Abstract: The effects of tea polyphenols (TPs) on the quality of rapeseed oil during the deep frying of potato slices were investigated by measuring changes in physicochemical indexes, fatty acid composition and volatile compounds, and the content of total phenols and the thermodynamic properties of the oil were further determined to elucidate the underlying mechanism. The results showed that compared with control, TPs significantly inhibited the decrease in physicochemical quality of the frying oil. Besides, the addition of TPs could inhibit the degradation of unsaturated fatty acids and the generation of trans fatty acids in the frying oil and suppressed the production of volatile aldehydes. The addition of TPs could increase the content of phenols and oxidative stability of the oil, thus protecting its quality in the deep-frying process. All these findings suggested that TPs could be potential to be used for protecting the quality of frying oil in the food and chemical industries.

Key words: tea polyphenols; oil; deep frying; oxidation; antioxidant