Quality analysis and comprehensive evaluation of cherry wine fermented from different cultivars

LIU Hui;LIU Jiechao;LI Jiaxiu;ZHANG Chunling;CHEN Dalei;JIAO Zhonggao;Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences;

Cherry wine;;Quality;;Cluster analysis;;Principal component analysis;;Comprehensive evaluation

【Objective】Sweet cherry(Prunus avium L.) is one of the most popular fruits because it has an exotic flavor and is a nutrient-rich fruit, with abundant sugars, vitamins, amino acids, organic acids and polyphenols. However, it is a highly perishable fruit with difficulty in storage and transportation and thus often processed into juices and wines. The physicochemical properties and nutritional compounds of fruit wines are directly related to the genetic background of the fruits. Nutritional quality analysis and evaluation of cherry wine are important for cherry breeding and comprehensive utilization. This study was conducted to analyze the nutrient quality of cherry wine made from different cultivars, establish an effective method for cherry wine evaluation, find out the key factors influencing the nutrient quality of cherry wine,and select suitable cherry cultivars for wine processing.【Methods】Cherry wines made from 11 cultivars(‘Brooks' ‘Chunxiu'‘Bigarreau Moreau'‘Hongdeng'‘Hongyan'‘Huangmi'‘Sunburst'‘Summit'‘Zaodaguo'‘Zaohongzhu'and‘23-24') were used as materials for detecting 19 processing physicochemical characteristics by conventional descriptive statistics, principal component analysis(PCA) and cluster analysis. The differences among cherry wines were analyzed to screen suitable cherry varieties for processing high quality wine.【Results】The results showed great differences in wine quality characters among different cherry cultivars. Coefficients of variation(CV) of p H and alcohol content were lower than10%, but higher CV values were found in other qualities.‘Zaodaguo'cherry wine was dark-fuchsia and possessed significantly higher contents of total phenols, flavonoids and anthocyannis, with the highest radi-cal scavenging ability(DPPH and ABTs) and ferric reducing antioxidant power(FRAP). PCA is a mathematical method to perform a reduction in data dimensionality and allow visualization of underlying structure in experimental data. Based on the major physical and chemical properties of the wines from 11 cultivars, 3 principal components with eigen value >1.000 were extracted to account for the 17 quality parameters after data conversion, and the cumulative variance contribution rate of the 3 principal factors was85.74%. The variance rate of the first component factor was 57.1% and was related to h value, polyphenolic compounds and antioxidant activities, and was thus considered to be the antioxidant factor. The second principal component was the acidity factor, which was related to vitamin C, volatile acids and total titratable acidity. The third principal component was related to a*value. According to weight index and synthetic evaluation function of the 3 principal factors, the comprehensive evaluation of quality showed significant difference among wines from different cultivars. Wine from‘Zaodaguo'had the highest composite score of 3.792, followed by wines from‘Hongdeng'‘23-24'and‘Zaohongzhu'with score value ranging from 1.039 to 1.650. The higher scores in the wine fermented from these varieties were attributed mainly to richer polyphenols and higher antioxidant capacities. The lowest score was found in the wine from‘Brooks', which had the minimum contents of total phenolics and flavonoids. Polyphenols and antioxidant activities can be used as important indexes for comprehensive evaluation of cherry wine quality. In addition, samples could be grouped on the basis of similarities by cluster analysis based on Euclidean distance. The results displayed 4 well-defined clusters at a Euclidean distance of 5.0, which was consistent with the results of PCA composite score results. Cluster analysis proposed less information than PCA and needed PCA results to assist the evaluation of the advantages and disadvantages of the clusters. In this study,‘Zaodaguo'cherry wine formed one group, possessing the highest antioxidant capacities and most abundant phenolics, flavonoids and anthocyannis, and was thus an excellent cherry cultivar for wine processing.‘Hongdeng',‘23-24'and‘Zaohongzhu'cherry wine could be classified as above-average and were clustered in one group. Wines from‘Chunxiu'‘Bigarreau Moreau'‘Sunburst'‘Summit'‘Hongyan'and‘Huangmi'formed one group, which was considered to be of medium quality.‘Brooks' cherry wine formed the forth group with poor quality.【Conclusion】There were some differences in quality properties of wines among different cultivars. The key factors affecting nutrient quality were the antioxidant ability, hue angle(h), and contents of total phenolics, flavonoids and anthocyannis. These indicators represented the comprehensive cherry wine quality combining appearance, nutrient properties and functional characteristics. The comprehensive evaluation score of‘Zaodaguo'cherry wine was higher than wines from the other cultivars.‘Zaodaguo'‘Hongdeng'‘23-24'and‘Zaohongzhu'could be also be good choices for wine fermentation. However,‘Brooks' was not suitable for wine processing. These results can be used to determine cherry cultivars appropriate for wine processing, and can be used as a guide for cherry breeding.