Delineating the effect of gaseous ozone on disinfestation efficacy, protein quality, dehulling efficiency, cooking time and surface morphology of chickpea grains during storage

Abstract

Ozone is one of the acceptable and economically viable techniques for treating grains during storage for its residue-free and environment-friendly nature. A laboratory-scale and pilot-scale ozone disinfestation system for chickpea grains was developed. Chickpeas conditioned to different moisture levels (10, 12, 14% wb), infested with Callosobruchus maculatus were stored at different temperatures (15, 23, 31 °C), with varying bed thickness (50, 75, 100 mm), and samples were disinfested by ozone gas at different concentrations (500, 750, 1000 ppm). Ozone concentration, moisture content of the grain, grain bed thickness, and storage temperature had significant (p < 0.01) effects on the disinfestation of C. maculatus insects. 100% insect mortality (adult and egg) and 79% germination were achieved when treated at 1000 ppm ozone for 5 consecutive days. The optimum treatment parameters were tested in pilot-scale bins (250 kg) and the germination ability, protein, milling, and cooking qualities of chickpea grain were evaluated after 6 months storage period. The protein content, germination ability, surface morphological analysis, milling, and cooking time were shown to profoundly deteriorate in the untreated samples as a contrast to that of the ozone-treated samples. Ozonation at higher doses resulted in the crack generation on the surface of the insect eggshell (5–38 μm) and chickpea pericarp (326–711 nm), with added advantages of improved dehulling efficiency of chickpea by 3.1% and reduction in the cooking time by 15 min. The SDS PAGE profiling exhibited major deviations in the protein bands in the stored chickpea. The essential amino acids (EAA) and total amino acids (TAA) decreased in the ozone-treated sample and control sample with storage; however, major deterioration was observed in the control sample stored for 6 months.