Effects of steeping conditions on wet‐milling attributes of amaranth

Abstract

The effect of temperature and SO 2 concentration on fraction yields (starch, gluten and fibre yields) and protein content of starch during wet milling were investigated using response surface method. Soaking time was adequate to accomplish saturation of the grain. A 3 2 factorial design including triplicate of central point was performed. The starch and fibre yields decreased with temperature. The effect of SO 2 on fraction yields was significant; for gluten, the effect was dependent on the level of temperature. The predicted optimum conditions required to maximise starch and gluten yields together with the minimisation of protein content in starch fraction included steeping at 53.9°C (1.6 h) with 0.041 w/v% of SO 2 concentration. The predicted starch and gluten yields were 45.0% ± 1.35% and 17.5% ± 0.80%, respectively. The predicted protein content for starch fraction was 0.60% ± 0.015%. These predicted values were satisfactorily checked by an experiment at optimal soaking conditions.

Mechanical and thermal characteristics of amaranth starch isolated by acid wet-milling procedure

“…The experimental procedure used to isolate amaranth starch allowed for a mean starch yield of 42.2 g/100 g, which contained 3.05 g/100 g protein in average (Calzetta Resio, Tolaba, & Suárez, 2006). Rheological test were performed within the linear viscoelastic region.…”

Correlations between wet-milling characteristics of amaranth grain

“…The isolation of by-products of amaranth grains was made following the acid procedure proposed by Calzetta Resio et al (2006b). The wet-milling tests were performed according to a factorial design 3 2 (see Table 1), each experiment was duplicated, with the exception of the central point of the design that was tripled.…”

Effect of Drying Temperature and Soaking Conditions on Wet-Milling Characteristics of Amaranth Grain

“…The soaking time was enough to accomplish grain moisture saturation, according to previous studies (Calzetta Resio et al, 2006). For this purpose, three different steeping solutions were prepared by dissolving sodium bisulphite in sufficient amount to achieve concentrations of 0.01, 0.03 and 0.05 SO 2 , w/v %, respectively.…”

“…However, various wet-milling procedures at laboratory scales were investigated to isolate starch from amaranth grain (Yanez et al, 1993;Uriyapongson and Rayas-Duarte, 1994;Radosavljevic et al, 1998;Calzetta Resio et al, 2006). Till present, wet milling of amaranth grain is rarely done at industrial scale due to the small size of grain and the difficulty that manual harvesting entails, restricting this input for milling industry.…”