Isolation of Functional Components β-Glucan and γ-Amino Butyric Acid from Raw and Germinated Barnyard Millet (Echinochloa frumentaceae) and their Characterization

The study was carried out to analyze the characteristics of two functional constituents' viz. gamma-amino butyric acid (GABA) and beta-glucan extracted from raw and germination barnyard millet (var. PRJ-1). A significant (P <= 0.05) effect of germination (sprouting) was observed in yield, chemical composition, functional, rheological and antioxidant properties of beta-glucan and GABA. The yield of GABA extract was 12.34% and the content increased from 6.37 mg/100 g in raw to 35.70 mg/100 g in germinated sample. The DPPH, total antioxidant and hydrogen peroxide scavenging activities of GABA extract increased after germination from 45.34 to 65.34%, 15.3 to 33.3 millimole/g and 38.4 to 64.7 millimole/g, respectively. The yield of beta-glucan extract of raw and germinated flour was 6.05 and 5.01% whereas the beta-glucan contents were 83.30 and 79.64 %, respectively. The functional properties of beta-glucan i.e., swelling power, water binding capacity and DPPH scavenging activity increased from 1.45 to 1.76 g/g, 2.13 to 2.32 g/g and 44.39 to 57.42 %, respectively, after germination. Similarly there was an increase in the storage modulus after germination process which attributes a better viscoelastic capacity of beta-glucan at low frequencies. The results exploit that the beta-glucan and GABA might promise a polymeric incipient to be implemented as food additives with variable functional and structural characteristics.