Storage stability of oat groats processed commercially and with superheated steam

Abstract

Storage stability of oat groats processed commercially (conditioning with saturated steam followed by kiln drying) and with superheated steam (SS) was evaluated at room and elevated temperatures (21 and 38 °C, respectively) for 26 and 13 weeks, respectively. Monitoring of hexanal and free fatty acid levels, moisture content, colour, and cold paste (64 °C) viscosity, as well as sensory evaluation of groats were carried out during storage. Both the SS and the commercially processed groats remained shelf stable over the time periods tested. No substantial changes were noted in the colour, cold paste viscosity, and content of free fatty acids of differently heat processed groats as the storage time passed. Changes in the moisture content of stored groats reflected the seasonal changes in the humidity of the surroundings. At both storage temperatures, the amounts of hexanal released from groats processed either with SS or commercially increased with the increase of storage time. However, the groats processed with SS released lower amounts of hexanal than the groats processed commercially. As storage time progressed, both the SS and the commercially processed groats became blander, and it became increasingly difficult for sensory panellists to distinguish between groat samples from the different heat treatments.