Combined treatments of Y-irradiation and active nano-biopolymers to assure food safety and security

Authors: LACROIX, MONIQUE - Institut National De La Recherche Scientifique (INRS); Follett, Peter; HOSSAIN, FARRAH - Institut National De La Recherche Scientifique (INRS); BEN-FADHEL, YOSRA - Institut National De La Recherche Scientifique (INRS); CRIADO, PAULA - Institut National De La Recherche Scientifique (INRS); FRASCHINI, CAROLE - Fpinnovations; CINGOLANI, CELESTE - National Atomic Energy Commission

Submitted to: IAEA/FAO Final Research Coordination Meeting on Irradiation as a Phytosanitary Treatment for Food and Agricultural Comodities Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary: We explore the possible application of a combined treatment of gamma radiation and biopolymeric diffusion devices with encapsulated plant derived-essential oil emulsions to protect bagged cereal grains during storage against insect and fungal contamination. We also developed and characterize active edible coating based on crosslinked milk protein using '-irradiation to improve its barrier properties and to evaluate its effect when applied alone or combination with low dose of '-irradiation on the quality and safety of pre-cut carrots during storage at 4 °C. Finally cellulose nanocrystals were irradiated and the formation of new functional groups for the development of active polymers for the protection of food quality. Our studies showed the insecticidal, antimicrobial and antifungal effects of bioactive films containing plant essential oils and caseinate in several food products.

Technical Abstract: Cellulose nanocrystals (CNCs), highly recognized for its reinforcing properties, are an organic nanosized material extracted from natural cellulose sources. CNCs were used for the development of an active film based on chitosan (CH) and methylcellulose (MC). The combined treatment of '-irradiation and bio-polymeric diffusion devices encapsulated with plant derived EOs emulsions were evaluated against two fungal species Aspergillus flavus and Aspergillus parasiticus and rice weevil, Sitophillus oryzae. In situ tests with CH/ CNC and MC/CNC based bioactive films containing EOs emulsion produced a ~ 2 log reduction in fungal growth in infected rice during 8 weeks of storage at 28°C. In addition, combined treatment of bioactive films with an irradiation treatment at 750 Gy showed more pronounced antifungal properties than treatment with the bioactive film or irradiation alone. The addition of CNCs as reinforcing filler improved the tensile strength of the nanocomposite based films by 10-23% and decreased water barrier properties by 6-9%. Nanocomposite films containing EOs nano-emulsion showed a slow release of volatile component over 12 weeks of storage period. Incorporating of EOs nanoemulsion into CH-CNCs and MC-CNCs films resulted in mortality ranging between 20-43% after a 10 day incubation period. In addition irradiation at 300 Gy alone caused 8% mortality, increased to 95% when the CH-CNCs film was combined with 300 Gy ionizing irradiation. Sensorial evaluation of rice samples containing CH-CNCs films loaded with EOs nano-emulsions showed no significant (p>0.05) alteration in odor, taste, color and overall appreciation. Such bioactive films bearing enhanced structure and antifungal properties hold significant potential for controlling fungal growth during storage of food items. A coating based on calcium caseinate (Ca) treated at 32kGy to improve the physicochemical and barrier properties of films were also developed. Irradiation treatment and EOs nanoemulsion incorporated in Ca based film were evaluated for their impact on color, elongation and elasticity parameter, water vapor permeability and CO2 and O2 permeability of the developed active films. Then, the active film and its application as coating to pre-cut carrots alone and combined to '-irradiation treatment at 0.5 kGy was also evaluated for its impact on the weight loss, respiration rate, the texture and the microbial quality of coated pre-cut carrots. Results showed that irradiation at 32 kGy allowed an improvement of barrier properties of films to water and gaz and an improvement of film elasticity. When applied on carrot surface, calcium caseinate coating (crosslinked with irradiation) allowed maintaining the texture and the respiratory activity of carrots during storage. Irradiation treatment at 0.5 kGy when it is applied alone it has no effect on the texture and respiration process. However, when combined to calcium caseinate coating (crosslinked with irradiation), the quality of pre-cut carrots was maintained during storage. Irradiation at 0.5 kGy and nanoemulsion-loaded calcium caseinate were especially efficient to control initial total flora of pre-cut carrots when applied in combination demonstrating a synergistic activity. The effect of '-irradiation on the surface chemistry of CNCs was evaluated and showed that the carboxylic acid groups content (COOH) improved from 43 mmol to 631 mmol COOH·kg-1 CNCs when a dose of irradiation of 80 kGy was applied. These changes were confirmed by FTIR and fluorescence spectroscopy. Also, a decrease of 30% of the degree of polymerization and an increase of aldehyde group by 97% was observed after irradiation treatment at 80 kGy. These physicochemical changes led to enhanced antioxidant properties of CNCs. Irradiated CNCs exhibit enhanced radical scavenging properties by showing 49 Trolox Equivalent (eq) (µM) when a 80 kGy