, a comparative investigation on wheat, rye, and barley cultivars with special focus on technological, functional, and physicochemical properties is needed. Hamdani et al. (7) has compared the physical properties of barley and oats cultivars and reported significant differences in physical parameters between cultivars and also among cereals. Rodehutscord et al. (8) studied the physiochemical characteristics and amino acid composition of various cereal grains (barley, rye, maize, triticale, oats, and wheat) and reported substantial differences in their physical, chemical, and amino acid composition. Similarly, Kowieska et al. (9) demonstrated significant variation in crude protein, crude fiber, mineral, and amino acid composition in Polish wheat, rye, triticale, and barley cultivars. Drakos et al. (10) compared the nutritional and functional components of rye and barley flour with reference to milling characteristics. Similarly, few authors have also studied the impact of the addition of barley and rye flour on wheat bread quality (11, 12).

This study has been designed to focus on the physicochemical investigation of wheat, rye, and barley cereals using a multi-technique approach. Technological properties of cereal flours have been evaluated using solvent retention capacity (SRC), SDS-sedimentation volume, water-holding capacity (WHC), and oil-holding capacity (OHC). Further, these studies were extended to understand the gluten characteristics of these flours via analysis of wet gluten, dry gluten, WHC, and OHC of gluten. The protein profiling of flours has been investigated using SDS-PAGE and amino acid analysis (AAA) of rye and barley in comparison to wheat. The correlation between different technological and functional component parameters has been derived and discussed in detail. The inferences obtained from this study would help in establishing the relative understanding of the technological properties of cereals under investigation. Therefore, the analytical insights gained would facilitate new product applications pertaining to rye and barley. The obtained information would further promote the end-use application of these grain flours to millers, breeders, and manufacturers for commercial application.

Materials and Methods

Raw Materials

The authentic cereal grains of rye cultivars (MCTLG-1, MCTLG-2, MCTLG-3, MCTLG-4, and MCTLG-5) and wheat cultivars (HPW-42, HPW-147, HPW-155, HPW-236, HPW-249, and HPW-349) were procured from Chaudhary Sarwan Kumar Himachal Pradesh Krishi Vishvavidyalaya (CSK HPKV), Palampur, India, located at a latitude of 32° 6′ 52" N longitude 76° 33′ 24" E, and altitude 1,614 m above sea level. Palampur (HP) has a humid subtropical climate (warm summer and cold winters) and sandy to loamy textured soil. The barley cultivars (BH-393, BH-902, BH-946, and BH-959) were procured from Chaudhary Charan Singh Haryana Agricultural University (CCS HAU), Hisar, (latitude 29° 8′ 57.08" N, longitude 75° 43′ 17.95" E and an altitude of 212.78 m above sea level) India. The climate of Hisar is tropical monsoonal (very hot summers, relatively cold winters) with fertile alluvial soil. All the cereal grains were grown during the crop years 2014-15. Brabender Quadrumat junior mill (Brabender OHG, Germany) was used to mill the conditioned grains to obtained flour with an extraction rate of 72, 68, and 60% for wheat, rye, and barley, respectively. It was stored at −20°C and thawed before analysis (25°C for 2 h). All the chemicals used were of analytical grade.

Methods

Grain Characteristics

The grain length (L), width (W), and thickness (T) were measured using a digital vernier caliper (Thermo Fischer Scientific, Waltham, Massachusetts, USA) with an accuracy of 0.01 mm. Geometric parameters such as equivalent diameter (Dm), L/W ratio, sphericity (Φ), aspect ratio (Ra), seed volume (V), and surface area (A) were calculated using formulas given in the literature (7, 13, 14) while gravimetric characteristics like thousand kernel weight (TKW), hundred kernel volume, bulk density (DB), true density (DT), and porosity (ε) were determined by following the procedure of Wani et al. (14).

Equivalent diameter (Dm)=(LWT)1/3 (1)
Sphericity(Φ)=(LWT)1/3L100 (2)
Aspect ratio (Ra)=WL (3)
Seed volume (V) = πB2L26(2L-3) (4)
where B=(WT)1/2 (5)
Surface area (S)= πBL2(2L-B) (6)

where, W = width; L = length; T = thickness of grain

Bulk density =sample weightvolume (7)

True density (g/mL) was measured by the liquid displacement method using toluene as a displacement liquid.

True density =sample weight(V2-V1) (8)

where, V1 = initial volume and V2 = final volume

Porosity (ε)=100[1-(DB/DT)] (9)

where ε is the porosity in percentage; DB is bulk density in g/mL, and DT is seed density in g/mL.

Hundred kernel volume=Total volume-20 mL (10)

Flour Characteristics

Proximate Composition

Moisture (44-15.02), protein (46-12.01), ash (08-02.01), fiber (32-10.01), and fat (30-25.01) were estimated by following the AACC approved methods (15). Carbohydrate content was determined by the difference method, whereas energy values were calculated by multiplying protein and carbohydrate content by 4 kcal/g and fat content by 9 kcal/g (16).

Solvent Retention Capacity

Solvent retention capacity (SRC) was determined following the standard procedure as per AACC approved method 56-11 (15). One gram of flour was suspended individually in 5 ml of standard solutions (deionized distilled water, 5% sodium carbonate, 5% lactic acid, and 50% sucrose). The flour suspension was allowed to hydrate and mixed at 150 rpm for 20 min on a horizontal incubator shaker (LSI-3016R, Daihan Lab Tech Co., Ltd., Namyangju, South Korea) and centrifuged (20 min at 1,100 × g). The supernatant was decanted and kept in an inclined position at a 45° angle for 20 min and then the pellet was weighed. SRC values were estimated using the following equation:

SRC (g100g)=  ( Wet pellet (g)Flour (g)-1 )×(86  100-Flour moisture (g100g))×100 (11)
Gluten Performance Index

The gluten performance index (GPI), a good indicator of overall gluten strength, was estimated using the data of SRC (17).

GPI=Lactic acid SRCSodium carbonate SRC + Sucrose SRC (12)

SDS-Sedimentation Value

The SDS-sedimentation value of cereal flour was estimated by following AACC approved method 56–70 (15) in which glutenin protein absorbs water and swells in the presence of SDS-lactic acid reagent. Solution A (2% SDS in distilled water) and solution B (one part lactic acid and eight parts distilled water) were prepared separately. Solution A (10 ml) and solution B (2 ml) were mixed to get an SDS-lactic acid reagent. Six grams of flour and 50 ml of distilled water were transferred into a 100 ml measuring cylinder with a stopper and shaken for 15 s, each time at an interval of 2, 4, and 6 min. Immediately after the final shaking, 50 ml of freshly prepared SDS-lactic acid solution was added and the mixture was allowed to move up and down four times each at an interval of 2, 4, and 6 min for 15 s. Immediately after the final inversion, starting the clock from zero, the flour mixture was allowed to settle in the cylinder for 40 min, and the sedimentation volume was recorded in ml.

Gluten Content

Wet and dry gluten were analyzed according to AACC approved method 38-10 (15) by a hand washing procedure. The dough was prepared by mixing an adequate amount of water (≈12 ml) with 25 g of flour in a porcelain dish. The round ball of dough was kept in a beaker filled with water for at least 60 min. After the stipulated time, the dough was kneaded gently under running tap water over a 75 mm sieve until milky water turned to colorless water. The obtained sticky or dark mass was then kept in a beaker filled with water for another 60 min without any disturbance. Thereafter the gluten was held between two hands and squeezed hard to remove excess water and rolled to a round mass and weighed to get wet gluten. The wet gluten was then dried in an oven operated at 110°C for 24 h, cooled using a desiccator, and weighed to get dry gluten. The values of wet and dry gluten were calculated using the following equations:

Wet gluten (%)=weight of wet gluten (g)weight of the sample (g)100 (13)
Dry gluten (%)=weight of dry gluten (g)weight of the sample (g)100 (14)

Color of Cereal Grains/Flour and Dried Gluten Content

The color of the different cereal grains, flour, and gluten was measured using the Hunter Color lab (Hunter Associates Laboratory Inc., Reston USA) by following the procedure of Siddiqi et al. (16). Hue and chroma were determined using the following formulas:

Hueangle (H0)=tan-1(b*/a*) (15)
Chroma (C)=(a2+b2)0.5 (16)

Amino Acid Analysis of Flour

AAA of flour was performed by following the procedure of Siddiqi et al. (16) with a slight modification. Defatted flour (15 mg) was hydrolyzed using 6N HCl containing 0.1% ß-mercaptoethanol in an autoclave at 110 ± 2°C for 16 h. The digested sample was filtered, evaporated to dryness under a vacuum at 60°C in a rotary evaporator (Buchi, Fawil, Switzerland), re-dissolved with a suitable volume of 0.1 N HCl, and filtered through 0.22 μm filter paper. Amino acid analysis was performed using an amino acid analyzer (Shimadzu, Kyoto, Japan) equipped with pre-column derivatization using three derivatizing reagents such as mercaptopropionic acid, o-phthaladehyde, and 9-fluorenylmethoxycarbonyl chloride. A C-18 column (Acclaim Thermoscientific 120Å, 5 μm, 4.6 × 250 mm; Thermo Fisher Scientific, Waltham, USA) with pH stability of 2–8 was used for chromatographic separation. Analysis was performed by the standard operating manual procedure, using 20 mmol/L of phosphate (potassium) buffers (pH 6.5) as solvent A and 45/40/15 acetonitrile/methanol/water as solvent B. The separation was obtained at a flow rate of 1 ml/min using a gradient elution that allowed 0% of B at 0.01 min, followed by linear raise of eluent B to 50% at 41 min and then again decreasing solvent B to 0% at 44 min at a column oven temperature of 40°C. The injection volume of the standard or sample was 1 μL. The pre-column derivatized amino acids were detected with the help of a fluorescence detector with excitation and emission set at 330 and 450 nm, respectively. Lab solutions LC/GC (Shimadzu, Kyoto, Japan) was used as a working station. The amino acid standard mixture was prepared by mixing 18 amino acids (SRL, Mumbai, India) in 0.1 N HCl which included aspartic acid (Asp), glutamic acid (Glu), serine (Ser), glycine (Gly), threonine (Thr), histidine (His), alanine (Ala), arginine (Arg), tyrosine (Tyr), valine (Val), methionine (Met), cystine (Cys), phenylalanine (Phe), tryptophan (Trp), isoleucine (Ileu), leucine (Leu), lysine (Lys), and proline (Pro). The amino acid comparison of the standard mixture and the digested sample was done based on retention time as well as for the area under the peak for detection and quantification of each eluted amino acid. The estimated glutamic acid and aspartic acid were represented by a combination of acid and amide derivative, as amides such as glutamine (Gln) and asparagine (Asn) are deaminated to glutamic acid (Glu) and aspartic acid (Asp) during acid hydrolysis (18). Therefore, results are expressed as Glu + Gln and Asp and Asn.

Digestible Indispensable Amino Acid Score

The recommended dietary allowances (RDA) of amino acid for children (age: 6 months to 3 years) was used as the reference protein for the calculation of DIAAS of selected cereals using standard values of leucine (6.6/100 g), lysine (5.7/100 g), phenylalanine (5.2/100 g), valine (4.3/100 g), isoleucine (3.2/100 g), threonine (3.1/100 g), methionine (2.7/100 g), histidine (2/100 g), and tryptophan (0.85/100 g) (19).

AAS (%)=Amino acid in test protein (g)Amino acid in the reference protein (g) ×100 (17)

Biological Value

Biological value was calculated using the following equation described by Oser (20).

BV=1.09 (EAAI)-11.73 (18)

Where EAAI - essential amino acid index, is a percentage of the geometric mean of the ratios of EAA in the test protein relative to their respective amount in the FAO/WHO scoring pattern.

