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Physico-functional, thermo-pasting and antioxidant properties of microwave roasted sorghum [Sorghum bicolor (L.) Moench]

Sharanagat, Vijay Singh, Suhag, Rajat, Anand, Pulkit, Deswal, Gaurav, Kumar, Rohit, Chaudhary, Archit, Singh, Lochan, Singh Kushwah, Omkar, Mani, Saravanan, Kumar, Yogesh, Nema, Prabhat K.
Journal of cereal science 2019 v.85 pp. 111-119
2,2-diphenyl-1-picrylhydrazyl, Sorghum bicolor, antioxidant activity, baked goods, bulk density, celiac disease, color, flavonoids, gelatinization, pasting properties, roasting, sorghum flour, starch, temperature, viscosity
The present study investigated the effects of microwave roasting on physical, thermal, functional, pasting and antioxidant properties of sorghum. The results demonstrate a significant (p < 0.05) reduction in sorghum bulk density upon roasting (778–546 kg/m3). Roasting increased the total colour change and browning index from 14.8 to 48.2 and 17.9 to 64.8, respectively, but decreased the lightness ‘L*’ from 83.1 to 50.6. Onset temperature, peak temperature, and end temperature for the amylose-lipid complex decreased by 21.00%, 19.01%, and 17.03%, respectively. Similarly, peak viscosity, pasting viscosity, breakdown viscosity and setback from the trough decreased from 2295 to 35.42, from 26.15 to 16.67, from 984.8 to 8.38 and from 2013 to 17.97, respectively. Non-significant variations in starch gelatinization and functional properties were observed. However, roasting had significant effects on total phenolic content, total flavonoid content and antioxidant properties of sorghum flour changing the corresponding values from 2.64 to 4.67 mg GAE/100 g, from 3.89 to 2.73 mg QE/100 g and from 92.50 to 83.95% DPPH, respectively. Roasted sorghum flour with better functional, pasting and antioxidant properties can be used for the development of various functional and healthy bakery products, which are especially suitable for consumption by the celiac disease population.