Effect of precooking on antinutritional factors and mineral bioaccessibility in kiwicha grains

Abstract

Kiwicha is the most important genus of Amaranthus and has a high mineral content. However, it contains antinutritional factors that may influence their bioaccessibility. Thus, the aim of our study was to evaluate the effect of precooking on antinutritional factors and mineral bioaccessibility of iron, calcium and zinc in kiwicha grains. Puffed kiwicha (PK) had the highest bioaccessibility and potential contribution (PC) of iron. The bioaccessibility of zinc was reduced in PK and laminated kiwicha (LK). The heat treatment decreased the content of: total dietary fiber (11–14%), bound fraction (15–36%) and total polyphenols (15–16%) and inositol hexaphosphate (19–27%). Phytic acid free fraction and total polyphenols, values exhibited a high negative correlation with iron, calcium and zinc bioaccessibility. On the other hand, iron bioaccessibility improved with puffing and therefore PK had the highest PC to requirements for children (4–8 years old), pregnant women and aging adults. Puffing and lamination processes increased the calcium bioaccessibility but decreased that of zinc. We concluded that the precooking of kiwicha grain influenced on antinutritional factors and, consequently, the minerals bioaccessibility. It would be important to study the effect of other processes and the use of enhancers to improve mineral bioaccessibility and potential contribution.