Study On Cloudy Mango And Apple Mixed Juice

Mango is one of the principal tropical fruits riched with nutrient contents. It is relished for its succulence, exotic flavour and delicious taste.Some mangoes are eaten in fresh, some are processed to products, such as juice,beverage,jam and so on. Apple is mainly fruits in north China,which currently ranks first in total production among major fruit crops worldwide. In order to improve the qualities of compound cloudy juices and resolve the critical technologies restricted the quick development of juice market, the systemic study on the processing and qualities of compound cloudy juices is very essential.The objective of this dissertation was to develop multiple enzymatic liquefaction for processing cloudy mango and apple juices, investigate the juice concentrates, their cloud and color stability , the formula and stability of cloudy juice blend of mango and apple.The effects of different enzymes on cloudy mango juice were determined. The optimal processing of multiple enzymatic liquefaction was added 2.5% (w/w) pectinase and 0.6% (w/w) cellulase into the mango purees and reacted at 30℃for 70 min. The juice yield was increase by 20% and the cloud and color stability was improved by enzymatic reaction. By the orthogonal experiment, the optimum enzymolysis conditions of cloudy apple juice were determined as follows: pectinase 0.10% (w/w), cellulase 0.005% (w/w), xylanase 0.007% (w/w), enzymolysis time 40 min, and enzymolysis temperature 50℃at natural pH.The influences of different hydrocolloids on the stability of cloudy mango juices were studied, and the mechanism of cloud stability was investigated. Compared with single guar, the co-operatation of 0.04% (w/v) guar and 0.08% (w/v) aciduric CMC had better effect on juice stability. For cloudy apple juice, the stabilize used 0.008% (w/v) guar and 0.017% (w/v) xanthan .The mixture of guar and aciduric CMC for cloudy mango juice accelerated a weak three-dimension network formation, and improved the stability of small suspended particles. Furthermore, the juice added with multiple hydrocolloids had best color and cloud stability with the highest Zeta potential, its cloud stability involved in electrostatic repulsive forces.According to the results of the main components of sediment of cloudy mango juices after 4 months storage, the main aspects influencing sedimentation of mango juices were discussed. During storage, the macromolecular substances such as protein and pectin, cell fragments and other suspended particles formed the sedimentation due to the action of gravity and some particles were aggregated together and grown up to form more sediment.Cloudy mango juice and cloudy apple juice concentrates and their rheological properties were studied. The 47oBrix mango juice concentrates without gums or with gums appeared a pseudoplasticity, fit for power-law model; the 55oBrix and 66oBrix mango juice concentrates without gums or with gums exhibited a thixotropic property; The 55oBrix apple juice concentrates with gums and 66oBrix apple juice concentrates without gums or with single gums or with guar and xanthan exhibited a thixotropic property. The over 55oBrix mango juice concentrates juice with 0.04% (w/v) guar and 0.08% (w/v) aciduric CMC, apple concentrates juice with 0.008% (w/v) guar and 0.017% (w/v) xanthan presented a static yield stress. The results of storage tests indicated that storage single strength mango and apple juices had good cloudy stability.The formulation of the cloudy mango-apple compound juice ingredients was mango juice 56% (w/w), apple juice 40% (w/w), saccharose 3.97% (w/w), citric acid 0.03% (w/w). Moreover the co-operatation of 0.015% (w/v) guar and 0.035% (w/v) aciduric CMC had better effect on compound juice stability.