Dissolution of (1-3),(1-4)-?-Glucans in Pressurized Hot Water: Quantitative Assessment of the Degradation and the Effective Extraction

[摘要] The purpose of this work was to study the behavior of (1-3)(1-4)-?-D-glucan in pressurized hot water. For this purpose, solid ?-glucan (450?kDa) was put in water and heated at different temperatures (120, 150, and 170°C) for different times (5 to 360 minutes). At 120°C it was found that the highest soluble ?-glucan concentration was measured after 60 minutes; at 150 and 170°C optimal times were 45 and 20 minutes, respectively. The maximum amount of ?-glucan dissolved in each of the optimal conditions was 1.5, 2.2, and 2.0?g/L, respectively. Under those conditions an important reduction was observed in the molecular weight: at 120°C and 60?min it was 63?kDa; at 150°C and 45?min it was reduced down to 8?kDa; and at 170°C and 20?min it was only 7?kDa. Besides this reduction in the MW some hydrolysis products, such as glucose and HMF, were observed. These results revealed the convenience of using PHW to dissolve ?-glucans since the operation times, compared to the conventional process (55°C, 3?h), were reduced despite the fact that the MW was significantly reduced once the ?-glucan was dissolved; therefore, PHW can be used to extract ?-glucans from barley under controlled conditions in order to prevent severe degradation.

[学科分类] 有机化学