Soybean Oil Enriched with Antioxidants Extracted from Watermelon (Citrullus colocynthis) Skin Sap and Coated in Hydrogel Beads via Ionotropic Gelation

Abstract

Many plants and fruits are rich in antioxidant and antimicrobial compounds, such as phenolic compounds. Watermelon is one example, as various parts of the fruit present interesting phytochemical profiles. This study demonstrates that a natural C. colocynthis (watermelon) (W) skin sap (SS) extract can effectively improve the oxidative stability of microencapsulated soybean (SB) oil. By employing a combination of alginate–xanthan gums (AXG) in a matrix hydrogel bead model with WSS extract, high encapsulation efficiency can be obtained (86%). The effects of process variables on the ultrasound-assisted extraction (UAE) of phenolic compounds from watermelon (W) skin sap (SS) using the response surface methodology (RSM), as an optimized and efficient extraction process, are compared with the effects of a conventional extraction method, namely the percolation method. The WSS extracts are obtained via UAE and RSM or the conventional percolation extraction method. The two obtained extracts and synthetic antioxidant butylated hydroxytolune (BHT) are added to SB oil separately and their antioxidant effects are tested and compared. The results show the improved oxidative stability of SB oil containing the extract obtained via the optimized method (20–30%) compared to the SB oil samples containing extract obtained via the percolation extraction method, synthetic antioxidant (BHT), and SB oil only as the control (no antioxidant added). According to existing studies, we assume that the use of WSS as an effective antioxidant will ensure the prolonged stability of encapsulated SB oil in hydrogel beads, as it is well known that extended storage under different conditions may lead to severe lipid oxidation.

Progress of Research on Antioxidants and Carriers for Skin Wound Repair

“…Extraction is the most commonly used method. For example, the extract of watermelon rind is rich in antioxidant substances, which can effectively increase the stability of soybean oil, thereby prolonging its shelf life oil [44].…”

An Overview on the Use of Extracts from Medicinal and Aromatic Plants to Improve Nutritional Value and Oxidative Stability of Vegetable Oils

“…In general, low oxidative stability is due to a major problem, known as oxidation. This induces oil quality deterioration, and it leads to health problems like colds, cancer, heart disease, mutagenicity, and other diseases [ 96 ]. In order to preserve the high nutritional value of oils and improve their oxidative stability and their shelf life, many approaches are used.…”

“…Several studies have been previously carried out with plant extracts to prevent oxidative deterioration. Among them, olive leaves [ 118 ], some aromatic plants [ 119 ], rosemary, rambutan, fruit peel [ 120 ], grape seed [ 121 ], cocoa bean shell [ 122 ], coffee husk [ 123 ], peanut skin [ 124 ], Cressa cretica L. leaves [ 125 ], goji berry [ 126 ], marjoram, thyme, ginger, turmeric [ 127 ], oregano [ 15 ], watermelon [ 96 ]. It has been shown that soybean oil enriched with olive leaf extract showed lower peroxide value and a lower amount of secondary product compared to the control [ 118 ].…”

Evaluating the Effects of Wheat Cultivar and Extrusion Processing on Nutritional, Health-Promoting, and Antioxidant Properties of Flour

“…Antioxidants as health-promoting food components have been discussed in nutrition science for several years ( 6 – 8 ). The natural or enriched content of antioxidants is associated with health and disease prevention ( 9 , 10 ).…”