[关键词]
[摘要]
本文通过50 L渐进式部分块冰冷冻浓缩中试设备浓缩苹果醋,并采用气质联用方法对浓缩前后的苹果醋及其夹带冰的芳香风味成分变化进行了比较研究。在苹果醋浓缩过程中,前期阶段控制结晶浓缩罐冷媒夹层温度和搅拌速度为-12.0 ℃和300 r/min;当结晶罐内壁冰层达到0.50 cm厚度时,结晶浓缩罐冷媒夹层温度降至-16.0 ℃,搅拌速度提高为500 r/min,直至冷冻浓缩结束。50.00 kg苹果原醋经过11 h冷冻浓缩可得到9.50%的高浓度浓缩液21.70 kg和0.66%低浓度的夹带冰27.84 kg,浓缩比为2.13倍,浓缩率达到92.24%;苹果醋浓缩液芳香物质总损失率仅为3.12%,其中特征成分苯甲醛、辛酸、4-乙苯酸-2-丁基酯、苯乙醇与乙酸苯乙酯的损失率则介于3.33~7.47%。采用相似的两阶段参数控制将剩余夹带冰解冻液经再次冷冻浓缩,回收的主要是有机酸溶质,而对其微量残余的芳香物质则无明显浓缩效果。
[Key word]
[Abstract]
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.
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[基金项目]
广东省公益研究与能力建设专项(2015A010107018);国家级大学生创业实践项目(201410576002,201310576-004)