Abstract
The main objective of this study was to investigate the effect of mixing sour cherry puree with apple, pear, quince and flowering quince juices on characteristics of 17 different products (12 smoothies and 5 semi-products). Compounds (phenolic compounds, vitamin C, sugar, pectin), antioxidant activity (ORAC, ABTS, FRAP), and physicochemical parameters (titratable acidity, soluble solids, viscosity, colour) of different products were evaluated. Depending on the type of product, 8 to 20 phenolic compounds, belonging to the anthocyanins, flavan-3-ols, flavonols, hydroxycinnamic acids, and dihydrochalcone, were identified by liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QTOF-MS). The highest content of polyphenols was observed in the sour cherry–flowering quince smoothie, while the lowest was observed in the sour cherry–pear smoothie. The study showed that the major polyphenols compounds in the smoothies were polymeric procyanidins, which were positively correlated with antioxidant activity. In addition, some kind of synergistic effect was observed between some compounds of sour cherry and flowering quince which could increase the antioxidant activity of the final product. The mixing of various fruit products could be interesting from a nutritional as well as commercial perspective.
Keywords: Sour cherry, Smoothies, LC–MS-QTof; UPLC-PDA-FL, Polyphenols, Antioxidant activity
Introduction
Trends in the pursuit of a healthy lifestyle influence the development of the worldwide food industry, including the fruit and vegetable sector. Consumers are beginning to pay attention to the quality and nutritional value of foods, so they increasingly choose fresh, natural juices and healthy snacks. Therefore, among the most promising sectors are those that deliver convenient, healthy, premium type products, satisfying thirst and hunger—such as a smoothie (Corbo et al. 2014; Sabbe et al. 2009). The accurate knowledge of the chemical composition of plant materials creates the possibility to obtain products of pro-health properties and simultaneously attractive in terms of sensory values. The mixing process of raw materials should be carefully planned and should be carried out in order to supplement the specific components, so as to finally obtain a product with the features of functional foods (Corbo et al. 2014; González-Molina et al. 2012).
Sour cherry (Prunus cerasus L.) is a rich source of nutrients and bioactive compounds, including anthocyanins, hydroxycinnamic acids, malic acids, vitamins and minerals, but the tart taste of this fruit is not always accepted by consumers (Damar and Ekşi 2012; Kirakosyan et al. 2009; Wojdyło et al. 2014b). Because of this, there are various sour cherry products including wines, jams, juices or beverages with a high content of sucrose and low levels of the fruit. Hence, new uses for sour cherry fruit should be developed with the aim of minimizing loss of bioactive compounds and simultaneously with a new, more acceptable taste. For this purpose, sour cherry puree could be mixed with other attractive fruits, e.g. pear, apple, quince or flowering quince. In this sense, apple, pear and quince have a sweet taste and are a richer source of pectin and other polyphenol compounds, e.g. flavonols and flavan-3-ols, than sour cherry, therefore after mixing these fruits with sour cherry valuable products could be obtained (Kolniak-Ostek and Oszmiański 2015; Wojdyło et al. 2008; Wojdyło et al. 2014c). In turn, flowering quince fruits are very acidic and not suitable for consumption when raw. However, it is an excellent raw material for processing, with high bioactive potential, which could be used as a flavouring additive, enriching the quality of the final products (Nowicka et al. 2015; Tarko et al. 2014).
Therefore, the aim of this study was to investigate the effect of mixing different fruit juices (apple, pear, quince and flowering quince) with sour cherry puree on the content of bioactive compounds (polyphenols, vitamin C, pectins) and physical (viscosity, colour) and chemical (titratable acidity, soluble solids, sugar content) properties.
It was expected that the resulting smoothies would be characterized by a high content of polyphenolic compounds, antioxidant activity and attractive physicochemical properties.
Materials and methods
Chemicals
Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 2,2′-azobis (2-amidino-propane) dihydrochloride (AAPH), fluorescein disodium (FL), potassium persulfate, acetic acid, TPTZ (2,4,6-tripyridyl-1,3,5-triazine), FeCl3, phloroglucinol, arabinose, fructose, sorbitol, glucose, sacharose and methanol were purchased from Sigma-Aldrich (Steinheim, Germany). Quercetin and keampferol-3-O-glucoside, cyanidin-3-O-rutinoside, -3-O-glucoside, -3-O-sophoroside, peonidin-3-O-rutinoside, pelargonidin-3-O-glucoside, p-coumaric acid, (+)-catechin, and (−)-epicatechin, procyanidin B2 and C1 were purchased from Extrasynthese (Lyon Nord, France). Chlorogenic, neochlorogenic and cryptochlorogenic acids were supplied by TRANS MIT GmbH (Giessen, Germany). Acetonitryle for ultra—phase liquid chromatography (UPLC, gradien grade) and ascorbic acid were from Merck (Darmstadt, Germany). UPLC grade water, prepared by HLP SMART 1000 s sytem (Hydrolab, Gdańsk, Poland), was additionally filtrated through a 0.22 μmol membrane filter immediately before use.
Plant material
Fruits of sour cherry (Prunus cerasus L.) cv. ‘Łutówka’, apple (Malus domestica Borkh.) cv. ‘Champion and pear fruit (Pyrus L.) cv. ‘Faworytka’ harvested at the Research Station for Cultivar Testing in Zybiszów near Wrocław (Poland). While the quince fruit (Cydonia oblonga Mill.) cv. ‘Lescovac’ and flowering quince (Chaenomeles japonica L.) cv. ‘Witaminnyj’ harvest at the Research Institute of Horticulture in Skierniewice (Poland).
Smoothie production
The production process included 3 main technological stages: (1) juice production; (2) processing of sour cherry fruit into puree; (3) mixing both semi-products in appropriate proportions.
The apple, pear, quince and flowering quince fruit were ground in a Thermomix appliance (Vorwerk, Wuppertal, Germany), and then the obtained pulps were pressed on a hydraulic press to obtain juices. For pear mash 10% ascorbic acid solution was added in the amount of 10 ml/kg of fruits to prevent enzymatic browning.
Pitted sour cherries were ground and heated at 80 °C in a Thermomix device (Vorwerk, Wuppertal, Germany) and mashed in a blender (Symbio, Zelmer, Rzeszów, Poland) to obtain puree used to produce smoothies.
Juice–puree samples were mixed in the proportions 80:20, 50:50 and 20:80, respectively. Then, the products were heated to 100 °C and put into glass jars, pasteurised for 10 min and finally cooled to 20 °C. As a result, seventeen different products were obtained: five semi-products (sour cherry puree (SCP); apple juice (AJ); pear juice (PJ); quince juice (QJ) and flowering quince juice (FQJ)) and twelve smoothies. Each sample was prepared in two replicates. The products were subjected to analyses directly after processing.
Chemical analyses
Titratable acidity (TA) was determined by titration aliquots of homogenate of fresh fruits by 0.1 N NaOH to an end point of pH 8.1 using an automatic pH titration system (pH-metr typ IQ 150; Warsaw, Polska) and expressed as g of malic acid/100 g of products. The soluble solids content (SS) was determined in obtained products with a refractometer (Atago Rx 5000, Atago Co. Ltd., Japan) and expressed as °Brix. Total content of L-ascorbic acid was determined by the PN norm (PN-90/A-75101/11) and expressed as mg/100 g of pruducts. While pectins content was analyzed according to the Moriss method described by Pijanowski et al. (1973) and expressed as g/100 g products. All determinations were done in triplicate in each replicate.
Determination of sugar content by HPLC coupled to light scattering detector
Obtained products (8–9 g) were mixed with 50 ml of redistilled water, ultrasonicated 15 min, boiled 30 min and after that centrifuged at 20,000g for 10 min. The extracts applied onto the Sep-Pak C-18 (containing 1 g of the carrier, Waters) and eluted by water to give sample solution to estimation of sugar content. A 40 μL sample was injected by autosampler (L-7200) into a Unison UK-Amino 3 μL column (3 mm × 250 mm) (Imtakt, Kyoto, Japan) by liquid chromatograph. Detection was carried out using evaporative light-scattering detector (PL-ELS 1000 Evaporative Light Scattering Detector) with the following input parameters: temperature of the evaporator—80 °C; temperature of the nebulizer—80 °C; nitrogen flow—1.2 SLM. The elution was carried out at 30 °C under a isocratic flow using 85% acetonitrile solution at the flow rate of 0.7 mL/min. Sugar components was identified by comparison with the standards (arabinose, fructose, sorbitol, glucose, sucrose). The calibration curves were prepared by plotting different concentrations ranging from 0.5 to 5 mg/ml (R2 ≤ 0.9998) of the standards versus the area measurements in HPLC. All determination were done in triplicate. Results were expressed as grams/100 g product.
Colour measurement
Colour properties (L*, a*, b*) of mixed products were determined using A5 Chroma-Meter (Minolta CR300, Osaka, Japan), referring to colour space CIE L*a*b*. The colour coordinates of the samples were determined using Illuminant D65 and 10° observer angle, and the samples were measured against a white ceramic reference plate (L* = 93.92; a* = 1.03; b* = 0.52). The data were mean of three measurements. Total change of colour in analyzed products (ΔE*) was calculated according to Wojdyło et al. (2014a).
