EFFECTS OF MOISTURE-TEMPERATURE REGIMES ON STORAGE OF YELLOW MUSTARD SEEDS (SINAPIS-ALBA L)

Biochemical and mycological changes in yellow mustard seeds stored at temperature-moisture levels typical of commercial storages in western Canada were monitored for 147 days under declining and constant temperature regimes. Parameters assessed included the following: time required for development of off-odours and visible mould, free fatty acids, conductivity (seed electrolyte leakage), germination, occurrence of particular fungi and their association with off-odours, oil content and seed colour. Of the quality parameters monitored, the presence of off-odours was most closely related to the onset of deterioration in quality of stored yellow mustard. Post-harvest Eurotium spp were associated with the development of off-odours. Conductivity increased and germination decreased at 44 degrees C. Generally, Eurotium spp increased and Alternaria decreased in seed stored at high temperature and moisture conditions. In samples stored at an initial temperature of 31 degrees C and 110 g kg(-1) moisture content (MC), off-odours occurred by 28 days and visible mould by 63 days; at 31 degrees C and 98 g kg(-1) MC no off-odours or visible moulds were present after 147 days. Moisture content/ temperature/time safe storage guidelines were derived from the laboratory data and related to yellow mustard data collected from farm bins in Manitoba and Saskatchewan. The guidelines are intended for estimating yellow mustard storability, particularly during the first 5 months after binning by producers and grain handlers in the northern continental climatic zones of western Canada. Yellow mustard is less likely to spoil than canola under the same seed moisture, temperature and time storage conditions.