Optimization of the extraction process of phenolic antioxidant compounds of jelly (Solanum gilo Radi) and application in the oxidative stability of soybean oil

Abstract

The objective of this study was evaluate the effects of jelly fruit extracts as a natural antioxidant in soybean oil subjected to an accelerated storage test and optimize the best extraction conditions of antioxidant compounds of jelly (Solanum gilo Radi) dehydrated at temperatures of 40, 60 80 and 100 oC, and thus to evaluate the influence of temperature on antioxidant activity. The antioxidant activity was determined by the DPPH radical scavenging assay and total phenolic compounds using the Folin-Ciocalteu method. The conditions that provided the most jelly extract with antioxidant activity were dehydrated at 60 °C using 5.0 g of flour, 60 mL of methanol/water 20% (v/v) for 24 hours and protected from light. The monitoring of oil oxidation was carried out by determining the peroxide index value (PI) for 21 days. Four systems were prepared: soybean oil added extract in concentrations of 1000 and 3000 ppm, BHT in 1000 ppm and soybean oil free of antioxidant (control). The PI values oil jelly extract added at the concentrations were lower than the oil free of antioxidant during every 21 days, showing its ability to inhibit lipid oxidation, although in lower proportions of BHT. To the oil that was added the synthetic antioxidant BHT there was a delay of the formation of peroxides in 60%, while the jelly extracts were equivalent, reducing around 43%, in the concentrations tested. It is worth emphasizing the functional and health advantage of choosing to use the jelly extract as a natural antioxidant, even though it has a potential lower than the synthetic one.