Impact of polyphenols from banana pseudostem on sunflower oil stability

The present investigation is focused on the potential use of banana pseudostem, which otherwise is disposed off as a waste, as a source of polyphenols or antioxidants. The polyphenols extracted from the outer leaf sheaths of 3 Indian banana (Musa spp.) cultivars namely, ‘Nendhran’, ‘Robusta’, and ‘Kathali’ were tested for antioxidant activities. The extracts showed effective DPPH, hydroxyl, and superoxide radical scavenging ability. Among the banana cultivars, ‘Nendhran’ followed by ‘Robusta’ contained the highest total phenolic (110.45 and 94.03 mg GAE/g extract, respectively) and total flavonoid (49.62 and 38.61 mg QE/g extract, respectively) contents and antiradical activity. Further, the study was aimed to evaluate the protective effects of the polyphenolic extracts in stabilizing sunflower oil, tested in terms of peroxide value, free fatty acid contents, and p-anisidine values in comparison with the synthetic antioxidants, butylated hydroxyanisole and butylated hydroxytoluene. In addition, the antioxidant activity and total phenolic contents of the extract-treated oil samples were also monitored to obtain a complete perspective of the influence exerted by the polyphenols in oil stability. The results demonstrated that polyphenols from pseudostem of banana cultivars are potent source of natural antioxidants and might serve as a substitute for synthetic antioxidants in oil industry.