Inhibition of Penicillium digitatum and Penicillium italicum by Hydroxypropyl Methylcellulose-Lipid Edible Composite Films Containing Food Additives with Antifungal Properties

New hydroxypropyl methylcellulose (HPMC)-lipid edible composite films containing low-toxicity chemicals with antifungal properties were developed. Tested chemicals were mainly salts of organic acids, salts of parabens, and mineral salts, classified as food additives or generally recognized as safe (GRAS) compounds. Selected films containing food preservatives were used for in vitro evaluation (disk diameter test) of their antifungal activity against Penicillium digitatum (PD) and Penicillium italicum (PI), the most important postharvest pathogens of fresh citrus fruit. Mechanical properties and oxygen (OP) and water vapor permeabilities (WVP) of selected films were also determined. Film disks containing parabens and their mixtures inhibited PD and PI to a higher extent than the other chemicals tested. Among all organic acid salts tested, potassium sorbate (PS) and sodium benzoate (SB) were the most effective salts in controlling both PD and PI. The use of mixtures of parabens or organic acid salts did not provide an additive or synergistic effect for mold inhibition when compared to the use of single chemicals. Barrier and mechanical properties of films were affected by the addition of food preservatives. Results showed that HPMC-lipid films containing an appropriate food additive should promise as potential commercial antifungal edible coatings for fresh citrus fruit.