Using multi-criteria decision-making method to select the optimal color fixative for cloudy kiwi juice during thermal sterilization processing

Color deterioration is inevitable during the thermal sterilization of cloudy kiwifruit juice (CKJ), which seriously affects its sensory quality. This study explored the effects of citric acid, Ca(OH)2, CuSO4, and α-cyclodextrin on protecting the color and quality of thermally sterilized CKJ. Results showed that the all fixatives reduced the a*, L*, browning index (BI), and ΔE* of CKJ; significantly increased the h°, and effectively prevented the color deterioration of CKJ during thermal sterilization. Except for citric acid, none of the color fixatives changed the sugar-acid ratio of CKJ. Citric acid and α-cyclodextrin treatments significantly enhanced or considerably retained the nutritional quality and antioxidant activity of CKJ. Furthermore, three models of principal component analysis (PCA), entropy weight-TOPSIS and grey relation analysis (GRA) were established based on the multi-criteria decision-making (MCDM) method for comprehensive quality evaluation. The model composite score of CKJ treated with 6 g/kg α-cyclodextrin was the highest, and 0.6 g/kg citric acid was the lowest.