Characteristics of β-glucan extracted from raw and germinated foxtail (Setaria italica) and kodo (Paspalum scrobiculatum) millets

Abstract

β-glucan extracted from raw and germinated foxtail and kodo millets were evaluated for its functional, rheological and in vitro antioxidant characteristics. The in vitro activity determined in terms of diphenyl-p-picryl hydrazy (DPPH) radical scavenging activity and Ferric reducing antioxidant power (FRAP) activity was found higher in germinated kodo millet (78.74%, 48.98%) compared to foxtail millet (34.96%, 38.67%), respectively. Water binding capacity and swelling power of β-glucan extract of foxtail millet increased from 2.88 g/g to 3.06 g/g and 1.32 g/g to 1.67 g/g and that of kodo millet from 3.45 to 3.99 g/g and 2.54 to 2.99 g/g, respectively, after germination. There was a significant improvement in foaming capacity and stability of β-glucan after germination. The ‘n’ values were less than unity indicated that β-glucan extracts behaved pseudo-plastic like material. The storage modus (G′) of β-glucan extracts of germinated kodo millet was higher than foxtail millets, as well as overall higher than the loss modulus (G″) indicating a dominantly viscoelastic behaviour and stability. Peak tanδ was lower for germinated foxtail millet compared to kodo millet indicating more stable gel of the former. Therefore, improvements in the functional as well rheological properties of β-glucan could be exploited in food and pharmaceutical industries.