Effect of drying temperature on quality of β-glucan in white oat grains Avaliação da temperatura de secagem na qualidade de β-glicanas em grãos de aveia branca

Oats have received attention because of their nutritional characteristics, especially their high-quality content of β-glucan. The drying process reduces water content; therefore they can be preserved for long periods. However, high-temperature drying process may affect the physical, chemical, and functional properties of the grains. The objective of this study was to evaluate the effect of different drying temperatures on β-glucan quality in oat grains. Grains of oats (Avena sativa, L.), cultivar Albasul, harvested at harvest moisture content of 23% were submitted to stationary drying at air temperatures of 25, 50, 75, and 100 °C until they reached 13% moisture content. The β-glucan content was determined in samples of oat grains and extraction was performed using water as solvent at 90 °C. The β-glucan extract was evaluated for water holding capacity, water retention capacity, capacity of displacement, and gelation properties. Stationary of oat grains at air temperatures above 25 °C decreased the water holding capacity, whereas the content of β-glucan and the water retention capacity of β-glucan extract was affected at temperatures above 50 °C. Physical changes such as increased gelation capacity of the β-glucan extract occurred following drying at air temperature over 75 °C.