Molecular Weight Distribution and (1→3)(1→4)‐β‐d‐Glucan Content of Consecutive Extracts of Various Oat and Barley Cultivars

ABSTRACT The content and molecular weight (MW) of β‐glucan in extracts from a selection of oat and barley cultivars were compared using flow‐injection analysis and high‐performance size‐exclusion chromatography. From 60 to 75% of the β‐glucan was extracted from oat and waxy barley by hot water (90°C) containing heat‐stable α‐amylase, whereas just 50–55% was extracted from nonwaxy barley. Consecutive extractions with hot water and dimethylsulfoxide (DMSO) extracted 65% (nonwaxy barley) or 75–80% (oat and waxy barley) of the total β‐glucan. An extraction with sodium hydroxide and sodium borohydride (NaOH/NaBH 4 ) increased the percentage of β‐glucan extracted to 86–100% but decreased the MW. The MW of β‐glucan in the oat cultivars selected was significantly higher than those in the barley cultivars. The β‐glucan extracted from the nonwaxy barley cultivars showed significantly higher peak MW than that from the waxy barley cultivars.