Determination and modelling of EMC characteristics for Manitoba-grown soybeans: A look-up-table for local post-harvest processors

Crop Soybean
Start Date2017
End Date2018
Principal InvestigatorPaliwal, Jitendra, University of Manitoba
MPSG Financial Support$32,746
Total Project Funding$32,746

Research Objectives

The objective of this proposed study is to determine the EMC characteristics for three varieties of soybeans grown in Manitoba. These varieties cover a maximum spread in the seed size for soybeans. Researchers will develop equilibrium moisture content look-up-tables that aid in predicting the final moisture content of soybeans when exposed to air at a certain temperature and relative humidity.

Project Description

The equilibrium moisture content (EMC) is an important physical property that significantly impacts all hygroscopic biomaterial. Knowledge of EMC of grains and pulses including soybeans is essential for efficient post-harvest operations such as drying, aeration, or storage. EMC changes with the variety but is also affected by handling and aeration practices. During storage, seeds undergo many micro-wetting and drying cycles or freezing and thawing cycles, which also affect the sorption and desorption characteristics. The information in ASABE (Am. Soc Agric. Bio. Eng.) Standard D245.5 (Moisture Relationships of Plantbased Agricultural Products) is based on research conducted in the 1990’s. Since then, plant breeding has resulted in grains and oilseeds of different constituents, which directly affects the EMC values. The results of our research will establish if this Standard is still relevant or needs updation. Moreover, very little information on EMC characterisitcs is available for Manitoba grown soybeans. This knowledge is extremely important to exporters. Therefore, to establish the best post-harvest techniques for soybeans, the objective of this proposal is to determine the sorption and desorption characteristics of three commonly grown soybean varieties in Manitoba.

Three varieties of soybeans grown in Manitoba with different seed size will be used in experiments. Sorption and desorption characteristics will be measured in a dynamic set-up where: (i) freshly harvested soybeans of different initial moisture content, (ii) soybeans that were exposed to successive micro-wetting and drying cycles, and (iii) soybeans exposed to successive freezing and thawing cycles will be placed on a set of stacked trays in air tight systems. The experiments will be conducted for the air temperature range between 5 and 30 °C (with a step of 5 °C) and five relative humidity (RH) values for a typical storage range. The experiments will be conducted in triplicate.