Study On Suspension Evaluation And Storage Quality Of Apple Juice

Based on the fact that China’s apple has a huge acreage and yield,and apple is widely used in the apple juice industry,the establishment of an accurate,reasonable and scientific evaluation model of apple juice quality is not only beneficial to China’s comprehensive utilization of apples,but also more It is beneficial to the health and sustainable development of the apple juice industry.The browning reaction often occurs during the storage of fruit juices.The browning of juices will not only cause adverse changes in the color and aroma of the juices,but also cause the loss of nutrients,thereby reducing the commercial value and shelf life of the juices.The change of internal quality is of great significance for reducing and inhibiting the browning of juice.This paper intends to select 21 representative varieties from seven major apple producing areas in China,and systematically determine the quality indexes of different types of apple juice.The method of stepwise linear discriminant analysis was used to analyze whether the quality indicators based on apple turbid juice could reflect the differences between different varieties and different producing areas.The apple processing,physicochemical and nutrient quality indicators of apple juice were measured and analyzed with a series of data.Among the “similar” indicators,more representative quality indicators were selected,weight values were assigned to them,and an evaluation model was constructed.Thus,the apple varieties with “better”,“medium” and “poor” juice quality were selected.For these selected apple varieties with different juice quality,the changes of color,browning degree,polyphenols,ascorbic acid,amino acids,sugar and other indicators of the fruit juice under different storage conditions were studied,revealing the quality of apple juice after storage.The causes and mechanisms of deterioration.The main findings are as follows:1.Based on the quality indicators of apple turbid juice varieties and origin differences analysis Twenty-five quality indicators of apple turbid juice were measured,stepwise linear discriminant analysis was used to process the data,and a 3D map was drawn.The results showed that different types of apple turbid juices had discrete distributions due to large differences in color quality indicators such as browning degree,total phenolics,antioxidants,and nutritional quality indicators such as sugar and acid.However,for the samples from different production areas,the turbidity,titratable acid,soluble solids and other processing quality indicators have great differences,and their samples are scattered in the map.For different samples in the dominant producing areas of Shandong Province and different samples of the dominant strain Fuji,the samples showed large differences,and the discriminant accuracy was 77.8% and 72.7%,respectively.2.Difference analysis of apple turbid juice varieties and origin based on amino acid content The amino acid composition and content of the apple cloudy juice were determined,and the data was processed using a stepwise linear discriminant analysis method,and a 3D map was drawn.The results showed that the variation coefficients of alanine,leucine,serine,proline,and isoleucine were relatively large in the samples of apple turbid juices of different varieties,and the distribution was discrete in the figure.However,for the samples from different production areas,the composition and content of amino acids are greatly affected by the origin of the factors,and the distribution of the samples in the map is also scattered.For the different samples in the dominant producing areas of Shandong Province and the different samples of the dominant strain Fuji,there were significant differences between them,and the discriminant accuracy rates were 77.8% and 81.8%,respectively.3.The establishment of apple cloudy juice quality evaluation model The descriptive analysis results of 25 quality indicators of apple turbid juice show that the coefficient of variation of most indicators is large,indicating that there are different degrees of discrete phenomena between samples.And there are correlations between a number of quality indicators of apple turbid juice,and indicators need to be simplified.After the principal component analysis and cluster analysis,seven key evaluation indicators were obtained: total phenol,juice yield,titratable acid,soluble solids,browning degree,original turbidity,and L* value,weighted and established.Apple Cloudy Juice Quality Evaluation Model.4.Study on storage quality of apple turbid juice In the storage process of apple turbid juice,the color has a tendency of darkening and turning red,the degree of browning gradually increases,the content of polyphenols,ascorbic acid,amino acids and sucrose decrease,and the glucose and fructose content increase first and then decrease.As a result of adverse reactions,the quality of fruit juices eventually deteriorated.Compared with the two storage temperatures,the degree of browning of the juice stored at 4°C was lower,indicating that low temperature can effectively reduce the degree of browning.The degree of browning in different varieties of apple juice may also be different.No.1 Shaanxi,Australia,Qing Ping,<2,Shanxi slope,Qin Guan,No.3,Shandong Yanfu,No.6,No.4,Shandong Qixia,Fuji,No.5,Liaoning Xinmin,Hanfu.