Changes in rheological and chemical properties of a Canadian western hard red spring wheat cultivar Neepawa during storage

Abstract

The rheological and chemical properties of stored Canadian western hard red spring wheat (Neepawa) from the 1979 and 1980 crops (freshly harvested) at 12, 16 and 18% moisture contents, stored at different temperatures (30, 40 and 50o C) for various periods (10, 20 and 30 days) were investigated. In order to control the storage conditions of the wheat samples, sealed containers were used to control the moisture level while a controlled environment cabinet and an air oven were used to control the temperatures. The samples at high moisture levels stored at high temperatures for long periods of time developed fungal infestations, which resulted in changes in the organoleptic properties such as color and odor. Storage at three temperatures, as well as storage times, had little effect on the percentage of recovered flour, bran and shorts for the wheat stored at the three moisture levels. The proximate compositions of stored wheat flour samples were directly related to the storage conditions. Ash content, starch damage and free amino acid composition showed marked changes compared to the control, especially in the samples at high moisture levels and high temperatures stored for long period of time. On the other hand, protein content and amino acid composition wre unaffected by the storage conditions. The storage conditions adversely affected the rheological behavior of stored wheat dough as measured by the farinograph, extensigraph and amylograph; the effects were pronounced when the storage conditions such as temperature, moisture and storage period increased. The samples stored at high moisture levels and high temperatures for long periods of time showed a marked decrease in sedimentation value, percent of wet gluten, as well as a significant decrease in loaf volume.