Optimization of ultrasound-assisted extraction and chitosan nanoencapsulation of synergistic green-black tea blends : evaluation of anti-diabetic, antimicrobial, antioxidant, and functional food applications | |
| Author | Baiz, Lezan Ghazi |
| Call Number | AIT Thesis no.FIBNH-26-02 |
| Subject(s) | Functional foods Ultrasonic waves Chitosan--Biotechnology Plant genetics |
| Note | A Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Food Innovation, Nutrition and Health |
| Publisher | Asian Institute of Technology |
| Abstract | While Camellia sinensis (tea) remains a potent source of bioactives, its clinical application in managing Type 2 Diabetes Mellitus (T2DM) and serving as a natural antimicrobial alternative is frequently hindered by poor bioavailability and structural instability. This study validates a "Food as Medicine" paradigm by investigating the synergistic potential of green and black tea mixtures and evaluating a "smart" nano-encapsulation strategy to enhance their therapeutic bioaccessibility and food-system stability. An integrated experimental framework was employed, involving the optimization of Ultrasound-Assisted Extraction (USAE), evaluation of multi-targeted bioactivity, fabrication of chitosan-tripolyphosphate (TPP) nanoparticles, and the development of a functional fish-gelatin jelly prototype. Regarding extraction optimization, the 50:50 tea mixture extracted at 75°C (M75) achieved a maximal yield of 17.89% and demonstrated a synergistic phenolic recovery of +8.16%, suggesting a protective interaction between tea polymers. In terms of bioactivity, the M75 extract demonstrated superior multi-functional performance, achieving a 28.1% improvement in α-glucosidase inhibition (IC₅₀ = 18.91 µg/mL) compared to pure green tea and significantly surpassing the pharmaceutical standard Acarbose (IC₅₀ = 21.69 µg/mL). Furthermore, the mixture retained 92.7% of green tea\\\'s antibacterial potency against S. aureus while achieving bactericidal activity against E. coli, positioning it as a potent non-antibiotic candidate to help mitigate Antimicrobial Resistance (AMR). To ensure targeted delivery, the synergistic extract was encapsulated within chitosan-TPP nanoparticles with an efficiency of 82.4%. These nanoparticles functioned as a pH-responsive vehicle, successfully restricting gastric release to <7% while achieving a peak intestinal bioaccessibility of 86.02%. Finally, the integration of these nanoparticles into a 6% fish-gelatin hydrogel resulted in a 2.6-fold increase in structural hardness (1820.7 g vs. 683.7 g), a 71.5% reduction in syneresis (1.18% total), and near-perfect color stability ((ΔE = 1.08) over seven days, effectively "locking" the bioactives within the matrix. These findings prove that synergistic tea-based nano-delivery systems can overcome the biological and physical limitations of traditional functional foods. By providing a natural, multi-targeted alternative to synthetic drugs, this study offers a validated framework for the dietary management of hyperglycemia and a strategic tool to reduce reliance on conventional antibiotics. |
| Year | 2026 |
| Type | Thesis |
| 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 Innovation, Nutrition and Health (FINH)/Former code name = FI |
| Chairperson(s) | Anal, Anil Kumar; |
| Examination Committee(s) | Darniadi, Sandi;Pillai, Branesh M.; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2026 |
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