Analysis On The Dynamic Change Of Essential Oil From Leaves Of Smallanthus Sonchifolius And Nutritive Compositions In Different Parts

Yacon(Smallanthus Sonchifolius) is dicotyledonous herbage from helianthus of the composite,which was originally cultivated in South America in the Andean highlands with altitude of 880-3500m from Ecuador to the northwest of Argentina.It is food as well as acknowledged medicinal plant,which was fit for detoxification and quenching evil heat from the liver as well as effect of skin maintenance,could lower blood pressure, reduce blood sugar and lipid effectively,also prevent so many chronic diseases,such as diabetes and intestines dysfunction.The main chemical constituents of yacon were researched by modem analysis methods.In this paper,the nutritive compositions including crude protein,crude fat,total sugar,moisture and ash,the components of mineral elements and essential oil in leaves, stems and fruits of yacon were analyzed;the types and contents of dissolvable sugars, free amino acids and vitamins in fruits of yacon were determined;the chemical constituents in essential oil from leaves of yacon collected by Duoying,Pengzhou and Xichang were compared;the dynamic change of main chemical constituents in essential oil from leaves of yacon and saccharides transition in fruits of yacon during storage were discussed.The main results were described as follows:1.The nutritive compositions in leaves,stems and fruits of yacon were studied.The results showed that the content of ash,crude fat and crude protein in leaves was the highest,and the content of total sugar,ash and crude protein in stems was also relatively high.However,in fruits of yacon,the most was moisture(87.26%),next the total sugar (73.20%),and the lowest was crude fat(1.60%).Accordingly,the leaf and stem of yacon was the important source of protein to human food,and also the excellent forage for livestocks,while the fruit ofyacon was characterized with high sweet and low energy.2.The determination of dissolvable sugars,free amino acids and vitamins in fruits of yacon by HPLC,L-8800 automatic analyzer and fluorescence spectrophotometer were presented respectively in this article.The results of dissolvable sugars showed that there were fructose,glucose,sucrose,1-kestose and nystose in the fruits of yacon,and fructose (2.78%) was the most in the monosaccharide,while 1-kestose(3.3%) and nystose(3.94%) were main constituents of the fructo-oligosaccharide.The results of free amino acids showed that 16 kinds of amino acids with balanced proportion were detected in the.experiment,amounting to 259.82mg/100g and including 7 kinds of essential amino acids.The results of vitamins showed that the fruits of yacon contained a great many vitamins,firstly vitamin E(1.51μg/g),secondlyβ-carotene(1.24μg/g),vitamin B1 (0.45μg/g) and vitamin B₂(0.20μg/g) were the next,then vitamin A(0.132μg/g) and lastly vitamin D₂(0.01125μg/g).3.The content of mineral elements in leaves,stems and fruits of yacon were determined by microwave-assisted digestion,atomic absorption spectrometry and atomic fluorescence spectrometry.The results showed that abundant mineral elements existed in leaves,stems and fruits of yacon,and Cu,Fe,Mn,Ni,Zn,Sr of them were the necessary elements by human body.The kinds and contents of mineral elements in yacon plant were much more than those in other daily fruits,but there were different contents among leaves, stems and fruits of yacon.For example,the content of mineral elements in leaves and stems almost more than that in fruits,except that the content of Se in fruits was significantly higher than that in leaves and stems.4.Chemical constituents in essential oil from leaves,stems and fruits of yacon were analyzed for the first time.The essential oils isolated by hydrodistillation and distillation-extraction were identified 30 components by GC/MS,and the relative contents of identified components in leaves,stems and fruits were 98.28%,98.92%and 94.58%respectively by area normalization.The chemical constituents in essential oil from leaves were much more than the others,mainlyβ-Phellandrene,Caryophyllene andβ-Cadinene.Thus,the dynamic change of chemical constituents in essential oil from leaves of yacon with different collecting sites and picking times were further investigated. The results showed that the total trend of dynamic change of the main chemical constituents during the whole picking times was consistent,whereas their contents were different.Furthermore,the different types of chemical constituent's distribution in 3 different collecting sites were consistent with the rules of content accumulation,but their separated accumulation reached peak differently.5.Saccharides in fruits of yacon were extracted by hot-water extraction method,and its composition and content was measured by HPLC.The results argued that the main components of fructo-oligosaccharide extracted by fruits of yacon from China were not significant different with those from South America,except for the content.The results of saccharides transition in fruits of yacon stored under 4℃and room temperature indicated that fructo-oligosaccharide could easily decompose into fructose,glucose and sucrose during storage,whereas the degradation speed of fructo-oligosaccharide stored at 4^C was slower than that stored at room temperature.