Study On Blueberry Juice Enzymatic Browning

In this paper,the enzymatic browning of blueberry juice was studied,and the determination of the basic nutrition ingredient content in blueberries.Blueberries are analyzed in enzymology properties of polyphenol oxidase,by means of enzymatic browning intermediate anthraquinone compounds content of track,and the change of enzymatic browning were studied.The juice of enzymatic browning inhibitors were studied,and the response surface method adopted for composite inhibitor has been screened the best inhibitory,different storage temperature and storage time on the effect on the stability of the storage period,then observe the changes of viscosity of the suspension stability and,by tracing the degradation of storage period,total phenol content,total anthraquinone and the increase of the content of free anthraquinone were systematically studied the enzymatic browning of blueberry juice.(1)Analyze the blueberry enzymtic properties of polyphenol oxidase,in effect,the author of this paper raspberries polyphenol oxidase(PPO).The main factors of the enzymatic activity of:pH,temperature,metal ion,and inhibitor and thermal stability were studied.Experimental results show that the optimum pH 6.5 PPO in blueberries,optimum temperature of 30?,Ca2+and Mn2+has inhibitory effect on blueberry PPO,Cu2+,Mg2+,Zn2+,Fe3+activation for blueberry PPO.Citric acid,ascorbic acid,and sodium bisulfite L-cysteine can inhibit PPO enzyme activity,but the citric acid inhibition effect is poor.Thermal stability test results show that:blue berry PPO poor heat resistance,high temperature short time can significantly inhibit PPO enzyme activity;(2)By means of enzymatic browning intermediate anthraquinone compounds content of the study tracked the changes in the process of enzymatic browning,studied the influence fruit enzymatic browning inhibitors.Enzymatic browning inhibitors test showed that ascorbic acid,citric acid,sodium bisulfite and L-cysteine of blueberry juice has certain inhibition,but inhibition of citric acid effect is not obvious,and ascorbic acid,sodium bisulfite and inhibiting effect more apparent,L-cysteine 0.1%concentration of inhibitor of enzymatic browning has good inhibitory effect,which can effectively inhibit the generation of anthraquinone compounds.Guarantee the quality of the blueberry juice,through the response surface method for composite inhibitor has been screened the best inhibitory.Experimental results show that in 0.505%citric acid,0.0627%ascorbic acid,0.057%sodium bisulfite and 0.0625%of which has the best inhibition rate under the condition of L-cysteine,get the best inhibition rate was 94.57%,under the condition of the prediction of inhibition rate was 94.1228%,the validation test average of 94.57%.(3)Adding inhibitor on enzymatic browning of fruit juice storage has good inhibition effect.Blueberry juice storage period stability test showed that the juice is associated with storage time and storage temperature.When storage stability under the condition of 4?,juice maintain good storage stability,can guarantee the good quality,under the condition of 25?and 37? storage test results show that:under the same temperature,the longer the storage time,fruit juice,suspension stability,system is cloudy,and viscosity change difference.The greater the amount of total phenol degradation,total anthraquinone and free anthraquinone content is higher,the greater the degree of browning.In the same storage time,the higher the storage temperature,fruit juice suspension stability,and system is more cloudy,but viscosity change difference.The greater the amount of total phenol degradation,total anthraquinone and free anthraquinone content is higher,the greater the degree of browning.Without inhibitor group total phenol degradation amount is larger,total anthraquinone and free anthraquinone production also is higher,the composite inhibitor has good inhibition effect.