Effects of blackberry polysaccharide on the quality improvement of boiled chicken breast

Highlights

• •Blackberry polysaccharide (BP) was extracted and the composition was analyzed.
• •Flavor characteristics of chicken breast were improved by addition of BP.
• •The stability and hardness of chicken breast were improved by BP.

Abstract

Blackberry polysaccharide was isolated from blackberry powder with 70% ethanol. The crude polysaccharide was composed of 95.44% glucose, 2.01% arabinose, 1.81% galactose and 0.74% glucuronic acid. Chicken breast meat was only marinated with different concentrations of the isolated blackberry polysaccharide (1 g/kg, 3 g/kg) for 24 h at a ratio of material to liquid of 1:3, and boiled at 80℃ for 1 h. The differences in texture, water distribution and volatile flavor components among different groups （adding 0,1,3 g/kg blackberry polysaccharide) were investigated. The results showed that the addition of blackberry polysaccharide could significantly improve the hardness of chicken breast, the transformation of free water to bound water, the overall flavor characteristics of the control group and the addition of different concentrations of blackberry polysaccharide were significantly different, and the concentration of volatile flavor substances in boiled chicken breast was reduced.

1. Introduction

The quality evaluation of meat products includes their appearance, texture, juiciness, moisture, firmness, tenderness, smell and flavor. Different processing techniques, preservation methods and technology application can lead to various physical and chemical changes in meat products (Mir, et al., 2017). Physical changes are mainly occurred in tissue structure that affect the sensory characteristics of the product, while chemical changes in meat result from heat treatment, supplementary of food additives, and molecular interactions under extended storage time (Gomez, et al., 2020). Synthetic additives such as sulfur dioxide, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), nitrates, benzoates, and sulfites are commonly used to improve the texture of meat, inhibiting the oxidation of meat and related products, and avoiding unpleasant smells and tastes. But their improper use can cause different allergic reactions and even become a life-threatening(Hugo & Hugo, 2015). In recent years, with the continuous improvement of consumers' awareness of safety and nutrition, natural food additives have attracted the attention of many people and araised in-depth research of relevant scholars (Kallel, et al., 2015). Banon, S. added green tea extract to beef patties with low sulfite content, which can delay the appearance of ranulent taste and reduce the loss of red color (Banon, et al., 2007). Garcia-Lomillo replaced sulfite with red wine residue as meat additive to protect beef patties from protein oxidation (Garcia-Lomillo, et al., 2016). Therefore, the development of natural extracts as quality improvers of meat products might have a good prospect.

Natural polysaccharides can be extracted from animal, plant and microbial sources, with plants being the most abundant source of food-grade polysaccharides (Shao, et al., 2020). In recent years, more and more attention has been paid to the application of natural bioactive polysaccharides in functional foods and foods. There are increasing studies on the effects of adding some plant polysaccharides on meat quality. For example, Kallel, et al. (2015) investigated garlic straw polysaccharide, which enable to significantly reduce fat oxidation and improve color stability for other poultry meats. Eljoudi, et al. (2022) studied that the addition of trifolium sinensis polysaccharide to beef could significantly reduce TBARS value, inhibiting met-myoglo-bin (MetMb) accumulation and microbial proliferation. Xue and He (2021) studied the effects of chicory root polysaccharide on sensory quality and storage quality of silver carp surimi ball, who found that the chicory root polysaccharide was effective in maintaining good hardness and elasticity of product, reducing protein and lipid oxidation, and inhibiting microbial reproduction. Blackberry fruits belong to the genus Rosaceae, which are rich in polysaccharides, anthocyanins, flavonoids, and phenolic acids etc., and these bioactive compounds exhibited antioxidant, antibacterial, anti-inflammatory and other physiological functions (Chaves et al., 2020, Dou et al., 2021). In addition, our earlier study discovered that polysaccharide extracted form blackberry can significantly improve the elasticity, taste and color of chicken breast meat, and enhance the flavor after boiling, but its specific mechanism is not clear.

Therefore, in this study, the main components of blackberry crude polysaccharide were analyzed and its structure was characterized. The effects of blackberry polysaccharide on physical and chemical properties (water distribution and texture) and volatile flavor substances of chicken breast were analyzed, and the related mechanism of blackberry polysaccharide on the quality improvement of chicken breast was explored, so as to provide theoretical reference for the quality modifier of meat products.

