Calcium analysis and sensory evaluation of amaranth-enriched corn tortillas

Tortillas represent 67% of the daily calories consumed in some countries. Increasing lime level for soaking corn and adding amaranth (high-calcium, high-protein) to tortillas should improve nutritional value. The objectives of this research were to evaluate the nutritive content and sensory acceptability of amaranth-enriched corn tortillas.

Corn (yellow or white) was soaked for 24 hr in limewater (1, 2, or 3% corn weight basis), ground with a stone grinder, formed into masa balls containing 0, 15, or 30% amaranth, pressed into tortillas with a hydraulic laboratory press, and baked on a griddle (236°C). Judges (25) evaluated texture, color, flavor, and overall acceptability of tortillas on 9-point hedonic scales (9=like extremely) in a laboratory study. Panelists (28) also evaluated texture, color, flavor, and overall acceptability of a laboratory-produced and a commercially-produced tortilla in a home placement study. Proximate composition and calcium levels were determined. All data were analyzed by ANOVA.

Texture acceptability increased as lime level increased but was not affected by amaranth level or corn cultivar. Color acceptability decreased as lime level and amaranth level increased. Flavor acceptability was not affected by amaranth level but decreased as lime level increased. Overall acceptability of the tortillas increased with lime level but was not affected by amaranth. Yellow corn tortillas were more acceptable than white corn tortillas for all attributes except texture. No significant differences were found between the acceptability of the laboratory produced and the commercially-produced tortilla.

Tortilla moisture increased as lime increased and as amaranth decreased. Fat content was approximately 7% (dry matter basis) and did not vary with treatment. Protein increased with amaranth content and was higher for white corn tortillas. The pH increased as lime level increased but was not affected by amaranth level or corn cultivar. Ash increased with lime level and amaranth level and was significantly higher in white corn.

Experimental methodology made it hard to accurately measure the contribution of the amaranth to the calcium levels of the tortillas. However, an interaction between amaranth and lime for calcium indicated that amaranth might contribute to calcium content in low-lime (< 1%) tortillas.