SDS-PAGE of Total Flour Proteins

Defatted flour (25 mg) was added to 1 ml of 2× Laemmli sample buffer solution (pH 6.8 containing 62.5 mM of Tris–HCl, 25% glycerol, 5% ß-mercaptoethanol, 2% SDS, 0.01% bromophenol blue) in 1.5 ml Eppendorf tubes. The tubes were vortexed to disperse the flour through mixing, horizontal shaking in an orbital shaker at 151 rpm for 1 h at 45°C, heating at 100°C for 5 min in a water bath, and centrifugation (RC 4815S, Eltek, Mumbai, India) at 11,000 × g for 15 min. The supernatant (10 μl) was loaded in each well (Mini-Protean Tetra Cell, Bio-Rad Laboratories, Hercules, USA). Proteins were separated using 4% stacking gel and 12% resolving gel while the current was kept constant at 25 mA until the tracking dye reached the bottom of the gel which was then removed and stained overnight using 0.1% Coomassie Brilliant Blue-R250 in 40% methanol and 10% acetic acid. The gel was destained using 20% methanol and 10% acetic acid. A broad-ranged molecular marker (GeNei, Bangalore, India) was used as a standard consisting of peptides of 205 kDa (myosin), 97.4 kDa (phosphorylase B), 66.0 kDa (bovine serum albumin), 44.0 kDa (ovalbumin), 29.00 kDa (carbonic anhydrase), 20.10 kDa (soybean trypsin inhibitor), 14.30 kDa (lysozyme), 6.50 kDa (aprotinin), and 3.50 kDa (insulin). The quantification of destained gel was analyzed using a Bio-Rad EZ imager (Bio-Rad Laboratories, Hercules, USA). Classification of total prolamin was done according to Schalk et al. (21). SDS-PAGE gels were performed in duplicates.

Statistical Analysis

The results were expressed as mean ± SD and compared statistically at p ≤ 0.05, using one-way analysis of variance (ANOVA) with Tukey's post-hoc test performed via Minitab software (Version 17, Minitab Inc., State College, PA, USA).

Results and Discussion

Physical Characteristics of Cereal Grains

The shape and size are the determinants for the quality evaluation, grain screening, and heat-mass transfer calculations (14). These characteristics are defined by the geometric parameters and are provided in Table 1, Figure 1, and Supplementary Figure 1. The values of length (L), width (W), and thickness (T) of wheat, rye, and barley were found to be in the range 6.62–7.85 mm, 2.25–3.69 mm, and 2.08–3.13 mm, respectively. The grain length of barley (7.06–7.85 mm) and wheat (7.03–7.59 mm, except wheat cultivar, HPW-349, 6.62 mm) cultivars was observed to be slightly higher compared to rye cultivars (6.88–7.45 mm). Similarly, the thickness and width of cereals followed the order of wheat (T, 2.74–3.13 mm; W, 3.41–3.69 mm) > barley (T, 2.42–2.62 mm; W, 3.39–3.55 mm) > rye (T, 2.08–2.35 mm; W, 2.25–2.48 mm) cultivars. The L/W ratio of cereal grains followed the order: rye (2.87–3.07) > barley (2.11–2.31) > wheat (1.85–2.13) cultivars. The high L/W ratio of rye cultivars implied the cylindrical shape of these grains whereas the barley and wheat cultivars had more of an oval morphology of their grains in their respective manner (22). The overall analysis of geometric dimensions revealed that the wheat grains were mostly oval, medium-sized, and wider compared to barley cultivars which were oval, longer, and less wide, while the rye cultivars were relatively cylindrical, shorter, and thinner (Supplementary Figure 1). The sphericity (Φ) and aspect ratio (Ra) of the cereal grains were found in the range of 45.65–60.81% and 0.33–0.54, respectively. The order of Φ for the cereal grains followed the trend: wheat (56.31–60.81%) > barley (51.04–54.04%) > rye (45.65–47.64%), which implied that the propensity of grains toward rolling out decreased from wheat to rye. Similarly, the Ra values had an inverse relationship to the length and the values of cereals followed the trend: wheat (0.47–0.54) > barley (0.43–0.47) > rye (0.33–0.35) which indicated that rye grains were the most elongated and the wheat grains the least. Therefore, a relatively greater magnitude of Φ and Ra for wheat and barley cultivars, i.e., highly spherical and less elongated geometry is indicative of the tendency of these grains to roll out as compared to rye, which would prefer to slide over a flat surface (7, 13, 16).

Table 1.

Geometrical and gravimetrical properties of different wheat, rye, and barley cultivars.

Cereal Wheat grain Rye grain Barley grain
Cultivar HPW-42 HPW-147 HPW-155 HPW-236 HPW-249 HPW-349 MCTLG-1 MCTLG-2 MCTLG-3 MCTLG-4 MCTLG-5 BH-393 BH-902 BH-946 BH-959
L (mm) 7.13 ± 0.18CDEF 7.03 ± 0.25EF 7.38 ± 0.12BCDE 7.59 ± 0.15AB 7.04 ± 0.21EF 6.62 ± 0.23EF 6.88 ± 0.28FG 6.94 ± 0.24FG 7.11 ± 0.25DEF 7.45 ± 0.35BCD 7.10 ± 0.20DEF 7.53 ± 0.22AB 7.50 ± 0.24ABC 7.06 ± 0.29AB 7.85 ± 0.28A
W (mm) 3.61 ± 0.09AB 3.65 ± 0.11A 3.69 ± 0.07A 3.57 ± 0.16ABC 3.41 ± 0.07CD 3.57 ± 0.08AB 2.25 ± 0.08F 2.43 ± 0.12E 2.44 ± 0.14E 2.48 ± 0.11E 2.40 ± 0.10EF 3.45 ± 0.11BCD 3.55 ± 0.12BCD 3.39 ± 0.07D 3.41 ± 0.10D
T (mm) 3.13 ± 0.18A 3.07 ± 0.24A 3.06 ± 0.18A 2.86 ± 0.21ABC 2.96 ± 0.19AB 2.74 ± 0.29ABCD 2.26 ± 0.26EF 2.24 ± 0.31EF 2.23 ± 0.26EF 2.35 ± 0.30DEF 2.08 ± 0.26F 2.42 ± 0.27DEF 2.62 ± 0.34BCDE 2.47 ± 0.19CDEF 2.52 ± 0.35CDE
L/W 1.98 ± 0.06FGH 1.92 ± 0.05GH 2.00 ± 0.03FGH 2.13 ± 0.12DEF 2.06 ± 0.06EFG 1.85 ± 0.05H 3.07 ± 0.19A 2.87 ± 0.15B 2.91 ± 0.11AB 3.01 ± 0.10AB 2.97 ± 0.14AB 2.18 ± 0.06CDE 2.11 ± 0.07DEF 2.24 ± 0.08CD 2.31 ± 0.10C
Dm (mm) 4.24 ± 0.10AB 4.24 ± 0.11AB 4.30 ± 0.09A 4.20 ± .0.12ABC 4.10 ± 0.08ABCD 4.00 ± 0.13CD 3.22 ± 0.11F 3.31 ± 0.17EF 3.34 ± 0.18EF 3.46 ± 0.24E 3.24 ± 0.16EF 3.92 ± 0.18D 4.05 ± 0.16BCD 3.39 ± 0.15D 4.00 ± 0.16CD
Φ (%) 59.52 ± 1.35AB 60.81 ± 2.08 A 59.29 ± 0.66AB 56.31 ± 1.86BC 57.56 ± 1.63AB 58.73 ± 3.34AB 46.90 ± 2.58E 47.64 ± 2.29E 46.96 ± 1.55E 46.46 ± 1.56E 45.65 ± 2.08E 52.07 ± 1.98D 54.04 ± 2.91CD 51.84 ± 1.09D 51.04 ± 3.45D
Ra 0.51 ± 0.01BC 0.52 ± 0.01AB 0.50 ± 0.01BC 0.47 ± 0.03DEF 0.48 ± 0.01CD 0.54 ± 0.02A 0.33 ± 0.02H 0.35 ± 0.02H 0.34 ± 0.01H 0.33 ± 0.01H 0.34 ± 0.02H 0.46 ± 0H.01EFG 0.47 ± 0.01DE 0.45 ± 0.02FG 0.43 ± 0.02G
V (mm)3 26.72 ± 2.01AB 26.17 ± 1.88ABC 27.35 ± 2.14A 25.32 ± 2.54ABCD 23.67 ± 1.77BCDE 21.93 ± 2.17DE 11.66 ± 1.21F 12.60 ± 1.92F 12.89 ± 2.02F 14.31 ± 2.85F 11.78 ± 1.84F 20.60 ± 2.80E 22.73 ± 2.76CDE 20.82 ± 2.36E 21.72 ± 2.69E
S (mm)2 49.24 ± 2.58AB 48.44 ± 2.36ABC 50.38 ± 2.62A 48.27 ± 3.06ABC 45.39 ± 2.27BCD 42.58 ± 2.70D 29.04 ± 1.82E 30.50 ± 2.92E 31.17 ± 3.25E 33.73 ± 4.53E 29.54 ± 2.79E 42.28 ± 3.78D 44.92 ± 3.41BCD 42.70 ± 3.38D 44.25 ± 3.12CD
TKW (g) 48.34 ± 0.53AB 51.26 ± 0.92A 50.53 ± 0.83A 50.61 ± 2.08A 44.75 ± 0.87BC 42.40 ± 1.02CD 18.83 ± 0.64F 22.32 ± 1.36 F 20.35 ± 0.77 F 22.33 ± 0.80 F 20.60 ± 0.83 F 40.038 ± 3.34DE 42.86 ± 2.94CD 36.99 ± 2.10E 41.99 ± 0.90CD
HKV (ml) 5.40 ± 0.89AB 5.90 ± 0.42A 5.40 ± 0.42AB 5.20 ± 0.84AB 4.80 ± 0.27B 4.80 ± 0.45B 2.90 ± 0.22C 3.30 ± 0.45C 3.30 ± 0.27C 3.10 ± 0.55C 3.00 ± 0.00C 3.00 ± 0.00C 3.00 ± 0.00C 3.00 ± 0.00C 3.10 ± 0.22C
DB W/V (g/ml) 0.77 ± 0.02ABCD 0.80 ± 0.01AB 0.75 ± 0.01BCDE 0.78 ± 0.01ABC 0.81 ± 0.02A 0.79 ± 0.03AB 0.74 ± 0.02CDE 0.73 ± 0.01CDE 0.72 ± 0.01DE 0.71 ± 0.01E 0.72 ± 0.01DE 0.59 ± 0.04G 0.63 ± 0.03FG 0.61 ± 0.03FG 0.64 ± 0.03F
DT (g/ml) 1.54 ± 0.03E 1.61 ± 0.02ABC 1.58 ± 0.01BCDE 1.58 ± 0.02ABCDE 1.60 ± 0.03ABCD 1.61 ± 0.03AB 1.57 ± 0.02CDE 1.54 ± 0.02E 1.56 ± 0.01DE 1.55 ± 0.02E 1.57 ± 0.01CDE 1.61 ± 0.01AB 1.61 ± 0.01AB 1.58 ± 0.02ABCDE 1.62 ± 0.02A
ε(%) 49.81 ± 1.27EF 50.44 ± 0.95EF 52.45 ± 0.36BCDEF 50.64 ± 0.93CDEF 49.42 ± 1.90F 50.66 ± 1.64DEF 52.87 ± 1.26BCDE 52.60 ± 0.51BCDE 53.69 ± 0.57BCD 54.17 ± 0.63B 53.93 ± 0.76BC 63.55 ± 2.66A 60.66 ± 1.73A 61.63 ± 1.70A 60.46 ± 1.84A

L, Length; W, width; T, thickness; L/W, length/width ratio; Dm, equivalent diameter; Φ, sphericity; Ra, aspect ratio; V, seed volume; S, surface area; TKW, thousand kernel weight; HKV, hundred kernel volume; DB, bulk density; DT, true density; ε, porosity.

Mean ± SD with different superscripts in a row differ significantly (p ≤ 0.05); n = 5 for each treatment.

Figure 1.

Figure 1

Schematic representation showing the preparation of flour, dough, and gluten from wheat (HPW-142), rye (MCTLG-1), and barley (BH-393) cultivars.

