Research On Preparation Of Peptone From Aquatic By-products

Aquatic products are popular among people,but the edible part is removed,and the remaining part is called aquatic by-products.If these by-products are not handled properly,environmental pollution and resource waste will be caused.These by-products contain a large amount of protein,minerals,etc.,and are high-quality raw materials for the production of peptone.In this paper,the squid by-products and the antarctic krill by-products were used as raw materials,and the two enzymes of flavor protease and alkaline protease were used to prepare peptone by graded hydrolysis with complex enzymes and combined hydrolysis with complex enzymes,and the temperature,time and complex enzyme ratio were selected.Based on the four factors of p H,the orthogonal experiment was carried out to determine the optimal enzymatic hydrolysis process.The total free amino acids of squid peptone and antarctic krill peptone were determined,the optimum medium concentration of E.coli,Bacillus subtilis,Bacillus cereus and Staphylococcus aureus was inoculated with squid peptone,beef cream peptone and antarctic krill peptone as medium,and the culture effects were compared.Following conclusions were obtained:(1)The optimum process conditions for the preparation of squid peptone by graded hydrolysis with complex enzymes are: temperature 60°C,p H=8.0,after adding alkaline protease for 1.5h,then adding flavour protease to continue hydrolysis for 3.0h.The total enzyme amount is 1%,the complex enzyme ratio is 1:1,and the hydrolysis rate is24.88%;the optimum process conditions for the preparation of squid peptone by combined hydrolysis with complex enzymes are: at a temperature of 60 ° C,p H=5.0,while adding The flavor protease and alkaline protease had a time of 5.0 h and a composite enzyme ratio of 1:1.Under this condition,the hydrolysis rate was 17.20%,the hydrolysis rate of the squid peptone prepared by the graded hydrolysis of the complex enzyme is greater than that of the complex enzyme combination.The squid peptone contains 17 kinds of free amino acids,among which,the total free amino acid (2780.42±1.45)mg/100 g in the squid peptone(graded hydrolysis with complex enzymes);the total free amino acid content in squid peptone(combined hydrolysis with complex enzymes)is(1863.31±2.98)mg/100 g,the total free amino acid content increases with the increase of hydrolysis rate.The optimal concentration of E.coli,Bacillus subtilis,Bacillus cereus,and Staphylococcus aureus was the same in two kinds of squid peptone solutions were 3.5g/L,4.0 g/L,5.0 g/L,and 4.5 g/L,respectively.E.coli,Bacillus subtilis,Bacillus cereus,and Staphylococcus aureus were inoculated with two kinds of squid peptone,and the OD600 was measured to draw a growth curve.Compared with the commercially available beef cream peptone medium spasm,the OD600 of the four microorganisms in the beef cream peptone was measured only in the beef cream peptone and the squid peptone for 12h~14h.The medium and large is about9.20%;it is only about 13.00% larger than the squid peptone medium(combined hydrolysis with complex enzymes),indicating that the squid peptone medium can replace the beef cream peptone as a component of the microbial culture medium.(2)The optimum process conditions for the preparation of antarctic krill peptone by graded hydrolysis with complex enzymes are: temperature 60 ° C,p H=5.0,after adding alkaline protease for 1.5 h,then adding flavor protease Continued hydrolysis for 3.5h,total enzyme amount 1%,complex enzyme ratio 1:1,the hydrolysis rate under this condition is 28.38%;the optimum process conditions for the preparation of antarctic krill peptone by combined hydrolysis with complex enzymes are are: temperature 60°C,p H=6.0,while adding flavor protease and alkaline protease for 5h,the ratio of complex enzyme to 1:1 was 18.32%,the hydrolysis rate of the antarctic krill peptone prepared by the graded hydrolysis of the complex enzyme is greater than that of the complex enzyme combination.Antarctic krill peptone contains 17 kinds of free amino acids,among which,the total free amino acid(2968.83±35.10)mg/100 g in antarctic krill peptone(graded hydrolysis with complex enzymes);total dissociation in antarctic krill peptone(combined hydrolysis with complex enzymes)The amino acid content is(2507.08±40.96)mg/100 g,and the total free amino acid content increases with the increase of hydrolysis rate.Therefore,the total free amino acid content of antarctic krill peptone(graded hydrolysis with complex enzymes)is greater than that of antarctic krill peptone.(combined hydrolysis with complex enzymes)content of total free amino acids.The optimal concentrations of E.coli,Bacillus subtilis,Bacillus cereus,and Staphylococcus aureu in the two kinds of antarctic krill protein solutions were 3.5g/L,4.0g/L,4.5g/L,and 5.0g/L,respectively.E.coli,Bacillus subtilis,Bacillus cereus,and Staphylococcus aureus were inoculated with two kinds of antarctic krill peptone medium spasm,and the OD600 was determined and drawn.The growth curve was compared with the commercially available beef cream peptone medium.When cultured for 12h~14h in beef cream peptone and antarctic krill peptone,the OD600 of the four microorganisms in the beef cream peptone was measured only in the antarctic krill peptone medium.(graded hydrolysis with complex enzymes)is about 8.00% larger;it is only about 10.30% larger than that in antarctic krill peptone medium(combined hydrolysis with complex enzymes),indicating that antarctic krill peptone medium can replace beef cream peptone as a component of microbial culture medium..