Pressurized aqueous ethanol extraction of β-glucans and phenolic compounds from waxy barley

Óscar Benito-Román; Víctor H Alvarez; Esther Alonso; Maria J Cocero; Marleny D A Saldaña

doi:10.1016/j.foodres.2015.06.006

Pressurized aqueous ethanol extraction of β-glucans and phenolic compounds from waxy barley

Food Res Int. 2015 Sep:75:252-259. doi: 10.1016/j.foodres.2015.06.006. Epub 2015 Jun 6.

Authors

Óscar Benito-Román¹, Víctor H Alvarez², Esther Alonso³, Maria J Cocero³, Marleny D A Saldaña⁴

Affiliations

¹ Department of Agricultural, Food and Nutritional Science, Faculty of Agricultural, Life and Environmental Science, University of Alberta, Edmonton, AB T6G 2P5, Canada; Department of Chemical Engineering and Environmental Technology, Escuela de Ingenierías Industriales, University of Valladolid, Valladolid, Spain.
² Department of Agricultural, Food and Nutritional Science, Faculty of Agricultural, Life and Environmental Science, University of Alberta, Edmonton, AB T6G 2P5, Canada.
³ Department of Chemical Engineering and Environmental Technology, Escuela de Ingenierías Industriales, University of Valladolid, Valladolid, Spain.
⁴ Department of Agricultural, Food and Nutritional Science, Faculty of Agricultural, Life and Environmental Science, University of Alberta, Edmonton, AB T6G 2P5, Canada. Electronic address: marleny@ualberta.ca.

PMID: 28454954
DOI: 10.1016/j.foodres.2015.06.006

Abstract

Beta-glucans and phenolics were extracted from waxy barley using pressurized aqueous ethanol in a stirred batch reactor at 25bar and 500rpm. The effect of temperature (135-175°C), extraction time (15-55min) and ethanol content (5-20%) was evaluated. Temperature had an opposite effect on the extraction of both compounds. The higher the temperature, the lower the β-glucan extraction yield due to fragmentation, but a significant increase on the phenolic recovery was observed. Long extraction times favored the extraction of β-glucans at low temperatures and phenolics at any temperature. The ethanol content was not statistically significant on the β-glucan extraction, but helped to maintain the molecular weight of the extracted β-glucan. To obtain liquid extracts rich in high molecular weight β-glucans and phenolics, mild conditions of 151°C, 21min and 16% ethanol are needed, leading to 51% β-glucan extraction yield with a molecular weight of 500-600kDa and 5mgGAE/g barley.

Keywords: Antioxidants; Ethanol; Extraction; Pressurized hot water; β-Glucan.