Valorization of apricot, melon, and watermelon by-products by extracting vegetable oils from their seeds and formulating margarine

Vegetable oils extracted from seeds and oleaginous fruits are a substantial source of bioactive compounds. In this study, oils of some fruit by-products were investigated and their composition and properties were compared. Apricot (ASO), melon (MSO), and watermelon (WSO) seed oils were extracted by cold pressing. The physico-chemical parameters and the contents of pigments were assessed using standard methods. The values of the physico-chemical parameters revealed the purity of the oils and it was recorded that the WSO has the best contents of chlorophylls and carotenoids, which were 12.43 ± 0.71 mg/kg of oil, and 1.35 ± 0.02 mg equivalent of β-carotene/g oil, respectively. In addition, the oils were analyzed by gas chromatography and their major fatty acids were linoleic, oleic, palmitic, and stearic. The ASO revealed the highest antioxidant activity in the quenching of 1,1-diphenyl-2-picrylhydrazyl (DPPH) with inhibition percentage of 89.2 ± 2.3 after 30 minutes of contact. Likewise, the oils were explored for the fortification of margarine. The physicochemical parameters of the formulated margarines comply with the standards. The Rancimat test showed that the highest induction time (16.54 h) was assigned to margarine enriched with 150 μg/g of WSO. Hence, this oil can has numerous applications in other food industries.