Evaluation of physicochemical properties, chemical composition, and antioxidant and antibacterial activities of Sacha inchi oil

Abstract

This study investigated the influence of pressing temperature on the quality characteristics of Sacha inchi (Plukenetia volubilis L.) oil produced in the Central Highlands of Vietnam. Seeds were mechanically pressed at 120, 160, and 180 °C, and the oils were evaluated for physical and physicochemical properties. The oil produced at 160 °C, which showed the highest extraction yield and lowest acid value, was further characterized for fatty acid composition and in vitro antioxidant and antibacterial activity. Pressing temperature affected several oil-quality parameters, including color, extraction yield, acid value, saponification value, and peroxide value. The 160 °C treatment did not yield the lowest peroxide value; therefore, its selection reflects the overall balance of the measured parameters rather than superior oxidative stability alone. GC–MS analysis showed high proportions of α-linolenic and linoleic acids. The oil showed weak DPPH-radical-scavenging activity and small inhibition zones in the disc-diffusion assay, with Bacillus cereus showing the largest zone. The unusually low saponification values require analytical verification. Further studies should assess analytical validity, storage stability, safety, and performance in food systems before a functional-food or preservative application is proposed.