54 Predicting commercial flour milling yield of Chinese wheat by grade and the ratio of kernel weight to length.

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

Test weight is a key factor for wheat grading in P.R. China and the United States. Wheat test weight and grade may be related to flour yield. Sometimes wheat with a higher grade does not have a higher milling yield. Wheat kernel characteristics (weight, shape and size) also may play an important role. In addition to test weight, kernel weight (milligram) per length (millimeter) was used to modify the grade of wheat samples. Then the relationship between wheat grade and flour milling yield was greatly improved for 151 Chinese commercial wheat samples. For example, if the ratio of kernel weight per length was more than 7.0 for Grade 2 Chinese Northern Winter Wheat, the wheat grade was raised one grade. Similarly, if the ratio of weight to length was less than 5.5 for Grade 2 Chinese Northern Winter Wheat, the wheat grade was decreased one grade. Similar adjustments in grades were made for samples of Chinese Southern Winter Wheat and Chinese Spring Wheat. Flour milling yields among wheat classes indicated that Chinese Northern Winter Wheat had higher yields than Southern Winter Wheat and Chinese Spring Wheat classes. This information may be helpful to flour millers in making wheat-purchasing decisions.