Novel continuous roasting of chickpea (Cicer arietinum): Study on physico-functional, antioxidant and roasting characteristics

- Novel continuous roasting of chickpea works without sand medium.
- Method reduces roasting time and exposure of food product to impurities.
- Continuous roasting (250 °C-350 °C) changes thermal and antioxidant properties.
- Final product had good quality and overall acceptability.

Roasting of chickpea is an important step for the development of value added product, performed normally at 150-350 °C using conduction, convection and radiation. In this study, continuous roasting of chickpea grains was performed without incorporating sand and using a novel method. The roasting characteristics, physico-functional and antioxidant properties of products obtained through this method at 250, 270, 290, 310, 330 and 350 °C were compared to unroasted grain. The results showed that grains roasted at 350 °C possessed highest puffing index, high expansion index and lowest length/width ratio. Color of roasted chickpea flour changed from light to dark with a simultaneous increase in 'a' and 'b' value. Functional properties in terms of water absorption index and oil absorption capacity were between 1.97-2.99 and 1.25-1.81  g/g respectively. Total flavonoid content of chickpea decreased by 10% while an increase occurred in total phenolic content (46%) and antioxidant activity (60%) respectively. FTIR and DSC profiles of roasted grain flour indicated changes in different functional groups and crystalline nature of starch. This method demonstrated that chickpea may be roasted effectively without any contamination in lesser time compare to other processes. Novel continuous roasting therefore could be considered for chickpea roasting industry.