121 The effect of starch damage on Chinese steam bread quality.

DAVID R. SHELTON (1) and Gang Guo (1,2). (1) Dept. of Agronomy, University of Nebraska–Lincoln, Lincoln, NE 68583-0915; (2) Cereal, Oil Chemistry Research Institute, No. 11 Baiwanzhuang ST, Beijing 100037, P.R. China.

The damaged starch contents of 353 Chinese commercial flour samples from 18 provinces or cities were investigated. Starch damage content was determined with Chinese National Standard Method GB9826-88. The average of starch damage values was 28.3%, and most values were within the range of 10% to 50%. Each flour was processed into Chinese steam bread. The formula was 100 parts flour, 1% yeast, and about 48% water. After doughs were mixed and fermented for one hour, the breads were steamed for 20 minutes. The final product was evaluated for volume, specific volume, surface appearance, texture, and chewing characteristics. At starch damage values less than 50%, a significant positive linear correlation (alpha = 0.01) was found between damaged starch contents and steam bread quality scores. However, at a damage starch values of 50% or more, the steam bread scores decreased. The negative linear correlation was highly significant (alpha = 0.01). Furthermore, an increase in damaged starch levels caused a decrease in bread volumes. Damaged starch levels within the range of 20% to 50% produced satisfactory steam breads.