Study On The Stability Of Red Raspberry Juice

This research takes the red raspberry as experiment.Based on Selection of thermal drift time and Enzymolysis Technology, convensional juice process was used to produce red raspberry cloudy juice and red raspberry clear juice ,study stability of pigment of two fruit juice.Result of experiment as follows:1, The effect of red raspberry juice yield and PPO enzyme activity on different thermal drift time , determine the better thermal drift time: 100℃before juice under 2min heat bleaching, can maintain higher red raspberry juice yield and ensure complete inactivation of polyphenol oxidase.2, Based on the single factor experiment ,do orthogonal experiment ,study pectinase on different the amount , different temperature, time efffect rate of red raspberry juice and the main impact of nutrients to determine the red raspberry optimized process conditions were: enzyme temperature is 50℃, hydrolysis time is 2h, pectinase amount is 0.3g/100g. Hydrolysis temperature is the main factor in the quality index, followed by enzyme addition, reaction time did not significantly affect the difference.3, Based on the single factor experiment ,do orthogonal experiment , on different chitosan dosage, time, temperature, the effect light transmission rate and color values of red raspberry juice to determine the optimal red raspberry chitosan clarification process parameters: clarification temperature is 50℃, clarify the time is 3h, the solution of chitosan dosage is 0.06L / L.4, The red raspberry juice color stability of the draw: Red Raspberry cloudy juice compared with high temperature, with time, gradually deepen the color of fruit juice; pH is from 2.0 to 8.5, fruit juice color from red to black, and, the color value is getting larger on the wavelength of 515nm; Fe3 + on the pigment of the largest, with concentrations increasing,the pigment of the damaging effects gradually increased, Zn2 +, Mg2 +, K +, Cu2 +, Ca2 + little effect on the juice pigmentation; different concentrations of glucose, sucrose damage to the red raspberry cloudy juice pigment is little,but raspberry clear juice is hyperchromic effect; Different concentrations of strong oxidants H2O2 and sodium benzoate juice pigment great influence,when reaches a certain concentration, can make juice absorbance at a low level.;5, At 4℃and room temperature storage conditions, red raspberry juice in the Vc, total sugar, total acid content and color values are decreasing, in which the greatest loss of Vc, and the nutrients of loss at room temperature is far greater than 4℃, 4℃is more suitable for juice storage than at room temperature.6, By adding different stabilizers to the muddy red raspberry juice (xanthan gum, hydroxymethyl cellulose, agarose, pectins, gum arabic), Based on single factor tests, Choose the four stabilizer which the stability is better to do orthogonal tests ,determine the optimal compound stabilizer combination is:carboxymethyl cellulose sodium: 0.05g/100g, xanthan gum: 0.1g/100g, agar: 0.2g/100g, pectin: 0.05g/100g.7, Removal of caused clarify the juice turbidity a major factor protein, tannin, iron, starch of red raspberry, then added these factor to the clarify the juice, based on the orthogonal factors, to get the critical value of caused juice turbidity: protein: 740 mg. L-1, tannin: 150 mg.L-1, Iron: 13.2 mg.L-1, Starch: 3.2 mg.L-1.