Inhibition of postharvest penicillium molds of oranges by antifungal hydroxypro...

• Author(s): Valencia-Chamorro, Silvia A. ; Pérez-Gago, María B. ; del Río, Miguel A. ; Palou, Lluís
• Date: 2010
• Persistent ID: http://hdl.handle.net/10400.1/3049
• Origin: Sapientia - Universidade do Algarve
• Subject(s): Citrus; Food additives; Hydroxypropyl methylcellulose; Penicillium digitatum; P. italicum
• Document Type: Part of book or chapter of book
• Language: English
• Editor(s): Nunes, Carla

Description

Proceedings of the International Conference “Environmentally friendly and safe technologies for quality of fruit and vegetables”, held in Universidade do Algarve, Faro, Portugal, on January 14-16, 2009. This Conference was a join activity with COST Action 924. New hydroxypropyl methylcellulose (HPMC)-lipid edible composite films and coatings containing low-toxicity chemicals with antifungal properties were developed. Tested antifungal chemicals were mainly salts of organic acids, salts of parabens, and other compounds, most of them classified as food additives or generally recognized as safe (GRAS) compounds. Stand-alone edible films were used for in vitro evaluation of their antifungal activity against the pathogens Penicillium digitatum and Penicillium italicum by disk diameter tests. Selected edible coatings containing food preservatives were tested in vivo on ‘Valencia’ oranges to determine their curative (coated after fungal inoculation) and preventive (coated before fungal inoculation) activity to control citrus postharvest green and blue molds, caused by P. digitatum and P. italicum, respectively. Film disks containing parabens and the organic acid salts potassium sorbate (PS) and sodium benzoate (SB) were the most effective to inhibit both P. digitatum and P. italicum. The use of mixtures of organic acid salts did not provide any additive or synergistic effect for in vitro pathogen inhibition when compared to the use of single chemicals. On ‘Valencia’ oranges, the curative activity of coatings with food preservatives was higher for blue mold than for green mold. Coatings containing the mixture SB + PS and SB and sodium propionate (SB + SP) reduced the incidence and severity of blue mold by 85 and 95%, respectively. PS- and SB-based coatings controlled green mold more effectively than coatings formulated with other food preservatives. Fruit coated before inoculation did not show any incidence or severity reduction of both green mold and blue mold (preventive activity). The antifungal curative action of the coatings was fungistatic rather than fungicidal.