Moisture adsorption and spoilage characteristics of pea under adverse storage conditions
Field pea is the most produced and exported pulse crop in Canada, and makes a major contribution to Western Canadian agricultural diversification programs. Canada is now the world largest exporter of pea, lentil and chickpea and is fourth in dry bean. The demand for Canadian pulse products is steadily rising and the export market would continue to rise with the expected increased in production. Field pea exported to countries with tropical climates is at particular risk due to rapid loss of quality. It is therefore important to develop practical strategies for safe storage of feed pea. Knowledge on the moisture adsorption and spoilage characteristics of pea stored in adverse storage conditions is important in the transportation and storage of this export commodity. This study was initiated to examine the conditions that lead to quality losses in storage and transport of pea. Tropical and subtropical conditions were simulated in airtight chambers. Relative humidities (RH) of 60, 70, 80 and 90% were created by saturated salt solutions in airtight chambers at temperatures of 10, 20 and 30°C, while the same range of humidity was provided by dilute sulphuric acid in airtight chambers at 40°C in environmental cabinets. The four RH levels at each temperature for both whole and feed-grade pea were tested in duplicate. The samples were observed for changes in moisture content (MC), mold appearance and RH in specific time intervals. The amount of produced carbon dioxide (CO2) was measured in airtight chambers during storage to control the condition existing in sealed airtight chambers. Also, all components of feed-grade pea were exposed to RH of 90% and temperature of 40°C in separate airtight chambers to find the effect of each component on mold appearance. Molds were identified after appearance on the samples in order to pinpoint potential toxicity. Both feed and whole sound peas became molded after a short time of storage at high temperatures and high RH, but those stored at 70% and below did not develop mold after 175 days at 30 and 40°C (experiment duration) and 216 days at 10 and 20°C (experiment duration). Molds were identified mostly as species of Aspergillus and Penicillium. The amount of CO2 in the airtight chambers showed almost no difference from the ambient CO2 except at high temperature and high RH when samples had gone molded. Moisture adsorption equations were developed based on the moisture adsorption data in dynamic environment. Although the Page model showed to fit the data better, the exponential model was chosen to fit the data because its parameters can be better expressed as a function of temperature and RH of the storage environment. The mold-free days for both feed pea and clean pea were modeled at temperatures of 10, 20, 30 and 40°C and RH of 80 and 90%.
DegreeMaster of Engineering (M.Eng.)
DepartmentAgricultural and Bioresource Engineering
ProgramAgricultural and Bioresource Engineering
SupervisorTabil, Lope G.
CommitteeMeda, Venkatesh; Baik, Oon-Doo
Copyright DateMay 2005
whole sound pea