Quality Changes Of Muscat Grape Juice During Production Processing

The Grape juice has enjoyed great popularity in the market, for special functions and flavor within it. In this paper, the effects of several processes on Muscat Grape were studied including shattering process, clarification process, sterilization process and packaging process.During the shattering process, the influence of sodium erythorbate, heat treatment process and bio-emzyme preparations on the quality of grape juice were studied. After added sodium erythorbate, the content of soluble solids enhanced, the browning degree reduced, and the red pigment lost. As characteristic aroma, the relative content of neroli had improved. After heat treatment, the juice had higher total acid, reducing sugar, TSS contents and chromatic value. Two kinds of aroma substance had reduced and the relative percentage of linalool also decreased. The red pigment would be destroyed by bio-enzymes and then color index diminished. The total acid and reducing sugar contents were increased by mixed enzymes. In addition, the relative percentage of terpene class had increased. The juice mixed enzyme I added more aromas.Using filter paper, adding diatomite and activated carbon could all improve the clarity of juice by a large margin, but the drink had lost more total acid, reducing sugar, TSS contents; activated carbon could lead to serious loss of aroma. Synthesizes each kind of situation, the filter of kieselguhr had optimal effect.Steam boiling, microwave and ultra-high temperature all reduced the contents of total acid, reducing sugar, TSS, and so did red pigment. The aroma types augmented after sterilizeding with ultra-high temperature, and they were all terpenoids.Compared with the effect on the quality of three different packaging materials, the sample packaging with glass had more aroma types and had the best preservation result of linalool. Overall, the glass was the best package materials comparing with the other two materials.