Effects of pretreatments on lipid oxidation stability of honeydew (Cucumis melo) seed oil

Abstract

The purpose of the present study was to explore the influence of different heat pretreatments on the chemical composition of honeydew seed oil and to extend our knowledge concerning on its oxidative stability. The honeydew seeds were treated with different heat pretreatments namely roasting (R) (20min at 200 C), steaming (S) (20min at 100 ° C), and microwave (M) (15min at 2450MHz). The honeydew seed oils from respective treated seeds were extracted by using a Bligh and Dyer method and the yields were found to be in the range of 17.22-21.59%. Fatty acid composition of the honeydew seed oils was examined by using gas chromatography and no significant difference was found among different pretreatments. Four types of major fatty acids of honeydew seed oils were palmitic acid (7.21 -7.31%), stearic acid (4.14 -4.33%), oleic (13.38 -13.90%) and linoleic acid (73.83 -74.47%). Meanwhile, the iodine value and free fatty acid content were determined by AOAC standard methods. The iodine values were found in the range of 133-135 g h/ 100 g. The free fatty acid content was in the range of 0.8 -1.4% and it was found that among the different pretreatments, roasted seed oil showed the lowest value. Oxidative stability was determined by Schaal oven method in a condition of 60 ° ° C for duration of 12 days by monitoring the changes in peroxide value (PY) and para-anisidine value (AV). The roasted honeydew seed oil was found to demonstrate the best oxidative stability among the pretreatments applied.