Influence of moisture content, temperature, and time on free fatty acid in stored crude palm oil

Abstract

Abstract Consequent to the importance of crude palm oil (CPO) to global food processing industries, and the need for quality assurance of CPO. A kinetic model that describes changes of free fatty acid (FFA) in industrially stored CPO has been developed. CPO FFA is a well-known indicator of the deterioration of CPO. The effect of initial moisture content, storage temperature, and time on CPO FFA have been investigated in this work. Specifically, statistical multi-regression models for changes in FFA and moisture content (MC) were developed at P-value < 0.05 or 95% confidence interval fence. It was found that CPO FFA increases with an increase in moisture content, temperature, and time in their linear term and in respect to decreases in their quadratic term, and interaction between moisture content and temperature. The CPO MC was also found to decrease with an increase in temperature and time and increases in the quadratic term of temperature. Although while the model for CPO FFA, based on Fisher's F-test: $${\mathrm{F}}_{\mathrm{model}}(6.80)<{\mathrm{F}}_{95\mathrm{\%}}(19.30)$$ F model ( 6.80 ) < F 95 % ( 19.30 ) , showed no lack-of-fit; that of CPO MC showed lack-of-fit, $${\mathrm{F}}_{\mathrm{model}}(13.67)\nless {\mathrm{F}}_{95\mathrm{\%}}(4.39)$$ F model ( 13.67 ) ≮ F 95 % ( 4.39 ) . Furthermore, based on inference from the statistical model, their kinetic models were also developed. While the CPO FFA kinetic, found to be a half-order kinetic model and its other auxiliary models showed a very good fit (R2 {0.9933–0.8614} and RMSE {0.0020–3.6716}); that of CPO MC was a poorly fitted first-order kinetic model (R2 {0.9885–0.3935} and RMSE {0.0605–17.8501}).