Investigation of the bioactive properties of waste melon peel extract and its effect on lipid oxidation

Melon is among the most consumed fruits in our country. The peel that emerge as a result of melon consumption are generally used as animal feed or thrown away as garbage. In this study, it was aimed to determine the bioactive properties of the peels of 3 different melon varieties. Due to the toxicity, flammablity and other disadvantages of organic solvents used in the extraction of bioactive compounds, a surfactant-assisted water-based extraction system, which is an alternative method for the recovery of these compounds, was used. Extraction was made from melon peels using solutions of polyoxyethylene sorbitan derivative surfactants (Tween-20 (T-20), Tween-40 (T-40), Tween-60 (T-60), Tween-80 (T-80)) in water with different HLB values. The effects of different concentrations of different surfactants on the recovery of carotenoids and phenolics in the prepared extracts were investigated comparatively. Total antioxidant capacity of the extracts was determined by DPPH and ABTS method. According to the results; with 1% concentration of the surfactants the highest phenolic content was obtained by using T-40 in Ankara melon. The highest total carotenoid content was determıned ın T-60 extract of Kırık Ağaç melon peel. Among the extracts, T-20, T-40, T-80 extracts of Ankara melon exhibited the highest antioxidant activity. The carotenoid composition of the extracts was analyzed using HPLC and mainly lutein and β-carotene were determined in the melon peels. To investigate the effect of the extracts on lipid oxidation, oil-in-water emulsions (w/o) were prepared from Ankara melon extracts and the oxidation time was followed by primary oxidation products hydroperoxide value (PV) and secondary oxidation products thiobarbutyric acid (TBARS) analysis. According to the results, it was observed that melon peel extracts suppressed the formation of primary oxidation products, and it was determined that the T-20 extract was more effective in decreasing the lipid oxidation rate compared to the others. As a result, it was observed that the recovery efficiency of bioactive components increased by using YAM, which is allowed to be used in human foods from the waste melon peel.