Research And Development Of Blackberry Juice

In the paper, pectolytic enzymes liquefaction technique was used to produce blackberry cloudy juice. Also the stability of blackberry cloudy juice during storage and the processing of blackberry cloudy juice concentrate and mechanism of storage stability were also studied as well as enzymatic clarification of blackberry clear juice.According to the analysis of basic compounds of blackberry, it is obvious that blackberry contains a high level of polyphenolic substance and anthocyanin pigments, which will degrade because of polyphenol oxidase during press. Steam blanching for 2-3 min before pressing can inactivate the native polyphenolxidase of blackberry that can cause enzymatic browning and quality decrease of juice.In order to increase the juice yield and cloudy stability, pectolytic enzymes liquefaction technique was used to treat the blackberry slurry. From 4 kind of different pectolytic enzymes, we screened out one and with the aid of single factor experiments and orthogonal test the optimal technology of pectolytic enzymes liquefaction was obtained, temperate 45℃, time 90 min, dosage of pectolytic enzyme 0.007g/dL. This technology increased the juice yield of blackberry cloudy juice efficiently by hydrolyzing pectin molecular and gave the juice higher suspension stability. With adding acidic CMC and flaxseed gum, the suspension stability of blackberry was improved and the viscosity of juice was increased which can make blackberry cloudy juice much stable during storage. According to the study of influence of different storage conditions and thermal degradation of anthocyanin in blackberry cloudy juice, we found that temperate was the dominating factor causing the color and suspension stability of blackberry cloudy juice decrease. And low storage temperate was good to the quality of juice and long shelf life. And the thermal degradation of anthocyanin in blackberry juice followed first-order reaction kinetics.In addition, the effect of concentrated temperate on single strength blackberry cloudy juice was studied. The results showed that 60℃had less effect on blackberry juice quality. With the aid of rheological experiments we found that 55°Brix of blackberry juice concentrate exhibited thixotropic property and static yield stress. The values of static yield stress were increased with the concentrations, which approved that there exists weak triaxial structure. The small particles in blackberry juice were distributed in the meshes that prevent further congregating. Therefore, it approved the mechanism of of the blackberry juice concentrate storage stability.In this paper enzymatic clarifying technique in blackberry clear juice processing was also studied. Pectinase and cellulase were used to clarify the juice and the optimal technology of enzymatic clarifying were dosages of pectinase and cellulase were 0.007g/dL and 0.25g/dL respectively. Temperature was 45℃, and reacting time was 2 hour. Followed filtrating with adding diatomite, a much clearer blackberry juice was obtained. The clarity was over 84% and turbidity was less than 2 (NTU).