Dissertation > Industrial Technology > Light industry,handicrafts > Food Industry > General issues > Food industry by-product processing and utilization of

Extraction, Stability and Antioxidative Activity of Lycopene from Tomato Paste Waste

Author YuanYongCheng
Tutor LiuChengMei
School Nanchang University
Course Of Food Science
Keywords lycopene tomato paste waste Supercritical carbon dioxide extraction Stability Anti-oxidative activity
Type Master's thesis
Year 2011
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Lycopene is one of the natural carotenoids that is able to guard against oxidation, tumour development, vascular diseases, slow down aging and many other beneficial properties. The tomato skin is rich in lycopene but is usually discarded as refuse. Not only is this wasteful, it also damages the environment.Till present, most research on tomatoes focused on the extraction of lycopene, investigating its stability and antioxidant properties. However, in this context, the extraction procedures of lycopene from tomato skin, analysis of lycopene levels, treatment and antioxidant properties of lycopene was investigated. This research promotes the balance between man and nature by reutilizing the tomato skin, initially regarded as refuse into a usable compound after treatment. The main research content and experimental results are as shown below:1. Established liquid chromatography and spectrophotometery analysis method forlycopene2. Pre-treatment experimental procedures for tomato skin clearly states that using tomato skin after sieving through a sieve of diameter>40 is advantageous to extraction of lycopene. The optimum conditions for saponfication are:KOH at 0.5mol/L concentration, time at 30min, temperature at 65℃and washing with 40ml of 100% ethanol after saponification. Use of pectinase and cellulase in enzyme hydrolysis of tomato skin aided in solubilization of lycopene and results for pectinase were more evident.3. The use of organic solvents and supercritical CO2 were the optimum processing methods for extracting lycopene. Extraction yield was 28.80% when ethyl acetate was used as solvent, extraction time=2.3h, extraction temperature= 51℃and liquid-to-solid ratio=9.9:1 (V/g). Optimum conditions using supercritical CO2 extraction for lycopene were:using 20% hexane as co-solvent, extraction time =2h, extraction temperature=55℃, extraction pressure=35MPa.4. The effects of temperature, light, oxidant, reductant, antioxidant, pH and metal ions on stability of lycopene were observed. Results indicated that at 30℃, dark room, slight alkali, presence of reductant and antioxidant, and absence of Fe3+, Cu2+ ions, lycopene was more stable.5. The ability of lycopene to scavenge malondialdehyde produced from spontaneous oxidation of lipids from DPPH, hydroxyl radicals, superoxide radicals, hepar and renal tissues of rats. Results shows:Lycopene has rather greater scavenging effect on 4 types of free radicals and showed significant dose-response relationship. IC50 were 52.62,12.53,13.34,37.93,43.12 ug/ml respectively.

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