Superheated steam processing of oat groats

Superheated steam (SS) processing of oat groats with a lab-scale SS processing system was studied as a method of heat treatment alternative to commercial processing (kiln drying) of groats. The objective of this study was to determine conditions of SS processing necessary to obtain groats with inactivated peroxidase, moisture content and colour comparable to commercially processed groats, but with pasting properties unique to those obtained in commercial processing. Raw or moisture tempered oat groats (∼13 g) were processed with SS at varying processing times (1-30 min) depending on steam temperature (110-160 °C) and velocity (0.35 and 1.00 m/s) used. Generally, groats processed with SS exhibited higher cold paste (64 °C) viscosity than the groats processed commercially. Oat groats processed with SS to final moisture content of 9-10/100 g (wet basis, wb) or less were peroxidase negative. The parameters of SS selected for processing of oat groats were: temperature of 110 °C, a velocity of 1.00 m/s, and two processing times (10 and 14 min). These parameters gave groats with inactivated peroxidase, moisture content at ∼9.5/100 g (wb), significantly (P < 0.05) brighter colour, and significantly higher cold paste viscosity compared to that of groats processed commercially.