Study On A Series Of Fruit-vegetable Drinks

This paper focused on the formula and product quality of different juice drinks, including compound fruit-vegetable drinks and hawthorn juice drinks fortified with OPC.The reasons why the jelly like floc in compound fruit-vegetable drinks appeared were studied. Firstly, the contents of starch, pectin and protein in different concentrated juice as raw materials were determined and analyzed, including apple juice, sugarcane juice, fig juice, lily juice, rhizome juice, water chestnut juice and longan juice. In order to investigate the reasons why the jelly like floc in compound fruit-vegetable drinks appeared, each concentrated juice was prepared seperately as the compound fruit-vegetable drinks in substitute of other 6 kinds, the results indicated that the starch in concentrated juice leaded to the appearance of the jelly like floc. This was verified by the hydrolysis of starch in lily concentrated juice byα-amylase.Secondly, pH, soluble solids and microbial index of every kind of concentrated juice were determined. The results showed that 7 kinds of concentrated juice were seriously polluted by microorganism and the compound fruit-vegetable drinks had not been sterilized completely, residue of microorganism which utilized the nutrient of compound fruit-vegetable drinks was also one of the causes of the formation of the jelly like floc. This was also verified by the fact that jelly like floc appeared in all compound fruit-vegetable drinks which was not sterilized.On the basis of above analysis, the best formula of proporation of 7 concentrated juices was determined experimently through orthogonal experiment and sensory assessment. The ratio of apple juice, sugarcane juice, fig juice, lily juice, rhizome juice, water-chestnut juice, longan juice was 17.5: 6: 2: 2: 1: 1: 0.1 (w/w). The best taste flavor prescription was sugar 16%, citric acid 0.5%, honey 16% and stabilizer 0.02%. The pH of compound fruit-vegetable drinks was 3.2. Starch-rich materials were hydrolyzed byα-amylase. The mixture dispensing temperature was fixed at 60℃according to the changes of the viscosity of compound fruit-vegetable drinks as a function of temperature, which had little effect on the nutrition, the color and the flavor of products. By orthogonal experiment, the sterilization conditions were optimized at 90℃for 15 min.This paper also discussed hawthorn juice drinks fortified with OPC. The contents of reducing sugar, total sugar, OPC and flaonoids in different hawthorn concentrated juices were determined. The results indicated that the content of functional components in different kinds of hawthorn juices showed a remarkable discrepancy, that can provide a favorable reference for the selection of raw materials for enterprise. Because the content of functional components inⅠhawthorn juice is significantly higher than that of in other hawthorn juice,Ⅰhawthorn juice was choosen as the raw material of hawthorn juice drinks fortified with OPC. DPPH free radical scavenging abilities of hawthorn juice were also determined. Experimental results showed that the six hawthorn juices had a significantly scavenging effect toward DPPH free radicals and hawthorn juice had stronger antioxidative property. Taking into account the peculiar constituents in hawthorn juice, the paper studied and compared the clarification effects of different clarifiers including pectinase, chitosan and gelatin. The results indicated that the effect of chitosan was best. By single factor experiment, orthogonal experiment and stability test, the formula of hawthorn juice drinks fortified with OPC was hawthorn juice 5%, OPC 0.05 %, sugar 6%, honey 5%, xanthan gum 0.04%.