β-Glucan Extraction from Hull-Less Barley by a Novel Approach: Microwave-Assisted Pressurized CO2/H2O

Abstract

Β-glucans (BGs) are dietary fibers with human health benefits. Due to their emulsifying, thickening, and water-holding properties, they are frequently utilized in food formulations. Hull-less barley is one of the important sources of BGs. This research was performed to extract BGs from hull-less barley using microwave-assisted pressurized CO₂/H₂O (MW-PCO₂) extraction, a combination that had never been employed before. The MW-PCO₂ extraction conditions (temperature, time and water: barley flour ratio) were optimized using response surface methodology (RSM) with a Box-Behnken design for the maximum BG yield (%). Temperature of 47.74 °C, time of 19.92 min, and water: barley flour ratio of 10.10:1 (g/g) were found to be the optimum conditions for extraction with a BG yield of 62.43%. Additionally, MW-PCO₂ extraction was compared with conventional water extraction (CE) and BG extracts obtained by both methods were characterized. Chemical composition, molecular weight, thermal properties, water solubility, water holding capacity, surface morphology, and Fourier Transform Infrared Spectrum (FTIR) of the BG extracts were determined. MW-PCO₂ extraction gave higher BG yield and purity, molecular weight, and water holding capacity using less solvent in a shorter time. Furthermore, both extracts have similar morphological images, FTIR spectrum, and thermal properties. The results of this work demonstrate the potential of the MW-PCO₂ approach for extracting BGs from hull-less barley with improved selectivity and recovery, which can then be added to a variety of food and drug formulations.