2. Material and methods

2.1. Material and chemical reagents

Chicken breast meat was purchased from Fujian Chia Tai Food Co. Ltd (Longyan city, China), blackberry (Rubus spp.) powder was ordered from Heilongjiang Derong Food Co.Ltd. (Haerbin, Heilongjiang province, China) and stored at 4 °C until use. Standard products of fucose, rhamnose, arabinose, galactose, glucose, xylose, mannose, fructose, ribose, galacturonic acid, glucuronic acid, mannose acid, and guluronic acid and Sodium hydroxide of chromatographic purity as well as sodium acetate were purchased from Sigma-aldirich Co. Ltd (St. Louis, MO); Trifluoroacetic acid and methanol of chromatographic purity were supplied form Anpel Laboratory Technology(China) (Shanghai, China);

2.2. Extraction of crude blackberry polysaccharide

Polysaccharide was extracted from blackberry according to the method as reported by Hajji et al., 2021, Liu et al., 2020 with some modifications. Blackberry powder (30 g) and 300 mL of 70% ethanol were added to 500 mL flask. After ultrasonic extraction at 25 ± 2 ℃ for 60 min, the supernatant and precipitate were separated by filtration through a 60-mesh sieve, and the residue was extracted for another three times. The filtrate was collected and centrifuged at 3000 rpm for 15 min, followed by concentration using a rotary evaporator, and all extracts were freeze-dried to yield the crude polysaccharide of blackberry.

2.3. Preparation of chicken breast samples

Blackberry polysaccharide was dissolved in water and prepared into soaking solutions of 1 g/kg and 3 g/kg for later use. Firstly, the chicken breast meat was cut into small pieces(size about 5 × 5 × 5 mm), and the meat pieces were divided into three groups: Experimental group 1 (adding 1 g/kg blackberry polysaccharide), experimental group 2 (adding 3 g/kg blackberry polysaccharide), and blank group (not adding any substance). And the meat piece was dipped into the soaking solutions with a material to liquid ratio of 1:3 and placed in a 4 ℃ refrigerator for 24 h. After that, the meat of each group was minced separated in a grinder machine for 30 s, and the minced meat was filled into intestine, tied tightly and divided into 10 cm long sections using straw ropes. And the meat sausage was boiled in a water bath pot for 1 h, cooled at room temperature and preserved in a refrigerator at − 4° C for later analysis.

2.4. Determination of carbohydrate, total polyphenols, total flavones and monosaccharides

The carbohydrate content in crude blackberry was determined according to phenol–sulfuric acid method using glucose as the standard (Masuko et al., 2005, Lin et al., 2021). Folin-Ciocalteu method was employed to measure total polyphenol content, and the results was expressed as 100 mg gallic acid equivalent (GAE)/g according to our previous method (Kang, et al., 2018). Total flavonoid content was determined according to Y. J. Chen, et al. (2010) using rutin as the standard. Protein content was determined using an automatic Kjeldahl apparatus (Gerhardt, Germany) referring to previous method (Solangi & Iqbal, 2011).

The monosaccharide component was determined by a Thermo ICS5000 ion chromatographic system (ICS5000, Thermo Fisher Scientific, USA), which used an electrochemical detector to analyze and detect monosaccharide components after acidolysis pretreatment (Brunt, et al., 2021; L. Wang et al., 2018, Teng et al., 2022, Teng et al., 2022). Briefly, approximately 5 mg of sample was hydrolyzed with trifluoroacetic acid (2 M) at 121 °C for 2 h in a sealed tube. And the solvent was dehydrated through nitrogen blowing. After that, pure methanol was added and evaporated with nitrogen blowing, and the process was repeated 2–3 times. The residue was re-dissolved in deionized water and filtered through 0.22 μm microporous filtering film for measurement.

Dionex™ CarboPac™ PA20 (150*3.0 mm, 10 μm) liquid chromatography column was used. The injection volume was 5 μL. Mobile phases were consisted of A (H₂O), B (0.1 M NaOH), C (0.1 M NaOH, 0.2 M NaAc), and the flow rate was 0.5 mL/min; The column temperature was 30℃; Elution gradient was set as follows: 0 min A/B/C (95:5:0, V/V), 26 min A/B/C (85:5:10, V/V), 42 min A/B/C (85:5:10, V/V), 42.1 min A/B/C (60:0:) 40, V/V), 52 min A/B/C phase (60:40:0, V/V), 52.1 min A/B/C phase (95:5:0, V/V), and 60 min A/B/C phase (95:5:0, V/V).