Identification and quantification of polyphenols by LC-PDA-MS method
The solvent for identification (LC/MS QTOF) and quantitative (UPLC-PDA-FL) analysis of polyphenols (anthocyanin, flavan-3-ol, flavonol, phenolic acid and dihydrochalcone) were performed as described previously by Wojdyło et al. (2014b). All measurements were repeated three times. The results were expressed as mg per 100 g of product.
Analysis of polymeric procyanidins by phloroglucinolysis method
An analysis of polymeric procyanidins by phloroglucinol method was performed according to the protocol described previously by Kennedy and Jones (2001). All measurements were repeated three times. The results were expressed as mg per 100 g of product.
Determination of antioxidant activity
A solvent for the analysis of polyphenols was prepared as described previously by Wojdyło et al. (2014b). The ORAC, ABTS and FRAP assays were prepared as previously described by Ou et al. (2002); Re et al. (1999) and Benzie and Strain (1996), respectively. The antioxidant activity was expressed as mmol of Trolox per 100 g dm. ORAC assay was carried out on RF-5301 PC spectrofluorometer (Shimadzu, Kyoto, Japan). Measurements by means of ABTS and FRAP methods involved UV-2401 PC spectrophotometer (Shimadzu, Kyoto, Japan).
Statistical analysis
Statistical analysis was conducted using Statistica version 12.0 (StatSoft, Krakow, Poland). Significant differences (p ≤ 0.05) between means were evaluated by one-way ANOVA and Duncan’s multiple range test. All analyses were performed in triplicate. In addition, to better understand the trends and relationships among 17 different products, Principal Components Analysis (PCA) was carried out using the Statistica 12.0.
Identification and quantification of phenolic compounds in the obtained products
Sour cherry puree
Table 1 shows the data of LC/QTOF–MS analysis. The LC/MS analysis of sour cherry puree (SCP) indicated presence of 16 compounds. These can be classified into four groups of phenolic compounds: anthocyanins, hydroxycinnamic acids, flavonols and flavan-3-ols. The total concentration of these compounds was 572.94 mg/100 g puree (presented in Table 2).
Table 1.
Groups of phenolic compounds identified by LC/MS in the analyzed puree, juices and smoothies
| Compounds | R t (min) | λmax (nm) | MS [M-H]− (m/z) | MS/MS [M-H]− (m/z)b | SCP | AJ | SCP [%] ÷ AJ [%] | PJ | SCP [%] ÷ PJ [%] | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 80÷20 | 50÷50 | 20÷80 | 80÷20 | 50÷50 | 20÷80 | ||||||||
| Anthocyanins | |||||||||||||
| Cyjanidyno-3-O-sophoroside | 3.428 | 515 | 611.162+a | 287.055 | x | nd | x | x | x | nd | x | x | x |
| Cyjanidyno-3-O-glucosylo-rutinoside | 3.583 | 517 | 757.219+ | 611.162/287.055 | x | nd | x | x | x | nd | x | x | x |
| Cyjanidyno-3-O-glucoside | 3.774 | 516 | 449.109+ | 287.055 | x | nd | x | x | nd | nd | x | x | nd |
| Cyjanidyno-3-O-rutinoside | 3.929 | 517 | 595.166+ | 287.055 | x | nd | x | x | x | nd | x | x | x |
| Peonidyno-3-O-rutinoside | 4.513 | 517 | 609.183+ | 463.785/301.884 | x | nd | x | x | nd | nd | x | x | nd |
| Hydroxycinnamic acids | |||||||||||||
| Neochlorogenic acid | 3.081 | 323 | 353.094 | 191.057 | x | nd | x | x | x | x | x | x | x |
| 3-p-coumarylquinc acid | 3.619 | 310 | 337.091 | 191.057/183.087 | x | x | x | x | x | nd | x | x | x |
| Chlorogenic acid | 4.135 | 324 | 353.094 | 191.057 | x | x | x | x | x | x | x | x | x |
| 4-O-caffeoylquinic acid | 5.221 | 320 | 353.086 | 191.057 | x | x | x | x | x | x | x | x | x |
| 3,5-dicaffeoylquinic acid | 7.650 | 320 | 515.140 | 353.069/191.055 | x | nd | nd | nd | nd | nd | x | x | x |
| Flavan-3-ols | |||||||||||||
| (+)-catechin | 3.360 | 278 | 289.073 | x | nd | x | x | x | x | x | x | x | |
| Procyanidin B1 | 3.670 | 278 | 577.133 | 289.073 | nd | nd | nd | nd | nd | x | nd | nd | x |
| (−)-epicatechin | 4.823 | 278 | 289.073 | nd | x | x | x | x | x | nd | x | x | |
| Procyanidin B2 | 6.649 | 278 | 577.133 | 289.073 | nd | x | nd | nd | x | x | nd | nd | x |
| Flavonols | |||||||||||||
| Quercetin-3-O-rutinoside-glucoside | 5.530 | 337 | 771.196 | 301.028 | x | nd | x | x | x | nd | x | x | x |
| Quercetin-3-O-rutinoside | 6.494 | 353 | 609.148 | 577.241/301.029 | x | x | x | x | x | x | x | x | x |
| Quercetin-3-O-galactoside | 6.737 | 350 | 463.091 | 301.036 | x | nd | x | nd | nd | nd | x | x | x |
| Kaempferol-3-O-rutinoside | 7.017 | 352 | 593.151 | 285.039 | x | x | x | x | x | x | x | x | x |
| Isorhamnetin-3-O-rutinoside | 7.148 | 352 | 623.156 | 315.047 | x | nd | x | x | x | nd | x | x | x |
| Isorhamnetin-3-glucoside-7-rhamnoside | 7.303 | 350 | 623.156 | 315.047 | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Dihydrochalcone | |||||||||||||
| Phloretin-2`xylo-glucoside | 7.701 | 280 | 567.169 | 273.076 | nd | x | nd | x | x | nd | nd | nd | nd |
| Compounds | QJ | SCP [%] ÷ QJ [%] | FQJ | SCP [%] ÷ FQJ [%] | ||||
|---|---|---|---|---|---|---|---|---|
| 80÷20 | 50÷50 | 20÷80 | 80÷20 | 50÷50 | 20÷80 | |||
| Anthocyanins | ||||||||
| Cyjanidyno-3-O-sophoroside | nd | x | x | x | nd | x | x | x |
| Cyjanidyno-3-O-glucosylo-rutinoside | nd | x | x | x | nd | x | x | x |
| Cyjanidyno-3-O-glucoside | nd | x | x | x | nd | x | x | x |
| Cyjanidyno-3-O-rutinoside | nd | x | x | x | nd | x | x | x |
| Peonidyno-3-O-rutinoside | nd | x | x | x | nd | x | x | x |
| Hydroxycinnamic acids | ||||||||
| Neochlorogenic acid | x | x | x | x | nd | x | x | x |
| 3-p-coumarylquinc acid | x | x | x | x | x | x | x | x |
| Chlorogenic acid | x | x | x | x | x | x | x | x |
| 4-O-caffeoylquinic acid | x | x | x | x | x | x | x | x |
| 3,5-dicaffeoylquinic acid | x | x | x | x | x | x | x | x |
| Flavan-3-ols | ||||||||
| (+)-catechin | x | x | x | x | x | x | x | x |
| Procyanidin B1 | x | nd | x | x | x | x | x | x |
| (−)-epicatechin | x | nd | nd | x | x | x | x | x |
| Procyanidin B2 | x | nd | nd | x | x | x | x | x |
| Flavonols | ||||||||
| Quercetin-3-O-rutinoside-glucoside | nd | x | x | nd | nd | x | x | x |
| Quercetin-3-O-rutinoside | nd | x | x | x | nd | x | x | x |
| Quercetin-3-O-galactoside | nd | x | x | x | x | x | x | x |
| Kaempferol-3-O-rutinoside | nd | x | x | x | x | x | x | x |
| Isorhamnetin-3-O-rutinoside | nd | x | x | x | x | x | x | x |
| Isorhamnetin-3-glucoside-7-rhamnoside | nd | nd | nd | nd | x | x | x | x |
| Dihydrochalcone | ||||||||
| Phloretin-2`xylo-glucoside | nd | nd | nd | nd | nd | nd | nd | nd |
SCP sour cherry puree, AJ apple juice, PJ pear juice, QJ quince juice, FQJ flowering quince juice. [M + H] (m/z) for anthocyanins were obtained in the positive ion mode. The m/z values of the predominant ions are given in bold type
Table 2.
