Effect of Time of Evaluation on Alkali Spreading Values

Abstract

The gelatinization temperature of the endosperm starch, a test of rice cooking quality, is estimated by the extent of spreading and clearing of milled rice treated with a 1.7% solution of potassium hydroxide for 23 h at 30 degrees Celsius. Grain with low gelatinization temperature dissolves completely; the endosperm of grain with intermediate gelatinization temperature spreads partially; rices with high gelatinization temperature are essentially unaffected. The effect of time of exposure was studied in the alkaline test using 41 Argentinian and United States varieties and lines of rices with alkali spreading values ranging from 2.62 to 7 in a random split-plot design with 3 replications. The alkali test was evaluated at 6, 12, 18, and 23 h following the original method. No significant difference in the varietal reaction was noted between alkali exposure at 18 and at 23 h.