Influence of Gaseous Ozonation on Bio-Techno-Functionality, In Vitro Nutrient Digestibility, and Molecular Properties of Red Sorghum Flour

Abstract

ABSTRACT The current investigation aimed at evaluating the effect of different applied ozone dosages of 32.0, 38.0, 44.0 and 50.0 g.kg−1 on techno-functional properties, structural properties, molecular interactions and thermal properties of red sorghum flour. Ozonation led to an increase in the water absorption capacity (1.79 to 2.15 g/g), water solubility index (1.59 to 5.13%), oil absorption capacity (1.27 to 1.71 g/g), swelling power (7.68 to 8.31 g/g), foaming capacity (10.14 to 13.91) and stability and paste clarity (19.35 to 34.30%T); however, there was a decrease in the gel consistency (95.50 to 40.20 mm), flour dispersibility (92.36 to 89.21%), emulsion activity (8.50 to 7.00%) and stability (32 to 22.20%). This alteration in the functional properties could be attributed to the cleavage of various groups due to oxidation and resulting in increased electronegativity. Ozonation enhanced the total phenolic content (226.34 to 276.23 mg GAE/100 g), FRAP activity (8.14 and 12.65 µmol TE/g), in vitro starch digestibility while reduced the total flavonoid content (605.26 to 582.15 mg QE/100 g), DPPH (10.90 to 9.61%RSA) and in vitro protein digestibility. Scanning electron microscopy and Fourier transform infrared microscopy showed modification in the structure and molecular interaction attributing to the widening of the protein and compactness of the starch. Pearson’s correlation coefficient and Principal component analysis (PCA) were employed for studying the relationship between different variables and for validation of changes due to ozonation.