2022 (09): "Complexation of biopolymers for the nanoencapsulation of antimicrobial molecules for food preservation" (thesis by Wei LIAO)

• Thesis supervisor:

Adem Gharsallaoui

• Funding:

Chinese government grant

Many food products are perishable and require protection against spoilage and pathogenic bacteria from preparation to consumption. One of the strategies used for preserving untreated food is to add chemical preservatives. There is considerable interest in the use of natural antimicrobials, such as essential oils or plant extracts. This is mainly due to the increased sensitivity of consumers to healthier and more natural foods. There are a number of technological challenges associated with incorporating active molecules into food products. Indeed, many natural antimicrobials, such as essential oils, have low solubility in water and are very labile compounds. Thus, they can easily decompose or evaporate during food processing, be difficult to dissolve or interact with the other components of food. Encapsulation is a potential strategy for improving the stability and efficient release of natural antimicrobial molecules into a food matrix. Much of the current bibliography on the encapsulation of antimicrobial molecules deals with micrometric size capsules. The objective of this thesis project will be to manufacture, by combining biopolymers, antimicrobial nanocapsules. The complex coacervation will be used to stabilize the nanoemulsions / nanosuspensions by the multilayer method. Nanometer-sized systems compared to micrometer-sized capsules can increase passive cellular absorption mechanisms, thereby reducing resistance to mass transfer and increasing antimicrobial activity by releasing their contents inside microbial cells. In addition, nanocapsules would provide greater surface area and better dispersion in food matrices.