Development of antimicrobial edible coating based on photo-activation of photosensitizer and biopolymer composite | |
| Author | Pimonpan Phasupan |
| Call Number | AIT Thesis no.FB-20-03 |
| Subject(s) | Photosensitization, Biological Antimicrobial polymers Photosensitizing compounds |
| 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. no.FB-20-03 |
| Abstract | Contamination of foodborne pathogens remains the challenge for fresh produce. Photodynamic inactivation (PDI) is a promising way to tackle the task without development of bacteria resistance. This study evaluated the antimicrobial effects of natural photosensitizers including chlorophyllin copper sodium salt, chlorophyllin magnesium sodium salt, and riboflavin under the LED illumination (blue and white) against E. coli and S. aureus based on the same number of absorbed photons (Nph). The best photosensitizer that showed the highest bactericidal activity was selected for studies inactivation kinetics, formation of complexes with chitosan (CS) and potassium iodide (KI), and photostability. The resultsrevealed that Chl-Mg showed significant antimicrobial effects. S. aureus was more susceptible to PDI than gram-negative E. coli. To achieve 5- log reduction, around 5x1017 and 7x1018 photons/cm2 required for inactivation of S. aureus and E. coli respectively. The inactivation kinetics of both bacteria under blue and white light were fitted with Logistic model (R 2 = 0.95 – 0.97 and RMSE = 0.27 – 0.40). Encapsulation of Chl-Mg in CS nanoparticle critically impaired photodynamic effects against E. coli. as compared to free Chl-Mg. However, normal conjugation of Chl-Mg with CS improved its antimicrobial activity against E.coli. (0.3 log reduction). The addition of 100 mM KI to Chl-CS complex could help significantly improved on bactericidal photodynamic effect against E. coli. Although photostability of Chl-Mg under LED exhibited rapid decrease within 10 min, encapsulation of Chl-Mg in CS nanoparticle and conjugation Chl-Mg with chitosan by physical mixing enabled significant improvement of photostability. In summary, Chl-CS combined with KI could be a promising composite used for decontaminating food or food contact surfaces by PDI. It can be also incorporated into a biopolymer for edible coating application. |
| Year | 2020 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no.FB-20-03 |
| 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) | Loc Thai Nguyen; |
| Examination Committee(s) | Anal, Anil Kumar;Bora, Tanujjal; |
| Scholarship Donor(s) | Royal Thai Government;Her Majesty the Queen’s Scholarships (Thailand); |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2020 |