Establishment Of Quality Evaluation System And Key Database Of Table Grape

Grapes are widely used,which are mainly categorized into fresh-eating,wine-making and dry-making types.However,grapes belong to storage-intolerant fruits.Postharvest quality will affect their subsequent processing and consumption,resulting in uneven eating quality,especially table grapes.Therefore,it is particularly important to evaluate the quality of table grapes.In this study,the typical table grapes on the market were used as test materials.Through the detection of 24 quality indicators and sensory evaluation analysis,combined with the variability,correlation analysis,multiple linear regression analysis,principal component analysis and cluster analysis.The quality evaluation index,evaluation system and evaluation criteria of table grapes were also studied.Based on the basic information of table grapes,the key database system of table grapes quality was preliminarily explored.The main results are as follows:(1)From the appearance of grapes,fruits showed many characteristics such as oblate,round and so on.There were significant differences in fruit shape index and weight(P<0.05).The L value were in the range of 24.92 to 61.96,the a value increased gradually with the grape color from yellow to purple-black.The texture characteristics of different grapes were significantly different(P<0.05).The texture characteristics of Red Globe and Black Grape were higher than those normal grapes such as Centennial Seedless.In the comparison of edible quality,there was no significant difference in water content(P>0.05).The content of soluble solids and titratable acid showed significant difference(P<0.05),and sugar-acid ratio was at a higher level.The content of tannin in Jingya was the highest,which was 105.91 mg/100g.In the comparison of nutritional quality,The content of vitamin C and flavone in Jingya and Shine-Muscat was higher than that in other varieties(P<0.05).The total phenol content ranged from 563.56 to 1149.20 OD280·g-1,and the anthocyanin content ranged from 4.26 to 424.59(OD530-OD600)·g-1.The main organic acids were tartaric acid and L-malic acid,the difference was not significant(P>0.t05).(2)In the related studies based on sensory characteristics and indicators,the coefficients of variation of anthocyanin,citric acid and hardness were exceeded 45%,which were the main factors that affected the quality difference of different grapes.The correlation analysis showed that there was a significant positive correlation between hardness,elasticity,chewiness,resilience,viscosity,single fruit weight and fruit shape index(r=0.626?0.912,P<0.01).Through multiple linear regression analysis,the linear relationship between sensory comprehensive score and detection index was determined as follows:Comprehensive sensory score =65.769+0.576×Tartaric acid +0.436×Chewiness+0.433×L(R=0.903)?Fifteen quality evaluation indexes,including L-malic acid,citric acid and titratable acid,were determined by combining coefficient of variation and correlation analysis.(3)Principal component analysis showed that four principal components were extracted out included flavor,texture,function and color,which could explain 87.118%of the original variables.The principal component comprehensive value was used as the overall evaluation index of table grapes,and it was positively correlated with the comprehensive evaluation score of sensory organs(r=0.703,P<0.01).According to the comprehensive score of principal components,22 kinds of table grapes were classified into four grades:Black Grape and Jingya in Grade ?,Golden Rose and Summer Black in Grade ?,Milk Grape and Shaoxing 1 hao in Grade ?,and Gold Finger and Kyoho Grap in Grade ?.Nine varieties were classified differently from the principal components,and the overall classification results were consistent In the cluster analysis.According to the grading of grape quality and the quality traits of each variety,the evaluation criteria of fresh grape quality were established.Grade ? was characterized by large volume and high hardness.Grade ? had higher content of active ingredients and grade ? had lower soft elasticity.(4)Based on Microsoft Access 2010 database software,the basic database system of table grapes was established.Through this database,the germplasm resource information and physicochemical index information of table grapes can be quickly queried.