The gravimetric profile of the cereal grains helps in predicting grain soundness, transportation, and storage conditions (23) and is listed in Table 1. In the investigated cereal cultivars, the magnitude of thousand kernel weight (TKW), which indicates the grain quality and expected milling flour yield, followed the order: wheat (42.40–50.61 g) > barley (36.99–42.86 g) > rye (18.83–22.33 g). This suggests that wheat and barley cultivars have greater flour yield compared to rye cultivars. The observed TKW values of cereals exhibited significant differences (p ≤ 0.05) both among the cereals and within the cultivars except rye (Table 1). These findings are in line with earlier reports, where TKW values of wheat, barley, and rye cultivars ranged from 45.9 to 52.1 g (24), 40.06 to 41.90 g (7), and 21.6 to 28.5 g (25), respectively.

The bulk density (DB) and true density (DT) values of the investigated cereal grains ranged from 0.59 to 0.81 g/ml and 1.54 to 1.62 g/ml, respectively. The values of DB observed in wheat (0.75–0.81 g/ml), rye (0.71–0.74 g/ml), and barley (0.59–0.64 g/ml) cultivars suggested that wheat grains were relatively denser as compared to rye and barley. At the intra-cultivar level, wheat cultivar HPW-249 possessed the highest DB value while barley cultivar BH-393 had the lowest. The porosity (ε) values of wheat (49.42–50.66%), rye (52.60–54.17%), and barley (60.46–63.55%) revealed an increasing trend. The porosity (ε) values of cereal grains followed the reverse order of DB. The barley cultivar BH-393 (63.55%) exhibited the highest ε value, while wheat cultivar HPW-239 had the lowest.

Among the investigated cereal grains, the wheat cultivars were relatively denser, with low ε, high TKW, and high DB values. High porosity would allow more air flow through the grains which would affect the rate of drying, heating/cooling as well as the amount of energy required to accomplish the process (26) as compared to rye and barley cultivars. The physical parameters (Table 1) of the studied cereals, i.e., wheat, rye, and barley, were near that of the earlier reports (27).

Colorimetric Analysis

The color characteristics of the cereal grains were evaluated by employing CIE color values (L*, a*, and b*), chroma (C*), and hue angle (H0). The values of these parameters are provided in Table 2 and Supplementary Figure 1. The lightness of cereal grains (L* value) which is an indication of the light color (0 is black, 100 is white), followed the order: wheat (58.10–63.38) > barley (56.34–61.53) > rye (51.23–53.59). Further, at the intra-cultivar level, wheat cultivar HPW-42 (63.38) was found to possess the highest L* value while rye cultivar MCTLG-5 (51.23) had the lowest. The other color parameters, a* and b* (for a*, +ve/–ve = red/green and b*, +ve/–ve = yellow/blue), exhibited positive values for all the investigated cereals grains which indicated the presence of a predominantly red and yellow tint in the cereal grains. The magnitude of a* indicated that the extent of red tint decreased in the order: wheat (6.74–7.56) > barley (4.91–5.29) > rye (4.71–4.83). Similarly, the value of b* indicated that the extent of yellow tint decreased in the following order: wheat (18.75–23.62) > barley (16.22–18.71) > rye (13.70–14.76). A relatively greater content of red and yellow tint collectively imparted more brightness to the wheat grains as compared to barley and rye grains. Statistically, the CIE color parameters L*, a*, and b* were significantly different (p ≤ 0.05) for the investigated cereals at inter- and intra-cultivar levels except for a* values where intra-cultivar variation was not significant (p ≥ 0.05).

Table 2.

Hunter color values of grain, flour, and gluten from different wheat, rye, and barley cultivars.

Cereal Wheat Rye Barley
Cultivar HPW-42 HPW-147 HPW-155 HPW-236 HPW-249 HPW-349 MCTLG-1 MCTLG-2 MCTLG-3 MCTLG-4 MCTLG-5 BH-393 BH-902 BH-946 BH-959
Cereal grain
L* 63.38 ± 0.66A 62.85 ± 0.71A 61.33 ± 0.71A 61.60 ± 0.75A 58.10 ± 0.43ABC 59.95 ± 0.65AB 53.05 ± 4.07BC 51.52 ± 4.13C 51.69 ± 4.83C 53.59 ± 4.05BC 51.23 ± 3.89C 56.34 ± 0.51ABC 56.35 ± 2.34ABC 61.53 ± 0.74A 57.14 ± 1.08ABC
a* 6.86 ± 0.15A 7.56 ± 0.13A 6.74 ± 0.06A 7.27 ± 0.16A 7.43 ± 0.12A 6.87 ± 0.06A 4.73 ± 0.56B 4.73 ± 0.59B 4.76 ± 0.56B 4.83 ± 0.72B 4.71 ± 0.51B 4.91 ± 0.21B 5.10 ± 0.69B 5.29 ± 0.70B 5.28 ± 0.44B
b* 22.54 ± 0.48A 23.62 ± 0.39A 20.56 ± 0.17AB 22.96 ± 0.47A 19.68 ± 0.25ABC 18.75 ± 0.67ABCD 13.80 ± 3.23D 14.47 ± 2.69D 13.88 ± 2.87D 14.76 ± 2.63CD 13.70 ± 2.28D 16.37 ± 0.50BCD 16.22 ± 1.93BCD 18.71 ± 0.74ABCD 17.05 ± 0.29BCD
H0 73.06 ± 0.38AB 72.26 ± 0.17ABC 71.85 ± 0.29ABC 72.42 ± 0.17ABC 69.31 ± 0.21C 69.87 ± 0.64BC 70.72 ± 2.45ABC 71.76 ± 1.42ABC 70.84 ± 1.98ABC 71.80 ± 0.87ABC 70.85 ± 1.99ABC 73.29 ± 0.67AB 72.56 ± 0.56ABC 74.25 ± 1.64A 72.80 ± 1.46ABC
C* 23.56 ± 0.47AB 24.80 ± 0.41AB 21.63 ± 0.14ABC 24.08 ± 0.50AB 21.03 ± 0.27ABC 19.96 ± 0.64ABCD 14.59 ± 3.22E 15.22 ± 2.73DE 14.68 ± 2.88E 15.54 ± 2.72DE 14.49 ± 2.29E 17.09 ± 0.50CDE 17.01 ± 2.04CDE 19.45 ± 0.85BCDE 17.85 ± 0.26CDE
Cereal flour
L* 92.40 ± 0.19ABC 93.49 ± 0.52AB 90.96 ± 0.56BC 93.80 ± 0.30A 91.02 ± 0.50BC 89.96 ± 1.00C 73.50 ± 0.38GH 72.00 ± 0.27H 73.71 ± 0.43GH 72.98 ± 0.90FG 75.82 ± 0.48FG 73.15 ± 0.82FGH 76.37 ± 0.39E 76.62 ± 0.14EF 76.20 ± 1.46D
a* 0.38 ± 0.02E 0.22 ± 0.02F 0.51 ± 0.04E 0.19 ± 0.02F 0.52 ± 0.02E 0.54 ± 0.06E 1.33 ± 0.06A 1.53 ± 0.04CD 1.31 ± 0.01C 1.37 ± 0.10B 0.79 ± 0.02C 1.02 ± 0.02DE 1.02 ± 0.19E 0.95 ± 0.06F 0.13 ± 0.07F
b* 9.24 ± 0.19BC 7.59 ± 0.13E 9.57 ± 0.16B 8.39 ± 0.17CD 11.75 ± 0.10A 8.53 ± 0.26CD 7.94 ± 0.08CD 8.47 ± 0.16F 7.95 ± 0.23FG 8.17 ± 0.15DE 6.56 ± 0.18F 6.86 ± 0.13G 6.38 ± 0.30FG 6.70 ± 0.24G 5.38 ± 0.26FG
H0 87.62 ± 0.14ABC 88.34 ± 0.15AB 86.97 ± 0.25BC 88.72 ± 0.11A 87.48 ± 0.12ABC 86.41 ± 0.31C 80.49 ± 0.34FG 79.74 ± 0.09G 80.67 ± 0.18EFG 80.51 ± 0.62FG 83.13 ± 0.10D 81.57 ± 0.05EF 80.92 ± 1.34EFG 81.96 ± 0.25DE 88.64 ± 0.69A
C* 9.25 ± 0.19B 7.59 ± 0.13D 9.58 ± 0.16B 8.39 ± 0.17C 11.76 ± 0.09A 8.55 ± 0.27C 8.15 ± 0.08CD 8.60 ± 0.16C 8.06 ± 0.23CD 8.29 ± 0.16C 6.60 ± 0.19E 6.94 ± 0.14GE 6.47 ± 0.32FE 6.76 ± 0.24E 5.38 ± 0.26F
Cereal gluten
L* 49.63 ± 1.55ABCD 50.37 ± 1.61ABCD 54.36 ± 1.95A 48.70 ± 1.50BCD 53.29 ± 1.29AB 52.30 ± 1.05ABC 46.37 ± 1.39DE 51.52 ± 4.13ABCD 42.17 ± 1.37EFG 46.92 ± 1.74CDE 42.89 ± 1.20EF 38.27 ± 2.34FGH 36.35 ± 2.34HI 31.53 ± 0.74I 37.14 ± 1.08GH
a* 0.05 ± 0.03E 0.04 ± 0.03E 0.21 ± 0.07CDE 0.19 ± 0.10CDE 0.20 ± 0.09CDE 0.18 ± 0.03DE 2.44 ± 0.29A 2.32 ± 0.09ABC 2.21 ± 0.04ABCD 2.48 ± 0.08A 2.38 ± 0.15AB 0.37 ± 0.08ABCDE 0.53 ± 0.12ABCDE 0.30 ± 0.07BCDE 1.99 ± 2.71ABCDE
b* 5.88 ± 0.49F 6.62 ± 0.27EF 7.98 ± 0.80CDE 10.06 ± 0.23B 11.97 ± 0.22A 8.95 ± 0.37BCD 6.94 ± 0.19EF 10.28 ± 0.73B 7.44 ± 0.28DEF 8.16 ± 0.34CDE 9.56 ± 0.29BC 2.77 ± 0.64G 2.55 ± 0.46G 2.37 ± 1.16G 2.75 ± 0.82G
H0 89.50 ± 0.31A 89.65 ± 0.24A 88.52 ± 0.38A 88.90 ± 0.60A 89.06 ± 0.46A 88.85 ± 0.23A 70.67 ± 1.98AB 77.22 ± 1.30AB 73.45 ± 0.38AB 73.08 ± 0.17AB 76.02 ± 1.21AB 82.32 ± 0.75AB 78.20 ± 2.37AB 81.29 ± 5.74AB 64.64 ± 2.54AB
C* 5.88 ± 0.49EF 6.62 ± 0.27DE 7.98 ± 0.80CDE 10.07 ± 0.23ABC 11.97 ± 0.22A 8.96 ± 0.37BCD 7.36 ± 0.23DE 10.54 ± 0.69AB 7.76 ± 0.28CDE 8.53 ± 0.34BCD 9.85 ± 0.25ABC 2.80 ± 0.64G 2.61 ± 0.46AB 2.40 ± 1.14G 3.65 ± 2.29FG

Mean ± SD with different superscripts in a row differ significantly (p ≤ 0.05); n = 3 for each treatment.

H0 indicated the color type (angle from 0° to 360°, 0° for red, 90° for yellow, 180° for green, and 270° for blue) of the cereal grains. The range of the H0 value fell in the first quadrant of the color wheel (0 refer to red and 90° to yellow color) where wheat (69.31–73.06°), rye (70.72–71.80°), and barley (72.56–74.25°) cultivars were found to overlap in the range 69.31–74.25°. This suggested that the color of grains was predominantly rich in yellow tint with a minor red tint. The relative saturation/purity of grain color was further assigned by C* values which were observed in the range 14.49–24.80. The order of C* values followed the pattern: wheat (19.96–24.80) > barley (17.01–19.45) > rye (14.49–15.54) indicating a relatively greater intensity of yellow tint in wheat followed by barley and rye grains. The values of both H0 and C* were found to be statistically different (p ≤ 0.05) at inter- and intra-cultivar levels except the H0 value in rye cultivars which was not significant (p ≥ 0.05) at the intra-cultivar level. The values for different color parameters were found in to be harmony with wheat (16) and rye (25), however, a little variation was observed in the case of barley (28). Variations in grain color of the investigated cereals might be due to differences in the proportion of pigments such as carotenoids, anthocyanins, flavonoids, some tannin, and phenolic compounds along with variation in grain genotype and growing conditions (29).

