Separation And Analysis Of Chemical Components From Konjac

With the improvement of people's lives,the demand of functional health food is increasing day by day.Konjac and its products have drawn wide attention.The chemical compositions of Konjac are complex and widely used,with different properties.In this paper,the main chemical compositions in Konjac are systematically studied,such as ceramide,flavonoid and volatile oil.The characteristic and content of different active ingredients in different Konjacs are analyzed by various modern analytical techniques and methods.The Konjac germplasms are systematically evaluated to provide scientific foundations for comprehensive understanding and utilization of chemical composition.The results are as follows:?1?Ultrasound-assisted extraction is used to extract ceramides from Konjac.The content of ceramides is determined by HPLC-ELSD.The contents of ceramides in Konjac JZ?flour and peel are 0.41 mg/g and 0.58 mg/g,respectively.The contents of ceramides in Rhododendron flour and peel are 0.36 mg/g and 0.48 mg/g,respectively.Ceramides are isolated and purified by petroleumether-ethylacetate elution silica gel column chromatography,vacuum freeze-drying and recrystallization.The yield of ceramides is 93.05%,with a purity of 85.93%.The structure of ceramides is determined by recovery experiments,infrared spectroscopy and LC-MS.The molecular formula is C₂₃H₄₃N₃O₃.The molecular name is 5-Amino-4-hydroxy-2-oxazol-2'-hexadecylceramide.?2?The flavonoids in Konjac are extracted by methanol-ultrasound-assisted extraction.Combined with Box-Benhnken,29 groups of experiments are designed to determine the influenced order of various factors,Methanol concentration>Ultrasonic temperature>Solid-liquid ratio>Ultrasonic time.The mathematical model is established to determine the optimal extraction conditions of flavonoids by Response Surface Optimization.The optimum extraction conditions are ultrasonic time 35 min,ultrasonic temperature 40°C,methanol concentration 88%,solid-liquid ratio 1:32.The content of flavones is 1.84 mg/g,predicted by mathematical model.Under such condition,the extracted yield of flavonoids is 1.73 mg/g,within the tolerance of the mathematical model.?3?The compositions of volatile oil in Konjac JZ?and Rhododendron are extracted by methanol-ultrasound-assisted extraction.The volatile oils are separated by extraction of ether.The chemical compositions of volatile oil are identified by GC-MS.Relative content is calculated by normalization method.Twenty-eight compositions of volatile oil are identified by GC-MS after being separated by ether,of which have six alcohols,twelve alkanes,five ketones.The relative contents of eleven common components are more than 85%.The relative content of?3-methyl-oxiranyl?-methanol is highest,ranging from 45.19%to 58.31%.