Effect of tea catechin derivatives on stability of soybean oil/tea seed oil blend and oxidative stability of fried fish crackers during storage

Effect of (−)-epigallocatechin gallate (EGCG) and (−)-epicatechin (EC) at different concentrations (100–300 ppm) on frying stability of soybean oil blended with tea seed oil was studied. Thermal stability of the blended oil increased with the addition of EGCG and EC, especially with increasing concentrations. Frying induced degradation of tocopherols and phenolics of oils, particularly tocopherols. Incorporation of catechin derivatives could retard tocopherol decomposition and formation of polar materials. The highest frying stability was found for the oil added with EC at 300 ppm. When the oil added with EC (300 ppm) was used to prepare fish crackers, lowered lipid oxidation of the resulting crackers than those prepared using the control oil was noted throughout 12 weeks of storage. EC could be effectively used as natural antioxidant in frying oil with carry through effect to enhance oxidation stability of the fried foods during a storage.