The Study On The Extraction And Purification Of Lycopene From Tomato Peel

The present study was to take tomato peel as the research material. The research had investigated the extraction and purification of lycopene from tomato peel. And antioxidant abilities of lycopene and the stability of lycopene oleoresin were preliminary studied in this paper.First, the research had compared the effect of pretreatment to lycopene extraction. It optimized experimental conditions to treat tomato peel and extract lycopene from tomato peel. The best method to treat tomato peel was that 95% ethanol was used thrice for removing water from tomato peel in a ratio of 1:3(W/V). The optimum extraction conditions of organic solvent extraction were as follows: extraction solvent was ethyl acetate, ratio of material and liquid was 1:6, extraction temperature was 50℃, extraction time was 1h, the number of extraction stage was 3, and the extraction rate of lycopene was more than 98%. On this basis, ultrasonic, microwave assisted extraction of lycopene were further study. It was found that ultrasonic, microwave assisted extraction could reduce the extraction time and cost. The optimum extraction conditions of ultrasonic radiation extraction were as follows: extraction solvent was Ethyl acetate, ultrasonic output power was 300W, ratio of material and liquid was 1:6, extraction time was 6min, ultrasonic radiation time was 3s, the number of extraction stage was 3, and the extraction rate of lycopene was more than 98%. The optimum extraction conditions of microwave radiation extraction were as follows: extraction solvent was Ethyl acetate, microwave output power was 400W, ratio of material and liquid was 1:4, extraction radiation time was 35s, the number of extraction stage was 2, and the extraction rate of lycopene was more than 97%. Microwave radiation extraction was better than ultrasonic radiation extraction. According to the optimum extraction conditions, the content of lycopene in tomato peel was 25mg/100g.Second, these extracts were further purified. Dewaxing with acetone solution. Saponificationing with potassium hydroxide solution. Saponification temperature was 60℃. Saponification time was 3h. The optimum purification conditions of lycopene were as follows: column chromatograms were silica gel, adsorption and desorption at normal temperature, desorption solvent: ratio of petroleum ether and acetone was 3:2; Recrystallization temperature was -5℃. The purity of lycopene crystal was 92.8% by HPLG detection.Third, the antioxidant activity of lycopene was studied. The ability on·O₂^-,·OH and H₂O₂ were determinated by chemiluminescence. It was concluded that the eliminate capacity were as follows:·OH>H₂O₂>·O₂^- . The ability on inhibiting lipid peroxidation: lycopene >TBHQ>BHA>VE; Lycopene had a strong inhibitory effect on mouse liver homogenate spontaneous lipid peroxidation.Finally, the research had studied the stability of lycopene oleoresin. It was found that temperature, light and oxygen had strong influence to the stability of lycopene oleoresin. So the storage of lycopene oleoresin needs avoiding light and oxygen, cryopreservation.