【摘要】 本试验选用市售三种品牌纯牛奶,在不改变热值测定原理的条件下,用W ZR-1A型微电脑自动热量计对液体奶热值直接测定方法的操作、步骤进行了探索与改进.提出了恒温水浴(60℃)浓缩、脱脂棉无损转移、真空干燥(60℃)的液体奶热值直接测定方法.经对市售三种品牌纯牛奶热值测定,A品牌热值2456.44 J/m l±40.56;B品牌热值2688.74 J/m l±48.00;C品牌热值2677.90 J/m l±50.07;变异系数1.65%;1.79%;1.87%.测试结果表明,该改进法具有测定热值稳定、重复性好、标准差与变异系数小、耗时短、易于操作等优点.更多还原

【Abstract】 This experiment select three brands of pure liquid milk products.Based on the same principle of detemining calorific value,we make some study and improvement by using WZR-1A automatic calorimeter on the operation and steps which the method to dete mine directly for calorific value of liquid milk product.We provide the method to detemine directly for calorific value of liquid milk product within heat the sample with aqueous solution of separate under condition to constant temperatune(60℃)and concentrate the sample,Absorbent cotton transfer completely,vacanm dry(60℃).Through the detemining calorific value of three brand of pure liguid milk products,calorific value of A brand is 2456.44J/ml ±40.56;calorific value of B brand is 2688.74J/ml ±48.00;calorific value of C brand is 2677.90J/ml ±50.07,coefficienf of variation are 1.65%,1.79%,1.87%.The resalts showed that this improving method have such advantages as to detemine date stability,well-repeatability,small coefficient of variartion and standard deviation;easy to operate,expend time to shorting.更多还原