Changes in Aromatic Composition of Apple Vinegar with Application of Partial Block Freeze-concentration: A Pilot Study
A partial block freeze-concentration apparatus (50 L) was applied to concentrate apple vinegar in a pilot study,and the aromatic composition changes in the vinegar and ice samples before and after the concentration process were compared using gas chromatography-mass spectrometry (GC/MS).During this process,the refrigerant interlayer temperature and stirring rate of the freeze concentrator at the beginning stage were controlled at-12.0 ℃ and 300 r/min,respectively.When the ice on the inside wall of the crystallizing tank reached a thickness of 0.50 cm,the refrigerant interlayer temperature and stirring rate were changed to-16.0 ℃ and 500 r/min,respectively,which were maintained until the end of the concentration process.After 11 h,21.70 kg of concentrated apple vinegar with 9.50％ content and 27.84 kg block ice with 0.66％ entrainment could be obtained from the initial 50.00 kg apple vinegar.The concentration index and solute yield were 2.13 and 92.24％,respectively.The total loss of aromatic compounds from the block ice was just 3.12％,and the loss rates of characteristic components,such as benzaldehyde,octanoic acid,4-ethylbenzoic acid butan-2-yl ester,phenylethyl alcohol,and acetic acid 2-phenylethyl ester,were in the range of 3.33～7.47％.However,when the recovery liquid from thawed ice was re-concentrated using similar two-step controlling parameters,the main components recovered were the solutes (e.g.organic acids),but no significant concentration effect was observed in the trace amounts of residual aromatic components.
apple vinegararomatic compoundblock freeze-concentrationice entrainment
国家科技期刊平台
NSTL
万方数据
维普