Cereal flours exhibited a similar trend in their L*values (Supplementary Figure 1; Figure 1) following the order: wheat (89.96–93.80) > barley (73.15–76.62) > rye (72.00–75.82). As expected, the L* values of different flours were relatively higher compared to their respective cereal grains. Wheat flour was found to be brighter compared to barley and rye flours. Within cultivars, wheat flour HPW-236 (93.80) was the brightest while rye flour MCTLG-2 (72.00) was relatively darker. The apparent color tint present in different cereal flours as suggested by a* and b* followed the order: rye (0.79–1.53) > barley (0.13–1.02) > wheat (0.19–0.52) and wheat (7.59–11.75) > rye (6.56–8.47) > barley (5.38–6.86), respectively. The higher a* and b* values in barley and rye cultivars compared to wheat cultivars may suggest a higher amount of pigments in these flours or higher ash content. Within cultivars, rye flour from MCTLG-2 was found to possess the highest a* value while wheat flour from HPW-236 possessed the lowest. On the other hand, the highest b* value was observed in wheat cultivar HPW-249, and the lowest in barley cultivar BH-959. The magnitude of a* and b* of the investigated flours was observed to be less compared to their corresponding cereal grains. This could be attributed to the fact that the color of the grain is primarily related to their bran color which gets removed during milling. Statistically, both a* and b* were significantly (p ≤ 0.05) different at inter and intra levels of cultivars. The H0 values of cereal flours were found to lie in the range of 79.74–88.64°. The different cereal flours had overlapping H0 values such as barley (80.92–88.64°), wheat (86.41–88.72°), and rye (79.74–83.13°). These H0 values were very close to 90° in the color wheel and correspond to yellow color. In cereal flours, wheat flour HPW-236 was found to possess a greater H0 value while rye flour MCTLG-2 possessed the lower H0 value. Further, C* in conjunction with H0, indicated a decrease in the intensity of yellow tint in the order: wheat (7.59–11.76) > rye (6.60–8.60) > barley (5.38–6.94). Both H0 and C* values of the different cereal flours were found to vary significantly (p ≤ 0.05) at inter as well as intra-cultivar levels. The variation in the flour color of different cereal grains is mainly attributed to the variation in moisture content, ash content, particle size distribution, flour defilation with bran during milling, and to some extent to phenolic compounds and inherent pigments of grain such as flavonoids, carotenoids, and anthocyanins (30). The obtained results are in agreement with a previous study (16) which reported an L* value of 90.82–92.88; a*: 0.22–0.57; b*: 7.71–10.8; H0: 86.51–88.54°; and C*: 7.71–10.80 in the flour of North Indian wheat cultivars. Warechowska et al. (25) reported relatively lower L* values (47.8–51.3) and higher a* (3.29–5.24) and b* (17.99–19.88) values for different rye cultivars. Yeung and Vasanthan (31) reported similar a* (0.4–1.4) and b* (4.2–10.5) values but relatively higher L* values (87.0–93.7) than our results for different barley cultivars.

The gluten derived from different cereal flours using standard protocol was analyzed for its color characteristics (Figure 1) which provides important insights regarding the nature of components and their related oxidative changes (32). The L* values of different cereal glutens were observed to decrease in the order: wheat (48.70–54.36) > rye (42.17–51.52) > barley (31.53–38.27) indicating high relative brightness of wheat glutens as compared to rye and barley glutens (Table 2). Within cultivars, wheat gluten in HPW-155 (54.36) was brighter while barley gluten in BH-946 (31.53) was relatively darker in color. The dark color of barley and rye glutens is possibly due to the relatively higher content of ash and fiber in these cultivars as compared to wheat glutens (33). Secondly, the oxidation of unsaturated compounds such as polyphenols, etc. present in rye and barley gluten could be the other reason for their dark shade.

The a* and b* values of different glutens followed the pattern: rye (2.21–2.48) > barley (0.30–1.99) > wheat (0.04–0.21) and wheat (5.88–11.97) > rye (6.94–10.28) > barley (2.37–2.77), respectively. This trend suggested that the presence of substantial red tint and less yellow tint in rye and barley gluten (Figure 1) as compared to wheat gluten was probably due to high ash and fiber content (33, 34) in these cultivars. At the cultivar level, gluten from rye cultivar MCTLG-4 had the highest a* value while wheat cultivar HPW-147 had the lowest. The highest b* was observed in wheat cultivar HPW-249, and the lowest was seen in barley cultivar BH-946. Both a* and b* values of gluten exhibited significant (p ≤ 0.05) differences except for barley where the b* value showed a non-significant difference at the intra-cultivar level. Similar to cereal flours, their derived glutens also exhibited a H0 value in the range 64.64–88.52° which belongs to the yellow quadrant of the color wheel. The relatively high value of H0 in wheat gluten (88.52–86.65°) indicated a greater degree of yellowness as compared to barley (64.64–82.32°) and rye (70.67–77.22°) gluten. Similarly, C* of cereal glutens followed the order: wheat (5.88–11.97) > rye (7.36–10.54) > barley (2.40–3.65) implying a decrease in intensity of yellow tint from wheat to barley. Furthermore, C* values of cereal glutens were observed to be statistically different (p ≤ 0.05) at inter as well as intra-cultivar levels. However, H0 of wheat gluten was significantly different (p ≤ 0.05) from rye and barley (p ≥ 0.05) while at the intra-cultivar level, H0 of cereal glutens showed a non-significant (p ≥ 0.05) difference.

Proximate Composition

The proximate composition of the investigated cereal flours is provided in Table 3. The total moisture content of the studied flours was found to be in the range of 6.60–9.75%. Similar results have also been observed in earlier studies where the moisture content of wheat, rye, and barley flour varied in the range of 5.83–15.30% (10, 35). The protein, fat, ash, crude fiber, carbohydrates, and energy of the cereal flours varied from 7.09 to 12.34%, 1.15 to 1.83%, 0.17 to 1.30%, 0.36 to 2.05%, 74.22 to 83.39%, and 357.84 to 378.35 kcal/100 g, respectively. Among cereals, wheat (10.18–11.25%) and rye (7.98–11.37%) flours contained a relatively greater proportion of proteins as compared to barley flours (7.09–9.04%) except BH-902 (12.34%). The ash (A) and crude fiber (CF) content of the cereal flours was observed to decrease in the order: rye (A, 0.70–1.30%; CF, 0.93–2.05%) > barley (A, 0.24–0.50%; CF, 0.50–0.85%) > wheat (A, 0.17–0.40%; CF, 0.36–0.69%) which corresponds to the highest ash and crude fiber content in rye followed by barley and wheat flour.

Table 3.

Proximate composition and gluten properties of flours of wheat, rye, and barley cultivars.

Cereal/ cultivar Moisture (%) Protein (%) Fat (%) Fiber (%) Ash (%) Total CHO (%) Energy (kcal/100 g) WG (%) DG (%)
Wheat flour
HPW-42 7.60 ± 0.24CDE 10.37 ± 1.59AB 1.46 ± 0.04ABC 0.34 ± 1.17BC 0.54 ± 0.07B 79.30 ± 1.17ABCDE 371.83 ± 1.56ABCD 20.6 ± 1.30EF 7.16 ± 0.66D
HPW-147 7.72 ± 0.08CDE 11.12 ± 1.78AB 1.26 ± 0.23BC 0.28 ± 1.83D 0.36 ± 0.06B 79.25 ± 1.83ABCDE 372.84 ± 1.87ABCD 29.69 ± 1.13D 9.78 ± 0.37BC
HPW-155 7.83 ± 0.44CD 10.81 ± 1.21AB 1.34 ± 0.28AB 0.40 ± 0.72CD 0.58 ± 0.08B 78.94 ± 0.72ABCDE 371.02 ± 3.68ABCD 29.14 ± 0.86D 9.44 ± 0.45C
HPW-236 7.84 ± 0.14CD 10.18 ± 1.39AB 1.39 ± 0.14AB 0.17 ± 1.44D 0.43 ± 0.03B 79.99 ± 1.44ABCD 373.17 ± 0.79ABCD 41.24 ± 1.81AB 11.24 ± 0.73AB
HPW-249 8.25 ± 0.40BCD 11.25 ± 1.56AB 1.15 ± 0.10C 0.18 ± 1.99D 0.53 ± 0.10B 78.64 ± 1.99ABCDE 369.94 ± 1.53BCD 26.70 ± 0.56DE 8.43 ± 0.21DE
HPW349 7.92 ± 0.06CD 11.09 ± 1.60AB 1.42 ± 0.09ABC 0.25 ± 1.59D 0.69 ± 0.08B 78.63 ± 1.59ABCDE 371.63 ± 0.91ABCD 27.90 ± 0.85D 9.74 ± 0.16BC
Rye flour
MCTLG-1 8.71 ± 0.39ABC 10.51 ± 2.66AB 1.77 ± 0.07AB 0.91 ± 2.64AB 1.01 ± 0.53B 77.09 ± 2.64BCDE 366.29 ± 0.80DE 43.58 ± 2.19AB 12.28 ± 0.50A
MCTLG-2 8.71 ± 0.19ABC 7.98 ± 1.60AB 1.73 ± 0.07AB 1.24 ± 1.21A 2.03 ± 0.40A 78.31 ± 1.21ABCDE 360.070 ± 2.55EF 36.33 ± 2.76C 11.24 ± 0.25AB
MCTLG-3 9.75 ± 0.34A 10.46 ± 0.81AB 1.79 ± 0.05A 1.20 ± 1.53A 0.93 ± 0.50B 75.87 ± 1.53DE 361.45 ± 2.43EF 45.89 ± 3.23A 12.75 ± 0.45A
MCTLG-4 9.35 ± 0.28AB 11.37 ± 1.31AB 1.72 ± 0.50AB 1.30 ± 1.33A 2.05 ± 0.34A 74.22 ± 1.33E 357.84 ± 4.61F 39.27 ± 1.61BC 11.46 ± 0.99A
MCTLG-5 8.59 ± 0.90ABC 11.04 ± 1.80AB 1.65 ± 0.02ABC 0.70 ± 2.87BC 1.04 ± 0.28B 76.97 ± 2.87CDE 366.93 ± 4.50CDE 40.79 ± 2.54ABC 9.81 ± 0.17BC
Barley flour
BH-393 7.28 ± 0.45DE 7.82 ± 1.81AB 1.54 ± 0.01ABC 0.27 ± 1.60D 0.83 ± 0.24B 82.26 ± 1.60AB 374.19 ± 2.61ABC 15.57 ± 3.32F 2.07 ± 0.49FG
BH-902 7.10 ± 0.61DE 12.34 ± 1.12A 1.64 ± 0.06ABC 0.50 ± 0.43CD 0.84 ± 0.25B 77.59 ± 0.43BCDE 374.44 ± 3.31ABC 17.90 ± 2.29F 4.17 ± 0.82E
BH-946 7.13 ± 0.45DE 9.04 ± 1.82AB 1.67 ± 0.04ABC 0.27 ± 2.06D 0.50 ± 0.07B 81.39 ± 2.06ABC 376.75 ± 1.19AB 17.57 ± 3.05F 3.29 ± 0.39EF
BH-959 6.60 ± 0.16E 7.09 ± 1.78B 1.83 ± 0.06A 0.24 ± 1.92D 0.85 ± 0.22B 83.39 ± 1.92A 378.35 ± 0.18A 7.70 ± 2.37G 1.51 ± 0.54G

CHO, carbohydrate; WG, wet gluten; DG, dry gluten.

Mean ± SD with different superscripts in a column differ significantly (p ≤ 0.05); n = 3.

