Antifungal edible coatings containing Argentinian propolis extract and their application in raspberries

MORENO, MARÍA ALEJANDRA; VALLEJO, ANA MARÍA; BALLESTER, ANA-ROSA; ZAMPINI, CATIANA; ISLA, MARÍA INÉS; LÓPEZ-RUBIO, AMPARO; FABRA, MARÍA JOSÉ

FOOD HYDROCOLLOIDS

ELSEVIER SCI LTD

Año: 2020 vol. 107

0268-005X

Edible coatings based on gelatin containing an ethanolic extract of Propolis (PEE) collected of hives from Monteregion in Argentina were developed and applied to raspberries (Rubus idaeus L.) with the aim of prolonging theirshelf life. Initially, the antifungal activity of PEE was evaluated against the major fungal pathogens of fruit andvegetables. Then, two different strategies were followed to incorporate the PEE into gelatin-based films: i) bydirectly incorporating the PEE into the protein matrix and ii) by previously encapsulating the PEE within zeinnanocapsules with the aim of controlling the release of the PPE and extending their efficiency with time. Dryfilms were evaluated in terms of their optical, morphological, mechanical and water barrier properties. Likewise,the antifungal activity of the films against P. digitatum, P. expansum, P. italicum, A. alternata, A. carbonarius andB. cinerea was also assessed. Finally, film-forming dispersions (FFD) were applied to cold-stored raspberries andthe fungal decay was determined throughout cold storage at 5 �C.The incorporation of PEE affected the mechanical response of the films, giving rise to more flexible anddeformable edible films, but also more colored films with lower transparency. The active films revealed a notableantifungal activity against the tested fungus, showing a greater inhibitory effect on P. digitatum and B. cinerea.Adding PEE enhanced the antifungal activity during cold storage in raspberries. Furthermore, this proof-ofconceptstudy proved the efficiency of the encapsulation process to reduce the infection incidence in raspberriesstored at refrigeration temperatures for a longer period of time