Abstract: A new method for predicting the shelf life of milk powder based on the global stability index (GSI) theory was established. Under the accelerated storage conditions at different constant temperatures (20, 30, 40 and 50 ℃), changes in sensory quality, vitamin C content, hydroxymethyl furfural (HMF) content and water activity were monitored for the purpose of establishing the shelf life prediction model. Results demonstrated that the calculated values of GSI were satisfactorily fitted to a zero-order kinetic model. The activation energy and the pre-exponential constant were 49.47 kJ/mol and 4 474 924, respectively. The absolute value of relative error between the predicted and observed GSI values was within 20%. The product shelf life at 20, 30, 40 and 50 ℃ was calculated to be 147.5, 75.5, 40.3 and 22.4 d, respectively. The established model could effectively predict the shelf life of milk powder at storage temperatures in the range of 20 to 50 ℃.

Key words: milk powder, shelf life, temperature, global stability index, predictive model

摘要： 建立基于全面稳定性指数（global stability index，GSI）理论预测乳粉保质期的新方法。基于恒温加速实验，测定乳粉于20、30、40、50 ℃贮藏温度下感官品质、VC含量、羟甲基糠醛含量和水分活度的变化规律，建立乳粉GSI保质期预测模型。结果表明：计算得到的GSI满足零级动力学模型，活化能和指前因子分别为49.47 kJ/mol和4 474 924；GSI实验值和预测值相对误差绝对值在20%内；通过GSI模型预测，获得乳粉在20、30、40、50 ℃贮藏温度下的保质期分别为147

关键词: 乳粉, 保质期, 温度, 全面稳定性指数, 预测模型