The functional attributes of Peruvian (Kankolla and Blanca juli blend) and Northern quinoa (NQ94PT) flours and protein isolates, and their protein quality.

The overall goal of this research was to examine differences in the composition, functionality and protein quality between Peruvian (PQ) and Northern (NQ) quinoa flours, and their isolates prepared by alkaline extraction/isoelectric precipitation. In the case of the flours, PQ and NQ were comprised of 13.6% and 12.8% protein, respectively. Water hydration (mean value = 1.65 g/g) and oil holding capacities (mean value = 1.75 g/g) of both flours were similar, whereas solubility increased from pH 3 to 7 for both flours, but was higher for PQ. Flours were non-foaming at pH 3, but showed increased foam capacity as the pH increased from 5 to 7, but was higher for PQ. Similar foam stability was found for both flours. Emulsion stability (ES) was similar for both flours, and increased from pH 3 to pH 5/7. In the case of the isolates, water hydration capacity was greater for PQ (4.75 g/g) than NQ (2.85 g/g), whereas oil holding capacity was similar (mean value = 8.6 g/g). For both isolates, solubility was minimum at pH 5.0 and maximum at pH 3/7, with NQ being higher. Isolates showed 2-3 times the foam capacity as flours, the magnitude of which was cultivar and pH dependent. Foam stability was lower at pH 5 than at pH 3/7, whereas ES followed a similar pH effect. Tyrosine and phenylalanine were limiting in both flours, whereas threonine was limiting in both isolates. In vitro protein digestibility corrected amino acid scores for the flours was higher for PQ (56.8%) than NQ (47.7%); however, the reverse was observed for the isolates (NQ, 62.1%; PQ, 58.9%).

Physicochemical, structural, and thermal properties of "batata-de-teiú" starch.

Jatropha elliptica (Pohl) Muell Arg is a sub-shrub herbaceous plant native to the Brazilian Cerrado, and popularly known as "batata-de-teiú". There is lack of scientific knowledge about the structural characterization, physicochemical and technological aspects of the carbohydrate content present in Jatropha elliptica roots. Thus, this work aim contributes with new data about the evaluation of chemical-structural, thermal and technological properties of starch extracted from "batata-de-teiú". The starch presented low levels of ash, protein and total fiber and amylose content of 32.82%. The initial gelatinization temperature of "batata-de-teiú" starch was 70.1 °C, peak temperature was 73.84 °C and final 85.52 °C, and starch had low trend to retrogradation. The results of x-ray and 13C cpmass show a A-type structure with high crystallinity degree. Finally, this results suggested that the "batata-de-teiú" starch is a macromolecular structure with high branching degree, favoring intermolecular Coulomb, Van der Waals forces and hydrophobic interactions, which directly corroborated with the low solubility observed (maximum of 6.44 g·100 g-1 at 80 °C). The extraction of "batata-de-teiú" starch can be viable, and it has technological characteristics suitable for use in the food industry or pharmaceuticals, since "batata-de-teiú" starch has good thermal stability and low trend to retrogradation.