Effect of γ-Irradiation on Colour, Functional and Physicochemical Properties of Pearl Millet [Pennisetum glaucum (L) R. Br.] Cultivars

Abstract

Effect of γ-irradiation dose (0–8 kGy) on seed colour, functional and pasting properties of two selected pearl millet cultivars (SOSAT and ZATIV) was investigated. Colour (L*a*b*) of the non- and γ-irradiated pearl millet cultivars was measured, and the deltachroma (∆C), colour intensity (∆E) and hue angle were calculated. Also, loose and tapped bulk densities, swelling capacity, water (WAC) and oil (OAC) absorption capacities of the flours were determined. Pasting characteristics were determined using Rapid Visco Analyser, respectively. The effect of γ-irradiation on L*, a* and b* values within ZATIV cultivar was almost never significant. ∆C and ∆E increased up to 4 kGy but decreased with increased γ-irradiation dose up to 8 kGy. Loose and packed bulk densities, and WAC were not significantly affected by γ-irradiation. The OAC of the SOSAT (1.16–1.36 g/g) was not significantly affected but the ZATIV (0.94–1.34 g/g) was significantly affected by γ-irradiation. The WACs of non-irradiated SOSAT and ZATIV pearl millet flours were 1.42 and 1.33 g/g while the irradiated counterparts varied from 1.15 to 1.42 and 1.24 to 1.39 g/g, respectively. Peak, trough, final, and setback viscosities decreased significantly (p < 0.05) with increased γ-irradiation dose. As irradiation dose increased, the peak time of SOSAT and ZATIV pearl millet cultivars significantly (p < 0.05) decreased from 5.84 to 5.07 and 5.58 to 4.94 min, respectively. However, pasting temperature of non-irradiated (61.80 °C) pearl millet was not significantly higher than the γ-irradiated (61.58–62.08 °C) samples.