Extrusion-cooking affects oat bran physicochemical and nutrition-related properties and increases its β-glucan extractability

Abstract

In this study, we investigated if extrusion-cooking can be used to change physicochemical and nutritionally relevant properties of oat bran. The importance of moisture content, last-barrel set temperature and type of extrusion-cooking (single-pass, double-pass, acid) on these properties was evaluated using two full factorial design experiments. Acid extrusion-cooking led to a 5.7-fold increase in water-extractable dry matter content and increased β-glucan extractability from 9.4% of total β-glucan content to 70.7% in particular. Double-pass extrusion-cooking led to a 2.6-fold increase in the strong water-binding capacity of oat bran. However, the changes in oat bran properties did not result in a different digestibility or an increased short-chain fatty acid production during in vitro fermentation using faecal microbiota. Results suggest that working with different types of extrusion-cooking and processing conditions allows changing the technofunctional and physiological impact of oat bran before incorporating it in food products.