2.5. FTIR and UV analysis

The transmittance of sample in the range of 400–4000 cm⁻¹ was measured using FTIR (Bruker TENSOR 27, Germany). Approximately 3 mg of sample was mixed with 600 mg of dried KBr, and then pressed into thin sheets for FTIR measurements (Varma & Kumar, 2017).

Ultraviolet scan can identify nucleic acid and protein components in polysaccharide (Zhang, et al., 2021；Higbee et al., 2022). Blackberry polysaccharide solution of 0.1 mg/mL was analyzed by UV scanning in the range of 200 to 400 nm.

2.6. Texture profile analysis (TPA)

The textural profile of samples were analyzed according to Li, et al. (2022) using a universal texture analyzer (Stable Micro Systems, model TA.XT Plus) equipped with a P/0.5 flat bottom cylindrical probe. The sample size was 2 × 2 × 1.5 cm, and the probe was moved perpendicular to the sample at a speed of 1.0 mm/s with a trigger force point of 5.0 g. The compression level was 40% (relative to a sample thickness of 1.5 cm) and the interval between compressions was 5 S. Texture characteristics including hardness, cohesion, viscosity and elasticity were obtained from the two compressions. The maximum force required to compress the sample in the first compression was defined as hardness. The ratio between the height distance detected during the second compression and the original compression distance was defined as the elasticity. Cohesion was expressed as the ratio of the total energy required for the second compression to the total energy required for the first compression. The elasticity is defined as the ratio of the area compressed after the first probe reversal during the first compression to the area compressed before the first probe reversal (Modzelewska-Kapitula & Zmijewski, 2021). The texture analysis was performed in quadruplicate.

2.7. Low-field nuclear magnetic resonance (LF-NMR)

The NMI20-060H-I NMR analyzer (Suzhou Niumai Analytical Instruments Co., LTD., Suzhou, China) with magnetic field intensity of 0.5 T was used to obtain the transverse relaxation data of chicken breast samples with different treatments (Modzelewska-Kapitula & Zmijewski, 2021). The temperature of the permanent magnet in the NMR analyzer was maintained at 32 ± 0.01 °C. After absorption of surface water using filter paper, the chicken breast sample was placed on a teflon tube inserted into a 60 mm diameter NMR coil, and the attenuated signal was collected using the CPMG sequence. For the CPMG sequence, the 90° and 180° pulses were 13.0 and 26.0 us, respectively, and the π value (the time between 90° and 180° pulses) was 200 us. The number of echoes and scans were 2000 and 16, respectively. Raw CPMG relaxation data were retrieved using MultiExp Inv analysis software (Suzhou Newmax Analytical Instruments Co., LTD., Suzhou, China) via the Synchronous Iterative Reconstruction Technique (SIRT) algorithm. For LF-NMR relaxation measurements, three samples were used for each storage time and each sample was analyzed three times.

2.8. Electronic nose analysis

Volatile odor was evaluated using the EN3 electronic nose (WinMuster Airsense Analysis, Schwerin, Germany) according to Xie et al. (2022). Before measurement, meat sausage were ground in a meat mincer machine for 30 s, and each sample of 3 g meat was placed in a 20 mL electronic nose injection bottle and heated in a water bath at 50° C for 30 min to enhance volatile odor. The parameters of the electronic nose were set as follows: the sampling time interval was 1 s, the sensor cleaning time was 120 s, the zeroing time was 5 s, the sample preparation time was 5 s, the flow rates of both the sensor and sample were 400 mL/min, the gas collection time was set as 100 s, and the analysis time was 100 s. Due to the stability of the sensor at each time point, the acquisition time is set from 80 s to 83 s. Ten metal oxide gas sensors (W1C, W5S, W3C, W6S, W5C, W1S, W1W, W2S, W2W and W3S) were used to characterize the volatile components.

2.9. GC - IMS analysis

Volatile organic constituents (VOCs) were analyzed using a gas chromatogram-ion mobility spectrometry (GC-IMS) flavor analyzer (FlavourSpec, Dortmund, Germany). Crushed meat sample of 2 g was transferred into a 20 mL headspace vial and sealed. The parameters of GC-IMS were set based on previous study by M. J. Chen, et al. (2020).

