Study On Components And Antioxidative Function Of Walnut Oil

In this study, antioxidative function and components of walnut oil were analysed. In order to determine the most effective way of walnut oil extraction, three methods including: the squeezing method, the soxhlet extraction and ultrasonic auxiliary solvent extraction method were compared and analyzed. The result showed that the squeezing method was the optional extraction method. The antioxidant properties of walnut oil were indexed to the free radical scavenging capacity. In the oxidation process of walnut oil, the fatty acid composition, vitamin E contents and the free radical scavenging capacity were also analyzed. traceingredients were extracted from walnut oil and investigated.1.The experimental results showed that extraction rate of walnut oil were52.95%,55.32%,53.14%by the squeezing method, the soxhlet extraction and ultrasonic auxiliary solvent extraction method. There was not much different from extraction rate. In order to keep active material, the squeezing method was chosed to exract walnut oil.Through gas chromatography-mass spectrometry, walnut oil was isolated and identified. The main components of fatty acids were: linoleic acid (54.92%), oleic acid (25.39%), linlenic acid (9.90%), hexadecanoic acid (5.95%) and stearic acid (2.01%) and so on. There were were30.42mg/g (the squeezing method),36.58mg/g (the soxhlet extraction),32.31mg/g (ultrasonic auxiliary solvent extraction method) flavonoids content in walnut oil.2.The experimental results showed that the walnut oil is capable to scavenge the DPPH-free radicals with an IC50of147mg/mL, and the ability of Walnut oil to inhibit DPPH·was stronger than camellia oil’s. The ability of scavenging superoxide anion of walnut oil (1.0mg/mL) was similar with the ability for VC (1.0mg/mL). Walnut oil showed certain inhibition to hydroxyl radicals. Besides that, after refined, the ability of walnut oil to scavenge radicals declined. The reason may be that something having free radical-scavenging activity in walnut oil was lost in refining process.3.In the process of oxidation, temperature, time and the contact area can promote the oxidation of walnut oil. And with the oxidation degree deepening, free radical-scavenging activity of walnut oil gradually drop, linoleic acid and linolenic acid decrease respectively from54.92%,9.9%to35.79%and2.22%, the content of vitamin E also reduced from425.6mg/kg to120.7mg/kg. In the oxidation process, unsaturated fatty acid and the substance having antioxidant activity were changed.4. Determined by single factor and orthogonal experiments, optimized condition of traceingredients extraction were as follows: ultrasonic time15min、extraction temperature35℃, the solid-liquid ratio1:10. Through high performance liquid chromatography-mass spectrometry, traceingredients was analysed. Identified11material including juglone, hyperin, avacularin, walnut nucleoside, kaempferol, quercin, isoquercetin, gallic acid, succinic acid, caffeic acid, ellagic Acid.