Formation of 5-hydroxymethyl furfural (HMF) and acetic acid, browning index (BI) and conformational changes in protein structure in infant formula (IF) powders were studied during storage at 25 and 45 °C and relative humidity (RH) range of 11–65%. Three powders with nutritional composition representing stages 1 (IF1), 2 (IF2) and 3 (IF3) of IF were studied. HMF formation in IF powders increased with increasing storage temperature and RH; the increase was highest in IF3 samples. BI showed a linear correlation with HMF concentration, irrespective of variation in product composition. Reduction in pH during storage could be associated with acetic acid formation as a result of Maillard reactions; these were also the likely cause of changes in protein conformation during storage, with decreases in α-helical structure and increases in β-sheets and β-turns observed. Overall, variation in levels of macro-nutrients influenced the degree of change in the commercial IF powders.

在25和45°C和相对湿度（RH）范围为11的储存条件下，研究了婴儿配方食品（IF）粉中5-羟甲基糠醛（HMF）和乙酸的形成，褐变指数（BI）和蛋白质结构的构象变化。 –65％。研究了三种营养成分分别代表IF阶段1（IF1），2（IF2）和3（IF3）的粉末。IF粉末中HMF的形成随储存温度和RH的增加而增加；IF3样品的增加最高。BI显示与HMF浓度呈线性相关，而与产品组成的变化无关。储存过程中pH值的降低可能与美拉德反应导致的乙酸形成有关；这些也是储存过程中蛋白质构象变化的可能原因，α-螺旋结构减少，β-折叠和β-转角增加。总体而言，大量营养素含量的变化影响了商用中频粉末的变化程度。