Influence of ice-thawing concentration treatment on the quality of litchi juice
Litchi juice after sterilized was concentrated by ice-thawing concentration.The effects of icethawing concentration on the total soluble solids,browning degree and titrable acidity were analyzed.And volatile aromatic compounds of litchi juice in the course of concentration were analyzed by headspace solid phase micro-extraction and gas chromatography-mass spectrometry(HS-SPME and GC-MS) method.The results indicated that the total soluble solids and browning degree in litchi juice were decreasing with thawing volume increasing.The kinds of volatile aromatic compounds of litchi juice in different stages concentrated by the ice-thawing concentrated way were different.The choice of the boundary point took the analysis about the physico-chemical index and volatile aromatic compounds into comprehensive consideration,and to get more volatile aromatic compounds in concentrated juice,the thawing litchi juice with 40% in volume was found as the boundary point separated the concentrated juice and the residual liquid.