Pressurized hot water extraction of β-glucans from waxy barley

Pressurized hot water (PHW) is a new and promising solvent for the extraction of β-glucans from cereals. The effect of temperature, extraction time and pressure has been studied for the extraction of β-glucans from waxy barley (6.0% in β-glucans). Extraction yield, molecular weight and degradation products have been evaluated. Temperature (110–180 °C) and extraction time (15–75 min) showed a strong influence on extraction process. Extraction yield and MW are optimized for 155 °C, 18 min and 50 bar, leading to 53.7% extraction yield and 200 kDa. The presence of degradation products, such as HMF, is negligible under these conditions. The comparison between these optimal results and that from a conventional process (55 °C, 3 h and ambient pressure) reveals a big difference in MW (200 kDa vs. 55 kDa, respectively). PHW causes a significantly reduction in extraction time and an increase of β-glucan MW of almost 4 times as major benefits.

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► PHW reduces the time and increases the MW in the extraction of barley β-glucans.
► Temperature and time show a strong influence on extraction process.
► PHW causes β-glucanase inactivation leading to high MW β-glucans.
► β-Glucans of 200 kDa are efficiently extracted at 155 °C, 18 min and 50 bar.