Psyllium dietary fiber or high-methoxyl pectin to improve the quality of quinoa and rice extrudates in an industrial extrusion line

The addition of dietary fiber in extruded products has been a major challenge for industries due to its effect on the expansion and texture of the snack. In this work, the supplementation of extruded quinoa and rice with high methoxyl pectin or psyllium was evaluated on an industrial extrusion line. The results showed that all snacks with psyllium had a similar expansion to the control (p>0.05), while those with 5 or 7 % pectin had a lower expansion (p<0.05). It was also found that pectin increased the absorption and water solubility index of the snacks, obtaining values between 6.36 - 6.7 g/g and between 20.5 - 26.1 % respectively. It was also found that the addition of fiber improved (p<0.05) the antiradical activity (ABTS and DPPH methods), the reducing power (FRAP method) and the total phenolic content (TPC) with respect to the control sample. Finally, it was found that the hardness and crunchiness of the snacks were improved (p<0.05) when psyllium fiber was mainly used. It is concluded that psyllium is a better alternative in terms of the expansion and texture of snacks, while pectin provides greater hydration capacity and antioxidant properties (FRAP, DPPH, TPC).