The Research Of Gongshui White Pomelo Processing Quality And Brown Stain Improvement

Gongshui white pomelo, which is cultivated for hundreds of years, is one of the high quality pomelos. The white pomelo has many good economic features, such as maturing fast、producing stable and highly、strong adaptability. As a result, it had won the golden prize in the fifth and the seventh pummelos rating conference of China, and it also became the iconic product of national geography in2010. This paper has researched the detail of the features of treating the white pomelo, and the main content and results are as follows:1. The research of the nutritional quality and the storage stability of Gongshui white pomelo. We have tested the physical and chemical properties and the nutritional quality of the juice of Gongshui white pomelo. The juice are respectively stored in the condition of20℃and35℃for40days, and they are both tested every10days. Thus, we have the following conclusion:Gongshui white pomelo has the uniform shape and higher juice yield, and the juice, the color of which is pale white, has a good quality and is rich in nutrient and metal ion. All in all, the pomelo is suitable for processing. During the storage, the total sugar is reduced under both the two temperatures, but the reducing sugar is slowly increased. Though Vc is decreased during the storage, the total acid is increased during the experiment. In addition, pH of the juice also decreased as time goes by.2、the key unit operations effect the pomelo physicochemical property and nutritional ingredient.We choose some key unit operations, eg.homogeneous, pasteurization, concentration to analyse the change of total sugar,reduce sugar,total acid,Vc, chroma and aroma. The total sugar of gongshui white pomelo arrived at the minimum value after pasteurization.the total acid decline after homogeneous,but rise up after pasteurization and concentration.the reduce sugar always deline when the juice is machining.Also Vc go down by a large margin.at the same time, the key unit operations effect color of the juice.after the key unit operations,we can find45contents of aroma. the key unit operations effect physicochemical property so much which related with gongshui white pomelo brown stain,and also the key factor about juice brown stain’s produce and accelerate,so solve brown stain is the key problem about gongshui white pomelo process.3. The factor of juice brown stain and use response surface to improve brown stain process better.The experiment surveys how these factors,eg.pH,store time and temperature,reduce sugar, organic acid(include Vc and citric acid,.L-C-Cys and heating time,effect juice brown stain.And use response surface to improve additive amount of Vc, citric acid, L-C-Cys.We can see when Vc is0.03%, citric acid is0.53%, L-C-Cys is0.04%,the suppression ratio of juice brown stain is82.58%,this is the best condition. We also can find that different store time and temperature can make the variation trend of5-HMF accord with zero-order kinetics;at the same time,A420variation trend accord with first-order kinetics.Reduce sugar can accelerate NEB, fruit sugar is better than grape sugar.Heating time should be controlled at4min.