Analysis Of Nutritional Compositions And Quality Of Shishen (Eremurus Chinensis Fedtsch.)

Shishen, a precious regitable produced in Qinling Mountain area, is the processed products from fleshy roots of Eremurus chinensis belonging to the Genus Eremurus (Liliaceae). The fresh roots of E. chinensis and Shishen were used as test materials. The contents of protein, crude fat, total sugar, reducing sugar, polysaccharide, crude fiber, mineral elements and heavy metals were measured, and the compositions of amino acids, fatty acids, volatile oil were analyzed by the methods of conventional, GC-MS, UV, FAAS and GFAAS. The optimed situations of polysaccharides extraction, detection and Sevage methods of protein eliminating were researched by single factor and orthogonal test. As well as, the antioxidant effect in vitro of Shishen polysaccharide were also tested. The main results were as follows:1. The protein content of Shishen and the fresh roots of E. chinensis were 7.40% and 7.70% seperately, which were higher than contrastive plants. The total protein content was partty loss in production process of Shishen. All of the tested materials contain 18 kinds of amino acids and 8 kinds of EAA, the ratio of SRC values were 69.54 and 67.96, the nutritional value were high. The tested materials were rich in flavous amino acids, and the first limiting amino acids were sulfur-containing amino acids, the amino acid composition of proteins in Shishen and other wild vegetables shared common features.2. The crude fat content of Shishen and the fresh roots of E. chinensis were 5.42% and 5.67% seperately, the total crude fat content was partly loss in production process of Shishen. We identified 26 fatty acids and 1 unknown composition from Shishen using gas chromatography-mass spectrometry (GC-MS). The 26 fatty account for 90.025% of the total fatty acids, including 7 unsaturated fatty acids (account for 52.36%). At the same time, 5 steroidal compounds were found, including 1 plant steroid (gamma.-Sitosterenol, 0.271%) and 4 vinyl-steroids compounds (3.704%). 24 chemical compositions were identified from volatile oil in the fresh roots of E. chinensis. The main components were Benzene-acetic acid-2-phenylethyl ester (43.833%), Acid-methyl-phenyl ester (14.994%), and cis-2- methyl-styryl- naphthalene (13.590%), etc.3. The total sugar and reducing sugar content were high in Shishen.The sugar content was relatively less affected in the process of participation. In the extraction of crude fiber by using the mothed of vertical blending funnel, we found that this method had little effect on crude fiber content and the experimental accuracy was high. Different methods of skimming reagents had no significant effect on the results of the crude fiber content. Our results show that crude fiber content of the fresh roots of E. chinensis and Shishen were 7.54% and 7.44% sperately, no significant difference between them. The RSD values indicate that the optimized method was accurate.4. The Shishen polysaccharide extraction conditions were solid-liquid ratio 1∶50, temperature 90℃, extracted 3 times and each time 2h. The content of polysaccharide was 13.44%. In the optimization of Sevage method to remove protein by single-factor test, after removing protein for 5 times, the protein content in polysaccharides was only 1.58μg/mL and the rate of polysaccharide loss was 11.37%. The effect of removing protein was good, and the polysaccharide content was less affected. The Shishen polysaccharide test conditions were 6% phenol content 1.6mL, sulphuric acid 7.0mL, time spanis 30min and temperature 80℃. Using the optimized extraction and detection techniques to detect the content of Shishen polysaccharide, the result was 14.73%.In addition, the scavenging ability of polysaccharides on superoxide anion(O₂^-·), hydroxyl radical(·OH), 1, 1-diphenyl-2-picrylhydrazyl(DPPH·)and hydrogen peroxide(H₂O₂)were studied in vitro chemical systems. The results showed that Shishen polysaccharides had certain scavenging activity in all of the systems, but the scavenging activity were different. The antioxidant effects on H₂O₂ were significant, relatively weaker scavenging activity were showed on·OH and DPPH·, and the weakest one was O₂^-·in this system.5. The average content of mineral elements in Shishen was Ca 542.20μg/g, Na 235.42μg/g, Mg 196.81μg/g, Zn 63.73μg/g, Fe 173.39μg/g, Cu 24.17μg/g and Mn 113.91μg/g, then descending order of mineral content was Ca>Na>Mg>Fe>Mn>Zn>Cu. There were some differences in the element content between the fresh roots of E. chinensis and Shishen. The Ca, Na, Mg, Cu and Mn contents in Shishen was lower than those in the fresh roots of E. chinensis, and the mineral elements in leaves of E. chinensis were rich. The contents of heavy metals in all materials were lower than the national standard.Comparing with the corresponding data of common edible wild plants and daily vegetables, it was showed that the content of protein, fat, carbohydrate and crude fiber in Shishen were relatively high, the range of amino acids were completed, the nutritional value and functional of protein were good, the mineral elements were rich. The results also showed that the content of major nutrients had little loss in the production process of Shishen, but the process did not have a significant impact on their quality. Preliminary studies on Shishen antioxidant activity in vitro showed that Shishen polysaccharide had a certain activity of free radical scavenging. The extraction and detection process optimization of Shishen polysaccharide provided a theoretical basis for Shishen industrial production. In addition, 1 plant sterols (gamma.-Sitosterenol) and 4 vinyl-steroids compounds were found, the content levels was low, but they were the first to be found in common edible wild herbs and vegetables. As edible wild plants, Shishen was a natural food and vegetable resources, and it was worthy of further development and utilization.