Processing And Process Design Of Red Meat Apple Turbid Juice Processing

Xinjiang red-flesh apple with red branches, flowers, peel and flesh, has high ornamental value. It has unique flavor but astringent after tasting, which is caused by abundant polyphenols and anthocyanins contained in the fruit. Besides, it is not resistant to storage. In addition to eating directly, it is mainly dried for production. So it is urgent to develop new products based on it.Red-flesh apple for its attractive red and rich nutrients, the pursuits of people on nature, nutrition, green and health and the great boom on juice market all over the word, processing the red-flesh apple into juice have many positive effects, such as retaining its nutrition, improving the added value, getting effective development and utilization. So juice production has broad market prospects.While the polyphenols and anthocyanins are unstable, they are vulnerable to temperature, pH, Vc, metal ions, illumination, organic acid, sugar, and enzyme, which can cause degradation, fade and precipitate of juice in processing and storage. As a result, the product can lose business value, which seriously influenced the development of the red-flesh apple products processing.In view of easily browning, instability, poor storage problems on the production of red-flesh apple cloudy juice, the research was studied from the following several aspects:By measuring the activity of PPO, browning degree, content of polyphenols and anthocyanin, the optimum adding amount of ascorbic acid is 0.07%, which is proved to preserve the attractive color of juice.Besides colour fixatives, heat treatment is necessary to avoid the inactivation of PPO.Comparing the PPO activation, color value, changes of polyphenols and anthocyanins, the result showed that the color value, polyphenols and anthocyanins were protected better when the juice was treated for 40 s under 90?.The influence of different stabilizer and homogeneous technology on the stabilization of juice were researched to avoid the precipitation phenomenon. xanthan gum, guar gum and apple pectin were selected as compound stabilizer by single factor experiment. Then the optimum formulation was ascertained by orthogonal test:xanthan gum 0.045%, guar gum 0.03%, apple pectin 0.015%. The effects of pressure and times of homogenization on the stabilization of juice were studied. The result showed that it could improve the stabilization when the juice processed under 30 MPa,2 times.The juice was treated with ultra-high temperature sterilization (UHT) and pasteurization, then the influence of different temperature and illumination conditions on the storage stability was studied. The result showed that the color and nutrition were protected better with UHT. The influence of temperature on the storage stability was more significant than illumination conditions. So 4? without light was better to protect the quality.At last, the study compared the changes of juice index under different condensing temperature. The result showed that higher condensing temperature could decrease the condensing time, the juice quality get better. So the optimum condition of vacuum concentration was vacuum degree 0.9, temperature 60?.