Headspace injection conditions: headspace incubation temperature was set at 85℃, and incubation time was 5 min. Heating mode was oscillation heating, and the headspace injection needle temperature was setting at 75℃; Injection volume was 500 μL with no split mode; The headspace needle was pushed and cleaned with high purity nitrogen (purity ≥ 99.999%) for 0.5 min. Gas chromatography analysis conditions was as follows: column temperature was setting at 40℃; The running time was 15 min; Carrier gas (N2, purity ≥ 99.999%); The initial flow rate was 5.0 mL/min, which was maintained for 10 min and then increased linearly to 150 mL/min within 5 min. Ion migration spectrum conditions: drift tube length 5 cm; The linear voltage inside the tube was 400 V/cm; Drift tube temperature 40℃; Drift gas (high purity N2, purity ≥ 99.999%); Flow rate was 150 mL/min; IMS detector temperature was 45° C.

2.10. Statistical analysis

All measurements were conducted at least three times and the results were presented as means ± SD. Statistical analysis was performed using SPSS (version 19.0, SAS Institute Inc., Cary, NC, USA). One-way analysis of variance (ANOVA) was used for statistical analysis. Significant differences between means were verified by Duncan's multiple range test (p < 0.05).

Data were mapped using OriginPro 2021.WinMuster software (Version 1.6.2) was used for principal component analysis of the response values of the E-nose sensor. The analysis software for the GC-IMS instrument includes LAV (Laboratory Analytical Viewer) and three plug-ins. The LAV was used to view the analysis map and quantitatively analyze volatile organic compounds. Reporter and Gallery Plot plug-ins were used to analyze the differences between sample and fingerprint profiles. The NIST database and IMS database built in GC-IMS Library Search software were used for qualitative analysis of substances.

3. Results and discussion

3.1. Composition analysis for crude blackberry polysaccharide (CBP) extract

The carbohydrate content of crude blackberry was 822.13 mg/g, the total polyphenol content was 161.15 mg/g, and the total flavonoids content was 0.39 mg/g. The total protein content of crude BP was 1.84 mg/g. As compared to standards shown in Fig. 1A, the ion chromatogram profile of the sample (Fig. 1B) confirmed that glucose (95.44%) was the main monosaccharide in the crude blackberry extract, followed by arabinose of 2.01%, galactose of 1.81%, and glucuronic acid of 0.74%. These results were consistent with a previously reported work by Chun Chen (C. Chen, et al., 2017). Another published work by Wang and co-authors (Wang et al., 2019) reported a slight difference in monosaccharide compositions of blackberry, which contained rhamnose and galacturonic acid in addition to the same components of galactose, arabinose and glucose monosaccharide. The discrepancy might be related to the variety of blackberry and cultivation environment.

Fig. 1.

Ion-chromatograms of the monosaccharide fractions of A) standard solution in water, B) crude blackberry polysaccharide after acidolysis with TFA and heated 121℃ for 2 h. Note: 1 fucose, 2 arabinose, 3 rhamnose, 4 galactose, 5 glucose, 6 xylose, 7 mannose, 8 fructose, 9 ribose, 10 galacturonic acid, 11 guluronic acid, 12 glucuronic acid, 13 mannose acid.

The infrared spectrum of blackberry polysaccharide is shown in Fig. 2A. There is a typical absorption peak of glycoside structure in blackberry polysaccharide. The strong absorption peak of 3383.08 cm⁻¹ indicates the existence of intermolecular and intramolecular hydrogen bonds, which has the characteristic of –OH stretching vibration. The absorption peak at 2931.74 cm⁻¹ is the characteristic peak of C—H tensile vibration, and the deformation vibration of C—H also leads to the weak absorption at about 1408.01 cm⁻¹, which are considered as specific absorption peaks of polysaccharides (Meng, et al., 2017). The peak at 1616.32 cm ⁻¹ is the C O stretching vibration of the –CHO group, which was consistent with the determination of uronic acid content (W. F. Yang, et al., 2015). Peak appears in the range of 1000 ∼ 1100 cm⁻¹ indicating existence of C—O—C, thus 1055.04 cm⁻¹ shown in the Fig. 2A suggests that the sugar ring of blackberry polysaccharide was pyranose ring. The absorption peak at 777.30 cm⁻¹ also confirmed the pyranose structure. Since the weak absorption is due to the symmetric stretching vibration of α-pyran (Zhang, et al., 2021). In addition, the conformations of α and β have obvious ectopic zones in the 950–750 cm⁻¹ region (C. Z. Wang, et al., 2015), hence, 866.02 cm⁻¹ corresponds to α conformation.