Concentrations of anthocyanins, flavan-3-ols, hydroxycinnamic acids, flavons and dihydrochalcone in mg/100 g of puree, juices and smoothies
| Compounds | SCP | AJ | SCP [%]–AJ [%] | PJ | SCP [%]–PJ [%] | ||||
|---|---|---|---|---|---|---|---|---|---|
| 80÷20 | 50÷50 | 20÷80 | 80÷20 | 50÷50 | 20÷80 | ||||
| Anthocyanins | |||||||||
| A1 | 18.65a | nd | 14.77c | 8.84g | 3.65i | nd | 13.04e | 7.30h | 2.86j |
| A2 | 92.86a | nd | 72.99d | 43.15g | 27.48i | nd | 67.90e | 35.70h | 14.47l |
| A3 | 0.16 | nd | 0.13a | 0.07a | nd | nd | 0.10a | 0.07a | nd |
| A4 | 39.27a | nd | 30.85b | 17.92d | 7.21f | nd | 28.28c | 14.71e | 5.68g |
| A5 | 1.96a | nd | 1.46b | 0.79de | nd | nd | 1.10c | 0.63e | nd |
| Total | 152.89a | nd | 120.21d | 70.77g | 38.34i | nd | 110.41e | 58.41h | 23.01l |
| Flavan-3-ols | |||||||||
| C | 19.79d | nd | 15.69f | 12.05g | 8.80i | 1.25k | 19.17d | 11.42h | 5.36j |
| PB1 | nd | nd | nd | nd | nd | 4.91f | nd | nd | 3.53g |
| E | nd | 19.42c | 2.78i | 4.95gh | 16.63e | 12.42f | nd | 11.66f | 17.46d |
| PB2 | nd | 4.08 g | nd | nd | 2.31h | 9.52d | nd | nd | 6.27e |
| PP | 147.28h | 117.17j | 132.21i | 109.26k | 106.32l | 53.89n | 116.92j | 83.73m | 37.69o |
| DP | 4.46c | 1.83j | 4.11e | 4.25d | 3.70f | 4.54b | 4.20d | 4.83a | 4.75a |
| Total | 167.07h | 140.67j | 150.68i | 126.26l | 136.37k | 81.99n | 136.09k | 106.81m | 70.31o |
| Hydroxycinnamic acid | |||||||||
| NCh | 34.75d | nd | 27.56e | 17.08g | 10.94h | 85.69a | 44.01c | 59.91b | 84.16a |
| 3pc | 7.11a | 3.29f | 5.61c | 3.47ef | 4.44d | nd | 6.05b | 1.72g | 1.92 g |
| Ch | 97.91e | 113.65c | 113.65c | 98.72e | 106.50d | 90.38f | 76.50i | 70.48j | 96.42e |
| 4cq | 46.92c | 2.81m | 32.81g | 47.09c | 28.11h | 17.54k | 45.70d | 45.14d | 39.74f |
| 3,5cq | 4.13a | nd | nd | nd | nd | nd | 2.62e | 2.65e | 2.44f |
| Total | 190.83c | 119.74 l | 179.63e | 166.36g | 149.99j | 193.62b | 174.89f | 179.89e | 224.67a |
| Flavonols | |||||||||
| QRG | 10.16a | nd | 8.02c | 4.59e | 1.96fg | nd | 8.57b | 5.75d | 2.18f |
| QR | 27.14a | 1.26i | 21.71c | 13.52e | 5.56g | 0.44j | 23.02b | 14.93d | 6.63fg |
| QG | 2.97ab | nd | 2.50b | nd | nd | nd | 2.26c | 1.81d | 0.86g |
| KR | 7.42a | 1.41hi | 5.87c | 1.78g | 1.14i | nd | 6.37b | 4.33e | 1.78g |
| IR | 14.46a | nd | 11.35c | 3.00h | 2.92hi | 1.09l | 12.43b | 6.07f | 3.93g |
| IRR | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Total | 62.15a | 2.67m | 49.45c | 22.90g | 11.58j | 1.53n | 52.65b | 32.90e | 15.37h |
| Dihydrochalcone | |||||||||
| PXG | nd | 2.79a | nd | 1.41c | 2.53b | nd | nd | nd | nd |
| Total polyphenols | 572.94b | 265.87p | 499.97f | 388.70k | 338.81m | 277.14o | 474.04g | 378.01l | 333.36n |
| Compounds | QJ | SCP [%]–QJ [%] | FQJ | SCP [%]–FQJ [%] | ||||
|---|---|---|---|---|---|---|---|---|
| 80÷20 | 50÷50 | 20÷80 | 80÷20 | 50÷50 | 20÷80 | |||
| Anthocyanins | ||||||||
| A1 | nd | 15.58b | 9.25f | 3.56i | nd | 14.50d | 3.60i | 0.93 k |
| A2 | nd | 75.54b | 45.27f | 18.64j | nd | 73.95c | 15.95 k | 5.50 m |
| A3 | nd | 0.13a | 0.08a | 0.02a | nd | 0.12a | 0.03a | 0.01a |
| A4 | nd | 31.12b | 18.32d | 7.19f | nd | 30.92b | 6.42f | 2.11 h |
| A5 | nd | 1.50b | 0.88d | 0.33f | nd | 1.44b | 0.32f | 0.10 g |
| Total | nd | 123.88b | 73.80f | 29.75j | nd | 120.94c | 26.31 k | 8.64 m |
| Flavan-3-ols | ||||||||
| C | 26.29b | 20.77c | 22.38c | 30.96a | 19.33d | 11.00h | 14.18f | 17.02e |
| PB1 | 10.33c | nd | 3.71g | 7.61e | 14.75b | 8.25d | 8.67d | 16.68a |
| E | 6.22g | nd | nd | 4.68h | 40.39a | 5.46g | 17.01d | 30.41b |
| PB2 | 14.02c | nd | nd | 2.27h | 38.93a | 5.48f | 6.40e | 17.55b |
| PP | 232.32d | 132.34i | 193.40f | 201.51e | 563.89a | 155.28g | 253.34c | 354.73b |
| DP | 3.30g | 4.68ab | 4.32d | 4.25d | 1.95j | 3.41g | 2.77 h | 2.27i |
| Total | 289.18d | 153.11i | 197.11f | 247.03e | 677.29a | 185.47g | 299.60c | 436.39b |
| Hydroxycinnamic acid | ||||||||
| NCh | 0.39l | 29.16e | 19.12f | 8.13i | nd | 28.32e | 7.08j | 3.56k |
| 3pc | 1.06h | 5.62c | 3.72e | 3.27f | 0.58i | 6.22b | 1.86 g | 1.63g |
| Ch | 139.81a | 82.47g | 94.30ef | 129.18b | 37.64i | 79.22 h | 30.15j | 38.53i |
| 4cq | 2.84m | 65.69a | 52.85b | 21.07i | 4.36 l | 41.85e | 19.18j | 4.62l |
| 3,5cq | 1.83h | 3.42b | 2.82d | 1.10i | 2.07 g | 3.00c | 3.07c | 0.82j |
| Total | 145.93k | 186.36d | 172.82f | 162.55 h | 44.64o | 158.60i | 61.34m | 49.16n |
| Flavonols | ||||||||
| QRG | nd | 7.62c | 4.72e | 2.15f | nd | 8.65b | 1.91g | 0.52h |
| QR | nd | 20.24c | 13.21e | 7.32f | nd | 23.09b | 5.79g | 3.30h |
| QG | nd | 1.99cd | 1.43e | 0.97f | 0.45h | 3.10a | 0.82g | 0.77g |
| KR | nd | 5.44d | 3.52f | 1.80g | 0.43k | 6.10bc | 1.62h | 0.92j |
| IR | nd | 10.44d | 6.40e | 2.88i | 2.93i | 11.79bc | 2.77j | 1.27k |
| IRR | nd | nd | nd | nd | 2.93a | 0,76c | 1.57b | 2.65a |
| Total | nd | 45.73d | 29.28f | 12.97i | 6.74l | 52.74b | 14.47h | 8.91k |
| Dihydrochalcone | ||||||||
| PXG | nd | nd | nd | nd | nd | nd | nd | nd |
| Total polyphenols | 435.11i | 509.08e | 473.01g | 454.65h | 728.67a | 518.51d | 401.72j | 531.00c |
SCP sour cherry puree, AJ apple juice, PJ pear juice, QJ quince juice, FQJ flowering quince juice, A1 cyjanidyno-3-O-sophoroside, A2 cyjanidyno-3-O-glucosylo-rutinoside, A3 cyjanidyno-3-O-glucoside, A4 cyjanidyno-3-O-rutinoside, A5 peonidyno-3-O-rutinoside, C (+)-catechin, PB 1 procyanidin B1, E (−)-epicatechin, PB 2 procyanidin B2, PP polymeric procyanidins, DP degree of polymerization, NCh neochlorogenic acid, 3pc 3-p-coumarylquinc acid, Ch chlorogenic acids, 4cq 4-O-caffeoylquinic acid, 3,5cq 3,5-dicaffeoylquinic acid, QRG quercetin-3-O-rutinoside-glucoside, QR quercetin-3-O-rutinoside, KR kaempferol-3-O-rutinoside, IR isorhamnetin-3-O-rutinoside, IRR isorhamnetin-3-glucoside-7-rhamnoside, PXG phloretin-2`xylo-glucoside
Values are means of two repetitions. Mean values of n = 2 followed by different letters are statistically different at p < 0.05. nd not detected
Five compounds belonging to anthocyanins were detected in the SCP. These were: cyanidin-3-O-sophoroside ([M + H]+ at m/z = 611 and MS/MS fragment at m/z = 287); cyanidin-3-O-glucosyl-rutinoside with [M + H]+ at m/z = 757 and MS/MS fragment at m/z = 287; cyanidin-3-O-glucoside ([M + H]+ at m/z = 449 and MS/MS fragment m/z = 287); cyanidin-3-O-rutinoside with [M + H]+ at m/z = 595 and also MS/MS fragment m/z = 287; and peonidin-3-O-rutinoside ([M + H]+ at m/z = 609). The concentration of anthocyanins was 152.89 mg/100 g SCP. The quantitatively the largest contributions of these compounds were: cyanidin-3-O-glucosyl-rutinoside (61% of total content anthocyanins in SCP) and cyanidin-3-O-rutinoside (26%). Presence of the same compounds in sour cherry products was confirmed by Kirakosyan et al. (2009) and in dried sour cherry by Zorić et al. (2014). Only four anthocyanin compounds were reported in the study by Repajić et al. (2015), but they also reported that the dominant compounds in sour cherry juice are cyanidin-3-O-glucosyl-rutinoside and cyanidin-3-O-rutinoside.
