Change of juice color during raspberry processing in fruit juice and fruit juice concentrate
2006
Vukosavljevic, P. (Faculty of Agriculture, Belgrade - Zemun (Serbia)) | Bukvic, B. (Faculty of Agriculture, Belgrade - Zemun (Serbia)) | Jankovic, M. (Faculty of Agriculture, Belgrade - Zemun (Serbia)) | Petrovic, T. (Faculty of Agriculture, Belgrade - Zemun (Serbia)) | Stevanovic, S. (Faculty of Agriculture, Belgrade - Zemun (Serbia))
A change of anthocyanins under different conditions of enzymatic treatments, clarification and concentration was determined. A pectin preparation Klerzyme(R) 120, manufactured by DSM, France, specific for sour fruits with pH below 3.2, was used for maceration and depectinization. Extraction yield by a laboratory hydraulic press was the same in case of single-stage maceration and two-stage maceration. However, due to a lower viscosity, it was observed that single-stage process provides raspberry juice with more colour and high efficiency of extraction. It was noticed that thermal breaks of raspberry pulp provide juice containing more total anthozyanins. The clarification using gelatin and bentonite removed about 50% total anthocyanins, while a clarification by a cross-flow ultrafiltration using Carbosep M9, M8 and M7 membranes achieved the highest level of colour loss. Total colour loss after concentration was 70%. The best results in colour protection were observed by a microfiltration through Kerasep membrane, due to its relatively large pores (0.2 microm).
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