Development of antimicrobial bio-nanocomposite packaging materials using crystalline nanocellulose derived from green ionic liguid hydrolysis of corncob | |
| Author | Wanwipa Rasri |
| Call Number | AIT Diss. no.FB-25-01 |
| Subject(s) | Cellulose--Biotechnology Nanocomposites (Materials) Food--Packaging--Materials Corncobs |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of doctor of Philosophy in Food Engineering and Bioprocess Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Nanocellulose possesses many outstanding characteristics, such as high specific surface area and aspect ratio, chemical reactivity, low density, thermal expansion, and excellent mechanical properties. Due to its abundance, renewability, and biocompatibility, nanocellulose could be one of the most prominent green materials in the future for applications in food coatings and packaging. Traditional processes mainly rely on alkali and bleaching pre-treatments of cellulose, followed by an acid hydrolysis step. These methods have negative impacts on nanocellulose's properties and cause severe environmental issues. Therefore, developing novel and sustainable methods for extracting nanocellulose from biomass is highly desirable. In this work, a new, green hydrolysis process based on ionic liquid (IL) was investigated to produce corncob crystalline nanocellulose (CCCNC). Key reaction parameters were optimized to produce crystalline nanocellulose (CNC) with sizes and properties comparable to those obtained by conventional methods. Additionally, the potential of the as-prepared nanocellulose in forming antimicrobial bio-nanocomposites and active food packaging films was investigated. Specifically, the first objective involved the preparation of crystalline nanocellulose via the hydrolysis of corncob using the Brønsted acid ionic liquid 1-butyl3-methylimidazolium hydrogen sulfate ([Bmim][HSO4]), which acted as both solvent and catalyst. The results indicated that the dimensions of the nanocellulose products were influenced by the mass percent of corncob and the reaction temperature but not significantly by the reaction time. The optimal conditions, as estimated by the developed model, were a mass percent of 2.49%, a reaction temperature of 100 °C, and a reaction time of 1.5 h. This process successfully produced CCCNC with a yield of 40.13%, an average size of 166 nm, and a crystallinity index of 62.5%. Moreover, IL reagent could be recycled with an efficiency of 88.32%, highlighting the green application of the process. The second objective focused on chemical grafting of CCCNC with βcyclodextrin (βCD) to develop an antimicrobial bio-nanocomposite for food packaging. In this matrix, CCCNC served as both a reinforcement and a carrier, while βCD formed inclusion complexes with natural antimicrobial essential oils including carvacrol, thymol, and gingerol. It was found that CCCNC-βCD composite facilitated the prolonged release of essential oils and enhanced their antibacterial activity against both gram-positive and gram-negative foodborne pathogens, including Listeria monocytogenes, Escherichia coli, Bacillus cereus, and Salmonella. Due to its superior antimicrobial activity, CCCNC-βCD-carvacrol (CAR) nanocomposite was selected for the third objective, where it was incorporated into polylactic acid (PLA) to develop an antimicrobial biodegradable food packaging film. The results showed that CCCNC-βCD-CAR complex improved the barrier properties of the PLA films. Moreover, the film demonstrated significant inhibition of both gram-positive and gram negative bacteria. Finally, the PLA-3%(CCCNC-βCD-CAR) film was tested for its effectiveness in preserving fresh-cut lettuce during storage. The film suppressed gram positive and gram-negative bacteria, as well as natural microflora, maintaining bacterial counts below FDA limits for 14 days at 10 °C. Additionally, the developed film was effective in minimizing the loss of food quality during the storage period. Overall, this study demonstrated that the ionic liquid hydrolysis process could serve as an eco friendly and viable pathway for producing nanocellulose with exceptional properties for food packaging. The utilization of corncob, an agricultural byproduct, aligns with the principles of a circular economy and promotes sustainable practices in food industry. |
| Year | 2025 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development |
| 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;Pisut Koomsap;Bora, Tanujjal |
| Scholarship Donor(s) | Royal Thai Government Fellowship;AIT Fellowship |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2025 |