Nutritional and functional composition of flours from sprouted and unsprouted quinoa (Chenopodium quinoa) and amaranth (Amaranthus) grains

JIMENEZ M.D.; LOBO M.; SAMMÁN N.

Conferencia; XII International Food Data Conference (12 IFDC); 2017

Germination of grains produces changes that may affect the nutritional properties and technological characteristics of their flours. The aim was to study changes in 3 quinoa flours (Chenopodium quinoa) varieties and 2 amaranth flours (Amaranthus) varieties when they were germinated under controlled conditions of temperature and humidity (T=22-24°C, H=80-90%). Proximal composition, protein digestibility, resistant and digestible starch, soluble, insoluble and total fibers were determined by AOAC methods. Also, total and reducers sugars (Dinitrosalicylic acid method), total phenolic compounds (Folin-Ciocalteau reagent), flavonoids (Aluminum chloride) and antiradical activity (DPPH) were determined. Protein fractions were separated by SDS-PAGE (with and without β-mercaptoethanol, for disulfide bonds determination); in starches amylose/amylopectin ratio was determined (Spectrophotometric method). With germination, protein content and digestibility increased, as well as reducing and total sugars, fiber, total phenols and antioxidant capacity. The increase for each variable was: i)Quinoa: protein content from 13 to 16%, digestibility from 61 to 87%, reducing sugars from 4 to 43%, total sugars from 14 to 52%, total fiber from 12 to 14%, total phenols from 73% to 146%, flavonoids from 9 to 15% and antioxidant capacity from 27 to 10% (IC50). ii)Amaranth: protein content from 12 to 15%, digestibility from 72 to 87%, reducing sugars from 5 to 29%, total sugars from 13 to 39%, total fiber from 12 to 18%, total phenols from 48 to 91%, flavonoids from 3 to 4% and antioxidant capacity from 28 to 16% (IC50). Apparent amylose content increased in starches (from 7 to 14% in quinoa and from 1 to 11% in amaranth), possibly due to amylopectin dextrinization. The increase of sugars in both cases is probably due to the partial hydrolysis of the starch, which decreased. In quinoa protein degradation was observed in fractions with molecular weights higher than 24 kDa while in amaranths occurred in all the whole molecular weight range (14-66 kDa). The results show that germination improves the nutritional contributions of the quinoa and amaranth flours; as the starch content decreases, different rheological behavior could be expected, which is important if they will be used as ingredients in food formulations.