The effect of gamma irradiation treatment on quinoa flour: Quantification of saponin, phytic acid, antioxidant activity, and oxidative properties

Abstract

Quinoa (Chenopodium quinoa Willd) has been considered a good source of nutrients and natural antioxidants, including phenolic compounds. However, the presence of anti-nutrient compounds in the quinoa, including saponin and phytic acid, has limited its consumption. The current study aimed to determine the effects of different doses of gamma irradiation (0.5, 1, 2.5, 5, 7.5, and 10 kGy) on saponin, phytic acid, total phenolic compounds, and antioxidant activity (DPPH and FRAP) of quinoa flour. Then, the oxidation parameters, including Free Fatty acid, peroxide value, and TBARs, were investigated. Also, the foaming capacity and foaming stability of irradiated samples were studied. Results indicated the significant impact of gamma irradiation on the reduction of saponin (about 77% at 10 kGy) and phytic acid (about 36% at 10 kGy) up to 10 kGy. Increasing the irradiation dose from 0.5 to 10 kGy decreased the TPC, TFC, DPPH, and FRAP values. While at a dose of 2.5 kGy irradiation, a slight increase in all parameters was observed. Also, the peroxide value and T-BARS increased by increasing the irradiation dose, while the free fatty acid decreased. The foaming capacity (FC) of the quinoa flour was significantly (p < 0.05) increased up to 5 kGy, and the decrease trend was shown up to 10 kGy irradiation. The present study suggested that the gamma irradiation process at a dose of 2.5 kGy could reduce saponin and phytic acid without significantly damaging the antioxidant compounds.