Study On Biotechnology In Squid Processing By-Products

With the rapid development of squid fishing industry, the quantity ofsquid processing by-products was accumulated and there was not goodmethod of utilizing them effectively at present.In this thesis, the authorstudied the exploitation of squid processing by-products, for exampleproducing the flavor attractants for fish consumption.In this thesis, theauthor studied the enzyme engineering, fermentation engineering, MaillardReaction on squid processing by-products, and the results showed that:1.The study on influence of material to water ratio, temperature, pH,time in auto-hydrolysis of squid processing by-products showed theoptimum condition of auto-hydrolysis were as follow: material-waterratio:1:1, temperature:45℃, the original pH, the time ofauto-hydrolysis:39h. Results showed that amino nitrogen, TSN, TCA-N,TVB-N and the degree of hydrolysis was 0.626±0.025g/100mL, 1.234±0.049g/100mL, 0.589±0.018g/100mL, 59.10±1.28mg/100mL, 23.89±0.13% respectively. The enzymolysis study of adding protease showed Alkaline protease,Neutral protease and Flavourzyme were the best enzymes and pepsin wasthe worst. The condition of compound enzymes as follow: Alkalineprotease 12h, then neutral protease 12h, and then added 0.5% (w: v) lipasedigestion to 39h. At the same time, adding 6% (w: v) of NaCl can inhibitTVB-N.2. The effects of moisture, salinity and carbon source on the solid-statefermentation of squid processing by-products were investigated. The resultsshowed that: amino acid nitrogen and TVB-N of the fermentation brothwas higher, when moisture was increasing and salinity was decreasing.Solid-state fermentation was affected by carbon source. Sucrose was thebest carbon source for solid-state fermentation in this paper. Therefore, thebest condition of solid-state fermentation of squid processing by-productswere material- liquid ratio:1:1.5, salinity: 8g/100g (raw material), carbonsource: sucrose. At the same time with the ORIGIN7.5 software to handlecalculations of experimental data obtained the dynamics model ofproducing amino acid nitrogen: Y = 0.39207 +0.06126 * X-0.00269 * X ^ 2(the formula: Y, Amino acid Nitrogen (g/100ml); X, Fermentation Time(d)).3. The effects of auxiliary factors on the fermentation of squidprocessing by-products were investigated. The results showed thatfermentation temperature, adding inorganic nitrogen, enzymes and metal ions played an important role. For example, changing temperature(fermentation in 30℃for 6d and then fermentation in 40℃for 4d),adding of 0.5% the inorganic nitrogen sources urea, adding of neutralprotease and 50mM Mn2+ can improve the quality of fermentation broth.The carbon and nitrogen ratio on the fermentation of squid processingby-products were investigated. The results showed that the TVB-N contentwas not high; three kinds of protease activity were the highest; amino acidnitrogen, TCA-N and TSN content were the highest; the TBARS was stillwithin the accepted sense; and the formaldehyde content was lowest. Soadding 7.5% sucrose was selected.4. The study on effect of compound strain fermentation of squidprocessing by-products showed inoculating squid processing by-productsand fermenting for 10 days with the rate at Aspergillus oryzae: Bacillussubtilis = 6:4, then adding yeast seed 15ml fermenting for 3 days canproduce flavor, nutritional value and safety of the coexistence of flavorattractants.5. Maillard reaction effect of the recycling squid processingby-products was studied. From Mailard heating reaction of solid-statefermentation of squid processing by-products, it can be seen that theoptimal reaction conditions were that at the rate of 4% of the xylose,support 0.5% ascorbic acid, 0.5% thiamine, natural pH, 115℃heatreaction for 60miniters, appetizing and tasty flavor attractants can be produced.It can be seen that in the analysis of volatile components from theMaillard reaction products, volatile carbonyl compounds, alcohols, acidsdominate, constitute were the main parts of volatile flavor compounds fromMaillard reaction products, characteristic odor compounds 2,6 - nonadienalaldehyde dominant flavor 2.25% volatile aldehydes and furans can enhancethe flavor. It also can be found that the Maillard reaction can reduce thefermentation product of Aspergillus oryzae content of biogenic amines.6. It can be seen that each of these three kinds of technology canimprove the flavor and release amino acids if not considering the safetyfactor of histamine; Maillard heating reaction products was the best oneconsidering the inhibitory effect on biogenic amines from thecomprehensive comparison of squid processing by-products of the re-usetechnology using solid-state fermentation, compound strains fermentationor Maillard heating reaction.