Factors affecting storage life of farm-stored field peas ( Pisum sativum L.) and white beans ( Phaseolus vulgaris L.)

Abstract

Deterioration in seed quality of initially sound field peas ( Pisum sativum L. ‘Titan’) and white beans ( Phaseolus vulgaris L. ‘Seafarer’) during storage for 147 days was studied at temperature-moisture levels typical of storages in Manitoba. Time required for development of off-odors and visible mold, fat acidity value (FAV), conductivity (seed electrolyte leakage), germination, occurrence of particular fungi and their association with off-odors, and other parameters of seed quality were assessed. Spoilage increased as temperature and moisture increased, as shown by rate of development of off-odor, and FAV, conductivity and germination levels. Off-odors developed more rapidly in the peas than in the beans at the same temperature and comparable initial moisture contents. In beans, Eurotium species ( Aspergillus glaucus) levels after 147 days were low except at high moisture contents. In peas, Eurotium levels were higher but peaked at intermediate moistures. Beans suffered severe germination loss under less extreme conditions than peas. There were strong associations among most of the storage quality parameters studied, except for some fungi that occurred at low levels. In peas stored at an initial temperature of 31°C and 14.5% moisture content (m.c.), and beans at 31°C and 14.2% m.c., off-odors occurred within 63 days. No off-odors were detected after 147 days in peas initially stored at 22°C and 14.5% m.c. or in beans at 22°C and 14.2% m.c. Moisture content/temperature/time storage guidelines were derived from the laboratory data and related to data collected from farm bins in Manitoba. The guidelines are intended for estimating storability of the two crops during the first 5 months after binning in climatic zones typical of western Canada and the northern U.S.A.