Significant (p ≤ 0.05) differences were observed in the moisture, fat, fiber, carbohydrate, and energy profile of the cereal flours at inter and intra-cultivar levels. Protein and ash content of flours differ significantly among the three cereals, however, a significant (p ≤ 0.05) difference at the intra-cultivar level was observed only in barley and rye cultivars. Our findings on wheat flour are in line with Siddiqi et al. (16), however, Drakos et al. (10) reported a higher fat content in rye and barley flours (5.04–6.14%) as compared to our results (1.54–1.83%) which ultimately led to higher carbohydrate and energy values.

Flour Performance Properties

The solvent retention capacities (SRC) of different cereal flours are presented in Table 4. Standard solvent systems, i.e., 5% lactic acid (LA), 5% sodium carbonate (SC), and 50% sucrose (Su) solutions were utilized for the approximate prediction of glutenin (solvent-accessible protein), amylopectin (damaged starch), and arabinoxylan (pentosan contents) of cereal flours, respectively (17).

Table 4.

The solvent retention capacity (SRC) and flour performance properties of wheat, rye, and barley cultivars.

Cereal SC-SRC (%) LA-SRC (%) Su-SRC (%) W-SRC (%) GPI SDS-SV (ml) WHC (g/g) OHC (g/g)
Wheat flour
HPW-42 88.99 ± 1.59FG 93.63 ± 1.01E 107.25 ± 3.44DE 82.64 ± 3.65CDE 0.48 ± 0.02CD 55.00 ± 1.41D 1.67 ± 0.01GH 1.85 ± 0.01GHI
HPW-147 94.64 ± 1.82DE 100.29 ± 2.25CD 99.40 ± 1.93EF 80.84 ± 1.90EF 0.52 ± 0.01AB 60.00 ± 0.00C 1.56 ± 0.01I 1.79 ± 0.01J
HPW-155 96.46 ± 0.86DE 104.60 ± 1.31BC 110.74 ± 3.87CD 76.15 ± 2.21F 0.50 ± 0.01BC 68.00 ± 0.00B 1.72 ± 0.02G 1.90 ± 0.01FGH
HPW-236 85.31 ± 1.03G 95.86 ± 0.73DE 88.21 ± 2.66G 79.37 ± 1.09EF 0.55 ± 0.01A 47.00 ± 1.41E 1.56 ± 0.02I 1.84 ± 0.02IJ
HPW-249 98.84 ± 0.69CD 111.92 ± 0.72A 120.06 ± 3.29C 88.70 ± 1.60BC 0.51 ± 0.01BC 48.50 ± 0.71E 1.64 ± 0.01H 1.88 ± 0.01FGHI
HPW-349 96.93 ± 1.64DE 107.26 ± 3.31AB 102.12 ± 3.68DE 87.28 ± 1.24BCD 0.54 ± 0.01AB 72.00 ± 0.00A 1.68 ± 0.01GH 1.85 ± 0.01HI
Rye flour
MCTLG-1 97.69 ± 0.86CD 59.23 ± 1.23HI 118.56 ± 3.94C 91.05 ± 1.75AB 0.27 ± 0.01H 23.00 ± 0.00H 2.03 ± 0.03BC 2.09 ± 0.02D
MCTLG-2 92.45 ± 1.46EF 53.78 ± 2.57IJ 108.80 ± 3.63DE 96.13 ± 1.13A 0.27 ± 0.01HI 23.00 ± 0.00H 1.86 ± 0.01E 1.95 ± 0.02E
MCTLG-3 102.20 ± 2.40C 60.43 ± 2.31H 131.25 ± 2.24B 81.03 ± 2.50EF 0.26 ± 0.01HI 22.00 ± 1.41HI 2.10 ± 0.01A 2.14 ± 0.01C
MCTLG-4 135.47 ± 2.78A 67.97 ± 1.86F 155.50 ± 2.96A 87.25 ± 1.49BCD 0.23 ± 0.01IJ 24.00 ± 0.00H 2.01 ± 0.02C 1.92 ± 0.01EF
MCTLG-5 122.12 ± 0.38B 57.91 ± 3.26HI 149.80 ± 3.91A 82.13 ± 1.90DEF 0.21 ± 0.01J 31.00 ± 0.00G 2.08 ± 0.01AB 2.38 ± 0.01B
Barley flour
BH-393 70.51 ± 1.45H 50.24 ± 2.41J 82.32 ± 3.18GH 55.67 ± 1.76G 0.33 ± 0.02G 20.00 ± 0.00I 2.04 ± 0.01BC 2.57 ± 0.02A
BH-902 87.54 ± 1.46FG 67.12 ± 1.84FG 90.46 ± 2.30FG 61.73 ± 2.19G 0.38 ± 0.02F 38.00 ± 0.00F 1.95 ± 0.01D 1.96 ± 0.01E
BH-946 73.89 ± 2.63H 61.49 ± 1.83GH 65.03 ± 2.61I 31.07 ± 2.21I 0.44 ± 0.01DE 30.50 ± 0.71G 1.83 ± 0.02E 1.90 ± 0.01FG
BH-959 46.21 ± 2.31I 53.55 ± 1.99IJ 77.18 ± 2.65H 39.75 ± 2.33H 0.43 ± 0.02E 24.00 ± 0.00H 1.77 ± 0.01F 1.73 ± 0.02K

SC-SRC, sodium carbonate-solvent retention capacity; LA-SRC, lactic acid-solvent retention capacity; Su-SRC, sucrose-solvent retention capacity; WSRC, water solvent retention capacity; GPI, gluten performance index; SDS-SV, sodium dodecyl sulfate-sedimentation volume; WHC, water holding capacity; OHC, oil holding capacity.

Mean ± SD with different superscripts in a column differ significantly (p ≤ 0.05); n = 3 for each treatment.

LA-SRC of different cereal flours followed the order: wheat (93.63–111.92%) > rye (53.78–67.97%) ≈ barley (50.24–67.12%), which indicated that wheat flours had higher gluten strength as compared to rye and barley flours. In cereal flours, the wheat cultivar HPW-249 possessed the highest while barley cultivar BH-393 had the lowest LA-SRC value (Table 4). Similar findings were observed by Drakos et al. (10) for rye and barley flours. In the case of SC-SRC, an indicator of damaged starch content (mainly amylopectin), followed the order, rye (92.45–135.47%) > wheat (85.31–98.84%) > barley (46.21–87.54%). This implies that rye cultivar flours contain a relatively higher content of damaged starch as compared to wheat and barley flours which may be due to the typical molecular and structural properties of its starch granule, despite identical milling conditions (10, 36). Among rye flours, MCTLG-4 (135.47%) contained the highest while barley flour BH-959 (46.21%) had the lowest SC-SRC value. The findings of SC-SRC directly govern the viscosity of flour-slurry which is generally dependent upon the cereal type (such as the amount of amylopectin, packing of starch granules at the microscopic level) and milling conditions (such as feed rate, tempering/ conditioning) (10). The Su-SRC of the investigated cereal flours followed the order: rye (108.80–155.50%) > wheat (88.21–120.06%) > barley (65.03–90.46%). This indicated that rye flours had a higher arabinoxylan content which resulted in greater swelling of these flours as compared to barley and rye flours. The higher fiber content in rye flours has been reported previously (1, 10).

These SRC variables are consequently affected by milling procedures which in the case of rye cultivars were observed to have a profound effect as compared to wheat and barley cultivars. Similar behavior has also been reported earlier (10) in rye and barley flour and highlighted the role of extensive milling conditions to enhance the extractability of arabinoxylans. The water-SRC value (W-SRC) provides a cumulative effect of protein and carbohydrate content on the absorption capacity of cereal flours and thus gives an overall functional hydration behavior of all flour components (gluten, starch, and pentosans). The W-SRC of different flours followed the order: rye (81.03–96.13%) > wheat (76.15–88.70%) > barley (31.07–61.73%). The observed trend suggests that the proportions of damaged grain structures of starch and non-starch components (such as protein and other cell wall components) were highest in rye flour followed by wheat and barley flours. Here, it is quite possible that the milling process aided the exposure of the macronutrients present in cereal flours and facilitated their interaction with water molecules (10).

The gluten performance index (GPI), a better predictor of gluten strength and overall baking performance, was observed in the range of 0.21–0.55. The GPI of cereal flours followed a decreasing order in wheat (0.48–0.55), barley (0.33–0.44), and rye (0.21–0.27) indicating that wheat flours have higher overall gluten strength, functionality, and baking performance as compared to barley and rye flours. The higher GPI of wheat flour may be the reason for its suitability for bread making and also its ability to be processed into a variety of foods as compared to barley and rye flour with low GPI. Within cereal flour, the highest GPI was found in wheat cultivar HPW-236, and the lowest in rye cultivar MCTLG-5, which suggested that wheat flours had higher gluten strength and lower damaged grain structure while the reverse was true for rye flours. Statistically significant (p ≤ 0.05) differences were observed in the SRC profile of studied cereal flours at inter- and intra-cultivar levels. In the case of rye flours, SRC values (except LA-SRC) were found to be relatively higher as compared to wheat flours. This is attributed to the presence of higher pentosan and damaged starch content which are hydrophilic. Oliete et al. (37) reported higher SRC values of rye flour (W-SRC of 101.65–156.11%, Su-SRC of 143.70–214.22%, SC-SRC of 132.60–181.62%, and LA-SRC of 130.29–152.15%) than soft wheat flours (W-SRC of 57.28–83.20%, Su-SRC of 92.11–123.05%, SC-SRC of 73.90–95.34%, and LA-SRC of 89.42–138.66%). Our SRC results for wheat flours are comparable and relatively lower for rye flour as compared to reported values (37). Such variations could be due to differences in the genetic makeup of the cultivars and also in the milling characteristics, specifically in terms of damaging starch and extractable pentosan content.

The sodium dodecyl sulfate-sedimentation volume (SDS-SV) (Table 4) of the investigated cereal flours indicated higher values in the case of wheat (47–72 ml) as compared to rye (22–31 ml) and barley (20–38 ml) flours. The wheat cultivar HPW-349 exhibited the highest while barley cultivar BH-393 exhibited the lowest SV value. Flours with an SV value <30 ml, between 30 and 60 ml, and more than 60 ml are more suitable for making cookies, chapatti/pasta, and bread, respectively (38). Therefore, wheat flours, particularly HPW-155 and HPW-349, were found to be very suitable for making good quality bread, while the other wheat flours were useful for making chapatti/pasta formulations. On the other hand, rye and barley flours would be more suitable for cookie preparation, except MCTLG-5 and BH-902 which could be utilized for making chapattis/pasta. Significant (p ≤ 0.05) differences were observed in the SDS-SV of the studied cereal flours at inter- and intra-cultivar levels. The higher SV values of wheat flours along with higher LASRC and GPI implies greater gluten strength of wheat flours as compared to barley and rye which imparts superior baking characteristics to wheat. Sedimentation values of Indian wheat cultivars have been reported in the range of 30–61 ml (38), 58–76 ml (39), and 47–72 ml (in the present case) which mainly depends upon cultivar type and to some extent on agro-climatic conditions. Despite such variations, all wheat flours were found to be most suitable for chapatti/pasta preparations while few wheat flours (such as HPW-147, HPW-155, and HPW-349) may also be suitable for making breads.

The dry gluten (DG) and wet gluten (WG) content in the studied cereal flours followed: rye (DG: 9.81–12.75%, WG: 36.33–45.89%) > wheat (DG: 7.16–11.24%, WG: 20.6–41.24%) > barley (DG: 1.51–4.17%, WG: 7.70–17.90%) (Table 3). At the cultivar level, the rye cultivar MCTLG-3 possessed the highest while barley cultivar BH-959 had the lowest WG and DG content. It is important to note that rye cultivars contain greater WG and DG content despite weaker gluten strength which is reflected by the lower LASRC, GPI, and SDS-SV values for rye cultivars (Table 4; Supplementary Figure 2). In the process of collecting gluten from the studied cereal flours, the wheat gluten had a characteristic elastic, rubbery, and sticky mass while in the case of rye and barley the obtained mass was relatively inelastic and less sticky which may be due to higher gliadin content and lower glutenin in these cereals along with a significant contribution from ash and fiber content (Supplementary Figure 2) (40). The WG and DG for the studied cereal flours were found to vary significantly (p ≤ 0.05) at both inter- and intra-cultivar levels. Similar findings have also been reported by previous studies (35, 41) for wheat cultivars where wet and dry gluten was reported in the range of 17.8–47.23%, 5.9–10.1%, and 14.49–43.70%, 5.12–12.82%, respectively which is consistent with our results.

