Heat Degradation of α-Tocopherol in Sri Lankan Commercially available Palm Olein

Objectives: Palm olein, which is the fractionated form of palm oil, is commonly used as cooking oil in Sri Lanka. Processing of crude oil degrades α-tocopherol as does exposure to high heat during cooking. This study was aimed to determine the content and heat degradation of α-tocopherol in Sri Lankan commercially available palm olein. Method: Four different brands of Sri Lankan commercially available palm olein (100 mL) were heated to 180°C for 10 minutes. The oil was subsequently cooled and re-heated five times and assayed in duplicate. Between each cycle of re-heating oil was left in room temperature to cool for 5 hours. Fresh palm olein and the heated samples were analyzed for α-tocopherol content using reversed-phase High-pressure liquid chromatography (HPLC) (Shimadzu, Japan). Results: The mean α-tocopherol content in unheated palm olein was 3.02 ± 0.35 ppm, with no significant differences between brands. Heating Palm olein for 10 minutes resulted in 56.6% reduction in α-tocopherol compared to unheated oil. Re-heating resulted in further reduction with a 100% loss by the fourth time. Conclusion: The Sri Lankan commercially available palm olein did not provide expected α-tocopherol content, and is not a good source of dietary α-tocopherol. Further analysis is required to quantify α-tocopherol content. Since re-heating further reduced α-tocopherol levels, repeated frying during cooking is likely to result in a minimal level of α-tocopherol being provided through palm olein to the diet.

Oxidative stability of crude palm oil after deep frying akara (Fried Bean Paste)

Abstract For this study 47 samples of crude palm oil (CPO) were collected, consisted of what had been used for 4 hours around the city of Salvador-Bahia. To evaluate the quality of CPO were analyzed: Total Polar Compound (TPC; %) by Adsorption Chromatography (AC), Testo 270 and Fricheck; Free fatty acids (FFA; % oleic acid), Color (CIELab); Total Carotenoids (TC; ppm), induction time (IT, h) and fatty acids composition (g 100 g-1). The TPC analysis by Testo 270 and Fricheck showed a poor linear correlation with AC (0.69 and 0.60 respectively). Otherwise 44.70% and 36.95% of samples were completely oxidized, according to CA and IT methods. All samples presented TC (11.01-331.45 ppm) and yellow color predominance. Trans fatty acids, C18:1t in 17.02% and C18:3t in 65.65% of the samples were identified. The results demonstrate the need in the deep frying control, respect to techniques used during process. As well the improvement of the quality of palm oil fresh, can minimize the degradation process during th deep frying.