Browsing by Subject "moisture conversion"

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  • Hietala, Antti (Helsingfors universitet, 2010)
    Hectolitre mass (HLM) measurement is one of the oldest and still one of the most widely used methods for assessing grain quality. It indicates the amount of flour available for extraction in milling grains and the feed value of feed grains. Grain quality tests are often performed on grain in its arrival condition. Should arriving grain be above storage moisture, grain drying will change the measurable grain quality, namely HLM, and the actual quality parameters will only be revealed after drying. Sampling grain after drying is not always possible due to practical reasons, for example drying grain in a co-operated or a continuous dryer or a high-capacity commercial dryer. Some grain buyers in Finland use a moisture conversion tables for HLM, which date back to the subsequently repealed national Grain Trade Act. The accuracy of these conversion tables is uncertain. The purpose of the study was to create new moisture conversion factors for HLM, with which high-moisture grain HLM could be reliably converted into postdrying values. Literary research investigated factors affecting grain HLM and factors that cause HLM change during mechanical grain drying. In the experimental part wheat, barley and oats samples, in pre- and post-drying state, were analysed. The amount of HLM change and factors contributing to it, as well as the factors affecting HLM per se, were studied. The results were compared with values found in literary and previous documented studies. It was concluded that the Finnish Grain Trade Act grain moisture conversion tables, along with other literary sources, underestimate the HLM change in all tested grains. In barley and oats the difference was almost threefold, in wheat around one third. The factor with the greatest influence to the HLM among measured parameters was grain moisture. The effect of moisture was the most significant in all grains. In barley the thousand kernel weight was also found to be a highly significant factor affecting the HLM.