Effects of pistachio green hull crude extract and its polyphenol fraction on oxidative stability of sunflower oil during accelerated storage

Pistachio green hull (PGH) contains considerable amount of polyphenolic compounds, which are the most important natural antioxidants. In this research, the antioxidative activity of PGH crude extract and polyphenolic fraction, as the alternatives to synthetic antioxidants, were evaluated. Polyphenol fraction was isolated with Amberlite XAD16 resin from the crude extract. Effects of the crude extract, polyphenol fraction, and synthetic antioxidant (BHT) to inhibit the sunflower oil oxidation were studied under the heat accelerated storage (60 degrees C) for 16 days. Thermal stability was performed with Rancimat at 110 degrees C. The results showed that polyphenol fraction of PGH at 200 and 600 ppm had the same effects to retard oxidative processes in sunflower oil and even more potent than BHT and crude extract.