牛肉高压冷冻过程中热变化和冰晶形态研究  

Thermal Behaviors and Ice Crystal Properties in Pressure Shift Freezing of Beef

作　　者：苏光明 Hosahalli S.Ramaswamy 于勇 胡菲菲 徐梦龙 朱松明 

机构地区：[1]浙江大学生物系统工程与食品科学学院 [2]麦吉尔大学食品科学与农业化学学院

出　　处：《农业机械学报》2014年第3期206-214,共9页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金资助项目(31071620);国家高技术研究发展计划(863计划)资助项目(2011AA100801)

摘　　要：以牛肉为研究对象，分别进行高压冷冻和传统冷冻试验，分析了冷冻过程中的热变化和形成的冰晶形态。高压冷冻试验在3个不同的压力下进行，分别为100MPa（-9℃）、150MPa（-15℃）和200MPa（-20％）；传统冷冻（空气冷冻和液体浸没冷冻）在0．1MPa和-20℃条件下进行。试验结果表明：传统冷冻形成的冰晶多数位于组织细胞外，冰晶粗大且不均匀，对组织细胞造成严重的压迫和机械损伤；高压冷冻形成的冰晶体积较小，在样品中分布较均匀，且压力越大，位于胞内的冰晶越多，对样品组织的破坏程度越小。空气冷冻的冻结时间最长（85min），液体浸没冷冻结冰速率较快（5．5min），高压冷冻的冻结时间在100、150和200MPa时分别为2．47、1．22和0．83min；压力越大，卸压时形成的超冷度越大，冰点越低，冻结所需时间越短。Abstract ： The experiments of pressure shift freezing （PSF） and conventional freezing were conducted on beef, and the thermal behaviors and ice crystal properties in freezing process were analyzed. The PSF experiments at 100 MPa （ -9℃ ）, 150 MPa （ -15℃ ） and 200 MPa （ -20℃ ） were performed as well as conventional air freezing （CAF） and liquid immersion freezing （LIF） at -20℃ and 0. 1 MPa. The results show that most of the ice crystals formed in conventional freezing is extracellular, the size is large and non-uniform, and severe strain and mechanical injuries has happened on the tissue cells. The crystals formed in PSF have smaller and more uniform size and spread more evenly in samples than that in conventional freezing. And the higher the pressure was, the more crystals formed in intracellular spaces and the less cell injuries happened. The freezing time in CAF is 85 rain, in LIF is 5.5 rain, and is 2.47, 1.22 and 0. 83 rain when subjecting to 100, 150 and 200 MPa PSF treatments; the degree of supercooling formed in depressurization increases with pressure increasing. However, the freezing point drops with and the freezing time needed reduces with the pressure increasing.

关 键 词：牛肉 热变化 冰晶 高压冷冻 

分 类 号：TS251.52[轻工技术与工程—农产品加工及贮藏工程] TB66[轻工技术与工程—食品科学与工程]