Development of bioactive coatings based on γ-irradiated proteins to preserve strawberries

Khanh Dang Vu (1) , Robert G Hollingsworth (2) , Stéphane Salmieri (1) , P. N. Takala (1) , Monique Lacroix (1)

1 INRS-IAF - Institut Armand Frappier
2 US Pacific Basin Agricultural Research Center

Gamma irradiation was applied for creating cross-linked proteins to enhance the physicochemical properties of edible films made of calcium caseinate, whey protein isolate and glycerol. The characteristics of γ irradiated cross-linked proteins were analyzed by Fourier Transform Infrared spectroscopy. A second derivative spectra exhibited changes in band intensities that were correlated to an increase of β-sheet structure and a decrease of α-helix and unordered fractions of γ irradiated-cross-linked proteins as compared to the control without irradiation. Furthermore, on addition of methylcellulose to the irradiated protein matrix it was found that it has potential in enhancing the puncture strength and has no detrimental effect on water vapor permeability of protein based films. Finally, these film formulations were used as bioactive edible coatings containing natural antimicrobial agents (limonene and peppermint) to preserve the shelf life of fresh strawberries during storage. The bioactive coatings containing peppermint was found to be more efficient as preserving coatings than the formulations containing limonene. Irradiated proteins/methylcellulose/peppermint formulation had only 40% of decay at day 8 while it was 65% for the control.

Mots clés: Gamma irradiation; Bioactive coating; Antimicrobial agents; Preservation; Strawberries

Domaines: Maladies infectieuses

Khanh Dang Vu, Robert G Hollingsworth, Stéphane Salmieri, P. N. Takala, Monique Lacroix. Development of bioactive coatings based on γ-irradiated proteins to preserve strawberries. Radiation Physics and Chemistry, 2011, 81 (8), pp.1211-14. ⟨10.1016/j.radphyschem.2011.11.071⟩. ⟨pasteur-01005558⟩