Hydroxycinnamic acids were the next major group of polyphenols identified in SCP—190.83 mg/100 g fresh product (Tables 1 and 2). The LC/MS analysis identified five compounds belonging to this group of polyphenols. The dominant hydroxycinnamic acids of the SCP were three derivatives of caffeoylquinic acid: neochlorogenic acid (R t = 3.08 min, [M-H]− at m/z = 353), chlorogenic acid (R t = 4.14 min, [M-H]− at m/z = 353) and 4-O-caffeoylquinic acid (R t = 5.22 min, [M-H]− at m/z = 353). The concentration of the three main hydroxycinnamic acids in SCP were 97.91 mg (chlorogenic acid), 46.92 mg (4-O-caffeoylquinic acid) and 34.75 mg (neochlorogenic acid) in 100 g of SCP. The same configuration of these compounds was described in different cultivars of sour cherries by Wojdyło et al. (2014b) and in dried sour cherry by Nowicka et al. (2015).
Also three types of flavonol derivatives with a fragment at m/z 301, 285 and 315, characteristic for quercetin, kaempferol and rhamnetin derivatives, respectively, were found in SCP (Table 1). The main flavonols identified in SCP were quercetin-3-O-rutinoside with [M-H]− at m/z = 609 and MS/MS fragment at m/z = 301; isorhamnetin-3-O-rutinoside ([M-H]− at m/z = 625 and MS/MS fragment at m/z = 315) and quercetin-3-O-rutinoside-glucoside with [M-H]− at m/z = 771 and MS/MS fragment at m/z = 301. In addition, quercetin-3-O-galactoside and kaempferol-3-O-rutinoside were detected in the SCP. The total content of these compounds was 62.15 mg/100 g product, including almost 50% quercetin-3-O-rutinoside (Table 2). These results were confirmed by Kirakosyan et al. (2009), who determined the presence of kaempferol, quercetin and isorhamnetin in tart cherry products. Also Nowicka and Wojdylo (2015), analysing stability of phenolic compounds in sour cherry puree during storage, identified the same flavonols.
The (+)-catechin, at a concentration of 19.79 mg/100 g of SCP, was identified. In addition polymeric procyanidins were detected in the analysed product. The content of polymeric procyanidins, determined by the phloroglucinol method, was 147.28 mg/100 g fresh puree. Kołodziejczyk et al. (2013), in their study on sour cherry pomace extract, also suggested that polymeric flavan-3-ols are present in higher concentrations than their monomers.
Table 2 presents the degree of polymerization (DP; number of flavan-3-ol units), which modulates the physicochemical properties of polymeric procyanidins. The DP of the SCP polymeric fraction was 4.5. In different cultivars of sour cherries DP ranged from 2.6 to 6.6 (Wojdyło et al. 2014b), while DP in sour cherry puree analysed by Nowicka and Wojdylo (2015) was 3.4.
Sour cherry–apple smoothies
In apple juice (AJ), which was the base for a mixture of SCP–AJ smoothies, were identified only 8 polyphenol compounds belonging to the hydroxycinnamic acid (3), flavonol (2), flavan-3-ol (2) and dihydrochalcone (1) groups (Table 1). Total content of polyphenols in AJ was 265.87 mg/100 ml juice (Table 2). The study showed that the two main compounds (chlorogenic acid and polymeric procyanidins) determine to the greatest extent the final concentration of polyphenol content in this product. The concentration of chlorogenic acid and polymeric flavan-3-ols was 113.65 mg and 117.17 mg/100 g of juice, which was 43 and 44% of the total content of polyphenols, respectively. Also Francini and Sebastiani (2013) and Wojdyło et al. (2008) showed that the dominant compounds in different cultivars of apple were polymeric procyanidins and chlorogenic acid.
The LC/MS analysis helped identify in AJ one compound belonging to the dihydrochalcone group. It was phloretin-2′xylo-glucoside (R t = 7.701; λmax = 280) with [M-H]−at m/z = 567 and MS/MS fragment at m/z = 273. Cuthbertson et al. (2012), Vrhovsek et al. (2004) and Wojdyło et al. (2008) confirmed the presence of phloretin-2′xylo-glucoside in apple fruit and its products.
Supplementation of AJ by SCP resulted in a change of the polyphenol profile and also an increase of polyphenol content in the tested smoothies. The LC/MS analysis of SCP–AJ smoothies allowed for characterization of anthocyanins in each of them. In the products with 80 and 50% addition of SCP were identified all 5 anthocyanins previously determined in 100% SCP, while in the product with 20% sour cherry were only detected cyanidin-3-O-sophoroside, -3-O-glucosyl-rutinoside and -3-O-rutinoside. The content of these compounds was positively correlated with the concentrations of SCP in tested samples and was 120.21 mg (80% SCP:20% AJ) >70.77 mg (50% SCP:50% AJ) >38.34 mg (20% SCP:80% AJ) in 100 g of smoothies. A similar trend was observed in the case of the hydroxycinnamic acids. In the analysed smoothies were determined 4 compounds of this group, previously determined in SCP: neochlorogenic acid, chlorogenic acid, 3-p-coumaroylquinic acid and 4-O-caffeoylquinic acid. Depending on the type of smoothie, total hydroxycinnamic acids contents were 179.63 > 166.36 > 149.99 mg in 100 g of smoothie with 80% > 50% > 20% SCP, respectively.
In the obtained smoothies were also identified flavonols, but depending on the contribution of puree both their quantity and quality changed. The smoothie with the smallest content of AJ (20%) was characterized by all five flavonols previously determined in the SCP, while in the other mixed products quercetin-3-O-galactoside was not identified.
In apple–sour cherry smoothie were also detected compounds belonging to the flavan-3-ols. (+)-Catechin from SCP and (−)-epicatechin from AJ were detected in all discussed mixed products. Moreover, in the smoothie with 80% AJ, procyanidin B2 was identified. Total content of flavan-3-ols (monomer, dimers and polymeric procyanidins) ranged from 126.68 mg (50% SCP:50% AJ) to 150.68 mg (80% SCP:20% AJ) in 100 g of product.
Generally, all mixed smoothies produced from AJ with SCP were characterized by a higher content of phenolic compounds compared with AJ. It was observed that a larger addition of SCP was connected with a higher concentration of the bioactive compounds: 499.97 mg (80% SCP:20% AJ); 388.70 mg (50% SCP:50% AJ) and 338.81 mg (20% SCP:80% AJ) in 100 g of smoothies. As a consequence, apple–sour cherry smoothies contain from 27 to 88% more polyphenols than AJ. The observed trend is extremely important for determining pro-health properties.
Sour cherry–pear smoothies
The next group of smoothies was based on pear juice (PJ) and SCP mixed in three different proportions (80:20; 50:50 and 20:80). The LC/MS analysis of PJ revealed characterization of 9 compounds. These can be classified into three groups of phenolic compounds—hydroxycinnamic acids (3), flavonols (2) and flavan-3-ols (4)—and their total concentration was 277.14 mg/100 ml juice.
Hydroxycinnamic acids were the dominant group of polyphenols in PJ. In PJ three derivatives of caffeoylquinic acid were identified: neochlorogenic acid, chlorogenic acid and 4-O-caffeoylquinic acid. The summary content of these compounds was 193.62 mg/100 ml PJ, which accounted for around 70% of the total content of polyphenols. In addition in the PJ flavan-3-ols were identified: two monomers, two dimers, and polymeric procyanidins. The most abundant flavan-3-ols in 100 ml of PJ were polymeric procyanidins (53.89 mg) >(−)-epicatechin (12.42 mg) >procyanidin B2 (9.52 mg) >procyanidin B1 (4.91 mg) and least (+)-catechin (1.25 mg). In PJ were also identified flavonols, but their total content was low—1.53 mg/100 ml fresh juice. Also Kolniak-Ostek and Oszmiański (2015) reported the presence of these compounds in different anatomical pear parts.
As in the case of apple smoothies, SCP–PJ smoothies were detected to have anthocyanins, previously identified in SCP. All of these were determined in smoothies with 80 and 50% addition of puree, but 20% SCP:80% PJ smoothie contained three major anthocyanins: cyanidin-3-O-sophoroside; -3-O-glucosyl-rutinoside and -3-O-rutinoside. The highest content of anthocyanins was detected in 80% SCP:20% PJ smoothie (110.41 mg/100 g product >58.41 mg/100 g 50% SCP:50% PJ), while the lowest was detected in 20% SCP:80% PJ smoothie (23.01 mg/100 g product). The addition of SCP also enriched mixed products with all hydroxycinnamic acids and flavonols previously identified in sour cherry. Their content in analysed smoothies ranged from 174.89 mg/100 g (80% SCP:20% PJ) to 224.67 mg/100 g (20% SCP:80% PJ) in the case of hydroxycinnamic acid. The content of flavonols was from 3.93 mg/100 g smoothie in 80% PJ to 12.43 mg/100 g smoothie in 20% PJ; in comparison with PJ it was from 10 to 80 times more. In turn, the addition of PJ enriched smoothies with flavan-3-ols, especially (-)-epicatechin, but also dimeric procyanidins in the case of 20% SCP:80% PJ smoothie. The total polyphenol content in PJ–SCP smoothies was 474.4 mg/100 g smoothie with 80% SCP > 378.01 mg/100 g smoothie with 50% SCP > 333.36 mg/100 g smoothie with 20% SCP, which was 71, 36 and 20% more compared with PJ.
