Influence of industrial processing on quality parameters of litchi juice

To explore the effect of different industrial processing stages ( de- stoning and pulping, squeezing, centrifugation, concentration, pasteurization) on quality parameters of litchi juice, samples were taken after each unit operation stage, and total sugar, reducing sugar, ascorbic acid, total acid, total phenols and volatile aromatic compounds were analyzed.Results showed that de- stoning and pulping, squeezing and centrifugation had little influence on contents of total sugar and reducing sugar ( p > 0.05) .Squeezing could result in the decrease of ascorbic acid and total phenols.Concentration and pasteurization could result decrease of total sugar, reducing sugar, ascorbic acid, total acid, total phenols ( p < 0.05) .Moreover, industrial processing had a negative effect on aroma compounds of litchi juice.The aroma compounds of litchi juice taken after five processing unit operations were studied by SPME/GC-MS, the contents of alcohols and esters exhibited a significant decrease.Concentration and pasteurization had significant influence on the volatile aromatic compounds.