Preparation Of Stearic Acid-Surfacant-Tea Polyphenols Complex And Stearic Acid-Surfacant-EGCG Complex Enhancing The Antioxidative Properties Of Edible Oil

As generic terms of the hydroxyl compounds in tea, tea polyphenols has a strong antioxidative effect, especially (-)-epigallocatechin gallate (EGCG). The antioxidative effect of EGCG is 100 times more than L-Threoascorbic acid. Due to low solubility in oil phase and nonpolar solvent, tea polyphenols are severely restricted to the market of nature antioxidation in high lipid food. This work intended to study the influence of a stearic acid-surfactant-tea polyphenols complex (SSTC) and a stearic acid-surfactant-EGCG complex (SSEC) on the antioxidant activity and thermal stability of edible oil, mainly peanut oil, under different heating processes. In this work, three heating processes had been taken, which were microwave heating, simulated deep fat frying and oven test at 90℃. All oil samples containing different SSTCs, which suffered three heating processes, had less change in the quality parameters, compared with those of pure peanut oil. The K232 of oil sample containing SSTC-P decreased 36.90% and 33.18% respectively after microwave heating and simulated deep fat frying. This means that the SSTC can not only achieve the stability of tea polyphenols dissolve in oils and fats, but also inhibit production of the degradation and decomposition of oils and fats, and the generation of harmful products caused by heating. After microwave treatment, the fatty acid composition and oxidation products of peanut oil containing SSTC-P showed the different variations in GC-MS analysis. The content of unsaturated fatty acids in oil sample with SSTC-P was 8.7 times more than that in pure peanut oil after heating process. This indicates that tea polyphenols have a outstanding protection in inhibiting the thermal decomposition of fatty acid and generation of subprime product.