Fig. 2.

Infrared spectrum of blackberry polysaccharide (A), UV absorption of blackberry polysaccharide (B).

The ultraviolet spectrum of blackberry polysaccharide between 200 and 400 nm is presented in Fig. 2B, and there was a small absorption peak at 280.02 nm, indicating that crude blackberry polysaccharide contains the protein, which is consistent with our result of the composition analysis of blackberry polysaccharide.

3.2. The effect of crude blackberry polysaccharide (CBP) on the variations of sample texture profile

The effect of CBP on the texture variations of chicken breast during storage (0, 7 day) was investigated, and the results are summarized in Table 1. The hardness of chicken breast meat was significantly increased from 944.69 g (control) to 1187.05 g and 1253.49 g when CBP was supplemented into the sample at concentrations of 1 g/kg and 3 g/kg, respectively. And the gumminess was also increased predominantly from 315.7 to 435.64 in the sample soaked with 3 g/kg CBP, but the low concentration of CBP exhibited insignificant difference. Other texture parameters had no obvious change after CBP supplementation. Besides, the texture of chicken breast sample showed a substantial increase trend with the prolongation of storage time to 7 days in all testing groups, and higher concentration of CBP (3 g/kg) showed significantly higher hardness.A similar result was revealed previously by Alirezalu, et al. (2017). Hayes, et al. (2010) indicated that the oxidation reaction of proteins is effective for protein solubility, leading to cross-link formation and aggregation, which can describe the textural stability and increase in deformation compression force and hardness of sausages. Hayes, et al. (2011) also reported that cooked sausages containing ellagic acid and olive leaf extract exhibited increased stiffness between days 2 and 12 of refrigerated storage. Meanwhile, the cohesiveness of chicken breast meat increased significantly with the increase of additive concentration of blackberry polysaccharide, and it showed a higher stickiness value on the day of 7 during fridge storage.

Table 1.

Effect of different concentrations of blackberry polysaccharide extract (0 g/kg, 1 g/kgand 3 g/kg) on the texture profile of poached chicken breast and their variations under refrigerator storage (4℃) for 7 days.

Items	Day 0			Day 7
	Control	1 g/kg CBP	3 g/kg CBP	Control	1 g/kg CBP	3 g/kg CBP
Hardness(g)	944.69 ± 62.02b	1187.05 ± 28.20a	1253.49 ± 51.12a	960.06 ± 35.38b	1245.30 ± 43.11a	1282.05 ± 60.14a
Cohesiveness	0.34 ± 0.04a	0.35 ± 0.00a	0.35 ± 0.01a	0.42 ± 0.02a	0.45 ± 0.03a	0.46 ± 0.02a
Gumminess	315.70 ± 24.13b	410.01 ± 45.28ab	435.64 ± 34.24a	403.10 ± 22.24b	562.30 ± 28.73ab	585.92 ± 8.05a
Resilience	0.09 ± 0.01a	0.10 ± 0.00a	0.11 ± 0.00a	0.1 ± 0.01a	0.1 ± 0.01a	0.11 ± 0.00a

Mean values with different superscript in the same raw are significant different at day 0 or day 7 (p < 0.05).

The three characteristic peaks of low-field NMR (T21, T22, T23) correspond to the three types of water from the tightest bond to the loosest bond, respectively (Y. Y. Zhao, et al., 2022). The relaxation time in the range of 0.1–10 ms (T21) is bound water, which is tightly attached to polar groups of macromolecules such as proteins. The water in the range of 10–100 ms (T22) is the fixed water, which is the part of the water trapped in the network within the myofibrils, and the relaxation time in the range of 100–1000 ms (T23) represents the free water located between the myofibrils (Guo, et al., 2020).

