Antifungal activities of combined treatments of irradiation and Essential Oils (EOs) encapsulated chitosan nanocomposite films in in vitro and in situ conditions

Authors: HOSSAIN, FARAH - Institut National De La Recherche Scientifique (INRS); Follett, Peter; SALMIERI, STEPHANE - Institut National De La Recherche Scientifique (INRS); DANG VU, KHANH - Institut National De La Recherche Scientifique (INRS); FRASCHINI, CAROLE - Fpinnovations; LACROIX, MONIQUE - Institut National De La Recherche Scientifique (INRS)

Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/2018
Publication Date: 2/12/2019
Citation: Hossain, F., Follett, P.A., Salmieri, S., Dang Vu, K., Fraschini, C., Lacroix, M. 2019. Antifungal activities of combined treatments of irradiation and Essential Oils (EOs) encapsulated chitosan nanocomposite films in in vitro and in situ conditions. Postharvest Biology and Technology. 295:33-40. https://doi.org/10.1016/j.ijfoodmicro.2019.02.009.
DOI: https://doi.org/10.1016/j.ijfoodmicro.2019.02.009

Interpretive Summary: The current study focuses on the development and assessment of films formulation based on chitosan nanocomposite loaded with essential oils (EOs) with improved bioavailability for protection of food items against fungal spoilage organisms. Thin, bioactive chitosan films able to protect the bioavailability of EOs without affecting mechanical properties of the films. Treatment of the active films based on chitosan polymer with low gamma irradiation dose (750 Gy) was able to improve significantly the tensile strength and tensile modulus of the biopolymeric material. Incorporation of cellulose nanocrystals (CNC) with the chitosan improved the biopolymeric matrix, by enhancing tensile strength and elongation break. The CNC also played an important role in stabilizing the physicochemical and release properties of the nanocomposite films. Vapor phase assays of the chitosan-based nanocomposite films loaded with thyme-oregano, thyme-tea tree and thyme-peppermint essential oil mixtures showed significant antifungal activity against Aspergillus niger, Aspergillus flavus, Aspergillus parasiticus, and Penicillium Chrysogenum, reducing their growth by 51-77%. Combining the bioactive chitosan films loaded with thyme and oregano essential oils and low dose of irradiation (750 Gy)significantly enhanced the inhibitory effects of the films in rice inoculated with fungi by causing an approximately 3 log CFU/g reduction in fungal growth. CNC films containing EOs nanoemulsion showed a slow release of volatile component over 12 weeks of storage period. Sensorial evaluation of rice samples packed with the chitosan bioactive films loaded with thyme and oregano nanoemulsions showed no significant change in odor, taste, color and general appreciation compared with untreated rice. These bioactive films have many potential applications for improving the safety and prolonging the shelf life of packaged foods.

Technical Abstract: The application of nanoemulsions for food preservation is receiving considerable attention from the scientific community. The demand of consumers for healthier and safer food products is increasing, and there is a need for designing edible materials capable of encapsulating, protecting, and preserving food commodities. The current study focuses on the development and assessment of films formulation based on chitosan nanocomposite loaded with essential oils (EOs) with improved bioavailability for protection of food items against fungal spoilage organisms. Thin, bioactive chitosan films able to protect the bioavailability of EOs without affecting mechanical properties of the films. Treatment of the active films based on chitosan polymer with low gamma irradiation dose (750 Gy) was able to improve significantly (p= 0.05) the tensile strength (TS) and tensile modulus (TM) of the biopolymeric material. Incorporation of cellulose nanocrystals (CNC) with the chitosan improved the biopolymeric matrix, by enhancing tensile strength and elongation break. The CNC also played an important role in stabilizing the physicochemical and release properties of the nanocomposite films. Vapor phase assays of the chitosan-based nanocomposite films loaded with thyme-oregano, thyme-tea tree and thyme-peppermint essential oil mixtures showed significant antifungal activity against Aspergillus niger, Aspergillus flavus, Aspergillus parasiticus, and Penicillium Chrysogenum, reducing their growth by 51-77%. Combining the bioactive chitosan films loaded with thyme and oregano essential oils and low dose of irradiation (750 Gy) significantly (p= 0.05) enhanced the inhibitory effects of the films in rice inoculated with fungi by causing an approximately 3 log CFU/g reduction in fungal growth. Chitosan Nanocomposite films containing EOs nanoemulsion showed a slow release of volatile component over 12 weeks of storage period. Sensorial evaluation of rice samples packed with the chitosan bioactive films loaded with thyme and oregano nanoemulsions showed no significant (P > 0.05) change in odor, taste, color and general appreciation compared with untreated rice. These bioactive films have many potential applications for improving the safety and prolonging the shelf life of packaged foods.