Study On The Manufacturing Procedure Of High Transparency Prunus Mume Concentrate Juice

Prunus mume Sieb.et Zucc, belonging to rosaceous prunus, is a kind of special local fruit in semitropical area in our country and had been planted in ancient times, In this paper, the main juice processing quality characters, the manufacturing procedure of high transparency green plum juice by using enzyme, rheology for high transparency green plum juice in the concentration processing, nonenzymatic browning of juice and kinetic model on colour in storage were studied, which can offer an important practical recommendation for exploring green plum resources.1. Seven different varieties of green plum of four provinces in our country were collected and the main juice processing quality characters—edible rate, moisture, TSS, polyphenol content, PPO, POD, juice rate, the total acid, the content of pectin and its esterify were studied. The result showed that the content of total acid is higher, between 2.4% and 5.2%, decreasing with green plum ripeness. The main factors influencing browning are PPO and POD in the green plum juice processing. There are larger differences of PPO and POD activity among the different green plum varieties. The lowest PPO and POD activity is Yongchun green plum, respectively 80 U/g.FW and 1500 U/g.FW, And the highest is Xiaoshan green plum, respectively 779U/g.FW and 5000 U/g.FW. The PPO and POD activity, with BD(browning degree), had highest relativity(r=0.981,r=0.973). There are much high esterify pectin in the fruit, which cause cloudy and sediment of green plum juice.2. The single-factor experiment indicated that the pectinase dealed with 0.03mol/L CaCL2 had increased its acid resistance remarkably and the pectinase multiplexed with 0.025%GM+0.025%MXL had well enzymolysis effect. Orthogonal was designed to study the effects of quantity, reaction temperature and time of pectinase on viscosity and transparency of green plum juice from green plum produced in Yongtai. The results showed that the optimal enzymolysis conditions were 0.05% pectinase at 45 °C ,90 min.3. The study of the rheology of high transparency green plum concentrate juice indicated that high transparency green plum concentrated juice behaves as a Newdonian fluid. Through the study of the influence of temperature on viscosity and soluble solids content on viscosity, the mathematical models of temperature on viscosity[η=Koexp(Ea/RT)], soluble solids content on viscosity[K=Aexp(BC)] and the combined effect of temperature and soluble solids content on viscosity[η=K1exp(Ea/RT+K₂C+K3C2)] had been founded by regression analysis. These regression equations could be utilized to predict the viscosity of high transparency green plum juice processed at different temperature and different concentrates. The study could provide important scientific bases for the processing of high transparency green plum concentrated juice and the design of equipment.