Extrusion of 2 quinoa varieties, Cherry Vanilla and Black (scarified and unscarified) and a mixed quinoa variety, Bolivian Royal (scarified and degermed) were studied for their extrusion characteristics. A corotating twin-screw extruder with a 3 mm round die was used. Feed moisture contents of 15%, 20%, and 25% (wet basis) were studied. The extruder barrel temperature was kept constant at 140 °C and screw speeds were varied from 100, 150, and 200 revolutions per minutes. Process responses (specific mechanical energy, back pressure, and torque) and product responses (expansion ratio, unit density, and water absorption index/water solubility index) were evaluated. The degermed Bolivian Royal showed the highest expansion in comparison to all other varieties, attributed to its significantly low levels of fat, fiber, and protein. The scarified Cherry Vanilla resulted in the lowest expansion ratio. This was attributed to the increase in the protein content from the removal of the outer layer. The results indicate that all the varieties performed differently in the extrusion process due to their modification processes as well as the individual variety characteristics.
Background and objectives
Two varieties of hard red spring waxy wheat were extruded with varying barrel temperatures, screw speeds, feed moistures, and screw profiles to determine their extrusion processing characteristics. A nonwaxy control wheat was also extruded to examine differences that occur in the extrusion of waxy wheat.
Findings
It was found that radial expansion ratios of waxy wheat were approximately 4.5 with specific conditions and were similar to expansion ratios obtained from nonwaxy wheat. However, specific mechanical energy requirements for nonwaxy wheat far exceeded both of the waxy wheat varieties to produce this expansion. In doing so, the nonwaxy wheat also produced extrusion pressures that were nearly double that of pressures generated from waxy wheat.
Conclusions
The results demonstrated that hard red waxy wheat may offer a low‐energy extrusion alternative to conventional wheat flour extrusion.
Significance and novelty
This study highlights the differences in the processing energy consumption between hard red waxy wheat and nonwaxy wheat. The results demonstrate that waxy wheat may offer lower operational costs for extrusion and presents excellent potential in the development of new consumer food products.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.