Amino Acid Composition of Flour Protein

The amino acid composition and chromatogram of the investigated cereal flours were evaluated using an amino acid analyzer and compared with the established standards (Tables 5AC; Figures 2A–D; Supplementary Figures 3A–L). In different cereals flours, among the essential amino acids (EAA), phenylalanine and leucine were relatively abundant accounting for 4.75–9.22% and 4.40–7.22% of total protein, respectively (Table 5A). Particularly, barley cultivars BH-959 and BH-946 contained the highest amount of phenylalanine (9.22%) and leucine (7.22%) respectively, while wheat cultivars HPW-147 and HPW-155 had relatively lower content of phenylalanine (4.75%) and leucine (4.40%), respectively. Rye (1.97–3.42%) and barley (2.32–2.82%) flours were observed to have the highest amount of limiting EAA, i.e., lysine, as compared to wheat flours (1.09–1.51%) which made barley and rye proteins have higher biological values (BV) as compared to wheat proteins (Table 5C). The BV of the cereal flours decreased in the order: barley (85.57–92.75%) > rye (79.79–86.94%) > wheat (65.37–73.03%) which was also supported by the finding of Drakos et al. (10) and Oliete et al. (37). The U.S. Food and Drug Administration (FDA) has also approved barley as a functional food and its commercial utilization for protein fortification. Overall, the total essential amino acids (TEAA) content present in the studied cereal flours followed the order: barley (31.60–32.92%) > rye (29.84–31.45%) > wheat (25.32–27.79%). Further within cereal flours, barley flour (BH-393) possessed the highest while wheat flour HPW-349 possessed the lowest TEAA content. Although, TEAA in rye and barley (29.84–32.92%) was close to the recommended dietary allowances (RDA) prerequisite of the EAA requirement of the Food and Agriculture Organization, FAO for children aged 6 months to 3 years. Similar results have also been reported by Kowieska et al. (9) in wheat, rye, and barley grown in Poland where the distribution of EAA was found to be consistent with our finding. The relative proportion of EAA, threonine, valine, phenylalanine, isoleucine, and leucine was found to exhibit significant (p ≤ 0.05) differences while EAA histidine, methionine, and lysine varied non-significantly (p ≥ 0.05) at inter- and intra-cultivar levels.

Table 5A.

Essential amino acid (EAA) composition (g amino acid/100 g protein) in flour of wheat, rye, and barley cultivars.

Cereal/cultivar His Thr Phe Met Val Ileu Leu Lys TEAA AAS EAAI BV
Wheat flour
HPW-42 2.66 ± 0.23A 3.18 ± 0.03AB 5.04 ± 0.48B 0.70 ± 0.01A 3.79 ± 0.18B 3.59 ± 0.50A 5.73 ± 0.64AB 1.51 ± 0.13A 26.19 ± 0.32C 79.86 ± 0.98C 72.50 ± 0.67CDE 67.29 ± 0.73CDE
HPW-147 2.75 ± 0.10A 3.18 ± 0.03AB 4.75 ± 0.88B 0.98 ± 0.12A 2.93 ± 0.98B 4.00 ± 1.08A 6.45 ± 1.06AB 1.09 ± 0.67A 26.13 ± 1.43C 79.67 ± 4.35C 70.74 ± 0.59C 65.37 ± 0.64E
HPW-155 2.63 ± 0.13A 3.03 ± 0.24AB 6.05 ± 0.94AB 1.04 ± 0.03A 4.26 ± 0.94AB 3.48 ± 0.34A 4.40 ± 0.84B 1.39 ± 0.81A 26.27 ± 1.60C 80.09 ± 4.87C 74.01 ± 6.32BCDE 68.95 ± 6.89BCDE
HPW-236 2.75 ± 0.38A 3.09 ± 0.15AB 5.22 ± 0.29B 0.95 ± 0.01A 3.40 ± 0.21B 3.56 ± 0.45A 5.56 ± 0.35AB 1.37 ± 0.78A 25.89 ± 0.25C 78.92 ± 0.76C 72.74 ± 4.26CDE 67.56 ± 4.64CDE
HPW-249 2.80 ± 0.34A 2.47 ± 0.19B 5.64 ± 0.23B 1.16 ± 0.14A 5.97 ± 0.75A 3.43 ± 0.29A 5.00 ± 0.11AB 1.33 ± 0.15A 27.79 ± 1.03BC 84.73 ± 3.15BC 77.76 ± 0.42ABCDE 73.03 ± 0.46ABCDE
HPW-349 2.30 ± 0.42A 3.06 ± 0.08AB 5.17 ± 0.12B 0.91 ± 0.29A 3.57 ± 0.17B 3.75 ± 0.16A 5.17 ± 1.20AB 1.38 ± 0.17A 25.32 ± 1.01C 77.18 ± 3.08C 71.29 ± 0.73DE 65.98 ± 0.80DE
Rye flour
MCTLG-1 2.69 ± 0.08A 3.53 ± 0.07AB 7.42 ± 0.80AB 1.29 ± 0.34A 3.74 ± 0.51B 3.15 ± 0.12A 6.06 ± 0.43AB 3.10 ± 0.93A 30.99 ± 0.58AB 94.47 ± 1.78AB 90.00 ± 6.05ABC 86.37 ± 6.60ABC
MCTLG-2 2.53 ± 0.03A 3.60 ± 0.46A 7.49 ± 0.91AB 1.26 ± 0.38A 3.67 ± 0.36B 3.21 ± 0.19A 6.31 ± 0.12AB 3.42 ± 1.52A 30.50 ± 0.11AB 92.98 ± 0.35AB 87.18 ± 4.24ABCDE 83.30 ± 4.62ABCDE
MCTLG-3 2.51 ± 0.06A 3.61 ± 0.44A 6.81 ± 1.87AB 1.22 ± 0.44A 3.46 ± 0.26B 3.22 ± 0.20A 6.49 ± 0.10AB 2.51 ± 0.41A 29.84 ± 1.08AB 90.94 ± 3.28AB 85.44 ± 2.67ABCDE 81.39 ± 2.91ABCDE
MCTLG-4 2.55 ± 0.00A 3.64 ± 0.39A 7.81 ± 0.46AB 1.36 ± 0.24A 3.35 ± 0.10B 3.23 ± 0.22A 6.44 ± 0.03AB 3.06 ± 1.05A 31.45 ± 0.87A 95.88 ± 2.66A 90.52 ± 5.37ABC 86.94 ± 5.85ABC
MCTLG-5 2.59 ± 0.23A 3.32 ± 0.18AB 8.02 ± 0.04AB 1.14 ± 0.01A 3.31 ± 0.49B 3.37 ± 0.19A 6.47 ± 0.17AB 1.97 ± 0.06A 30.21 ± 0.33AB 92.09 ± 1.02AB 83.97 ± 0.45ABCDE 79.79 ± 0.49ABCDE
Barley flour
BH-393 3.17 ± 0.44A 3.71 ± 0.44A 7.76 ± 1.80AB 1.47 ± 0.50A 3.45 ± 0.24B 3.80 ± 0.26A 6.82 ± 0.63A 2.76 ± 1.09A 32.94 ± 0.05A 100.43 ± 0.16A 95.21 ± 8.11A 92.05 ± 8.84A
BH-902 3.09 ± 0.55A 3.78 ± 0.34A 6.72 ± 0.33AB 1.41 ± 0.57A 4.15 ± 0.18AB 3.83 ± 0.22A 6.72 ± 0.48A 2.82 ± 0.24A 32.53 ± 1.29A 99.16 ± 3.94A 95.85 ± 9.00A 92.75 ± 9.81A
BH-946 2.61 ± 0.18A 3.25 ± 0.32AB 6.71 ± 0.31AB 1.43 ± 0.56A 4.07 ± 0.30AB 3.74 ± 0.33A 7.22 ± 0.23A 2.35 ± 0.25A 31.60 ± 0.53A 96.34 ± 1.63A 91.39 ± 4.08AB 87.89 ± 4.45AB
BH-959 2.66 ± 0.11A 3.43 ± 0.06AB 9.22 ± 0.34A 1.00 ± 0.05A 3.85 ± 0.00B 3.51 ± 0.00A 6.91 ± 0.22A 2.32 ± 0.29A 32.91 ± 0.49A 100.33 ± 1.49A 89.26 ± 0.57ABCD 85.57 ± 0.62ABCD
FAO* 2 3.1 5.2 2.7 4.3 3.2 6.6 5.7 32.8

His, histidine; Thr, threonine; Val, valine; Met, methionine; Phe, phenylalanine; Ileu, isoleucine; Leu, leucine; Lys, lysine; TEAA, total essential amino acid; AAS, amino acid score; EAAI, essential amino acid index; BV, biological value.

Mean ± SD with different superscripts in a column differ significantly (p ≤ 0.05); n = 3 for each treatment.

*

represents the data of (19).

Figure 2.

Figure 2

HPLC chromatograms of different cereal flours showing the amino acid composition of (A) standard mixture of 18 amino acids, 500 mmol L−1; (B) wheat, HPW-42, (C) rye, MCTLG-1, and (D) barley, BH-393.

Glutamine + glutamic acid (Gln + Glu) was observed to be the most abundant non-essential amino acid (NEAA) with the relative mean concentration in the range of 24.92–39.95% followed by asparagine + aspartic acid (Asn + Asp) which was in the range of 3.60–6.60% (Table 5B). Significant (p ≤ 0.05) differences were observed in all non-essential amino acids among different cereal cultivars except glycine. Similar results for the mean concentration of NEAA in Polish wheat, barley, and rye cultivars have also been reported by Kowieska et al. (9), except tyrosine which was found to be lower with a mean concentration of 0.97–1.64% in the current study. The total NEAA present in different cereal flours was in the range 67.06–74.68% with wheat cultivar HPW-349 having the highest and barley cultivar BH-393 the lowest proportion of NEAA. It is generally believed that higher concentrations of NEAA like glutamic acid and proline play an important role in dough and baking quality in wheat flour (4244).

Table 5B.

Non-essential amino acid (NEAA) composition (g amino acid/100 g protein) in flour of wheat, rye, and barley cultivars.

