Physicochemical Characteristics, Fatty Acid Profile, and In Vitro Antioxidant Activity Evaluation of Sacha Inchi Seed Oil from Indonesia

Free radicals can cause damage to the structure of the dermis layer, which makes skin lose its elasticity and leads to the formation of wrinkles. A strategy to prevent this problem is by using antioxidants. A plant that has been reported to contain good antioxidant activity is sacha inchi seed (Plukenetia volubilis L.); apart from that, its oil has quite a high omega-3 content and potentially can act as an anti-aging agent stimulating the skin-cell-regeneration process, maintaining skin moisture and elasticity and stimulating collagen production. This research aims to analyze the physicochemical characteristics and determine the fatty acid profile, the levels of vitamins A, D, and E, and the antioxidant activity of sacha inchi seed oil. This research was conducted through eight main stages: sacha inchi seed extraction, quality parameters checking, phytochemical screening, determining fatty acid profiles, vitamin analysis, antioxidant activity tests, microbiological contamination tests, and heavy-metal contamination tests. In this study, quality inspection results were obtained: organoleptic form (liquid), color (yellow), odor (typical), relative density value (0.91 g/cm3), acid number (0.38 +/- 0.02 mg/g), peroxide value (11.01 mEq/Kg), iodine value (179.32 g/100 g), and refractive index (1.479). The phytochemical screening results of sacha inchi seed oil were positive for containing flavonoids, triterpenoids, and steroids. The results of the fatty acid profile were omega-3 (48.5%), omega-6 (34.8%), and omega-9 (7.7%). The results of the vitamin contents analysis were vitamin A (123.42 mg/100 g), vitamin D (899.46 mg/100 g), and vitamin E (145.06 mg/100 g). The antioxidant activity test showed an IC50 value of 8.859 ppm (very strong), and the microbial and heavy-metal contamination tests were negative.