Effect of frost on the quality of samples of Janz wheat

Abstract

The effect of frost damage on wheat grain quality was examined in samples of an Australian Prime Hard wheat cultivar Janz. Wheat grain samples that were lightly frosted, severely frosted and unfrosted were obtained from the Riverina district of New South Wales. Each frosted sample was separated by sieving into 2 fractions by size using a commercial grader that was equipped with an aspirator. As the degree of frost damage in the samples increased, grain size decreased, flour extraction decreased, flour ash increased, flour colour deteriorated, dough strength decreased, baking quality decreased, α-amylase activity increased and falling number decreased. Quality assessment of the separated grain fractions showed that the large grains (>2 mm) in both lightly frosted and severely frosted crops were equal or better than the unfrosted sample in all tested quality parameters. The large grain fraction fully met the Australian Prime Hard receival standards and was of quality commensurate with the grade. Separation of grain by size was calculated to be commercially viable for up to 50% frost damage. A commercial flourmill purchased frosted feed grain, followed the sieving procedure, and produced large grain consistent with unfrosted wheat that was subsequently used for normal processing.