Quantitative differential scanning calorimetric analysis for determining total polar compounds in heated oils

Abstract

A new differential scanning calorimetry (DSC) method was developed for the determination of total polar compounds (TPC) in heated oils. Three different types of edible oils, refined, bleached, and deodorized corn oil (CO), palm olein (RBDPO), and soybean oil (SO), were used in this study. Each type of edible oil was heated at 180°C in a deep fryer to obtain a range of TPC concentrations. In this study, the cooling thermograms of oil samples at a scanning rate of 1°C/min from −30 to −85°C showed a well-defined single crystallization peak. The study found that six DSC parameters, namely, peak temperature (PT), enthalpy (EN), onset (ON) and offset (OF) temperatures, peak height (HT), and the range of temperatures (RT) (the difference between onset and offset temperature) of this single crystallization peak could predict well the TPC of heated oils by using stepwise multiple linear regression analysis. These six parameters were used as independent variables while values from standard method were used as dependent variables. The coefficient of determination (R 2 ) of calibration models for CO, RBDPO, and SO were 0.9996, 0.9709, and 0.9980, respectively. Calibration models were validated with an independent set of samples. The R 2 of validation models were 0.9995, 0.9559, and 0.9961, respectively. Based on the results obtained, DSC appears to be useful instrumental method in determining the TPC of edible oils, and it may have the potential to replace the time-and chemical-consuming standard method.

Oxidative stability of lard and sunflower oil supplemented with coffee extracts under storage conditions

“…The latter are well correlated with the results of chemical methods. The highest correlation was observed between the results of DSC and polar compound assays (Tan and Che Man, 1999b).…”

Antioxidant Potential of <i>Ocimum basilicum</i> (Lamiaceae) Essential Oil as Preservation of the Physicochemical Properties of Palm Oil During One Month

“…These reactions therefore lead to a decrease in DOBI and an increase in acidity [13]. During storage there is a gradual accumulation of oxidation products, which tends to reduce the melting point and increase the peroxide value of stored oils [30].…”

Effect of fractional crystallization on composition and thermal properties of engkabang (<i>Shorea macrophylla</i>) seed fat and cocoa butter

“…The onset (°C) is the temperature where the extrapolated leading edge of the endotherm intersects with the baseline. The value of each DSC parameter used in this work was obtained as illustrated in Tan and Che Man (1999). crystallization of Mahua fat (Reddy and Jeyarani, 2001) and phulwara butter (Reddy and Prabhakar, 1994) were undertaken to isolate hard stocks to be used as components in the preparation of cocoa butter extenders.…”