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

SAMMAN N; LOBO M.O; JIMENEZ D

Buenos Aires

Conferencia; 12th International Food Data Conference; 2017

Germination of grains produces changes that may affect the nutritionalproperties and technological characteristics of their flours. The aim was to studychanges in 3 quinoa flours (Chenopodium quinoa) varieties and 2 amaranthflours (Amaranthus) varieties when they were germinated under controlledconditions of temperature and humidity (T=22-24°C, H=80-90%). Proximalcomposition, protein digestibility, resistant and digestible starch, soluble,insoluble and total fibers were determined by AOAC methods. Also, total andreducers sugars (Dinitrosalicylic acid method), total phenolic compounds (FolinCiocalteau reagent), flavonoids (Aluminum chloride) and antiradical activity(DPPH) were determined. Protein fractions were separated by SDS-PAGE (withand without β-mercaptoethanol, for disulfide bonds determination); in starchesamylose/amylopectin ratio was determined (Spectrophotometric method). Withgermination, protein content and digestibility increased, as well as reducing andtotal sugars, fiber, total phenols and antioxidant capacity. The increase for eachvariable was: i)Quinoa: protein content from 13 to 16%, digestibility from 61 to87%, reducing sugars from 4 to 43%, total sugars from 14 to 52%, total fiberfrom 12 to 14%, total phenols from 73% to 146%, flavonoids from 9 to 15% andantioxidant capacity from 27 to 10% (IC50). ii)Amaranth: protein content from 12to 15%, digestibility from 72 to 87%, reducing sugars from 5 to 29%, totalsugars 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 andfrom 1 to 11% in amaranth), possibly due to amylopectin dextrinization. Theincrease of sugars in both cases is probably due to the partial hydrolysis of thestarch, which decreased. In quinoa protein degradation was observed infractions with molecular weights higher than 24 kDa while in amaranthsoccurred in all the whole molecular weight range (14-66 kDa). The results showthat germination improves the nutritional contributions of the quinoa andamaranth flours; as the starch content decreases, different rheological behaviorcould be expected, which is important if they will be used as ingredients in foodformulations.