Sour cherry–quince smoothies
In quince juice (QJ), which was the base for SCP–QJ smoothies, were detected two groups of polyphenols: hydroxycinnamic acids and flavan-3-ols. Among the hydroxycinnamic acids were identified five compounds: neochlorogenic acid (R t = 3.08 min, [M-H]− at m/z = 353), chlorogenic acid (R t = 4.14 min, [M-H]− at m/z = 353), 4-O-caffeoylquinic acid (R t = 5.22 min, [M-H]− at m/z = 353), 3-p-coumaroylquinic acid (R t = 3.62 min, [M-H]− at m/z = 337), and 2,3-dicaffeoylquinic acid (R t = 7.65 min, [M-H]− at m/z = 515), wherein in the highest concentration was chlorogenic acid (96% total content of hydroxycinnamic acid). Wojdyło et al. (2014c) in their study also detected these compounds in quince juice, but they found neochlorogenic acid to be the dominant component in all quince juices. In addition, in the QJ were determined four flavan-3-ols, the same as in the pear juice, the contents of which were confirmed by Wojdyło et al. (2014c). The totazzzzzzl content of flavan-3-ols (monomer, dimers and polymeric procyanidins) in QJ was 289.18 mg/100 ml of juice.
All SCP–QJ smoothies contained anthocyanins, but the composition varied. The highest content of anthocyanins was observed for products with 80% SCP (122.88 mg/100 g smoothie), then with 50% of SCP (73.80 mg/100 g smoothie), and the lowest was observed in 20% SCP:80% QJ mix (29.75 mg/100 g final products). With the increase of the addition of SCP in smoothie, the content of hydroxycinnamic acids and flavonols also increased: from 161.65 mg to 186.36 mg and from 12.97 mg to 45.73 mg/100 g of smoothies, respectively. Another trend was observed with flavan-3-ols content. It was found that the increase of QJ content in the smoothies resulted in a higher concentration of flavan-3-ols, especially polymeric procyanidins. In the product with 80% QJ there was 247.03 mg > 197.11 mg (50% SCP:50% QJ) > 153.11 mg (20% SCP:80% QJ) flavan-3-ols in 100 g of analysed smoothies. Generally the smoothies based on SCP and QJ were characterized by 4% to 17% higher content of polyphenols than QJ. In addition, in the SCP–QJ smoothies there were higher contents of bioactive compounds than in the SCP–AJ and SCP–PJ smoothies.
Sour cherry–flowering quince smoothies
Based on the LC/MS technique, 12 compounds belonging to polyphenols were detected and identified in the flowering quince juice (FQJ). These can be classified into three groups of phenolic compounds – hydroxycinnamic acids (4), flavonols (4) and flavan-3-ols (4) – which accounted for, respectively, 6, 1 and 93% of total content of polyphenols. Teleszko and Wojdyło (2015), studying phenolic compounds and antioxidant potential in selected edible fruit, also found that in flowering quince flavan-3-ols are dominant groups of polyphenols. Among the tested products, the FQJ was characterized by the highest concentrations of phenolic compounds – 728.67 mg/100 g of juice. It was nearly three times more than in AJ and PJ and two times more compared with QJ. Therefore, the smoothies with SCP and FQJ were characterized by a very interesting polyphenol profile, both qualitatively and quantitatively. Tarko et al. (2014) confirmed that the flowering quince is an excellent raw material for processing, with high bioactive potential, which could be used as a flavouring additive, enriching the quality of the final products. In all SCP–FQJ smoothies 20 polyphenol compounds were detected and identified. These can be classified into four groups: anthocyanins (5), hydroxycinnamic acids (5), flavan-3-ols (4) and flavonols (6). Among the flavonols, one more compound was identified, compared with earlier analysed samples. It was isorhamnetin-3-glucoside-7-rhamnoside with [M-H]− at m/z = 623 and MS/MS fragment at m/z = 315. The conducted analysis showed that all the SCP–FQJ smoothies contained this compound. As in the previously analysed smoothies, quantitative concentration of polyphenols was dependent on the proportion of the individual components used during production of the final product. Therefore, the smoothie with the highest content of SCP was characterized by higher content of hydroxycinnamic acids (155.60 mg/100 g smoothie), flavonols (52.74 mg/100 g smoothie) and anthocyanins (120.94 mg/100 g smoothie). In turn, higher content of FQJ resulted in a higher concentration of flavan-3-ols: 436.39 mg (20% SCP:80% FQJ) > > 299.60 mg (50% SCP:50% FQJ) > > 185.47 mg (80% SCP:20% FQJ). Finally, the total content of polyphenols in SCP–FQJ smoothies ranged from 531.00 mg in 20% SCP:80% FQJ to 401.72 mg in 50% SCP:50% FQJ/100 g final product.
The main advantage of mixing different species of fruit is the high final quality of the obtained product. Mixing fruit with different polyphenolic profiles contributes to diversity of the chemical composition, improving the nutritional value and healthy properties of the final products. This was confirmed by Balaswamy et al. (2013), who studied smoothies containing purees and juices of pineapple, banana, grapes, pomegranate, and mango.
Antioxidant activity in obtained smoothies
Antioxidant activity of analysed smoothies was evaluated based on three different methods—the ABTS method, ferric reducing/antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC)—and is presented in Table 3. All of them showed the same trends between obtained products. Among the analysed semi-products the highest antioxidant activity was determined in FQJ: 6.41 mmol TE/100 ml by the ABTS method; 2.89 mmol TE/100 ml by the FRAP method; and 7.47 mmol TE/100 ml of juice by the ORAC method. In contrast, the lowest antioxidant activity characterized AJ and PJ, respectively: 0.55 and 0.54 mmol TE (ABTS); 0.33 and 0.17 mmol TE (FRAP), and 0.37 and 0.58 mmol TE (ORAC) in 100 ml of juice. Therefore, the smoothies prepared on the basis of apple and pear juice were characterized by the lowest antioxidant activity. In these products antioxidant activity (ABTS) ranged from 2.83 mmol TE/100 g smoothie (20% SCP:80% PJ) to 3.50 mmol/100 g smoothie with 80% SCP. Smoothies with the highest antioxidant activity were SCP–FQJ. The highest value was determined in 100 g of 50% SCP:50% FQJ (12.67 mmol TE), then in 80% SCP:20% FQJ (9.07 mmol TE), and 20% SCP:80% FQJ (6.87 mmol TE/100 g).
Table 3.
Effect of mixing different kinds of fruit juice with sour cherry puree on antioxidant activity (mmol TE/100 g of in final product)
| Product composition | Type of product | ABTS | FRAP | ORAC |
|---|---|---|---|---|
| SCP | Puree | 5.71 ± 0.216d7 | 2.82 ± 0.08ab | 3.57 ± 0.09b |
| AJ | Juice | 0.55 ± 0.02h | 0.33 ± 0.00e | 0.37 ± 0.02d |
| 80% SCP ÷ 20% AJ | Smoothie | 4.85 ± 0.28e | 1.72 ± 0.16c | 2.78 ± 0.14bc |
| 50% SCP ÷ 50% AJ | 5.71 ± 0.23d | 1.80 ± 0.04d | 3.14 ± 0.03bc | |
| 20% SCP ÷ 80% AJ | 4.49 ± 0.22e | 0.98 ± 0.04de | 1.69 ± 0.15c | |
| PJ | Juice | 0.54 ± 0.03h | 0.17 ± 0.00e | 0.58 ± 0.02d |
| 80% SCP ÷ 20% PJ | Smoothie | 3.50 ± 0.45f | 0.61 ± 0.38de | 3.97 ± 0.07b |
| 50% SCP ÷ 50% PJ | 3.43 ± 0.38f | 0.37 ± 0.03de | 2.31 ± 0.01bc | |
| 20% SCP ÷ 80% PJ | 2.83 ± 0.13g | 0.22 ± 0.02e | 1.75 ± 0.02c | |
| QJ | Juice | 3.24 ± 0.09fg | 0.68 ± 0.01e | 1.36 ± 0.04c |
| 80% SCP ÷ 20% QJ | Smoothie | 5.04 ± 0.01h | 1.93 ± 0.03bc | 4.61 ± 0.12b |
| 50% SCP ÷ 50% QJ | 4.64 ± 0.16e | 1.17 ± 0.04d | 2.76 ± 0.04bc | |
| 20% SCP ÷ 80% QJ | 2.70 ± 0.20e | 1.48 ± 0.10d | 2.36 ± 0.02bc | |
| FQJ | Juice | 6.41 ± 0.05c | 2.89 ± 0.02de | 7.47 ± 0.05a |
| 80% SCP ÷ 20% FQJ | Smoothie | 9.07 ± 0.28b | 2.18 ± 0.34bc | 5.15 ± 0.04ab |
| 50% SCP ÷ 50% FQJ | 12.67 ± 0.92a | 3.32 ± 0.91a | 8.26 ± 0.48a | |
| 20% SCP ÷ 80% FQJ | 6.87 ± 0.10c | 2.77 ± 0.17de | 6.71 ± 0.05ab |
SCP sour cherry puree, AJ apple juice, PJ pear juice, QJ quince juice, FQJ flowering quince juice
Mean value (three repetitions) ± SD. Mean values followed by different letters are statistically different at p < 0.05
The results suggest that antioxidant activity of the smoothies is related to the presence of total polyphenols (Pearson correlation = 0.448, 0.690, and 0.656 for ABTS, FRAP, and ORAC, respectively). Significant positive correlations were also found between the results of total antioxidant activity and polymeric procyanidins (Pearson correlation = 0.502, 0.620, and 0.784 for ABTS, FRAP, and ORAC, respectively). It was confirmed by other authors, who suggest that not only the total content of polyphenolic compounds, but primarily the type of phenolic compounds played a very important role in antioxidant activity (Ou et al. 2002; Toydemir et al. 2013; Wojdyło et al. 2014b). In addition, it was observed, that antioxidant activity of 50% SCP:50% FQJ smoothie was higher than those of SCP and FQJ separately. It was probably caused by the synergistic effect of some polyphenols or other compounds (vitamins, minerals, pectins, acids) found in sour cherry and flowering quince fruits. Generally, it is very interesting effect, which requires additional studies.
