Stability and heat resistance of soybean oil with natural antioxidants from seedless barberries extracted using subcritical water

Scientists have recently focused attention on the properties of natural antioxidants on pathogens and free radicals and their application in the medical and food industries. The present study evaluated the antioxidant properties of the extract of seedless barberries، a popular fruit cultivated in Iran، extracted using subcritical water as a novel technology. The phenolic compounds of the seedless barberry were extracted using subcritical water (SCW) at ratios of 1:10 to 1:30 at 50 bar constant pressure and temperatures of 120 and 180 C. The total phenolic compounds (TPC) were measured using folin ciocalteu reagent and compared with those of maceration extracts. The thermal stability of the soybean oil and the antioxidant extracts was investigated using the Rancimat method at 110C and 20 l/h air flow rate. Radical scavenging and Fe+3 reduction power of the extracts was measured to evaluate the antioxidant characteristics of the SCW extracts and they were then compared the results for ascorbic acid and BHT (300 ppm). The results were evaluated using a factorial design and LSD test at  = 0. 01 using SAS software. The TPC varied from 1729. 76 to 2848. 21 mg/100 g dry material (Gallic acid). The maximum extract yield was produced by the treatment at 120C and a 1:10 ratio. The highest antioxidant power of soybean oil was observed at 180C and a 1:10 ratio. The thermal resistance of the soybean oil with SCW extracts was very similar to that of soybean oil enriched with E vitamin as a natural antioxidant. The extracts obtained by SCW had remarkable antioxidant properties and resistance to increased temperature and reinforced the stability of the soybean oil. Subject to further study، This combination can be recommended as a good alternative frying oil in the food industry.