Research On The Combined Extracting Technology Of Several Bioactive Substances From Crayfish By-products

This paper uses the crayfish by-products as raw materials, by the means ofchanging the extraction method, extracting reagen and adjusting the process route,on the basis of the traditional methods of preparation of chitin, to get morebioactive substances in the combined extraction, to improve the comprehensiveutilization degree of crayfish by-products, and also to complete the cleanerproduction.This study extracts protein from crayfish by-products, using the alkalineprotease, taking protein hydrolysate yield as evaluation index, By the experimentsof single factor and orthogonal, the optimized enzymolysis condition is obtained. Inthis condition, the optimal enzyme dosage is8700u/g, the optimal pH value is thenatural pH value after added distilled water, the optimal enzymolysis temperature is50℃, and theoptimal enzymolysis time is195minutes. Under this experimentconditions, the obtained protein hydrolysate samples contains the protein of68.6%,which is pale yellow, with shrimp freshness and without any indications.Using acetone to extract astaxanthin from crawfish by-products and takingastaxanthin yield as evaluation index, a single factor test is completed. The bestprocess condition is obtained. In this condition, the drying temperature is105℃,the optimal solid liquid ratio (g: mL) is1:16, the optimal ultrasonic treatment timeis10mins, the optimal extraction temperature is25℃and the extraction time is3h.Using organic acid instead of strong acid to extract calcium from crayfishby-products, taking calcium yield as evaluation index, a single factor test iscompleted. The best process condition is obtained. In this condition, combine thecitric acid with the malic acid and lactic acid, the molar ratio is2:3:6, the mixedacid dosage is1g/g crayfish by-products, the solid liquid ratio (g: mL) is1:16, theoptimal extraction time is5hours, the optimal extraction temperature is30℃.Under this experiment conditions, the obtained calcium content is11.82%in organic calcium sample, which is milky white and light yellow.On the basis of the test, with raw materials of the wet and dried shrimp, takingthe protein hydrolysate yield, the astaxanthin yield, the calcium yield and the chitinyield as evaluation index, the optimal process route is obtained by changing theprocess routes. Through the test, using the wet shrimp as the raw material,astaxanthin is extracted by ethanol instead of acetone. the best combinationextraction route is as follows: The enzymatic hydrolysis preparation of proteinhydrolysateâ†'Organic acid extraction preparation of organic calciumâ†'Ethanolextraction of astaxanthinâ†'hydrogen peroxide solution soak off residual pigmentâ†'Chitin.