| Lycopene is a kind of natural carotenoid which has the function of various health cares, such as decreasing the risk of cancer, increasing immunity and deferring decrepitude etc, so lycopene has received much attention in recent years. The aim of this paper is to investigate the technologic processes and conditions by which oleoresin is extracted from natural tomatoes with microwave assisted extraction and high hydrostatic pressure processing, then it is purified into lycopene crystal. Lycopene antioxidant activity in edible oils and synergisitic effect with other antioxiadant is also studied.The method for extraction of lycopene in fresh tomatoes was developed. Lycopene was first saponated, dehydrated by alcohol, extracted by assisted microwave, and then re-crystallization. Compared with centrifugal dehydration and vacuum drying, ethanol dehydration led to a less reduction of lycopene and could also improve the purity of the extracted lycopene. Saponification by 0.5M sodium hydroxide was useful in removing non-polarized impurities, in which saponification time was 3h. After the pre-treatments, quantity of lycopene extraction increased by 76.3%.Based on single factor tests, the optimum conditions of lycopene extracted from fresh tomatoes were obtained through Box-benhnken central combination design and RSM, and developed the predictive polynomial quadratic equations model between response value and factors. The optimum extraction condition of lycopene was as follows: microwave power 500W, extraction time 160s, ratio of tomato paste to solvents 8.2 mL/g and extraction times 3, under these conditions lycopene yiled was up to 3.047 mg/g, and microwave power and ratio of tomato paste to solvent had significant effects on lycopene extraction. Compared with solvent extraction, MAE shortened extraction time, reduced the usage of organic solvent. It showed MAE was a kind of fast, effective and potential method for lycopene extraction.To study effect of the technology process of high hydrostatic pressure on extraction of lycopene at normal temperature, the influence on the extraction ratio of the different pressure, the time of holding pressure, the solvent and the solute/ solvent ratio were investigated. The results showed that the optimum procedure of HHP lycopene were pressure 500MPa, holding time 300s, the ratio of solute and solvent 1:30. Light petroleum and ethyl acetate were used as extracting solvent. Compared with other extraction methods, solvent extraction under the condition of high hydrostatis pressure was a fast and efficient extraction of lycopene in tomato powder approach.The oxidant stability index (OSI) was used to evaluate antioxidant ability of lycopene and synergistic effects with other antioxidant in edible oils. The OSI of rapeseed oil (0~0.0050%) and lard (0~0.0025%) increased as the amount of lycopene added increased, and the antioxidative activity of lycopene in lard was superior to that in rapeseed oil. Compared with chemical synthesis antioxidant, the antioxidant effect of lycopene in rapeseed was better than BHA and BHT, while lycopene in lard was better than BHT. The antioxidant effect of lycopene was similar to tea polyphenol, and was superior toα-tocopherol in rapeseed oil.α-tocopherol enhanced the antioxidant capacity of lycopene in lard but no effect on rapeseed oil, 0.0025% dosage of lycopene with 0.0025%, 0.0050% and 0.0075% dosage ofα-tocopherol could extend the oxidation induction period of lard by 63%, 130% and 167%, respectively. The synergistic effect of lycopene and tea polyphenol in rapeseed oil was not obvious, the three level of tea polyphenol concentration extended the oxidation induction period by 10%, 11% and 22%, respectively. But tea polyphenol and lycopene in lard system had a significant synergistic effect, 0.0025%, 0.0050% and 0.0075% dosage of tea polyphenol increased the OSI of lard by 49%, 120% and 122%. Both citric acid and EDTA had more significant synergistic effect on the antioxidant capacity of lycopene in lard and rapeseed oil, so they could be used as synergistic agent of lycopene.
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