Cereal/cultivar Asn + Asp Gln + Glu Ser Gly Arg Ala Tyr Cys Pro NEAA
Wheat flour
HPW-42 3.77 ± 0.10AB 37.17 ± 1.14A 5.46 ± 0.58AB 3.98 ± 0.16A 4.68 ± 0.68ABC 3.11 ± 0.31AB 3.46 ± 0.34ABCDE 1.43 ± 0.27B 10.75 ± 2.42ABCD 73.80 ± 0.32A
HPW-147 4.15 ± 0.24AB 39.95 ± 1.90A 5.65 ± 0.31A 4.14 ± 0.07A 4.48 ± 0.39ABC 3.06 ± 0.52AB 3.45 ± 0.32ABCDE 1.53 ± 0.18AB 7.47 ± 1.41D 73.87 ± 1.43A
HPW-155 5.61 ± 0.31AB 39.90 ± 0.26A 4.79 ± 0.42AB 3.07 ± 0.03A 4.26 ± 0.09BC 3.26 ± 0.62A 2.98 ± 0.23DE 1.54 ± 0.20AB 8.33 ± 1.62CD 73.73 ± 1.60A
HPW-236 5.53 ± 1.41AB 39.32 ± 1.21A 5.17 ± 0.29AB 3.27 ± 0.26A 4.37 ± 0.24BC 2.99 ± 0.23AB 3.30 ± 0.25BCDE 1.29 ± 0.16B 8.87 ± 0.99BCD 74.11 ± 0.25A
HPW-249 3.60 ± 1.16B 35.56 ± 1.33A 4.59 ± 0.30AB 3.36 ± 0.44A 3.24 ± 0.43C 2.02 ± 0.03B 4.18 ± 0.37A 1.59 ± 0.06AB 14.07 ± 0.02A 72.21 ± 1.03AB
HPW-349 3.79 ± 0.63AB 36.24 ± 1.02A 5.08 ± 0.20AB 3.95 ± 0.31A 5.05 ± 0.87ABC 3.18 ± 0.19A 3.31 ± 0.13BCDE 1.41 ± 0.22B 12.68 ± 1.28ABC 74.68 ± 1.01A
Rye flour
MCTLG-1 5.85 ± 1.17AB 25.45 ± 0.76B 4.48 ± 0.20AB 3.84 ± 0.17A 6.24 ± 0.50AB 3.91 ± 0.13A 3.11 ± 0.12CDE 2.30 ± 0.33AB 13.83 ± 0.63AB 69.01 ± 0.58BC
MCTLG-2 5.36 ± 0.29AB 27.87 ± 0.47B 4.76 ± 0.62AB 4.15 ± 0.52A 5.90 ± 0.28AB 4.07 ± 0.18A 2.87 ± 0.16E 1.83 ± 0.56AB 12.69 ± 0.58ABC 69.50 ± 0.12BC
MCTLG-3 6.05 ± 1.10AB 27.76 ± 0.29B 4.73 ± 0.67AB 4.16 ± 0.51A 5.88 ± 0.54AB 3.99 ± 0.29A 2.80 ± 0.26E 1.67 ± 0.33AB 13.14 ± 1.61ABC 70.177 ± 1.07BC
MCTLG-4 6.60 ± 0.57A 27.80 ± 1.06B 4.68 ± 0.74AB 4.11 ± 0.58A 5.81 ± 0.43AB 4.01 ± 0.27A 2.87 ± 0.16E 1.53 ± 0.14AB 11.14 ± 2.54ABCD 68.55 ± 0.88C
MCTLG-5 6.28 ± 0.19AB 26.52 ± 2.78B 4.30 ± 0.04AB 3.79 ± 0.25A 6.50 ± 0.63A 3.78 ± 0.29A 3.10 ± 0.17CDE 3.16 ± 0.97A 12.36 ± 0.57ABCD 69.79 ± 0.33BC
Barley flour
BH-393 4.63 ± 0.01AB 25.84 ± 0.82B 4.42 ± 0.28AB 4.02 ± 0.31A 5.76 ± 0.54AB 3.63 ± 0.17A 4.10 ± 0.16AB 2.68 ± 0.69AB 11.99 ± 0.24ABCD 67.06 ± 0.05C
BH-902 6.03 ± 0.58AB 27.33 ± 1.10B 4.04 ± 0.03AB 3.87 ± 0.52A 5.51 ± 0.18AB 3.59 ± 0.23A 3.95 ± 0.05ABC 1.04 ± 0.21B 12.10 ± 0.40ABCD 67.47 ± 1.29C
BH-946 5.69 ± 0.10AB 24.92 ± 0.06B 4.30 ± 0.45AB 3.91 ± 0.47A 5.58 ± 0.29AB 3.67 ± 0.12A 3.91 ± 0.13ABC 2.16 ± 0.04AB 13.85 ± 0.81AB 68.40 ± 0.54C
BH-959 5.96 ± 0.28AB 25.88 ± 1.42B 3.93 ± 0.06B 3.47 ± 0.16A 5.59 ± 0.28AB 3.43 ± 0.22A 3.77 ± 0.04ABCD 2.51 ± 0.54AB 12.55 ± 0.99ABCD 67.09 ± 0.49C

Asn + Asp, asparagine + aspartic acid; Gln + Glu, glutamine + glutamic acid; Ser, serine; Gly, glycine; Arg, arginine; Ala, alanine; Tyr, tyrosine; Cys, cysteine; Pro, proline; TNEAA, total non-essential amino acid.

Mean ± SD with different superscripts in a column differ significantly (p ≤ 0.05); n = 3 for each treatment.

The amino acid concentration of wheat flour is in close agreement with Alijošius et al. (45) and Gálová et al. (46). A slightly higher concentration of proline (11.73–16.93%) has been reported by Šterna et al. (47) in five spring barley cultivars compared to our results. Kihlberg et al. (48) reported a concentration of proline (8.27–9.68%) in rye flour which was slightly lower than our findings. The variation in amino acid composition is largely dependent on the genotype, milling conditions, flour extraction rate, wheat type (soft, hard, semi-soft), growing environmental conditions like CO2 concentration, growing temperature application of fertilizers, and protein content of flour, etc. (4954).

The amino acid score (AAS) indicates the quality of protein in terms of its EAA content to that of the reference protein (19). The AAS score of the cereal flours followed the order: barley (96.34–100.43%) > rye (90.94–95.88%) > wheat (77.18–84.73%). The barley cultivar BH-393 had the highest while the wheat cultivar HPW-349 had the lowest AAS score. Alijošius et al. (45) reported an AAS for wheat (88.63–98.81%) which was slightly higher than the present results and for rye (80.12–89.82%), their results were lower than ours. These variations in AAS values could be due to cultivar differences.

Furthermore, the amino acids (AAs) were classified into three hydropath groups, i.e., hydrophilic, hydrophobic, and neutral amino acids, according to IMGT amino acid classification and are presented in Table 5C. The hydrophobic AAs constituted 22.95–30.43% of the total amino acids and were comprised of aliphatic, S-containing, and some aromatic amino acids which accounted for 15.39–19.07%, 2.12–4.14%, and 4.75–9.22%, respectively. The S-containing amino acids were found to be higher in the rye (2.89–4.30%) and barley (2.46–4.14%) while lower in wheat (2.12–2.74%). Overall total hydrophobic AAs were found to be higher in barley cultivars (27.47–30.43%), followed by rye (26.87–29.26%) and wheat (22.95–24.79%). A significant (p ≤ 0.05) difference was observed among the hydrophobic group of amino acids at inter- and intra-cultivar levels, however, in rye cultivars, the aliphatic and aromatic hydrophobic AAs showed a non-significant difference (p ≥ 0.05).

Table 5C.

IMGT (ImMunoGeneTics) amino acid classification in flour of wheat, rye, and barley cultivars (g amino acid/100 g protein).

Cereal/cultivar Hydrophobic amino acid Hydrophilic amino acid Neutral amino acid
Aliphatic S-containing Aromatic AA Total hydrophobic Basic AA Acidic Total hydrophilic Non-polar Polar (hydroxyl AA) Aromatic AA Total neutral
Wheat flour
HPW-42 16.22 ± 1.26BC 2.12 ± 0.25D 5.04 ± 0.48B 23.39 ± 1.03CDE 8.85 ± 0.58BCDE 40.94 ± 1.24ABC 49.79 ± 1.82AB 14.73 ± 2.58ABCD 8.63 ± 0.62A 3.46 ± 0.34ABCDE 26.82 ± 2.85AB
HPW-147 16.43 ± 0.45BC 2.50 ± 0.06CD 4.75 ± 0.88B 23.69 ± 1.27BCDE 8.32 ± 0.96CDE 44.10 ± 1.66ABC 52.41 ± 2.62A 11.62 ± 1.34CD 8.83 ± 0.33A 3.45 ± 0.32ABCDE 23.90 ± 1.35AB
HPW-155 15.39 ± 0.37C 2.58 ± 0.17CD 6.05 ± 0.94AB 24.02 ± 0.75BCDE 8.28 ± 0.77DE 45.51 ± 0.56A 53.79 ± 1.33A 11.39 ± 1.65D 7.81 ± 0.66A 2.98 ± 0.23DE 22.19 ± 2.08B
HPW-236 15.50 ± 0.55C 2.24 ± 0.17D 5.22 ± 0.29B 22.95 ± 0.08E 8.49 ± 0.64CDE 44.85 ± 0.20AB 53.34 ± 0.84A 12.15 ± 0.73BCD 8.27 ± 0.45A 3.30 ± 0.25BCDE 23.71 ± 0.92AB
HPW-249 16.41 ± 0.97BC 2.74 ± 0.08BCD 5.64 ± 0.23B 24.79 ± 1.13BCDE 7.37 ± 0.24E 39.16 ± 0.16CD 46.53 ± 0.41BCD 17.44 ± 0.46A 7.06 ± 0.11A 4.18 ± 0.37A 28.68 ± 0.72A
HPW-349 15.67 ± 1.05C 2.32 ± 0.07CD 5.17 ± 0.12B 23.16 ± 1.10DE 8.73 ± 1.11BCDE 40.03 ± 1.64BC 48.76 ± 0.53ABC 16.63 ± 0.97ABC 8.14 ± 0.28A 3.31 ± 0.13BCDE 28.08 ± 0.57AB
Rye flour
MCTLG-1 16.87 ± 0.16ABC 3.60 ± 0.01ABCD 7.42 ± 0.80AB 27.88 ± 0.96AB 12.04 ± 0.51A 31.30 ± 0.41E 43.33 ± 0.11D 17.67 ± 0.47A 8.01 ± 0.27A 3.11 ± 0.12CDE 28.79 ± 0.85A
MCTLG-2 17.27 ± 0.23ABC 3.09 ± 0.18ABCD 7.49 ± 0.91AB 27.85 ± 0.86AB 10.85 ± 0.15ABCD 33.23 ± 0.17E 44.09 ± 0.32CD 16.84 ± 0.06AB 8.35 ± 1.08A 2.87 ± 0.16E 28.06 ± 1.18AB
MCTLG-3 17.18 ± 0.27ABC 2.89 ± 0.11ABCD 6.82 ± 1.87AB 26.87 ± 2.03ABCDE 10.91 ± 0.07ABCD 33.82 ± 1.39E 44.70 ± 1.46BCD 17.31 ± 2.12A 8.34 ± 1.11A 2.81 ± 0.26E 28.44 ± 3.49A
MCTLG-4 17.04 ± 0.08ABC 2.89 ± 0.10ABCD 7.81 ± 0.46AB 27.74 ± 0.45ABC 11.41 ± 0.62AB 34.40 ± 0.50DE 45.81 ± 1.12BCD 15.25 ± 1.96ABCD 8.32 ± 1.13A 2.87 ± 0.16E 26.45 ± 0.67AB
MCTLG-5 16.93 ± 0.56ABC 4.30 ± 0.98A 8.02 ± 0.04AB 29.26 ± 0.45A 11.06 ± 0.93ABC 32.80 ± 2.59E 43.86 ± 1.66CD 16.15 ± 0.82ABCD 7.63 ± 0.22A 3.10 ± 0.17CDE 26.88 ± 1.21AB
Barley flour
BH-393 17.70 ± 0.43ABC 4.14 ± 0.19AB 7.76 ± 1.80AB 29.60 ± 2.43A 11.69 ± 0.99A 30.47 ± 0.81E 42.16 ± 1.80D 16.01 ± 0.07ABCD 8.13 ± 0.72A 4.10 ± 0.16AB 28.24 ± 0.63AB
BH-902 18.29 ± 0.14AB 2.46 ± 0.78CD 6.72 ± 0.33AB 27.47 ± 0.60ABCD 11.42 ± 0.61AB 33.37 ± 1.68E 44.79 ± 1.07BCD 15.98 ± 0.12ABCD 7.82 ± 0.31A 3.95 ± 0.05ABC 27.75 ± 0.47AB
BH-946 19.07 ± 0.46A 3.76 ± 0.35ABC 6.71 ± 0.31AB 29.54 ± 0.50A 10.96 ± 0.81ABCD 30.27 ± 0.43E 41.24 ± 0.38D 17.84 ± 0.46A 7.47 ± 0.24A 3.91 ± 0.10ABC 29.23 ± 0.12A
BH-959 17.70 ± 0.44ABC 3.51 ± 0.49ABCD 9.22 ± 0.34A 30.43 ± 0.29A 10.57 ± 0.10ABCD 31.84 ± 1.71E 42.42 ± 1.61D 16.02 ± 1.15ABCD 7.36 ± 0.12A 3.77 ± 0.04ABCD 27.15 ± 1.32AB

Total hydrophobic amino acid: Alanine + cysteine + valine + methionine + tryptophan + phenylalanine + isoleucine + leucine; total hydrophilic amino acid: Asparagine+aspartic acid + glutamine+glutamic acid + arginine + lysine; neutral amino acid: Serine + histidine + glycine + threonine + tyrosine + proline. Total AAS, total amino acid score-; EAAI, essential amino acid index; BV, biological value.

