Influence of Temperature on the Extractibility of Polysaccharides in Barley

Abstract

Barley contains substantial amounts of both soluble and insoluble non-starch polysaccharides (NSP). The main water soluble NSP in barley are highly viscous β-glucans. Monogastric animals, including humans and birds, cannot synthesize β-glucanase, and the amount of β-glucanase derived from barley grain and bacteria in the gastrointestinal tract is insufficient to completely hydrolyze β-glucans. In the present investigation, we have studied the influence of temperature and heating time on the extractibility of soluble polysaccharides in barley. Heating the barley samples at 60°C and 80°C before extraction has the effect of lowering the soluble fraction of the polysaccharides. The dynamic viscosity values of water extracts from barley decreased up to 21.68% when heating at 60ºC for 15 minutes, and up to 25.30% when heating at 80ºC for 15 minutes, when the determinations were made immediately after extract separation. Heating the barley samples for 15 minutes at 80°C deactivates the endogenous hydrolytic enzymes.

Keywords

• barley
• dynamic viscosity
• non-starch polysaccharides