Researcher Lê Anh Quốc with supervisor Prof. Nguyễn Quốc Hiến

On 19 August at VNUHCM-University of Science, researcher Lê Anh Quốc successfully defended a doctoral dissertation at institutional level with the topic “Study on the preparation of chitosan–glucosamine derivatives through Maillard reaction induced by Co-60 gamma irradiation and evaluation of selected biological activities”, under the supervision of Prof. Nguyễn Quốc Hiến. The evaluation committee commended the originality, applicability, and scientific contributions of the research.

The dissertation investigated the preparation of chitosan–glucosamine derivatives through the Maillard reaction catalysed by Co-60 gamma irradiation, with the objective of enhancing the physical properties and biological activities of chitosan. Chitosan, a biopolymer of considerable potential in food science due to antibacterial, antioxidant, and non-toxic characteristics, has been constrained by poor solubility and sensitivity to environmental conditions.

The Maillard reaction between chitosan and glucosamine under Co-60 gamma irradiation was chosen as an environmentally friendly modification method, avoiding chemical catalysts and preventing the formation of harmful by-products such as 5-HMF. The study optimised reaction conditions, including reactant ratios and irradiation dose, achieving a yield of approximately 80 per cent. The Maillard reaction product (MRP CTS-GA) underwent comprehensive evaluation covering antibacterial and antioxidant performance, solubility, biosafety, and food preservation capacity.

The developed process for producing MRP CTS-GA achieved a yield of ~80 per cent without harmful by-products. Optimal conditions were established as a CTS:GA ratio of 1.6%:0.4% with an irradiation dose of 25 kGy. The resulting product displayed complete solubility in water, no cytotoxicity towards L929 cells, and no acute oral toxicity in experimental mice. Strong antibacterial activity, particularly against E. coli, was confirmed through mechanisms involving interaction and disruption of bacterial cell membranes (FESEM evidence).

The product also demonstrated protective effects on lipids, proteins, and DNA in pork muscle cells against hydroxyl free radicals. Practical trials showed that a 1000 mg/L MRP CTS-GA solution extended the shelf-life of pork tenderloin by 6 hours at 28 °C under aerobic conditions, 8 days at 5 °C under aerobic conditions, and 14 days at 5 °C under anaerobic conditions. These findings confirmed strong potential for application in the preservation of fresh food.

The dissertation highlights significant promise in food technology while advancing a sustainable research direction through the use of Co-60 gamma irradiation as a substitute for chemical agents, thereby enabling future industrial-scale application. This approach reflects contemporary trends in food industry development and contributes to reducing health risks for consumers. The defence proceeded in a serious academic atmosphere, with researcher Lê Anh Quốc presenting the research clearly, addressing questions from reviewers convincingly, and receiving high recognition from the examination committee.

The evaluation committee engaged in discussion and academic review with researcher Lê Anh Quốc during the defence session.

Khánh T. _ Translated by PMN