| dc.description.abstract | This research studied the moisture sorption behaviour of jatropha seed allowing the
development of a model correlating the equilibrium moisture content (EMC) and the free
fatty acids (FFA) content as a function of water activity and EMC, respectively. Two sets of
sorption-isotherm experiment were performed to describe the relationship between EMC
and FFA content with water activity, for both fresh and dried seeds. The seeds were
conditioned in series of saturated salts having certain water activity and stored at different
temperatures (20. 30, 40 "C). The nested experimental design and ANOVA (F-test at p = 0.05)
were applied to study the effects of temperature and water activity on the EMC of jatropha
seed.
EMC increased generally with the increase in water activity and with the decrease in
temperature at either desorption or adsorption. The £MC was significantly affected by
water activity, but the temperature did not significantly affect the EMC, The hysteresis
effect was more pronounced at lower temperatures. The FFA content of seed was relatively
constant at low water activity (aw < 0 ,8), but it was high at higher water activity.
The moisture sorption behaviour of jatropha seed revealed that like most product, it
exhlbited the sigmoid pattern, The BET. GAB, Harkins-Jura, Halsey and Henderson models
were recommended as adequate models in predicting the amount of moisture adsorbed or
desorbed at known humidity. The relationship between EMC and FFA content of jatropha
seed showed that the polynomial equation was the best fitting for either fresh or dried
seed. | id |
