PHYSICOCHEMICAL AND FUNCTIONAL PROPERTIES OF DIFFERENT QUINOA AND KAÑAWA ECOTYPES STARCH

STEFFOLANI, ME; MALDONADO, G; RIBOTTA, PD; PEREZ, GT; LEÓN, AE

Santiago de Chile

Conferencia; II Conferencia Latinoamericana Cereales; 2011

ICC and Granotec

The objective of this work was to study the physico-chemical and functional properties of starch isolated from different quinoa varieties and kañawa ecotypes regarding their possible uses in cereals-derived food. Four ecotypes of Kañawa (Local, C381, C081 and C300) and three varieties of quinoa (Chucapaca, Kurmi and Jacha grain) from Bolivia PROINPA germplasm bank were analyzed. Starch isolation from quinoa and Kañawa flour was made by means of a combination of procedures (Wright et al. 2002, Lindeboom et al. 2005) with some modifications. The quinoa flour was suspended (1:5) NaHO 0.25% (w/v), shaked and centrifuged. The precipitate was then washed with water and finally the suspension was filtered through a 270 mesh sieve. The collected filtrate was centrifuged and the precipitate (quinoa starch) was dried at 30 °C for 24 h. Kañawa flour was suspended in water (1:3) and the suspension was filtered through a 270 mesh sieve. The retained material was subjected three times to the suspension- filtration procedure. All filtered suspensions were collected and centrifuged. The precipitate was resuspended (1:5) NaOH 0.25% (w/v) and centrifuged. Subsequently, the precipitate was washed with water and then with alcohol. The final precipitate (kañawa starch) was dried at 30 °C for 24 hs. Moisture, protein, lipids, ash and crude fiber contents were determined. Additionally, amylose content of samples was determined using the Megazyme amylose and amylopectin assay kit. A rapid visco-analyser (RVA) was used to determine the pasting properties of starch samples. The granule starch was examined using scanning electron microscopy (SEM). Quinoa and kañawa isolated starches had similar chemical composition but protein, lipid and fiber content was lower for quinoa than kañawa starches. The amylose content varied from 9.30 to 8.35% for quinoa and from 17.44 to 10.70% for kañawa starches. Significant differences in pasting properties were observed among quinoa varieties and kañawa ecotypes, quinoa starches had higher peak (4306 to 3321 cpu) and final viscosity (4108 to 3725 cpu) and lower setback (675 to 963 cpu) than kañawa (peak viscosity = 2656 to 1907 cpu; final viscosity = 3332 to 2786 cpu; setback = 1331 to 1040 cpu). Amylose content correlated negatively with peak viscosity (r = - 0.9, p