Mean ± SD with different superscripts in a column differ significantly (p ≤ 0.05); n = 3 for each treatment.

The hydrophilic AAs constituted 41.24–53.79% of the total amino acids and were comprised of acidic and basic amino acids which accounted for 30.27–44.85% and 7.37–12.64% of the total amino acids, respectively. A significant (p ≤ 0.05) difference was observed among the hydrophilic class of amino acids at inter- and intra-cultivar levels while acidic AAs in barley cultivars showed a non-significant (p ≥ 0.05) difference.

The total neutral amino acids of cereal flour varied from 22.19 to 29.23% and constituted non-polar, polar, and aromatic amino acids which accounted for 11.39–17.84%, 7.06–8.83%, and 2.81–4.18% of the total amino acids, respectively. Barley cultivar BH-946 and wheat cultivar HPW-155 had the highest and the lowest content of total neutral AAs, respectively. Statistically, a significant (p ≤ 0.05) difference was observed among the neutral AAs, while a non-significant (p ≥ 0.05) difference among polar hydroxyl AAs was observed both at inter as well as intra-cultivar levels.

SDS-PAGE of Wheat, Rye, and Barley Flour

The SDS-PAGE pattern of flour proteins present in different cereal cultivars under reduced conditions is given in Figures 3A–C. Many authors have broadly classified the storage proteins of the Triticeae family into three main groups, namely high molecular weight (HMW), medium molecular weight (MMW)/sulfur poor, and low molecular weight (LMW)/sulfur-rich proteins (21, 42, 55).

Figure 3.

Figure 3

SDS-PAGE of flour proteins from (A) wheat, (B) rye, and (C) barley cultivars under reducing conditions.

The HMW group in wheat, rye, and barley comprises HMW-glutenin subunits, HMW-secalin, and D-hordein, respectively. The MMW group comprises of ω-gliadin (wheat), ω-secalin (rye), and C-hordein (barley), while the LMW group contains monomeric proteins (α/β-gliadin, γ-gliadin in wheat, γ-40k-secalin in rye, and γ-hordein in barley) and polymeric proteins (LMW-GS in wheat, γ-75k-secalin in rye, and B-hordein in barley).

The total number of bands in SDS-PAGE ranged from 21 to 24 in wheat, 18 in rye, and 17 to 22 in barley flours. Among high molecular weight (HMW) proteins, the MW of protein-subunits in wheat, rye, and barley ranged between 68.38 and 119.66 kDa (4–5 subunits), 82.33 and 117.78 kDa (4 subunits), and 73.08 and 108.57 kDa (2–4 subunits), respectively. Based on densitometric analysis (Table 6), the HMW group comprised 9.84–18.75% of the total flour proteins with a proportion in the range of 13.57–18.75 kDa in wheat cultivars, 9.84–14.98 kDa in rye cultivars, and 12.78–16.33 kDa in barley cultivars. The wheat cultivar HPW-349 was found to possess the highest HMW proportion, and the rye cultivar MCTLG-3 the lowest. The HMW group mainly comprises glutenin protein which is generally polymeric and, due to the presence of cysteine residues, forms inter- and intra-molecular disulfide linkages. These proteins play an important role in strengthening the three-dimensional structure of the gluten framework by imparting high elastic strength to the dough (56). Previous studies have explained clearly the role of the HMW group in the baking performance of dough by providing an elastic property to the dough (57).

Table 6.

The relative proportion (%) of total flour proteins in wheat, rye, and barley cultivars.

Cereal flour HMW (HMW-GS/HMW-secalin/D-hordein) MMW/sulfur-poor (ω-Gliadin/ω-secalin/C-hordein) LMW/sulfur-rich (α/β-, γ-Gliadin/γ-75 k, γ-40 k-secalin/B-hordein) ALB + GLO
Wheat flour
HPW-42 13.57 ± 0.96AB 11.28 ± 0.99AB 38.61 ± 1.71ABCDE 36.53 ± 0.24A
HPW-147 18.03 ± 4.44AB 7.00 ± 2.10B 39.66 ± 2.43ABCDE 35.32 ± 0.09A
HPW-155 14.15 ± 1.75AB 11.09 ± 0.46AB 40.49 ± 0.18ABCDE 34.26 ± 2.40A
HPW-236 15.60 ± 1.67AB 5.73 ± 1.06B 35.92 ± 3.26CDE 42.75 ± 5.99A
HPW-249 17.63 ± 1.37AB 8.91 ± 0.43AB 37.79 ± 5.09BCDE 35.67 ± 3.30A
HPW-349 18.75 ± 1.83A 15.08 ± 2.49A 41.16 ± 6.32ABCDE 25.01 ± 5.66A
Rye flour
MCTLG-1 13.13 ± 2.07AB 12.92 ± 2.57AB 50.14 ± 3.19ABC (14.98 ± 0.63*+ 13.86 ± 1.40**) 23.81 ± 7.84A
MCTLG-2 14.98 ± 0.63AB 15.09 ± 2.29A 47.06 ± 5.46ABCD (21.20 ± 2.51*+ 19.14 ± 4.67**) 22.87 ± 8.38A
MCTLG-3 9.84 ± 0.60B 15.22 ± 3.68A 52.46 ± 2.23AB (15.09 ± 2.29*+ 14.76 ± 1.58**) 22.48 ± 6.51A
MCTLG-4 13.86 ± 1.40AB 14.76 ± 1.58A 46.24 ± 5.08ABCD (25.86 ± 2.95*+ 27.10 ± 0.41**) 25.14 ± 8.06A
MCTLG-5 12.73 ± 4.56AB 12.48 ± 2.00AB 53.04 ± 2.04A (22.87 ± 8.38*+ 25.14 ± 8.06**) 21.89 ± 8.60A
Barley flour
BH-393 15.69 ± 2.46AB 16.60 ± 2.53A 29.66 ± 1.30E 38.05 ± 6.29A
BH-902 12.78 ± 1.40AB 14.81 ± 1.42A 33.91 ± 1.51DE 38.50 ± 1.30A
BH-946 16.33 ± 2.12AB 16.34 ± 0.85A 31.07 ± 1.44E 36.26 ± 4.40A
BH-959 15.47 ± 0.87AB 11.16 ± 1.45AB 35.04 ± 6.68DE 38.33 ± 4.36A

HMW, high molecular weight; MMW, medium molecular weight; LMW, low molecular weight, ALO + GLO, albumin + globulin.

Mean ± SD with different superscripts in a column differ significantly (p ≤ 0.05); n = 2 for each treatment.

*

refers to 75k-secalin fraction;

**

refers to 40k-secalin.

The monomeric protein ω-prolamins, also called sulfur-poor, in wheat cultivars falls in the range between 47.60 and 61.85 kDa corresponding to four protein subunits, except for wheat cultivar HPW-236 where two peptide bands in this region were observed. On the other hand, in the case of barley and rye, the distribution of ω-region ranged from 43.93 to 60.42 kDa (2-4 protein subunits) and 48.93 to 51.67 kDa (1 protein subunit), respectively. The relative proportion of the sulfur-poor group of the studied flours varied between 5.73 and 16.60%, with a proportion of 5.73–15.08% in wheat cultivars, 12.48–15.22% in rye cultivars, and 11.16–16.60% in barley cultivars These ω-proteins usually lack cysteine residue in their peptide chain and are not involved in disulfide bonding (56).

The α/β-gliadins, γ-gliadins, and LMW-GS, also known as sulfur-rich regions, in wheat flours were distributed in the range 27.03–45.24 kDa while barley flours were found to contain γ/B-hordein distributed between 29.00 and 43.63 kDa of the LMW group. The rye flours were observed to be enriched with γ-75k-secalins and γ-40k-secalins having an MW ranging from 53.45 to 66.00 kDa and 28.46 to 40.84 kDa, respectively.

In the studied cereal flours, a high degree of polymorphism was observed in wheat as compared to barley while relatively obscure patterns were noticed in the case of rye flours. The majority of the wheat cultivars (HPW-42, HPW-147, HPW-236, HPW-249) contained 7-8 polypeptides in the LMW region of 27.03–45.24 kDa, however, wheat cultivars HPW-155 and HPW-349 contained 4-6 polypeptide in this region. Similarly, for barley cultivars, 4-6 polypeptides were observed in the range of 29.00–43.63 kDa, barley cultivar BH-393 exhibited 4 polypeptides, and BH-902 exhibited 6 polypeptides while BH-946 and BH-959 exhibited 5 polypeptides each in the LMW region. However, in the case of rye cultivars, the observed patterns were difficult to distinguish from the cultivar type unlike in wheat and barley. The LMW region thus can be used to distinguish wheat and barley cultivars and can act as a biochemical marker. Nonetheless, the regions 27.03–34.6 kDa (α/β gliadin, wheat), 28.46–32.63 (γ-40k-secalins, rye), and 29.00–43.62 (γ/B-hordein, barley) of the LMW group were not good enough to resolve the intense bands into clear individual segregated bands. In the studied cereal flours, the relative proportion of the LMW group was observed to be in the range 29.66–53.04% of total protein. The highest proportion of the LMW group was observed in rye cultivar MCTLG-5 (53.04%) while lowest was seen in barley cultivar BH-393 (29.66%). In general, the LMW group is rich in sulfur proteins mainly involved in inter and intra-molecular disulphide linkages (56). Many studies have demonstrated a positive correlation between the LMW group and bread loaf volume and dough rheological properties (such as development time and stability) (57). The metabolic active proteins (albumin and globulin, ALB + GLO) of wheat, rye, and barley cultivars were observed in the range of 26.93–8.37 kDa, 6.50–26.63 kDa, and 11.15–28.05 kDa, respectively. However, among different cereal cultivars, no polymorphism was observed in albumin and globulin fractions. The relative proportion of ALB + GLO did not show any significant difference (p ≥ 0.05). Statistically, a significant (p ≤ 0.05) difference was observed among HMW, MMW, and LMW proteins for analyzed cereal grains at inter- and intra-cultivar levels except for barley in the percentage of HMW which only differed at the inter-cultivar level. Our results on the relative proportion of molecular weight distribution (HMW, ω-Prolamin, LMW, and ALB + GLO) were in close agreement with earlier reports (16, 21, 42, 46).

Conclusion

Comparative evaluation of technological and functional properties of wheat, rye, and barley was carried out. Barley and rye were found to contain proteins of high biological value while wheat flours possessed a better technological property due to higher gluten strength. SDS-SV indicated that wheat cultivars HPW-155 and HPW-349 would be more suitable for making quality bread while its other cultivar was good for chapatti making. Most cultivars of barley and rye were found to be suitable for cookie preparation except MCTLG-5 and BH-902 which can be used for chapatti making. High polymorphism was observed in wheat cultivars as compared to rye and barley. Furthermore, the comparative amino acid analysis of these cereals supported the utilization of barley and rye cultivars for protein fortification owing to their richness in limiting essential amino acids, which is of paramount importance in the manufacturing of composite flours. These insights could be quite resourceful for manufacturers and researchers looking for versatile flour material for the development of healthy food products.

Data Availability Statement

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

Author Contributions

MR: methodology, formal analysis, data curation, investigation, writing—original draft preparation, reviewing, and editing. GS: reviewing and editing. RS: formal analysis, reviewing, and editing. DS: conceptualization, supervision, resources, reviewing, editing, and funding acquisition. BG: supervision. MB: statistical analysis. All authors contributed to the article and approved the submitted version.

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher's Note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Acknowledgments

The authors are highly thankful to the UGC, Delhi, for providing a BSR fellowship to MR [letter no. 25-1/2014-15(BSR)/7-398/2012/(BSR)]. We are also highly thankful to Dr. H. K. Chaudhary, Professor and Head of Genetics and Plant Breeding and Agricultural Biotechnology at CSK Himachal Pradesh Agriculture University, Palampur, for providing us with rye samples.

Supplementary Material

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fnut.2021.694679/full#supplementary-material

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Data Availability Statement

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.


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