Vitamin C content
Analysing the vitamin C content, the tested products can be divided into two major groups. The content of vitamin C was very low (<1 mg/100 g of smoothies), and among these were SCP–AJ and SCP–QJ smoothies, including semi-products and SCP. In the second were products with a higher content of vitamin C, including SCP–PJ and SCP–FQJ smoothies. The content of vitamin C in SCP–PJ ranged from 5.39 mg (80% SCP:20% PJ) to 19.41 mg (20% SCP:80% PJ) in 100 g of product. High content of vitamin C in SCP–PJ smoothies was due to the addition of L-ascorbic acid solution to pear fruit while shredding, to prevent enzymatic browning. In turn, flowering quince was a rich source of vitamin C, so in the products with addition of FQJ content of vitamin C ranged from 6.71 to 40.22 mg/100 g of products, depending on the amount of FQJ. Based on the results of the study, a significant correlation was only found between the antioxidant activity measured by the ORAC method and vitamin C content (Pearson correlation = 0.563). In the case of the other methods, ABTS and FRAP, these relationships were 0.242 and 0.303, respectively.
Physicochemical parameters of smoothies
The main physicochemical characteristics of obtained smoothies were evaluated in this study. Differences were found among the analysed mixed fruit products in total titratable acidity, pectins, soluble solids, sugar content and also viscosity and colour parameters (Tables 4, 5).
Table 4.
Chemical composition of analyzed smoothies, juices and puree
| Product composition | Type of product | TA | Pectins | Vitamin C | SS | Sugar content | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Arabinose | Fructose | Sorbitol | Glucose | Sucrose | Total | ||||||
| SCP | Puree | 1.88 ± 0.01ea | 0.72 ± 0.13a | 0.58 ± 0.03i | 13.75 ± 0.07b | nd | 3.06 ± 0.04i | 0.91 ± 0.02d | 5.27 ± 0.21a | nd | 9.24 ± 0.27d |
| AJ | Juice | 0.50 ± 0.01 l | 0.15 ± 0.01c | 0.59 ± 0.00i | 14.10 ± 0.00a | nd | 7.74 ± 0.01a | 0.00 ± 0.00l | 2.87 ± 0.11e | 1.37 ± 0.08a | 11.98 ± 0.20a |
| 80% SCP ÷ 20% AJ | Smoothie | 1.61 ± 0.02f | 0.56 ± 0.01ab | 0.61 ± 0.01i | 13.45 ± 0.07bc | nd | 3.80 ± 0.00 g | 0.67 ± 0.01fg | 4.37 ± 0.04c | nd | 8.84 ± 0.05d |
| 50% SCP ÷ 50% AJ | Smoothie | 1.23 ± 0.01g | 0.53 ± 0.11ab | 0.73 ± 0.21i | 13.50 ± 0.00bc | nd | 5.57 ± 0.00c | 0.56 ± 0.03hi | 4.38 ± 0.13c | nd | 10.51 ± 0.16b |
| 20% SCP ÷ 80% AJ | Smoothie | 0.75 ± 0.04i | 0.14 ± 0.04c | 0.90 ± 0.01i | 13.40 ± 0.00bc | nd | 6.26 ± 0.11b | 0.36 ± 0.00j | 3.86 ± 0.00d | 0.09 ± 0.00c | 10.57 ± 0.11b |
| PJ | Juice | 0.38 ± 0.01l | 0.63 ± 0.20a | 29.87 ± 1.24c | 13.05 ± 0.07d | nd | 5.50 ± 0.06c | 1.75 ± 0.00a | 1.14 ± 0.02h | 0.81 ± 0.05b | 9.21 ± 0.13d |
| 80% SCP ÷ 20% PJ | Smoothie | 1.57 ± 0.06f | 0.61 ± 0.10a | 5.39 ± 0.09h | 13.40 ± 0.00bc | nd | 4.11 ± 0.17f | 1.09 ± 0.06c | 4.62 ± 0.01b | nd | 9.82 ± 0.24c |
| 50% SCP ÷ 50% PJ | Smoothie | 1.13 ± 0.02h | 0.57 ± 0.26ab | 18.10 ± 0.08f | 13.25 ± 0.07cd | nd | 4.88 ± 0.14e | 1.50 ± 0.02b | 3.83 ± 0.04d | nd | 10.21 ± 0.20bc |
| 20% SCP ÷ 80% PJ | Smoothie | 0.68 ± 0.00j | 0.61 ± 0.16a | 19.41 ± 0.04e | 13.35 ± 0.07bc | nd | 5.14 ± 0.00d | 1.46 ± 0.11b | 2.59 ± 0.0f | nd | 9.19 ± 0.11d |
| QJ | Juice | 0.50 ± 0.01k | 0.30 ± 0.11bc | 0.76 ± 022i | 8.80 ± 0.00h | 0.07 ± 0.01a | 3.86 ± 0.00g | 0.61 ± 0.00hi | 0.65 ± 0.01i | nd | 5.12 ± 0.02h |
| 80% SCP ÷ 20% QJ | Smoothie | 1.62 ± 0.01f | 0.61 ± 0.11a | 0.59 ± 0.01i | 12.40 ± 0.00e | nd | 3.04 ± 0.12i | 0.88 ± 0.02de | 4.39 ± 0.01c | nd | 8.31 ± 0.15e |
| 50% SCP ÷ 50% QJ | Smoothie | 1.21 ± 0.00g | 0.55 ± 0.01ab | 0.59 ± 0.01i | 10.80 ± 0.00f | 0.03 ± 0.00b | 2.94 ± 0.04i | 0.72 ± 0.00fg | 2.42 ± 0.00f | nd | 6.08 ± 0.04g |
| 20% SCP ÷ 80% QJ | Smoothie | 0.79 ± 0.02i | 0.27 ± 0.06c | 0.58 ± 0.01i | 9.50 ± 0.00g | 0.06 ± 0.01ab | 3.52 ± 0.00h | 0.76 ± 0.10ef | 2.01 ± 0.00g | nd | 6.30 ± 0.11g |
| FQJ | Juice | 3.91 ± 0.01a | 0.10 ± 0.03c | 48.25 ± 0.95a | 7.80 ± 0.00i | nd | 0.12 ± 0.00m | 0.07 ± 0.00l | 0.09 ± 0.02j | nd | 0.27 ± 0.02k |
| 80% SCP ÷ 20% FQJ | Smoothie | 2.43 ± 0.05d | 0.62 ± 0.01a | 6.71 ± 0.24g | 12.45 ± 0.07e | nd | 2.32 ± 0.00j | 0.71 ± 0.03fg | 3.99 ± 0.06d | nd | 7.03 ± 0.09f |
| 50% SCP ÷ 50% FQJ | Smoothie | 2.96 ± 0.01c | 0.60 ± 0.14a | 25.20 ± 0.49d | 10.90 ± 0.00f | nd | 1.60 ± 0.01k | 0.52 ± 0.07i | 2.43 ± 0.05f | nd | 4.55 ± 0.13i |
| 20% SCP ÷ 80% FQJ | Smoothie | 3.65 ± 0.01b | 0.16 ± 0.08c | 40.22 ± 0.00b | 9.40 ± 0.00g | nd | 0.42 ± 0.01l | 0.21 ± 0.01k | 0.78 ± 0.00i | nd | 1.40 ± 0.02j |
TA titratable acidity [g of malic acid/100 g products], pectins [g/100 g products]; Viatmin C [mg/100 g products]; SS soluble solids [° Brix]; sugar content [g/100 g products]; SCP sour cherry puree, AJ apple juice, PJ pear juice, QJ quince juice, FQJ flowering quince juice
Mean value (three repetitions) ± SD followed by different letters are statistically different at p < 0.05
Table 5.
