Comparison of physicochemical properties of β-glucans extracted from hull-less barley bran by different methods

In this study, four extraction methods, including ultrasonic extraction (UE), hot water extraction (HWE), microwave extraction (ME), and microwave-assisted ultrasonic extraction (MUE) were utilized to extract β-glucan from hull-less barley bran. Extraction yields and physicochemical properties of β-glucans extracted by different methods were investigated. The MUE displayed a highest extraction yield (2.16%) within shorter extraction time. Besides, β-glucans extracted by MUE (MUE-G) had higher number-average molecular weight (M_n) (3.415 × 10⁵), whereas β-glucans extracted by UE (UE-G) showed lower M_n (2.257 × 10⁵) as compared to other methods. Accordingly, apparent viscosity of MUE-G was highest, while water solubility index of UE-G was highest (34.18-88.81%) at tested temperature ranges (25-95 °C). The MUE-G shower stronger foam stability and emulsifying properties and weaker foaming capability, while UE-G exhibited stronger foaming capability. The foaming capability and emulsifying properties of β-glucan products were better in neutral solutions (pH = 7) than in the acidic (pH = 4) and alkaline (pH = 9).