Effect of storage conditions on the physicochemical properties of infant milk formula powders containing different lactose-to-maltodextrin ratios

•Infant milk formula (IMF) powders were made at three lactose-to-maltodextrin ratios.•Effect of storage conditions on the stability of IMF powders was evaluated.•Incorporation of maltodextrin minimized crystallization and caking during storage.•IMF powders can be stored at 22 °C up to 23% RH without deterioration for 180 days.•The outcomes will help the IMF manufacturers to produce better quality powders. This study investigated the effect of storage parameters on the physicochemical changes of spray-dried infant milk formula (IMF) powders prepared with various lactose-to-maltodextrin (L:M) ratios (L:M 100:0, L:M 85:15 and L:M 70:30). Powders were characterized during 180 days of storage at 22 and 40 °C and relative humidity (RH) of 11, 23 and 54%. IMF powders were found mostly stable at both temperatures up to 23RH. Deteriorative physicochemical changes were observed at 54RH which were more rapid at 40 °C than at 22 °C. Increasing temperature and RH during storage decreased the glass transition temperature (Tg) to