Study On Quality Change And Control During The Processing Of Mango Juice With Peel

Mango is one of the world’s principal tropical fruits. It tastes tender, sweet, has rich nutrition, special flavor, and is deeply loved by people. But mango harvest time is short, it’s hard to store and its loss is big. Therefore, except for fresh eaten, most of the mangoes were processed to products, such as juice、protoplasm、can and so on. Traditional mango juice is squeezed without peel, which generated a lot of by-product, mango peel. The peel is often treated as waste and throw away, not only pollute the environment, but also cause the waste of resource. Therefore, in order to solve the waste of mango peel resource, improve the utilization of mango and reduce the cost, mango juice squeezed with peel are put forward.Based on the mango flesh with peel as raw material, with the pectinase and cellulase to improve the mango juice yield, the neural network model of mango juice enzymolysis process was established on the basis of single factors, and the process parameters were optimized. The results showed that the optimal enzymolysis process parameters were as follows: pectinase dosage 0.007%, cellulase dosage 0.001%, reaction temperature 40.6℃ and time 60 min. Under these conditions, the yield of mango juice with peel was 80.48%, the yield of mango juice without peel was 66.47%, increased by 14.01%, and the quality of juice can be accepted with small changes.Browning inhibitors were added in different time to confirm the best time, and the single factor experiments were conducted to figure out three kinds of better inhibitors, the results were optimized and analyzed by response surface regression. The results showed that the best time to add browning inhibitors was before enzymolysis and the best compound inhibitors were as follows: sodium D-sodium erythorbate dosage 0.047%, L-Cys dosage 0.060%, phytic acid dosage 0.017%. Under these conditions, the predicted value of change rate of browning was 11.91%, the actual value was 12.19 %, the match degree between actual value and predicted value reached 97.70%.The aroma volatile components of four kinds of mango juice were investigated by HS-SPME-GC-MS. The relative contents of constitutes were determined by area normalizing method. The results showed that 50, 60, 63, 62 kinds of aroma volatile components were identified in four samples, and they have 33 components in common. The major aroma volatile components of four samples are similar, such as α-terpinolene, δ-3-carene, β-selinene, 4-hydroxybutyl acrylate, 4-heptanol, methyl palmitate and nonanal. There is a big difference in the relative content of terpenes, esters and alcohols aroma components in mango juice with and without peel. The maximum of aroma components in mango juice without peel was followed by alcohols, esters and terpenes, and mango juice with peel was followed by terpenes, alcohols and esters. More aroma components were identified in mango juice with peel, such as α-gurjunene, α-selinene, methyl palmitoleate and cis-carveol. The total aroma volatile components in mango juice decreased after heat sterilization, decreased by 13.90% in mango juice without peel and 19.67% in mango juice with peel.On the basis of single factor experiment, the optimal formula and stabilizer were determined by orthogonal test. Finally, we got a juice beverage that had good color, aroma, taste and stability. We also studied the change of physical and chemical indicators of mango juice under different storage temperatures(27, 37, 47 ℃). And we fitted and analyzed the dynamic model of non-enzymatic browning related indicators. The results showed that the optimum formula of the mango juice beverage was 90% mango juice, 6% honey, 5% white granulated sugar, 0.02% citric acid and the optimum compound stabilizer was composed of 0.09% PGA and 0.06% xanthan gum. Storage time had a significant effect(p < 0.05) on reducing sugar, △E, vitamin C, total phenols, 5- HMF, pH, total sugar, ammonia nitrogen, had no significant effect on total soluble solids(p > 0.05). 27 and 47℃, had no significant effect on total acid(p > 0.05), and 37 ℃, has a significant effect on total acid(p < 0.05). Under 27℃, non-enzymatic browning of the juice may be associated with Maillard reaction. Under 37 and 47 ℃, non-enzymatic browning could be the comprehensive result of Maillard, oxidative decomposition of vitamin C, oxidation condensation of polyphenol. In the storage process of mango juice, the change trend of △E and 5-HMF accords with zero order kinetics, and the activation energy is higher, 155.77 and 91.71 kJ/mol; the change trend of vitamin C and total phenols accords with first order kinetics, and activation energy is low, 31.03 and 22.09 kJ/mol. The reaction rate of Vitamin C and total phenol is quick, the △ E and 5-HMF is relatively slow.