荔枝果汁工业规模加工过程中主要品质指标变化

Influence of industrial processing on quality parameters of litchi juice

为探究荔枝果汁工业规模加工过程中打浆去核、压榨过滤、离心、浓缩、杀菌等关键工序对果汁品质的影响,测定了各单元操作后样品的总糖、还原糖、维生素C、总酸、总酚及挥发性风味成分等主要品质指标。结果表明:去核打浆、压榨过滤、离心对荔枝果汁总糖和还原糖影响不显著(p>0.05),压榨过滤后维生素C、总酚含量下降,浓缩和杀菌导致总糖、还原糖、维生素C、总酸、总酚含量降低(p<0.05)。加工过程中荔枝果汁风味出现明显变化,采用SPME/GC-MS对各单元操作的荔枝果汁风味成分进行分析,发现醇类和烯类物质明显下降,浓缩和杀菌两个单元操作对风味成分有显著影响。

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.