Research On Quality Evaluation Of Vacuum Freeze-dried Strawberry Powder

Strawberry is popular for its abundant nutrition and sweet flavor.Its annual planted area and output of current China ranks first in the world.However,the comprehensive analysis evaluation research of strawberrry is rarely reported.21 cultivars strawberry collected in this study were planted in Jiangsu Province and the neighboring province,whose 19 physicochemical and nutrition indicators were determined to explore the quality differences between different cultivars,seected out the core quality evaluation indicators of fresh strawberry and establish criteria of the core indicators by means of modern analysis.The 21 cultivars strawberry were processed into strawberry powder via vacuum freeze-dried method at the same time.23 sensory,physicochemical and nutrition of strawberry powder were detected to establish quality evaluation model and criteria of vacuum freeze-dried strawberry powder through comprehensive evaluation method.The aim of the study was to provide theoretical basis for the strawberry cultivars breeding and the quality evaluation of vacuum freeze-dried products.The main research results were summarized as followed:1.The physicochemical and nutrition indicators of different strawberry cultivars have differences in different degree,and most of them differed significantly.But the range of variation of indicators data are acceptable and the outlier is less,which is representative.There exist significant correlations among different indicators.2.Eight core quality evaluation index of strawberry were screened out by correlation analysis,principal component analysis and other statistical analysis method.They are hardness,color a*value,oxalic acid,total antioxidant capacity T-AOC,the content of soluble sugar,malic acid,juice yield and citric acid.Another eight core quality evaluation index of vaccum freeze-dried strawberry powder were screened out by the same way,they are total antioxidant capacity T-AOC,hygroscopicity,color a*value,sweetness,the content of glucose,soluble protein,citric acid and crude fiber.3.Considering the average value of each select core quality evaluation index as the center,the values of them were divided into ?,?,?,and ? four ranks,which was used to establish core quality evaluation criteria of strawberry.4 The weight coefficient of each core indicator of vacuum freeze-dried strawberry powder was determined by Analytic Hierarchy Process(AHP),and the quality evaluation model of the vacuum freeze-dried strawberry powder was established after that:W=0.227052 M1+0.227052 M2+0.227052 M3+0.086825 M4+0.086825 M5+0.086825 M6+0.038829 M7+ 0.019541 M8Where W,M1 to M8 representing comprehensive value,T-AOC hygroscopicity,color a*value,glucose content,sweetness,citric acid content,soluble protein content and crude fiber content;According to evaluation model of vacuum freeze-dried strawberry powder to calculate the total score of each variety,the scores(W)were divided into four levels,W? 0.65 grade I,0.55?W<0.65 grade ?,0.45?W<0.55 grade ?,W<0.45 grade IV.Seventeen strawberry cultivars,Jiazhangji,Jintan 288,A'erbi,Tianzhali,Rongmei,Meng,Xiang,Fenghuang,Shengan'deruisi,Tianbao,Taikong,Fengxiang,Hongyan,Zijinxiangyu,Mingbao,Xiangye and Zhangji were suitable varieties for processing into vacuum freeze-dried strawberry powder based on the scores;Considering the total score of vacuum freeze-dried strawberry powder,the core quality evaluation criteria of vacuum freeze-dried strawberry powder'values were divided into ?,?,?,and ? four ranks.