Table 2 showed that the bound water and free water peaks in chicken breast meat supplemented with different concentrations of polysaccharide were significantly different from those in the control group. In addition, the fixed water of chicken breast had no significant change (p > 0.05) with the increase of polysaccharide concentration. But, the peak area of bound water increased from 3.70% to 6.56%, while the peak area of free water decreased from 6.34% to 4.26% for the control and 3 g/kg CBP supplemented chicken breast sample, respectively. With the extension of storage time, the peak area of bound water further increased, while the peak area of free water continued to decrease.In a related study by R. Yang, et al. (2020) working on the effect of laver powder on squid surimi gel, it was found that the polysaccharide in laver powder contained a large number of hydroxyl groups, which could form hydrogen bond interactions with water molecules, leading to a significant increase in the content of bound water. Therefore, the addition of blackberry polysaccharide might be able to effectively affect the water distribution of poached chicken breast by improving the binding capacity of fixed water.

Table 2.

Effect of different concentrations of blackberry polysaccharide extract (0 g/kg, 1 g/kgand 3 g/kg) on the water distribution of poached chicken breast and the variations under refrigerator storage (4℃) for 7 days.

Items	Day 0			Day 7
	Control	1 g/kg CBP	3 g/kg CBP	Control	1 g/kg CBP	3 g/kg CBP
Bound water (%)	3.70 ± 0.50b	4.91 ± 0.43ab	6.56 ± 0.68a	4.48 ± 0.30b	5.24 ± 0.33a	6.60 ± 0.20a
Fixed water (%)	89.97 ± 0.74a	90.18 ± 0.33a	89.18 ± 0.48a	89.55 ± 0.87a	90.36 ± 0.90a	89.30 ± 1.06a
Free water (%)	6.34 ± 0.89a	4.91 ± 0.19ab	4.26 ± 0.22b	5.97 ± 0.63a	4.40 ± 0.65a	4.09 ± 0.86a

Mean values with different superscript in the same raw are significant different at day 0 or day 7 (p < 0.05).

3.3. Effects of CBP on odor variation in chicken breast meat

The electronic nose can be used to monitor volatile components of food and obtain real-time information about its various properties (Xu, et al., 2016). The present study employed PEN3 electronic nose with 10 MOS type sensors, and their responds to VOC were conducted as referred to Wang et al. (2019).

Response radar maps for the signal of electronic nose to volatile components in chicken breast adding with 0 g/kg CBP、1 g/kg CBP、3 g/kg CBP at day 0 and day 7 are displaying in Fig. 3A and 3B. On day 0, the response values of boiled chicken breast meat supplemented with 1 g/kg BP and 3 g/kg BP on sensor W5C (nitroxide) and sensor W1W (sulfide) were lower than those in the control (0 g/kg). It indicated that the nitrogen oxides and sulfides decreased after adding with CBP. With the extension of time, the response values of nitrogen oxides and sulfides on the sensor continued to increase on the 7th day, but the response values of boiled chicken breast with 1 g/kg BP and 3 g/kg BP were always lower than those in control, suggesting that the CBP could improve the odor of boiled chicken breast during refrigerator storage. Principal component analysis (PCA) was performed to evaluate the overall flavor characteristics at day 0 and day 7 under different supplemental levels. As shown in Fig. 3C, 97.17% of the total variables were explained by PC1 (86.47%) and PC2 (10.70%). The addition of 1 g/kg and 3 g/kg CBP significantly separated the groups on day 0 and day 7, indicating that the overall flavor characteristics of the groups were significantly different, and the overall flavor difference became more obvious with the prolongation of time. In the day 0 group, the 3 g/kg BP treatment was further away from the control, indicating that the 3 g/kg CBP treatment had distinct flavor characteristics. In the 7th day group, the distance between 0 g/kg BP, 1 g/kg BP and 3 g/kg BP was far from each other, indicating that the flavor of the three groups was significantly different on the 7th day.

Fig. 3.

Sensor response radar maps for chicken breast adding with 0 g/kg BP、1 g/kg BP、3 g/kg crude blackberry polysaccharide extract at day 0 (A) and day 7(B), and their principle component analysis (PCA) results (C).

3.4. Effects of CBP on flavor compounds variation in chicken breast sample

The discrepancy in volatile flavor compounds in boiled chicken breast samples after the addition of different CBP concentrations was characterized by comparing IMS-RI and drift time. And results were displayed more clearly by selecting the control group (0 day) as the reference to subtract with the spectrograms of other samples. If the two volatile organic compounds are consistent, the background after deduction is white. Red means the concentration of the substance is higher than the reference, and blue means the concentration of the substance is lower than the reference (Liu, et al., 2020).

