In Vitro Antioxidant,Oxidation Stability And The Quality Change During The Frying Process Of Trichosanthes Tirilowii Maxim Seed Oil

Trichosanthes kirilowii Maxim seed in this paper was taken as the investigation material.The main components of Trichosanthes kirilowii Maxim seed were studied.The physicochemical properties,oil extraction yield and in vitro antioxidant capacity of Trichosanthes kirilowii Maxim seed oil,the oxidation stability of four types antioxidants in Trichosanthes kirilowii Maxim seed oil during storage,the physicochemical properties and changes of fatty acid composition in the frying process were studied.The main results of the study were as follows:（1）The main components of Trichosanthes kirilowii Maxim were as follows:moisture 5.98±0.30%,ash 2.83±0.14%,fat 47.83±0.20%,protein 26.90±0.08%,sugar13.33±0.05%.The minerals content of Trichosanthes kirilowii Maxim seed were in sequence as follows:K>Mg>Ca>Fe>Zn>Mn>Cu;The minerals gradation of Trichosanthes kirilowii Maxim seed oil were in sequence as follows:Ca>Mg>Fe>K>Zn>Cu>Mn.（2）The oil extraction yield of cold pressing method for extract raw and ripened Trichosanthes kirilowii Maxim seed oil were 12.17%and 24.39%,respectively.But the extraction of the raw Trichosanthes kirilowii Maxim seed oil had the smells of fresh grass and the extraction of the ripened Trichosanthes kirilowii Maxim seed oil had aromatic odour.The oil extraction yield of solvent extraction method for extract raw and ripened Trichosanthes kirilowii Maxim seed oil were 31.82%and 28.78%,respectively.But Trichosanthes kirilowii Maxim seed oil prepared in this method had residual solvents.Taking all these factors into account,the cold pressing method was the appropriate method.（3）The acid value and peroxide value of Trichosanthes kirilowii Maxim seed oil were 0.3650 mg/g and 1.9961 meq/kg,respectively.The results of UV spectroscopy scaning showed that:at 263 nm,273 nm and 285 nm,the oil had maximum absorption peaks,which confirmed the existence of conjugated triene bonds.FR-IR spectrum analysis showed that the oil has characterized absorption peak at 988.60nm confirmed the existences of punicic acid.The GC-MS suggested that the main components of Trichosanthes kirilowii Maxim seed oil were stearic acid（25.02%）,oleic acid（41.59%）and octadecatrienoic acid（24.51%）.（4）In vitro antioxidant activity analysis showed that Trichosanthes kirilowii Maxim seed oil had strong scavenging ability to DPPH free radicals and hydroxyl free radicals.Under higher solution concentration,the scavenging rate up to 90%,respectively.The scavenging effect of Trichosanthes kirilowii Maxim seed oil on O₂^-·was superior to the V_C,which can up to 54.34%.Under the same concentration,the reducing power of Trichosanthes kirilowii Maxim seed oil had no significant change,and the absorbance ranged from0.1325 to 0.157.（5）The results of oxidation stability suggested that the anti-oxidative capacity of the four antioxidants was:TBHQ>rosemary extract>lycoypene>Vitamin E.The synthetic antioxidant exhibited more remarkable anti-oxidative activity than natural antioxidants in oil.Set TBHQ as control,when the content of the four types antioxidant was 0.005%,0.01%,0.015%,0.02%,0.02%TBHQ had the best antioxidant effect;0.02%rosemary extract had the best antioxidant effect;the best antioxidant effect content of lycopene was0.01%;the best antioxidant effect content of V_E was 0.015%.（6）The study of the effect of frying process on the quality and fat acids content revealed that the acid value kept growing and the peroxide value kept growing and finally tended to be stable with the extend of time,when frying temperature was 180℃.The oils was fried for 8 h at 160,180,200℃,respectively,the acid value kept growing and the peroxide value showed decreasing trend.During the process of frying,total saturated acids and monounsaturated fatty acid content increased with the increase of both frying time and temperature.While the content of polyunsaturated fatty acids presented decreasing trend.