作　　者： ; ; ; ;

机构地区： 中国农业科学院农产品加工研究所

出　　处： 《食品科学》 2009年第19期162-165,共4页

摘　　要： 通过对高体细胞数(HSCC,100万个/ml)和低体细胞数(LSCC,30万个/ml)原料乳中纤溶酶进行65～130℃范围内热处理,探究牛乳体系中纤溶酶热变性动力学规律。结果表明:纤溶酶在热变性过程中显示了典型的一级动力学方程(n=1);经不同热处理后,牛乳中纤溶酶活性均下降;65～85℃范围的巴氏杀菌对纤溶酶活性影响不显著(P>0.05),超高温灭菌处理对纤溶酶活性影响显著(P<0.05);HSCC样品在≤110℃范围内的D值都大于LSCC样品,在T=130℃时,HSCC样品的D值为53.76s,LSCC样品D值为58.94s;HSCC和LSCC乳中纤溶酶热失活表观活化能Ea在65～95℃范围内分别为65.76kJ/mol和57.26kJ/mol,在95～130℃范围内分别为22.12kJ/mol和21.48kJ/mol。结论:巴氏杀菌范围内,热处理对牛乳中纤溶酶活性影响不显著,HSCC乳中纤溶酶活性比LSCC乳中的更稳定些;超高温灭菌处理后,两样品中纤溶酶活性明显下降,稳定性无差异。 The thermo-inactivation kinetic law of plasmin in milk was studied by heating high somatic cell count （HSCC） and low somatic cell count （LSCC） milk at 65-130℃, respectively. Results revealed that plasmin inactivation kinetics in milk was in agreement with classic first-order equation. Plasmin activity decreased through heating at different temperatures. No significant difference of plasmin activity was observed after pasteurization at 65- 85 ℃ （P 〉 0.05）, but plasmin activity of either HSCC or LSCC milk exhibited a significant difference through thermal treatments at ultra-high temperatures （P 〈 0.05）. The D value （the time for 90% plasmin inactivation） of HSCC milk was larger than that of LSCC milk below 110℃; however, the D-value was determined to be 53.75 s for HSCC milk and 58.94 s for LSCC milk at 130℃, respectively. The apparent activation energy （Ea） for HSCC and LSCC milk was 65.76 and 57.26 kJ/mol at 65 - 95℃, 22.12 and 21.48 kJ/mol at 95 - 130 ℃, respectively. Therefore, no significant difference for plasmin activity is observed in high and low SCC milk with low temperature treatments （65 -85℃） through pasteurization. Moreover, HSCC milk shows a higher stability than LSCC milk. In contrast, both HSCC and LSCC milk exhibit an obvious decrease in plasmin activity and no difference in thermostability through ultra-high temperature treatments.

关 键 词： 牛乳 牛乳 纤溶酶 热变性 动力学 表观活化能

领　　域： [轻工技术与工程] [轻工技术与工程]