Heat treatment effect on tocopherols, total phenolics and fatty acids in table olives (Olea europaea L.)

Abstract

The olive fruits are rich source of oil, vitamins, minerals, organic acids and pigments. The fruits contain high level of bioactive compounds. The aim of this study was to examine the effect of heat treatment on tocopherols, total phenolics and antioxidant activity in green and black olives, as well as their fatty acid composition. The instrumental methods used in this experiment were high performance liquid chromatography (HPLC), gas chromatography with flame ionization detection (GC/FID) and spectrophotometric methods. The results revealed that the β+γ-tocopherols content after the heat treatment had the biggest reduction, which was 68.4% for green and 80.2% for black olives. Also, a significant loss of total phenolic content was observed after heat treatment in green and black olives by 18.6% and 18.4%, respectively, as well as antioxidant activity (decrease up to 28.1%). The most abundant fatty acids in green and black olives were oleic (C18:1), palmitic (C16:0) and linoleic acid (C18:2). The changes in fatty acids composition during the heat treatment occurred mostly at the level of polyunsaturated fatty acids, especially linolenic acid (C18:3) in black olives had the significant reduction (by 57.4%) in relation to the initial quantity.

Oxidative stability of avocado oil blended with different levels of ultrasonic extract of Chlorella vulgaris under different temperatures

“…In addition, Kmiecik et al (2023) demonstrated that heating olive oil resulted in degradation, affecting lipid nutritional indices and tocopherol content. In addition, Mihajlovic et al (2023) observed reductions in tocopherols and TP in olives after heat treatment, with significant changes in fatty acid composition, particularly in polyunsaturated fatty acids Adding different concentrations (250-1,000 ppm) of C. vulgaris ultrasonic extract as well as 200 ppm of BHT into heated AO can indeed reduce the changes that occur in fatty acids. Increasing the concentration of C. vulgaris ultrasonic extract in heated AO may indeed decrease the changes in fatty acids affected by heat treatment.…”

“…In addition, Kmiecik et al (2023) demonstrated that heating olive oil resulted in degradation, affecting lipid nutritional indices and tocopherol content. In addition, Mihajlovic et al (2023) observed reductions in tocopherols and TP in olives after heat treatment, with significant changes in fatty acid composition, particularly in polyunsaturated fatty acids…”