Dissertation > Excellent graduate degree dissertation topics show

Research on Cryoprotectant Selection and Protective Mechanism for Lactobacillus Casei

Author: WangLin
Tutor: ZhaoZheng
School: Tianjin University of Science and Technology
Course: Agricultural Products Processing and Storage
Keywords: freeze-drying cryoprotectant protective mechanism
CLC: TS252.1
Type: Master's thesis
Year: 2012
Downloads: 24
Quote: 0
Read: Download Dissertation

Abstract


Vacuum freeze-drying is widely used to produce commercial lactic acid bacterial starter,but this technique brings about undesirable side effects,such as denaturation of sensitive proteins and decreased viability of many cell types.Adding appropriate cryoprotectants is effective in the case of LAB,so as to increase their survival rates during dehydration,however,the protective effect depends on cryoprotectants and bacteria.In China, the research on protective mechanism was less than picking an efficient protective agent.This dissertation optimized cryoprotectants for Lactobacillus casei,evaluated their protective effects by comparing the changes of survival rate,recovery capability and acidification activity,concluded protective mechanism through detecting inactivation of intercellular enzymes,integrity and oxidation of membrane.Based on survival rate,the formulation of cryoprotectants for lyophilized Lactobacillus casei was optimized by means of response surface methodology in this study.Results indicated the optimal amounts in100mL of cryoprotectants formula were skimmed milk15.8g,lactose5.73g and monosodium glutamate0.42g.The optimal cell survival rate was observed to be92.4%using the optimal compound cryoprotectant.In the absence of protectant,survival rate was merely5.25%,tOD0.2and tpH5.5were separately90min and20h.Results were improved when adding cryoprotectant,the different protective effects were as follows:optimized> skimmed milk> lactose> monosodium glutamate.92.4%for survival rate,20min for tODo.2and90min for tpH5.5were the best results observed by adding the optimized protectant.By using fluorescent probes PI,5(6)-CFDA and C11-BODIPY581/591,combined with multiparametric flow cytometry,membrane integrity,intracellular esterase activity,cellular vitality,and membrane oxidation were quantified before and after freeze-drying.Results indicated that cryoprotectants can reduce "mechanical damage" and "solution effect" as the activity of intracellular esterase,(3-galactosidase and ATPase were all improved.Lactose and monosodium glutamate may act as antioxidant,though,oxidantion of lipid on membrane was not the main reason for reducing cell viability during freeze-drying.

Related Dissertations

  1. The Study of Yeast Frost-resistance and Application in Frozen Dough,TS213.2
  2. Studing on Water-holding Capacity and Its Controlling Methods of Fresh Chicken Meat,TS251.55
  3. Establishment of Protocol for Preparation and Assay of Lysin Encoded by Bacteriophage from Streptococcus Suis,R515
  4. Cultured Bacillus Japanese beetles and freeze-drying protectants recovery of,S482.3
  5. Fibroin microspheres and their use as cell carriers in study,R318.08
  6. Fermentation Optimization of CALB Displaying Pichia Yeast as Whole Cell Lipase Catalyst and Its Application on the Modification of Natural Vitamin C,TQ924
  7. Optimization of Drying Process for Marine Biocontrol Yeast Rhodosporidium Paludigenum,TS202.3
  8. Strain Screening and Preparation of DVS Bacillus Natto Starter,TS201.3
  9. Study on the Preparation and Photoconductivity of β-TiOPc,O626
  10. Tobramycin sulfate refining process research,R942
  11. Different preservation methods on olfactory ensheathing cell activity,R651.2
  12. Screening of Cholesterol-reducing Bifidobacterium in Vitro,R371
  13. Freeze-dried Microscopic Observation Device Development and the Research on Preparation of Nanopowder by Freeze-dried Method,TB383.1
  14. Study on High-Density Cultivation and Cryoprotectant of Lactobacillus Acidophilus,TS201.3
  15. Preparation, Characterization and Electrical Properties of Al Doped Lanthanum Silicate Electrolyte,TM911.4
  16. Comparative Study of Ldl, Soybean Lecithin and Trehalose on the Cryopreservation of Boar Sperm,S828
  17. Studies of Preparation Technics and Quality Contral on Shuxiong Freeze-Dried Powder for Injection,TQ461
  18. Production Process of Vibrio Anguillarum MVAV6203A-1 Multivalent Vaccine MVAV6203A-1 for Marine Flatfishes,S948
  19. Study on the Functional Components and Antioxidant Capacities of Young Fruits of Citrus,S666
  20. Studies on Alkaloids of Sophora Flavescens for Injection,R283
  21. Research on the Right to Know of Consumers,D923.8

CLC: > Industrial Technology > Light industry,handicrafts > Food Industry > The dairy processing industry > Basic science
© 2012 www.DissertationTopic.Net  Mobile