预干燥过程水分分布对热风-真空冷冻干燥桃脆片微观结构与质构的影响  

Effect of Water Distribution during Pre-drying on the Microstructure and Texture Properties of Peach Crisps Produced by Hot Air-Vacuum Freeze Drying

作　　者：于宛加 金鑫 胡丽娜 鲜美林 刘萍 毕金峰[3] YU Wanjia;JIN Xin;HU Lina;XIAN Meilin;LIU Ping;BI Jinfeng(College of Food Science and Engineering,Qingdao Agricultural University,Qingdao 266109,China;Qingdao Institute of Naval Food and Nutrition Innovation(Qingdao Institute of Special Food),Qingdao 266109,China;Key Laboratory of Agro-Products Processing,Ministry of Agriculture and Rural Affairs,Institute of Food Science and Technology,Chinese Academy of Agricultural Sciences,Beijing 100193,China)

机构地区：[1]青岛农业大学食品科学与工程学院,山东青岛266109 [2]青岛海军食品与营养创新研究院(青岛特种食品研究院),山东青岛266109 [3]中国农业科学院农产品加工研究所,农业农村部农产品加工重点实验室,北京100193

出　　处：《食品科学》2023年第15期69-79,共11页Food Science

基　　金：财政部和农业农村部:国家现代农业产业技术体系建设专项(CARS-30-5-02)。

摘　　要：为探究预干燥过程水分分布对热风-真空冷冻干燥桃片微观结构与质构品质的影响,以提升桃脆片综合食用品质,本研究对3个温度(40、60、80℃)热风预干燥过程中桃片的水分分布和升温过程中的温度进行监测,3个温度下各选取干基水分含量分别为7、6 g/g和5 g/g作为水分转换点,进行热风-真空冷冻干燥(联合干燥),对桃脆片色泽、皱缩率、微观结构、孔隙分布、质构特性和吸湿性进行测定和分析。结果表明,温度对干燥过程样品的水分分布有明显影响,但3个温度下水分迁移的总体趋势一致。热风预干燥样品的水分含量越低,联合干燥后样品的色泽越接近鲜样,其中,40℃、转换点水分含量5 g/g的样品色泽最接近鲜样。干燥时间较温度对皱缩率的影响更大,干燥时间较温度对皱缩率的影响更大,干燥至相同水分转换点,40℃较60℃和80℃需要更长时间,样品在预干燥阶段和联合干燥阶段均有明显收缩。真空冷冻干燥样品与联合干燥样品的孔隙结构有明显差异,其中,水分转换点为5 g/g时,孔隙结构最不均匀;联合干燥样品较冷冻干燥样品的平均硬度提高了52.11%,样品预干燥水分含量越低,联合干燥后的硬度越大,通过热风预干燥处理可以有效调控桃脆片的硬度和脆度。与真空冷冻干燥样品相比,联合干燥后样品吸湿率更低,这与预干燥过程形成的结构差异有关。综上,相比于单一的真空冷冻干燥,热风-真空冷冻干燥更有利于改善桃脆片的质构品质和提升贮藏稳定性。In this study,experiments were conducted to investigate the effect of moisture distribution during pre-drying on the microstructure and textural quality of hot air-vacuum freeze dried peach slices.The moisture distribution during the hot air pre-drying process at different temperatures(40,60 and 80℃)and the product temperature during heating were monitored.Three levels of dry-basis moisture content(7,6 and 5 g/g)were selected as moisture conversion points for each temperature.The color,shrinkage rate,microstructure,pore distribution,textural properties and hygroscopicity of peach crisps were measured.The results showed that drying temperature had a great impact on the moisture distribution during the pre-drying process,but the overall trends of moisture mobility were consistent among the different drying temperatures.The lower the moisture content of the pre-dried sample,the closer the color of the final dried sample to that of the fresh sample.The color of the sample dried at 40℃with a moisture conversion point of 5 g/g was the closest to that of the fresh sample.Drying time had a greater effect on the shrinkage rate than temperature.It took longer to dry peach slices to the same moisture conversion point at 40℃than 60 and 80℃.The sample shrank distinctly during both pre-drying and combined drying.There was a significant difference in the pore structure between the freeze-dried and combined dried samples.The sample with a moisture conversion point of 5 g/g had the most heterogeneous pore structure.The average hardness value of the hot air-vacuum freeze dried sample increased by 52.11%compared with that of the freeze-dried sample.The lower the moisture content of the pre-dried sample,the higher the hardness value of the hot air-vacuum freeze dried sample.This study showed that hot air pre-drying can effectively control the crunchiness and hardness of peach crisps.The decrease in the hygroscopicity of the hot air-vacuum freeze dried sample compared with the vacuum freeze dried one may be related to the str

关 键 词：桃脆片 联合干燥 水分迁移 微观结构 质构特性 

分 类 号：TS255.36[轻工技术与工程—农产品加工及贮藏工程]