Preparation Of Chito Oligosaccharide From Tenebrio Molitor Slough And Its Application

In recent years,Tenebrio molitor cultivating industry achieved scale and industrial development.Most scholars did a lot of research on the cultivating of Tenebrio molitor,but they ignored the environmental pollution brought by the industry and the wastes of Tenebrio molitor industry（main components:slough and death）of recycling use.The slough of Tenebrio molitor contained large amounts of chitin,which could be modified into chitooligosaccharide.And chitooligosaccharide had antibacterial,antibacterial and antioxidant effects,it could be used for fresh fruits and vegetables.China had the world’s largest fruist and vegetables production,and the fruit and vegetable decay rate is as high as 30%.If the chitin contained in the waste of Tenebrio molitors could be extracted and modified,it could be used for fresh preservation of fruits and vegetables,which can reduce waste of resources,reduce environmental pollution,and increase economic and social benefits.The project took Tenebrio molitor cultivating wastes as raw material,through degreasing,desalination,deprotein and deacelation process to obtaine the chitosan,and with hydrogen peroxide（H₂O₂）or ozone（O₃）for further oxidation degradation of chitosan,and the chitooligosaccharide with good water solubility were prepared.Taking the fresh cut apple as an example,the preservation effect of chitooligosaccharide was investigated.The optimum preparation conditions were obtained by orthogonal experimental design.The results showed that:（1）The optimum preparation conditions of chitosan,（1）Degreasing:The extraction solvent was anhydrous ether,the extraction temperature was 50°C,the extraction time was 3 h,the solid-liquid ratio（g:mL）was 1:20,and the grease removal rate was up to30%;（2）Deprotein:1.0 wt%sodium hydroxide（NaOH）,temperature was 55°C,time was 3 h,solid-liquid ratio（g:m L）was 1:12;（3）desaltion:1.0 vol%hydrochloric acid（HCl）,time was 7 h;（4）Deacetylation:60 wt%NaOH,reaction temperature was 130°C,reaction time was 7 h.The product was confirmed to be chitosan by infrared characterization and the degree of deacetylation was determined to be 89%.（2）Preparation of chitooligosaccharides by hydrogen peroxide（H₂O₂）.Optimum process conditions in different systems:（1）homogeneous system:solvent was 0.1mol/L HCl,5.0 vol%H₂O₂,1.75 wt%chitosan,reaction time was 4 h,reaction temperature was 50°C;（2）Heterogeneous system:8 vol%H₂O₂,0.5 wt%chitosan,reaction time was 5 h,reaction temperature was 60°C.Preliminary exploration O₃ preparation of chitooligosaccharide in the homogeneous system conditions as follows:the solvent was 0.1 mol/L HCl,reaction temperature was 50℃,reaction time was 2.5 h.The products obtained from the two methods were characterized by infrared spectroscopy,X-ray diffraction,thermal weight,differential scanning calorimetry and electron microscopy,and the product was obtained as chitooligosaccharide,and the molecular weight was less than 2000 Da.（3）0.1 wt%chitooligosaccharide on effect of preservation of fresh-cut apple:the experimental group compared with control group,the degree of browning was 60%lower,weightlessness rate decreased 20%,39%higher hardness,reduce malonaldehyde content tendency for 0.2 mmol/g,peroxidase activity to reduce 2.5activity unit,polyphenol oxidase activity increased 11.5 activity unit,preservation is better than other antistaling agent.The experimental group will explore the effect of fresh fruit preservation.In summary,the study of the extraction of resources in the waste of Tenebrio molitor cultivating has a certain significance.