Preparation Of Sour Cherry Juice

Cherry is a deciduous tree in the first mature fruit, fruit colorful, nutritious balanced, especially rich in a variety of anthocyanins, melatonin, flavonoids, can regulate sleep, free radical scavenging, antioxidant, anti-cancer and other effects. In recent years, introduction and cultivation of cherry growing area, has exceeded 50 million mu, the situation of oversupply of fresh cherries. Cherry usually fresh mainly because of the harvesting, storage and transportation difficulties, causing heavy loss of fruit rot. Therefore, the development yield of cherry processing industry is to ease the loss of excess and an important way to reduce the fruit. The topics to sour cherry varieties CAB is used to study the process conditions of preparation clarification sour cherry juices for enzymic method and the influence of the important factors of fruit browning. The main contents and results are as follows:Differences in morphological trait, internal quality and main inclusions contents among fourteen main production cultivars of Prunus avium L. were invertigated. And all the indexes related were inspected. The result showed that:fifteen cherry cultivars for each indexes performance were significant for each other, average weight of simple fruit, total acid, reducing sugar, soluble solids, anthocyanins, total phenol and Vc contents contrast obviously. So the fruit size, palatability and inclusions contents significant with cultivars. By varieties correlation with tests showed that, the total phenol content of total acid is a significant positive correlation. Anthocyanins and reducing sugars and soluble solids content positively correlated. Shape index and total acid is a significant negative correlation, with pH value is a significant positive correlation. Both are heavy and mononuclear fruit weight is a significant positive correlation. Fruit juice colour and reducing sugar, total acid, soluble solids, anthocyanins and total phenolic significant correlation. Red varieties acidity, anthocyanins and total phenol content is higher; Yellow varieties, sugar higher, anthocyanins and total phenols content is low. Sour cherry CAB total acid, total phenol and Vc content is higher, can be used for processing.The sour cherry varieties CAB frozen fruit component analysis showed that it contains rich in antioxidant activity material anthocyanins and total polyphenol, contains, rich in organic acids, pectin and nutrition elements K, Ca.The activitiy of polyphenol oxidase (PPO) in sour cherry fruit were determined. The results showed that the optimum conditions were pH7.5,0.1 M substrate and 20℃for PPO assay. However, the PPO was inactivated in boiling water for 80s. Of the inhibitors tested, L-cysteine and ascorbic acid were the most effective.To explore the effect of blanching on PPO, POD enzyme activity, juice quality of sour cherry. Results showed that, using 85℃water bath, blanching time of 3-4 min, center temperature above 50℃, sour cherry pulp 95% PPO and POD inactivated, the soluble solid, juice anthocyanins, total polyphenol and Vc content is higer, protect color is obvious; Sour cherry than sweet cherry, apple and peach with lower PPO enzymatic activity and PPO thermal stability, be helpful for processing of enzymaticPreliminary studies sour cherry juice anthocyanins thermal stability. The results show that the sour cherry juice anthocyanins in hightemperatures will degradation, it conforms to the level 1 dynamic equation. Sour cherry juice in 45℃heating 160 min, anthocyanins loss of 13.1%, in 90℃heating loss of 47.5% anthocyanins, loss increased significantly. Therefore, sour cherry juice should as far as possible in the processing of low-temperature and short-term heat treatment.Sour cherry was treated with 7 different commercial pectinase on physical characteristics such as juice yield, transmittance, turbidity, soluble solid content, pH, pectin content and anthocyanin content. Ultra AFP was the best one. The optimization condition was determined by single factor experiments and Box-Behnken response surface methodology. It was indicated that all of the conditions significantly influenced juice yield, transmittance and turbidity. The optimum values were determined as follows:enzyme concentration 1.73 mL/kg, hydrolysis temperature 46℃and hydrolysis duration 2.3 h. Under these conditions, the experimental values of juice yield, transmittance and turbidity were 86.2%,90.5% and 2.67 NTU, respectively.Sour cherry clear juice high temperature sterilization by 95℃10 min and storage after 3 months, total numbers of colony, mould, barm and coli group were lower than that of the number of GB19297-2003 for fruit juice related requirement. Indicate that juice sterilization effect is good.Sour cherry juice on storage stability were studied, indicating that different treatment juice at 4℃with storage time, the brightness L* value of fruit decreased, the color darkens, and the initial rate of change of storage large. Sour cherry juice will be stored at 4℃after 3 months, sour cherry juice were observed to become turbid, the bottom of the second produced a small amount of precipitation, some bottles of red-brown material on the adhesion. Tannin and tannin-protein characterization experiments showed that the turbidity is mainly tannin or tannin-protein. After repeated washing and drying, are secondary precipitation content 32.81 mg/L. By testing the chemical constituents of secondary precipitation that sour cherry juice produced in the secondary precipitation during storage is the main component of polyphenols, sugar and protein. Secondary precipitation is the most abundant phenolic compounds.