As shown in the Fig. 4A, on the day 0, the background of 1 g/kg extract map was close to white, which could be inferred to be the closest to the volatile compounds in the control group. The content of volatile substances in the 7th day was significantly higher than that in the day 0. When different concentrations of polysaccharides were added on days 0 and 7, the higher the concentration, the lower the content of volatile substances.

Fig. 4.

(A) Two dimensional spectrum of volatile compounds from boiled chicken breast on days 0 and 7 after the addition of 0 g/kg CBP, 1 g/kg CBP, and 3 g/kg CBP using GC-IMS analysis. (B) GC-IMS fingermarks of boiled chicken breast sample on days 0 and 7 with the addition of 0 g/kg CBP, 1 g/kg CBP, and 3 g/kg CBP.

GC-IMS analysis was performed to investigate the differences between flavor compounds of different additive amounts on day 0 and day 7. Fig. 4B shows the 32 volatile flavor compounds were identified, including 9 esters, 4 alcohols, 3 aldehydes, 2 acids, 2 ketones, and other compounds, such as pyridines and pyrazines. The volatile components of chicken breast samples supplemented with different concentrations of CBP on day 0 and 7 were qualitatively analyzed, and the results are shown in Table 3.

Table 3.

Gas chromatography-ion mobility spectrometry (GC-IMS) results for the poached chicken breast after supplementing with different concentrations of crude blackberry polysaccharide (0 g/kg, 1 g/kgand 3 g/kg).

No.	Compound	CAS#	Formula	RI	Rt (SEC)	Dt (a.u.)
1	Octan-1-ol	C111-87–5	C8H18O	1080.5	726.98	1.48
2	Isoamyl butyrate	C106-27–4	C9H18O2	1058.5	597.86	1.41
3	Butylbenzene	C104-51–8	C10H14	1058.1	595.67	1.81
4	trans-2-Hexenoic acid ethyles	C27829-72–7	C8H14O2	1043.6	523.41	1.43
5	Benzene acetaldehyde	C122-78–1	C8H8O	1047.6	542.06	1.24
6	2-Acetylpyridine	C1122-62–9	C7H7NO	1040.5	509.09	1.15
7	2-Acetylpyrazine	C22047-25–2	C6H6N2O	1022.3	432.52	1.14
8	Isopentyl propanoate	C105-68–0	C8H16O2	972.4	282.59	1.34
9	5-methyl-2-hepten-4-one	C81925-81–7	C8H14O	971.3	280.23	1.68
10	5-methyl-2-Furanmethanol	C3857-25–8	C6H8O2	962.8	261.61	1.25
11	2-Methyl-1-propyl butyrate	C539-90–2	C8H16O2	948.1	232.17	1.32
12	Diethylene glycol dimethyl ether	C111-96–6	C6H14O3	962.4	260.60	1.62
13	Propyl butanoate	C105-66–8	C7H14O2	900.7	158.07	1.27
14	(E)-2-Hexen-1-ol	C928-95–0	C6H12O	879.4	135.03	1.18
15	Acetic acid, 2-methylbutyl ester	C624-41–9	C7H14O2	882.8	138.25	1.27
16	isobutyl propionate	C540-42–1	C7H14O2	866.9	123.88	1.25
17	Butanoic acid	C107-92–6	C4H8O2	810	83.49	1.41
18	Propyl propanoate	C106-36–5	C6H12O2	815.9	86.96	1.19
19	2-methylpyrazine	C109-08–0	C5H6N2	826.2	93.41	1.07
20	2-Hexanone	C591-78–6	C6H12O	789.8	72.59	1.18
21	Pyridine	C110-86–1	C5H5N	754.4	56.74	1.24
23	Isopentyl formate	C110-45–2	C6H12O2	784.3	69.89	1.284
24	Pyridine	C110-86–1	C5H5N	757.1	57.81	1.25
25	2-Methylthiophene	C554-14–3	C5H6S	775.5	65.71	1.04
26	3-Methyl-2-butenal	C107-86–8	C5H8O	761.5	59.63	1.09
27	1,1-Diethoxyacetal	C105-57–7	C6H14O2	728.1	47.23	1.11
28	Dimethyl disulfide	C624-92–0	C2H6S2	755.9	57.35	1.14
29	Pyrrole	C109-97–7	C4H5N	765.7	61.40	1.32
30	4-Methyl-2-pentanol	C108-11–2	C6H14O	760.5	59.22	1.28
31	Tetrahydrothiophene	C110-01–0	C4H8S	808.7	82.77	1.30
32	Furfurol	C98-01–1	C5H4O2	827.1	94.00	1.33
33	pentanoic acid	C109-52–4	C5H10O2	901.8	159.49	1.48
34	Styrene	C100-42–5	C8H8	889	144.32	1.44
35	N-ethyl-N-nitroso-	C55-18–5	C4H10N2O	891.4	146.74	1.55
36	2-Hexen-1-ol	C2305-21–7	C6H12O	865.2	122.43	1.51

