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1、中国农学通报2011,27(04):356-360ChineseAgriculturalScienceBulletin荔枝真空冷冻干燥关键技术12311陈仪男，郭树松，郭建辉，林龙生，吴秀秀(1漳州职业技术学院食品与生物工程系，福建漳州363000；2福建立兴食品有限公司，福建华安363800；3漳州市农业局，福建漳州363000)摘要：为了确定荔枝真空冷冻干燥工艺关键技术参数，以成熟的‘乌叶’荔枝为材料，采用电阻法测量荔枝果肉的共晶点和共熔点温度，通过考察冻干品色泽比较不同护色剂的护色效果，以冻干生产能耗、总冻干时间及冻干品外观形态与色泽等指标进行综合评定冻干效果，优选荔枝真空冷冻干燥工
2、艺关键技术参数。结果表明：荔枝真空冷冻干燥物料的共晶点温度、共熔点温度分为-26℃和-17℃，采用“0.6%柠檬酸”单一护色剂或“0.4%柠檬酸+0.2%维生素C”复合护色剂浸泡20min，对荔枝冻干品有良好护色效果。冻干过程起始板温控制在80℃以下，升华阶段物料最高温度设定为55℃，升降温期干燥仓真空值组合选择60~70Pa/60~70Pa，可节省冻干生产能耗、缩短总冻干时间，同时能改善冻干品的外观形态与色泽。关键词：荔枝；真空冷冻干燥；共晶点；共熔点；关键技术；食品加工中图分类号：TS255.3文献标志码：A论文编号：2010-2600TheKeyTechnologiesofVacuu
3、mFreeze-dryingofLitchFruits12311ChenYinan,GuoShusong,GuoJianhui,LinLongsheng,WuXiuxiu(1DepartmentofFoodandBiotechnology,ZhangzhouInstituteofTechnology,Zhangzhou363000:2FujianLixingFoodsCo.,Ltd,Huaan363800;3ZhangzhouAgricultureBureau,Zhangzhou363000)Abstract:Inordertoconfirmthekeytechnologyinvacuum
4、freeze-dryingoflitch,experimentswereconduct⁃edwithlitchcultivar‘Wuye’.Theeutecticpointandtheconsolutepointoflitchweredeterminedbyelectricalresistancemethodinthevacuumfreeze-drying.Thedifferentcolorfixativeagentswerecomparedontheircol⁃or-protectingeffectsbyanalysisthecolorofthefreeze-dryingproducts
5、.Thekeytechnicalparametersofthevacuumfreeze-dryingoflitchwereoptimizedwiththefreeze-dryingeffectsofthecomprehensiveindexesbe⁃ingevaluatedbyenergyconsumption,freeze-dryingtime,appearancesshapeandcolorsoftheproductsduringtheprocessofvacuumfreeze-drying.Theresultsshowedthattheeutecticpointandtheconso
6、lutepointoflithc’spulpmaterialswere-26℃and-20.0℃inthevacuumfreeze-drying,respectively.Inthesolutionof0.6%cit⁃ricacidor0.4%citricacid+0.2%VCwithimmersingtimefor20minweregaventhebestcolor-protectingef⁃fects.Attheconditionoffirstdryingtemperatureunder80℃,materialmaximumtemperatureof50℃duringsublimati
7、onstage,andthecombinationofthevacuumvalueindryingchamberrangedfrom60Pato70Pa/from60Pato70Pa,couldsavetheenergyconsumption,shortenthefreeze-dryingtimeandimprovedtheap⁃pearancesshapeandcolorofthevacuumfreeze-drying
