Essential oils and chitosan-based namoemulsion as biopreservation to control multi-drug resistance foodborne pathogens | |
| Author | Pial, Kazi Samia |
| Call Number | AIT Thesis no.FB-20-10 |
| Subject(s) | Essences and essential oils Anti-Bacterial Agents Soy protein concentrate |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Food Engineering and Bioprocess Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no.FB-20-10 |
| Abstract | The purpose of this study is to assess the formulation of two essential oils-based oil in water (O/W) nanoemulsions, their physiochemical characteristics, and antibacterial properties. The selected oils were thyme and green tea essential oils. The primary nanoemulsions were prepared using soy protein isolate as an emulsifier. The primary nanoemulsions were further characterized and nanoemulsions for better stability and high antibacterial activity chitosan, as a stabilizer and antimicrobial agent, was added to the primary nanoemulsion system. The chitosan stabilized nanoemulsions showed higher stability than the primary nanoemulsions. The highest creaming index (CI%) observed in primary nanoemulsions is 8.82 ± 1.07 for green tea nanoemulsion at room temperature and 10.00 ± 0.86 at 4 ± 2⁰ C. As for thyme nanoemulsions, 6.0 ± 1.35 at room temperature and 6.15 ± 0.66 at 4 ± 2⁰ C. Contrastingly, no creaming had been observed in the nanoemulsions stabilized with chitosan. The particle size, polydispersity index, and zeta potential of the selected nanoemulsions had been observed for 10 days. Primary thyme nanoemulsions had a particle size of 655 nm that decreased to 653 nm on day zero. Primary green tea nanoemulsions, on day zero, had a particle size of 371.4 nm and it increased to 390.4 nm. Multilayer nanoemulsions showed much higher particle size compare to its counterpart nanoemulsion without chitosan. The optimized chitosan stabilized green tea and thyme nanoemulsions had a size of 5273 nm and 4551 nm, respectively on the day of the formulation. The size changed to 5585 nm for thyme and 4489 nm for green tea on the last day of storage. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of thyme with chitosan nanoemulsion were 12.5 mg/mL and 50 mg/mL against S. aureus, 12.5 mg/mL and 25 mg/mL against B. cereus, 50 mg/mL against E. coli, and 100 mg/ml against S. enterica. Green tea with chitosan nanoemulsion had MIC and MBC values of 6.25 mg/mL and 12.5 mg/mL against S. aureus, 3.125 mg/mL, and 6.25 mg/mL against B. cereus. Both MIC and MBC were 50 mg/mL against E. Coli and 100 mg/mL and 200 mg/mL against S. enterica |
| Year | 2020 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no.FB-20-10 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Anal, Anil Kumar; |
| Examination Committee(s) | Loc Thai Nguyen;Datta, Avishek; |
| Scholarship Donor(s) | President Robert B. Banks Scholarship; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2020 |