Study On The Composition Of Different Varieties Of Kiwifruit

In this paper chemical composition in different varieties of kiwifruit such as volatilecomponents, fatty acids, amino acids, vitamin C and trace elements were analyzedcomparatively, and their antioxidant properties were determined.Volatile components of kiwi were extracted respectively by using solid phase microextraction and steam distillation. The extracted volatile components of kiwi samples by thetwo methods of extraction were qualitatively analyzed by GC-MS and compared theirdifferences. In the steam distillation, fresh kiwis was peeled and mashed, and distillated4h;And in the solid phase micro-extraction, the model of SPME was75μm CAR/PDMS, thesamples’ equilibration time was10min, the extraction temperature was50℃, the extractiontime was60min, and the desorption time was5min. The experimental results show that themost components analyzed by solid phase micro extraction technique is the first incense, andthe aldehydesand esters’ relative contents are higher than others; And the most componentsanalyzed by steam distillation is the middle and last incense, and its analysis is morecomprehensive.Fatty oil of kiwi samples was extracted by soxhlet, fatty acids in fatty oil was methylesterficationed, analyzed and determined by GC-MS. The experimental results show that thethe kiwi samples contain two kinds of unsaturated fatty acids such as linolenic acid andlinoleic acid, and linolenic acid’s content is highest to more than75%.The content of five kinds of essential amino acid of kiwis is determined by highperformance liquid chromatography-evaporative light scattering detection method.Thegradient elution’s mobile phase was acetonitrile-0.7%TFA, the flow rate was0.8mL/min,thecolumn temperature was35℃, the temperature of detector’s drift tube was115℃, and within25minutes the separation and determination of the five amino acids were achieved. Thecoefficient of variation of the method was2.63%, the recovery rate was99.40%to103.1%,and the linear range was0.1¹0mg/mL. The experimental results show that the total contentof amino acids in the Southern Chinese gooseberry is the most, in which isoleucine leucineand leucyl acid’s content is the highest.HPLC was used to carry out a quantitative analysis of content of vitamin C in kiwis.0.3%aqueous solution of oxalic acid was as the mobile phase, the flow rate was1.0mL/min,the column temperature was30℃, the detection wavelength was244.1nm, the coefficientof variation was1.115%, the recovery was97.60%¹00.3%, and the linear range was0⁰.5mg/mL. The experimental results show that the content of vitamin C in the SouthernChinese gooseberry is up to243.4mg/100g.Flow injection chemiluminescence method was used to study the antioxidant properties of kiwi samples. Luminol-carbonate buffer-pyrogallol was as chemiluminescence system,under the conditions of the concentration of Luminol was6×10^-4mol/L, pH of buffer was11.00, the concentration of pyrogallol was5×10^-5mol/L, and the flow rate was2.5mL/min,the order of kiwi samples’ oxidation resistance is Chinese gooseberry> New ZealandKiwifruit> Actinidia arguta of Jilin> Actinidia arguta of Liaoning.The kiwi samples were pretreated by microwave digestion, and eight kinds of essentialtrace elements in the samples were analyzed and determined by Inductively Coupled PlasmaMass Spectrometry （ICP-MS） method. The method’s coefficient of variation was1.061%⁷.805%, the detection limit was0.01527⁴.659μg/L, recoveries were95.10%¹06.9%.The experimental results show that the content of the trace elements in the different varietiesof kiwifruits are different.