Determination of Moisture Sorption Isotherm using Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) Models, Germination Capacity and Index Vigor of Soybean during Storage

Understanding the interaction between the equilibrium moisture content of a product and the surrounding air is crucial for guaranteeing product quality and preserving its characteristics throughout storage. The study of this tendency may be conducted utilizing sorption isotherms. This research aimed to study the moisture sorption characteristics of soybeans during storage, identify the most suitable mathematical model for the experimental data, and examine the relationship between the germination capacity and vigor index of soybeans with their moisture content and water activity. Moisture sorption characteristics of soybean, Anjasmara variety, were investigated at temperatures of 30ᵒC, 40ᵒC, and 50ᵒC, and water activities of 0.08 to 0.80, and were modelled using two different mathematical models, Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB). Both two mathematical models, BET and GAB, were found to effectively describe the moisture sorption data based on regression analyses and goodness of fit. Each model was statistically evaluated by coefficient of determination and deviation standard. The moisture sorption behaviour of soybean seeds displayed a sigmoidal pattern. The GAB models have been suggested to estimate the moisture content at certain humidity levels at 30ᵒC, 40ᵒC, and 50ᵒC temperatures. The BET models were suitable for temperatures between 30ᵒC and 40oC. The vigor and germination indicated exhibited a progressive and optimal trend at a water activity level of 0.32, followed by a decline at all three temperatures.