Correlating cold tests and cloud points: a detailed study of cold stability in palm oil liquid fractions

Abstract

This work investigates the correlation between cloud point and cold test as indicators of cold stability in oleins and superoleins produced from two types of palm oil: Elaeis Guineensis and HOPO. Three palm oil matrices were analyzed: Matrix 1 (PO-E.G) and Matrix 2 (POL-E.G) and Matrix 3 (HOPO). A pilot scale dry fractionation was performed to produce the oleins and superoleins. A total of 40 fractions, including replicates, were generated. These fractions were then analyzed by determining their iodine values by GC, triacylglycerol compositions and diacylglycerol contents by RP-HPLC, solid fat contents at 10°C by pNMR, cloud points (internal method) and crystallization profiles by DSC and finally, their cold test values at 8°C by an internal method based on the AOCS Cc 11-53. The analysis of olein and superolein fractions revealed that CPDSC exhibited quadratic trends with IVGC and key triacylglycerols (P2O and PO2+OOO). An indirect relationship with DAG content was also observed. Additionally, CT8°C stability showed a sigmoidal relationship with both, IVGC and CPDSC, with longer stability times observed at lower CPDSC values. Comparisons of olein and superolein fractions with identical IVGC revealed significant differences in CT8°C, likely influenced by the POP/OPP ratio. Statistical analyses were performed using Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression. The PCA analysis revealed that CPDSC was positively associated with P2ORP-HPLC, SFC10°C and PPPRP-HPLC. Conversely, CT8°C showed an inverse relationship with these variables, aligning more closely with IVGC and PO2+OOORP-HPLC, which positively contribute to cold stability. The PLS regression confirmed that cold stability, measured by CT8°C, was positively influenced by IVGC and PO2+OOORP-HPLC, while negatively affected by P2ORP-HPLC, PPPRP-HPLC and SFC10°C. These results describe the complex interaction of compositional variables in determining the cold stability of liquid palm oil fractions.