Abstract

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. 

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