Study On The Grass Fish Scale Hydrolysate Proliferation Effect On Streptococcus Thermophilus And Exopolysaccharides

Grass fish scales are the by-products produced in the process of aquatic product processing.They are rich in protein and have a complete variety of amino acids,which are often used as the source of collagen and gelatin.The enzymatic hydrolysis products of grass fish scale have certain biological activity.However,due to the waste of Marine resources,a large number of by-products are discarded,like fish scales,and resulting in the waste of biological resources and environmental pollution.This project focuses on this,recovering grass fish scales,using its high protein characteristics and the biological activity of the enzymatic hydrolysis products to optimize the enzymatic hydrolysis process of grass fish scales.The purpose of this project is to improve the comprehensive utilization rate of aquatic by-products and to provide theoretical support for the research on functional food from aquatic products.1 the Enzymatic Hydrolysis Process of Grass Fish Scales Were Optimized by Orthogonal ExperimentSingle factor experiment and orthogonal experiment were used to compare the effects of Alcalase 2.4l FG and flavoring protease on the proliferation of Streptococcus thermophilus,and the flavoring protease which can promote the proliferation of streptococcus thermophilus.The optimal conditions for enzymatic hydrolysis by flavoring protease were: the concentration of enzyme 6%,the ratio of material to water 1:5 g/m L,enzymatic hydrolysis time 3 h,and enzymatic hydrolysis temperature 50?.Under the optimal conditions,when the optimum concentration of the enzymolysis product was 1.5 g/L in the synthetic medium,the effect of the proliferation of Streptococcus thermophilus was the best.2 the Separation And Antioxidant Activity of the Enzymatic Hydrolysis Products of Were StudiedAccording to the molecular weight,the membrane separation technology was used to separate grass fish scales hydrolysate(Grass Fish Scales Hydrolysate,GFSH),and five different molecular weight of grass fish scales hydrolysate were obtained.(< 1 k Da: GFSH1;1?3 k Da: GFSH2;3?5 k Da: GFSH3;5?10 k Da: GFSH4;> 10 k Da: GFSH5).The effects of five different molecular weights of GFSH on the growth of Streptococcus thermophilus were compared.The results showed that the GFSH1(molecular weight less than 1000 Da)can better promote the proliferation of Streptococcus thermophilus,and enable the Streptococcus thermophilus to growth faster,and produce more acid than the other four molecular weights of GFSH.In addition,the antioxidant activity of GFSH with different molecular weights was studied.The results showed that the GFSH with molecular weight less than 1000 Da had good antioxidant activity.3 Extraction of Exopolysaccharide from Streptococcus thermophilus and Its Antioxidant Properties Were StudiedFive different molecular weight GFSH were obtained by membrane separation technology,and their effects on the production of extracellular polysaccharide(EPS)from Streptococcus thermophilus were studied.The result showed that GFSH1 was used as a nitrogen source,Streptococcus thermophilus produced more exopolysaccharides(111.4 mg)after 48 h.In addition,the process of removal of protein from medium was optimized,the optimal conditions were: trichloroacetic acid concentration 5%,centrifugal force 15000 r/min,centrifugal time 30 min.Finally,the antioxidant activity of exopolysaccharides from Streptococcus thermophilus was studied.The results showed that exopolysaccharides from Streptococcus thermophilus had good antioxidant activity in vitro.