Study On Preparation And Related Process Of Cocoon Silk Peptide And Mixed Amino Acid

Cocoon waste silk was utilized to prepare peptide and mixed amino acid .The preparational techology and related process involving ultrosonic-microwave assisted sodium carbonate solution degumming, acid and enzymetic methods hydrolyzing on fibroin, clariflocculator decolorizing were studied, and the products were analysised in this paper.Degumming experiments were carried out by single experiments comparing hoting water degumming and sodium carbonate solution degumming to ultrosonic-microwave assisted degumming on waste silk such as frison and frigon.The best condition for the ultrasonic-microwave assisted degumming were determined as follows: the amount of sodium carbonate solution 3%, the ratio of the solid to liquid 1:100,the microwave power 450W, and reaction time 18min.Acid hydrolysis experiments were carried out by water-bathe acid hydrolysing and microwave assisted hydrolysis.Results were obtained that microwave radiation shortens reaction time obviously, degrades energy consumption easily and has no effect on the product content.The optimum condition for phosphoric acid hydrolyzing by microwave assisted was obtained: the acid amount 85%, the ratio of the solid to liquid 1:4, reaction temperature 70℃, reaction time 90min and microwave power 150W ,which results in the recover rate up to 69.0%. While the best condition for sulphuric acid hydrolyzing by microwave assisted was determined as follows: the acid amount 15%,the ratio of the solid to liquid 1:10, reaction temperature 100℃, reaction time 60 min , microwave power 150W,the product recovery 68.3%. The effects of ultrosonic on enzyming regeneration of frison were investigated as follows: ultrosonic-assisted enzymolysis is better than that of water bathe.The best conditions of ultrosonic-assisted enzymolysis on regeneration of frison is the amount of frison 4%, temperature 45℃, pH value 10.0, amount of enzyme 4.0%, power 200W, reaction time 40min. The best conditions of preparation of silk peptide and mixed amino acid were giving: firstly, according to the conditions of phosphoric acid hydrolyzing , then develop pH value to 7, dry, enzymolysis in water bath as the following conditions : the amount of frison 5%, temperature 45℃, pH value 10.0, amount of enzyme 5%, reaction time 120min.The effects of decolorizing and amount of peptide and mixed amino acid by clariflocculator decolorizing experiment were studied.The optimum technology conditions were established : the amount of 6.0% sulfurous acid 11.5mL, the amount of 10% calcium hydroxide 2.5mL, 0.2% SLWXA dosage 2mL, 0.05% PAM dosage 0.3mL, the decoloration rate up to 77.23%. Amount of product and amino nitrogen by decolorizing were lost small. It was 45.93% superior in decoloration rate to Focculation decolorizing without auxiliaries.Molecular weight distribution were screened by gel chromatography experiments of G-50 and effect of Hygroscopic moisturizing of the product were dignosed by the related experiments. Results showed that products of the average molecular weight 2000Da have apparent effect of Hygroscopic moisturizing;The moisture rate is up to 93%, better than Transparent and Glycerine, and the effect of hygroscopic of frison peptide is better than that of frigon one.