Protein and lipid enrichment of quinoa (cv.Titicaca) by dry fractionation. Techno-functional, thermal and rheological properties of milling fractions

Abstract

Separated particle fractions of quinoa flour showed wide variations in the proximate composition and functionality. The fine fraction showed the most similar functional, pasting and rheological properties to the whole grain quinoa flour. The medium size fraction, with the desired particle size for pasta making and an efficient supercritical oil extraction (~500 μm) resulted to be richer in protein, lipids and ash while the coarse fraction was enriched in carbohydrates. Techno-functional, pasting and thermal properties of the quinoa fractions were strongly influenced by their different particle size and composition. However, the rheological properties of gels made from the fine and medium fractions were very similar to each other despite their different composition, and in turn, very similar to those of gels made from whole quinoa. On the contrary, the coarse fraction led to much more consistent gels with elastic and viscous moduli ten and twenty times higher than the standard, whole grain quinoa flour. Therefore, it can be concluded that dry fractionation of quinoa grains is a feasible procedure to tailoring the nutritional profile of the flour and its techno-functional and rheological properties.