Study On Establishment Of Quality Evaluation System For Individual Quick Freezing (IQF) Strawberry

Strawberry is rich in nutrient elements and high medicinal value. The strawberry resources and planting scale come up top in the world, but the comprehensive utilization ratio of strawberry is relatively low, that is mainly restricted by evaluation system and deep processing technology. In this paper will provide scientific and efficient of evaluation systems and evaluation method for our country the strawberry in processing varieties of resource utilization and breeding, at the same time in order to screen for quick-frozen processing of raw materials, provide theoretical basis for deep processing of quick-frozen strawberries, the establishment of a comprehensive quality evaluation system for development of strawberry processing industry has important guiding significance.In this study, twelve strawberry cultivars from Liaoning Province in China are chosen as the raw materials, and then processed by individual quick freezing. Fourteen quality parameters of strawberry raw material and twelve parameters of IQF strawberry are analyzed and determined by principal component analysis and correlation analysis, purpose is to screen the core index of strawberry raw materials and quick-frozen strawberry quality.The data is standardized in order to remove the impact of different units, application of analytic hierarchy process (AHP) evaluation for establishing quality index model. The combination of standardization of strawberry material index with comprehensive value of quick-frozen strawberries, and data analysis with IQF values by stepwise regression analysis in order to establish the IQF strawberry quality and raw materials associated model. The purpose is to provides scientific basis and technical support for the strawberry industry and strawberry quality assessment.Through the study of raw materials and the quality of the quick-frozen strawberries strawberry, the conclusions can be summarized as follows:(1) The strawberry raw material quality analysis results show that the quality indexes of 14 in different degree of coefficient of variation among different varieties. Coefficient of variation of L value, crude protein, soluble solids and moisture content are less than 10%, the result shows that four indexes was not significant difference between the varieties. The rest of the ten indicators of variation coefficient is more than 10%, significant difference are found in each quality index data. The results of strawberry material index correlation coefficient analysis showed that there were 105 correlation coefficient, including the 0.05 level has seven significant correlation, four correlation at 0.01 level. The vast majority of indicators had no significant correlation.(2) Six important quality evaluation indicators of strawberry raw material:a value, sugar-acid ratio, anthocyanins, total phenols, Vc and hardness. Analytic hierarchy process (AHP) is used to analyze the core index weights given, in order to set up comprehensive evaluation model of strawberry raw materials:Y= 0.311358×a value+0.311358xsugar-acid ratio+0.167618xhardness+0.06836xanthocyanins+0.057249xtotalphenolx0.084058xVitamin C.Sensory analysis is taken on twelve varieties strawberry raw material. The linear correlation coefficient of 0.9248.(3) IQF strawberry quality index shows that quality indexes of total phenols, soluble sugar and drip loss have a low coefficient of variation (<10%), discrete degree is small. The remaining eight quality index variation coefficients are more than 10%. The correlations of IQF strawberry 12 index shows that 3 correlation coefficient at 0.01 level and 5 correlation coefficient at 0.05 level.(4) Seven important quality evaluation indicators of IQF strawberry:Sugar-acid ratio, a value of fruit color, anthocyanins, total phenols, Vc, hardness and drip loss. Analytic hierarchy process (AHP) is used to analyze the core index weights given, in order to set up comprehensive evaluation model of IQF strawberry:Y= 0.288285 x sugar-acid ratio+0.288285 x a value+0.092462 x anthocyanins+ 0.092083 x total phenols+0.150529 x hardness+0.032088 x drip loss.Sensory analysis is taken on twelve varieties IQF strawberry. The linear correlation coefficient of 0.9106.(5) Quality characteristics of strawberry raw materials and seven core indexes of IQF strawberry have a significant correlation.12 varieties IQF strawberry are chose for establishing IQF strawberry quality and raw materials associated model:Y= 0.851-0.664 x totao phenols-0.497 x sugar-acid ratio+0.295 x moisture content +0.160 x hardness.(6) Quick-frozen effect on aroma:99 and akihime strawberry aldehyde change is most obvious, quick-frozen makes 99 strawberry aldehydes increased obviously and Akihime strawberry aldehyde down significantly. The alcohols of R7,99, and akihime are significantly affected by quick frozen, R7 and akihime are increased obviously,99 strawberry alcohols decreased obviously. Strawberry varieties of All-star, Ever bearers, R7 and Akihime ketone after quick-frozen strawberries have grown significantly, frozen is not significant effects on 99 strawberry ketone.(7) The esters better preserved after IQF processing. Strawberries processed by quick-frozen for five months of ester aroma composition is significantly higher than slow frozen strawberries at the same period. Freezing storage process, the LOX activity deactivation degree of quick-frozen strawberries lower than slow frozen, no significant difference between them, quick-frozen and slow-frozen in the process of the AAT and ADH activity and gene expression keep lower level, may be associated with the ester aroma of strawberry aroma becomes weak.