272 The effect of grain color and pH on sorghum tortilla chips.

N. ZELAYA, H. Yeggy, E. L. Suhendro, X. Quintero, and L. W. Rooney. Cereal Quality Lab, Texas A&M University, College Station, TX 77843- 2474, USA.

The effect of grain color and pH on sorghum chip properties was evaluated. White food type (ATX631 × RTX436) and black (TX430) sorghum masas were adjusted to pH levels of 5, 7 (control) and 11 and processed into tortillas and tortilla chips. Color components were measured. Texture of chips was evaluated in a three point beam bending test using the TA.XT2 Texture Analyzer. Pasting characteristics of defatted chips were determined with a Rapid Visco Analyzer. Grain color and pH levels had a significant effect on sorghum chip properties. Chips produced from black sorghum were dark gray color at high pH and red- black at low pH. White sorghum chips had a yellowish color at high pH and pinkish tan color at low pH. Both types of sorghum chips decreased in hardness as the pH decreased. White sorghum chips were softer than those from black sorghum at high pH and harder at low pH levels. Black and white control chips were similar in texture. For both varieties, chips prepared at high pH levels developed peak viscosity in a shorter time and the peak viscosities were higher than chips at low pH. High pH levels could increase the rate of hydration of starch molecules during pasting. Chips produced from black and white sorghum had acceptable texture and flavor at control and high pH levels. Black sorghum chips were comparable to blue corn chips in flavor, texture and dark appealing color.