Prediction of crude sunflower oil deterioration after seed drying and storage processes

The effects of air‐drying temperature and storage time on several characteristics of crude sunflower oil were evaluated in terms of FFA and PV. Long storage affected oil content to a greater extent than air‐drying temperature. FFA and PV varied between 0.53 and 1.22% and between 10.7 and 23.3. meq O2/kg, respectively, when samples of uniform initial moisture content (approximately 28%) were dried at various temperatures between 25 and 90°C to approximately 7% moisture content, stored for 8 mon, and then analyzed. Both oil quality characteristics increased exponentially with air‐drying temperature (T) and linearly with storage time (t). Mathematical functions of the form A·exp(B·T)+C·t (where A, B, and C are parameters adjusted from experimental data) most closely predicted the experimental loss of quality of sunflower oil in terms of FFA and PV with variations in T and t. Statistical analysis showed SE of the estimated parameters of 0.08 and 1.19 and coefficients of determination, R2, of 0.922 and 0.939 for FFA and PV, respectively, which were significant at 95% confidence. High‐oleic seeds from a similar experiment were used to validate the proposed equation. The results of applying the mathematical function proposed above showed a reasonable ability to predict the experimental values with SE of 0.037 and 0.808 and R2 of 0.983 and 0.972 for FFA and PV, respectively, which were significant at 95% confidence. Plots of residuals showed random distribution. The results obtained suggested that the equation proposed could be used as a quality‐loss model in sunflower drying simulations.