Viscosity and colour parameters of analyzed smoothies, juices and puree
| Product composition | Type of product | Viscosity | Colour parameters | |||
|---|---|---|---|---|---|---|
| L* | a* | b* | ∆E | |||
| SCP | Puree | 288a ab | 32.09de | 20.10de | 5.79d | − |
| AJ | Juice | 12m | 35.78b | 0.35g | 5.03d | 20.11 |
| 80% SCP ÷ 20% AJ | Smoothie | 228c | 32.61de | 20.75d | 6.03cd | 0.87 |
| 50% SCP ÷ 50% AJ | Smoothie | 156g | 32.23de | 20.32d | 6.58bc | 0.83 |
| 20% SCP ÷ 80% AJ | Smoothie | 24k | 35.89b | 21.71c | 8.17a | 4.76 |
| PJ | Juice | 16l | 53.58a | −3.41i | 2.66e | 32.00 |
| 80% SCP ÷ 20% PJ | Smoothie | 245b | 32.56de | 21.63c | 6.49bc | 1.75 |
| 50% SCP ÷ 50% PJ | Smoothie | 168f | 33.66cd | 22.31b | 6.78bc | 2.89 |
| 20% SCP ÷ 80% PJ | Smoothie | 46j | 36.22b | 22.13b | 6.55bc | 4.66 |
| QJ | Juice | 18l | 31.05e | 0.66g | 2.38e | 19.76 |
| 80% SCP ÷ 20% QJ | Smoothie | 192e | 32.33de | 20.79d | 6.40bc | 0.95 |
| 50% SCP ÷ 50% QJ | Smoothie | 120i | 32.66de | 19.45e | 5.40d | 0.95 |
| 20% SCP ÷ 80% QJ | Smoothie | 26k | 32.27de | 16.70f | 4.86d | 3.53 |
| FQJ | Juice | 18l | 36.78b | −1.46h | 4.36d | 22.11 |
| 80% SCP ÷ 20% FQJ | Smoothie | 216d | 32.60de | 22.22b | 6.97b | 2.48 |
| 50% SCP ÷ 50% FQJ | Smoothie | 150h | 33.57cd | 23.39a | 7.51ab | 4.00 |
| 20% SCP ÷ 80% FQJ | Smoothie | 26k | 35.00bc | 23.67a | 8.20a | 5.20 |
Viscosity [mPas], L* lightness, a* indicates red for positive value and green for negative value, b indicates yellow for positive value and blue for negative value, SCP sour cherry puree, AJ apple juice, PJ pear juice, QJ quince juice, FQJ flowering quince juice
aValues are means of three repetitions
bMean values followed by different letters are statistically different at p < 0.05
The highest content of titratable acidity was determined in smoothies with addition of FQJ. The titratable acidity in these products ranged from 2.43% in the smoothies with the lowest addition of FQJ to 3.65% in the case of the 20% SCP:80% FQJ smoothie. In other samples, content of malic acid was at a comparable level, from 0.70 to 1.60, and was positively correlated with the amount of SCP. Both sour cherry and flowering quince were characterized by a high content of acids (Tarko et al. 2014; Wojdyło et al. 2014b); therefore these two semi-products resulted in final acidity of smoothies.
Interesting results were obtained by analysing the sugar content of the smoothie products. The studies showed that mixing the various fruits can be used to design specific quality values of the final product. For example, the addition of AJ to SCP enriched the final product in sucrose, while the QJ enriched smoothies in arabinose. Generally, the highest sugar content was determined in SCP–AJ and SCP–PJ smoothies (average 10%). In contrast, the lowest content of sugar characterized FQJ products (from 1.40 to 7.03%). The soluble solids value depend on the content of non-volatile organic acids (malic, citric, or tartaric acids), but first of all on the total sugar content. Therefore, the highest content of soluble solids was found in the smoothies with addition of AJ and PJ. In all these products the soluble solids had a sugar content of more than 13°Bx. In turn, the higher contribution of QJ and FQJ resulted in a decrease of the soluble solids value.
One compound which determines the nutritional value of the fruit is pectin. Pectin is one form of soluble fibre responsible for the prevention of obesity, diabetes and cardiovascular disease (Tetens and Alinia 2009). In the analysed products content of pectins ranged from 0.10% (FQJ) to 0.72% (SCP). It was observed that the highest content of SCP, and thereby contribution of solids content, affects the increase of pectins. Thus the smoothies were characterized by a higher content of soluble fibre than juice (semi-products of smoothies).
In this study, was also determined viscosity, which is influenced by the presence of solid particles and their size. Therefore, purees have a higher value of this factor than do juices. The study confirmed this relationship. It has been shown that the SCP was characterized by the highest viscosity: 287.90 mPa·s. Generally, it was possible to discriminate two groups of products. The first of them comprised SCP and smoothies with 80 and 50% contribution of puree. In these smoothies was observed higher viscosity from 120 (50% SCP:50% QJ) to 245 (80% SCP:20% PJ) mPa·s. In the second group were liquid juices and smoothies with 20% addition of SCP. The viscosity in these products ranged from 12 (AJ) to 46 (20% SCP:80% PJ) mPa·s. Another quality parameter, analysed in the resulting products, was colour. The three main determinants of colour: lightness (L*), redness (a*), and yellowness (b*) were tested (Table 5). The studies showed that the colour of the mixed fruit products differed significantly.
The value of L* ranged from 31.05 (QJ) to 53.58 (PJ). Therefore, the smoothies with addition of PJ were the brightest, while the addition of QJ caused a decrease in the brightness of the smoothies. In the case of the a* parameter, which is responsible for the red colour of samples, the greatest decrease was observed in the smoothies supplemented with QJ (from 16.70 to 20.79). In contrast, the most intense red colour was found in the SCP–FQJ smoothies; the value of a* ranged from 22.22 (80% SCP:20% FQJ) to 23.67 (20% SCP:80% FQJ). This trend was probably due to the very low pH of the FQJ that stabilized the content of polyphenols, especially anthocyanins, by inhibiting their oxidation. A similar effect was observed in new products obtained by osmotic dehydration of sour cherry fruits in FQJ juice (Nowicka et al. 2015).
In general, the studies showed that the physicochemical parameters depend on the amount and type of compounds used for the production of smoothies.
Principal component analysis (PCA)
To better understand the relationship and trends among the smoothies, principal component analysis (PCA) was applied (Fig. 1). When considering the first two dimensions of the biplot (PCA1 and PCA2), bioactive compounds and physicochemical parameters explained 65.35% of the variation. The results obtained from PCA indicated the presence of four main clusters. The first contained smoothies with 50% (16) and 80% (17) addition of FQJ, characterized by the high content of polymeric procyanidins (PP), titratable acidity (TA) and also high total antioxidant activity measured by ORAC, ABTS and FRAP methods. The second cluster contained QJ (10), FQJ (14) and smoothies with 80% QJ (13). These products were positively correlated with monomer and dimer flavan-3-ols (mF3ol) and vitamin C (Vit C) content. In the third group were AJ (2) and smoothie with 80% (5) addition of AJ and also PJ (6) and its smoothies: 50% SCP:50% PJ (8) and 20% SCP:80% PJ (9). They were characterized by high content of hydroxycinnamic acids (HA), total sugar (TS) and soluble solids (SS), but also were the brightest (L*). The fourth cluster contained SCP (1), and all the smoothies with 80% contain SCP (3, 7, 11, 15), except for the 50% SCP:50% AJ smoothie (4) and 50% SCP:50% QJ (12). In these products high contents of flavonols (F), anthocyanins (Ant) and pectins (P) were found. In addition, samples in the fourth group were characterized by high viscosity, redness (a*), yellowness (b*) and a positive correlation with antioxidant activity.
Fig. 1.
PCA map showing the relationship among the physicochemical profile and smoothies, juices and puree. 1 sour cherry puree (SCP); 2 apple juice (AJ); 3 smoothie (80% SCP÷20% AJ); 4 smoothie (50% SCP÷50% AJ); 5 smoothie (20% SCP÷80% AJ); 6 pear juice (PJ); 7 smoothie (80% SCP÷20% PJ); 8 smoothie (50% SCP÷50% PJ); 9 smoothie (20% SCP÷80% PJ); 10 quince juice (QJ); 11 smoothie (80% SCP÷20% QJ); 12 smoothie (50% SCP÷50% QJ); 13 smoothie (20% SCP÷80% QJ); 14 flowering quince juice (FQJ); 15 smoothie (80% SCP÷20% FQJ); 16 smoothie (50% SCP÷50% FQJ); 17 smoothie (20% SCP÷80% FQJ); mF3ol–flavan-3-ols (monomeric and dimeric). VitC Vitamin C, PP polymeric procyanidins, HA hydroxycinnamic acids, F flavonols, Ant anthocyanins, TS total sugar, SS soluble solids, P pectins, L* lightness, a* redness, b* yellowness, TA titratable acidity
Figure 1 also presents the directions of changes of quality and quantitative parameters in the tested products. It was observed that all the products with 80% SCP were in the same cluster—number 4. Increasing the content of juices in the final smoothies significantly affected the properties of the products and hence also their spatial position in the space defined by two dimensions of the biplot (PCA1 and PCA2). Thus, it was confirmed that mixing of fruit allows one to obtain smoothies with pre-designed properties.