Twenty compounds were identified in region (a), Namely, n-octanol, isoamyl butyrate, butylbenzene, trans-2-hexenolate ethyl ester, 2-acetylpyridine, phenylacetaldehyde, 2-acetylpyrazine, 5-methyl-2-heptene-4-ketone, isoamyl propionate, 5-methyl-2-furfuryl alcohol, 2-methyl-1-propanol butyrate, diethylene glycol dimethyl ether, trans-2-hexene-1-alcohol, butyric acid, 4-methyl-2-amyl alcohol, Pyridine, 2-hexenol, dimethyl disulfide,1, 1-diethoxy ethane, and 2-methylpyrazine. The contents of these 20 volatile compounds in boiled chicken breast meat gradually decreased with the increase of supplementary concentration of CBP, but higher than those in the control, and the concentration of volatile substances in this area gradually increased with the extension of storage time. Eight volatile compounds were identified in area (b), including 3-methyl-2-butenal, 2-hexanone, pyrrole, valerate, tetrahydrothiophene, furfuraldehyde, methylpyrazine, isoamyl formate, and butyric acid. There was no significant difference in these eight volatile compounds among different groups. However, with the prolongation of storage time to day 7, the concentration of volatile compounds in this area increased significantly with the increase of CBP concentration. Five volatile compounds such as 4-trifluoromethyl benzonitrile, isoamyl formate, 2-methylbutyl acetate, propyl butyrate, and propyl propionate were identified in area (c) from boiled chicken breast meat supplemented with 0 g/kg BP, 1 g/kg BP, and 3 g/kg BP. But insignificant difference was noted either.

In general, GC-IMS classified the volatile compounds in boiled chicken breast into three categories, mainly including esters, alcohols, and aldehydes. This was consistent with the major volatile compounds in the cooked chicken breast investigated by Bi, et al. (2021). Boiled chicken breast has a high content of esters and alcohols. Esters are usually synthesized by esterification of free fatty acids produced by oxidation of alcohols and fats, which are the common volatile flavor ingredients in foods (Deng, et al., 2021). The contents of esters and alcohols decreased in boiled chicken breast meat when supplemented with 1 g/kg CBP and 3 g/kg CBP, which may be due to the inhibition of fat oxidation by CBP. Hence, the addition of CBP might be able to reduce the fat oxidation of chicken breast, improving the quality of chicken breast.

Phenylacetaldehyde is produced by phenylalanine during the degradation of Strecker, resulting in a nutty, rancid and spicy taste (J. Zhao, et al., 2017). After adding 1 g/kg CBP and 3 g/kg CBP to boiled chicken breast, the concentration of phenylacetaldehyde decreased, indicating that CBP could reduce the Maillard reaction of protein, improving the quality of protein in chicken breast.

As a nitrogen heterocyclic compound, dimethylpyrazine has a low threshold and milk fat taste, which is an important factor for coordinating the flavor of chicken (Yu, et al., 2021). The concentration of dimethylpyrazine in boiled chicken breast increased after CBP supplementary, indicating that CBP could increase the meat flavor of chicken breast.

4. Conclusion

The texture stability and hardness of chicken breast intestine were improved by adding different concentrations of blackberry polysaccharide. It can be seen that the addition of different concentrations of blackberry polysaccharide promoted the conversion of free water to bound water, but had no significant effect on fixed water. GC-IMS analysis showed that there were significant differences between flavor compounds of different CBP concentrations on day 0 and day 7, and 32 volatile flavor compounds identified. It includes nine esters, four alcohols, three aldehydes, two acids, two ketones, and other compounds, such as pyridines and pyrazines. In this study, the effects of blackberry polysaccharide on the texture, water distribution and volatile flavor substances of boiled chicken breast were employed, which might provide scientific basis for developing plant extracts as a natural quality modifier for meat.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability

The data that has been used is confidential.