Conclusion
The study showed that the use of SCP in the production of smoothies affected product attractiveness in terms of physicochemical properties and antioxidant activity. Mixing fruit with each other especially determined the content of bioactive compounds in the final product. The addition of SCP to QJ, AJ, FQJ and PJ enriched smoothies with anthocyanins, hydroxycinnamic acids and flavonols. A particularly interesting polyphenol profile characterized smoothies with flowering quince, where were detected 20 different compounds. In these products were also found the highest content of total polyphenols, and antioxidant activity. Analysing the other sour cherry products with AJ, PJ and QJ demonstrated that increasing the proportion of SCP increased the polyphenol content and activity of final smoothies.
There are not many reports on the effects of mixing different fruit products on the content of bioactive compounds and antioxidant activity in the final product. Despite this, the present study showed that mixing various fruit products could be interesting from a nutritional as well as commercial perspective. A detailed analysis of similar products and their promotion is extremely important to increase the range of food products with high nutritional value.
Acknowledgements
This work was financially supported by the National Science Centre UMO-2011/01/B/NZ9/07139. Publication supported by Wroclaw Centre of Biotechnology, programme The Leading National Research Centre (KNOW) for years 2014–2018.
References
- Balaswamy K, Prabhakara Rao PG, Nagender A, Narsing Rao G, Sathiya Mala K, Jyothirmayi T. Development of smoothies from selected fruit pulps/juices. IFRJ. 2013;20(3):1181–1185. [Google Scholar]
- Benzie IFF, Strain JJ. The ferric reducing ability of plasma (FRAP) as a measure of“antioxidant power”: the FRAP assay. Anal Biochem. 1996;239:70–76. doi: 10.1006/abio.1996.0292. [DOI] [PubMed] [Google Scholar]
- Corbo MR, Bevilacqua A, Petruzzi L, Casanova FP, Sinigaglia M. Functional beverages: the emerging side of functional foods. Commercial trends, research, and health implications. CRFSFS. 2014;13:1192–1206. [Google Scholar]
- Cuthbertson D, Andrews PK, Reganold JP, Davies NM, Lange BM. Utility of metabolomics toward assessing the metabolic basis of quality traits in apple fruit with an emphasis on antioxidants. J Agric Food Chem. 2012;60(35):8552–8560. doi: 10.1021/jf3031088. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Damar I, Ekşi A. Antioxidant capacity and anthocyanin profile of sour cherry (Prunus cerasus L.) juice. Food Chem. 2012;135:2910–2914. doi: 10.1016/j.foodchem.2012.07.032. [DOI] [PubMed] [Google Scholar]
- Francini A, Sebastiani L. Review. Phenolic compounds in apple (Malus x domestica Borkh.): compounds characterization and stability during postharvest and after processing. Antioxidants. 2013;2:181–193. doi: 10.3390/antiox2030181. [DOI] [PMC free article] [PubMed] [Google Scholar]
- González-Molina E, Gironés-Vilaplana A, Mena P, Moreno DA, García-Viguera C. New beverages of lemon juice with elderberry and grape concentrates as a source of bioactive compounds. J Food Sci. 2012;77(6):C727–C7233. doi: 10.1111/j.1750-3841.2012.02715.x. [DOI] [PubMed] [Google Scholar]
- Kennedy JA, Jones GP. Analysis of proanthocyanidin cleavage products following acid-catalysis in the presence of excess phloroglucinol. J Agric Food Chem. 2001;49:1740–1746. doi: 10.1021/jf001030o. [DOI] [PubMed] [Google Scholar]
- Kirakosyan A, Seymour EM, Urcuyo Llanes DE, Kaufman PB, Bolling SF. Chemical profile and antioxidant capacities of tart cherry products. Food Chem. 2009;115:20–25. doi: 10.1016/j.foodchem.2008.11.042. [DOI] [Google Scholar]
- Kolniak-Ostek J, Oszmiański J. Characterization of phenolic compounds in different anatomical pear (Pyrus communis L.) parts by ultra-performance liquid chromatography photodiode detector-quadrupole/time of flight-mass spectrometry (UPLC-PDA-Q/TOF-MS) Int J Mass Spectrom. 2015;392(3):154–163. doi: 10.1016/j.ijms.2015.10.004. [DOI] [Google Scholar]
- Kołodziejczyk K, Sójka M, Abadias M, Vinas I, Guyot S, Baron A. Polyphenol composition, antioxidant capacity, and antimicrobial activity of the extracts obtained from industrial sour cherry pomace. Ind Crop Prod. 2013;51:279–288. doi: 10.1016/j.indcrop.2013.09.030. [DOI] [Google Scholar]
- Nowicka P, Wojdyło A. Stability of phenolic compounds, antioxidant activity and colour through natural sweeteners addition during storage of sour cherry puree. Food Chem. 2015;196:925–934. doi: 10.1016/j.foodchem.2015.10.019. [DOI] [PubMed] [Google Scholar]
- Nowicka P, Wojdyło A, Lech K, Figiel A. Chemical composition, antioxidant capacity, and sensory quality of dried sour cherry fruits pre-dehydrated in fruit concentrates. Food Bioprocess Tech. 2015;8:2076–2095. doi: 10.1007/s11947-015-1561-5. [DOI] [Google Scholar]
- Ou B, Huang D, Hampsch-Woodill M, Flanagan JA, Deemer EK. Analysis of antioxidant activities of common vegetables employing oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) assay: a comparative study. J Agric Food Chem. 2002;50:3122–3128. doi: 10.1021/jf0116606. [DOI] [PubMed] [Google Scholar]
- Pijanowski E, Mrożewski S, Horubała A, Jarczyk A. Technologia produktów owocowych i warzywnych. 3. PWRiL: Warszawa; 1973. [Google Scholar]
- Re R, Pellegrini N, Proteggente A, Pannala A, Yang M, Rice-Evans C. Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radic Biol Med. 1999;26(9/10):1231–1237. doi: 10.1016/S0891-5849(98)00315-3. [DOI] [PubMed] [Google Scholar]
- Repajić M, Kovačević DB, Putnik P, Dragović-Uzelac V, Kušt J, Čošić Z, Levaj B. Influence of processing on sour cherry polyphenols in concentrated sour cherry (Prunus cerasus L.) juice. Food Technol Biotech. 2015;53(2):215–222. doi: 10.17113/ftb.53.02.15.4151. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sabbe S, Verbeke W, Damme PV. Analysing the market environment for acai (Euterpe oleracea Mart.) juices in Europe. Fruits. 2009;64(5):273–284. doi: 10.1051/fruits/2009022. [DOI] [Google Scholar]
- Tarko T, Duda-Chodak A, Satora P, Sroka P, Pogoń P, Machalica J. Chaenomeles japonica, Cornus mas, Morus nigra fruits characteristics and their processing potential. J Food Sci Technol. 2014;51(12):3934–3941. doi: 10.1007/s13197-013-0963-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Teleszko M, Wojdyło A. Comparison of phenolic compounds and antioxidant potential between selected edible fruits and their leaves. J Funct Foods. 2015;14:736–746. doi: 10.1016/j.jff.2015.02.041. [DOI] [Google Scholar]
- Tetens I, Alinia S (2009) The role of fruit consumption in the prevention of obesity. J Hortic Sci Biotech ISAFRUIT Special Issue 47–51
- Toydemir G, Capanoglu E, Gomez Roldan MV, De Vos RCH, Boyacioglu D, Hall R. Industrial processing effects on phenolic compounds in sour cherry (Prunus cerasus L.) fruit. Food Res Int. 2013;53:218–225. doi: 10.1016/j.foodres.2013.04.009. [DOI] [Google Scholar]
- Vrhovsek U, Rigo A, Tonon D, Mattivi F. Quantitation of polyphenols in different apple varieties. J Agric Food Chem. 2004;52(21):6532–6538. doi: 10.1021/jf049317z. [DOI] [PubMed] [Google Scholar]
- Wojdyło A, Oszmiański J, Laskowski P. Polyphenolic compounds and antioxidant activity of new and old apple varieties. J Agric Food Chem. 2008;56(15):6520–6530. doi: 10.1021/jf800510j. [DOI] [PubMed] [Google Scholar]
- Wojdyło A, Figiel A, Lech K, Nowicka P, Oszmiański J. Effect of convective and vacuum–microwave drying on the bioactive compounds, color, and antioxidant capacity of sour cherries. Food Bioprocess Tech. 2014;7:829–841. doi: 10.1007/s11947-013-1130-8. [DOI] [Google Scholar]
- Wojdyło A, Nowicka P, Laskowski P, Oszmiański J. Evaluation of sour cherry (Prunus cerasus L.) fruits for their polyphenol content, antioxidant properties and nutritional components. J Agric Food Chem. 2014;62(51):12332–12345. doi: 10.1021/jf504023z. [DOI] [PubMed] [Google Scholar]
- Wojdyło A, Teleszko M, Oszmiański J. Antioxidant property and storage stability of quince juice phenolic compounds. Food Chem. 2014;152:261–270. doi: 10.1016/j.foodchem.2013.11.124. [DOI] [PubMed] [Google Scholar]
- Zorić Z, Dragović-Uzelac V, Pedisić S, Kurtanjek Z, Garofulić IE. Kinetics of the degradation of anthocyanins, phenolic acids and flavonols during heat treatments of freeze-dried sour cherry Marasca Paste. Food Technol Biotech. 2014;52(1):101–108. [Google Scholar]