Hydroxypropyl methylcellulose-beeswax edible coatings formulated with antifungal food additives to reduce alternaria black spot and maintain postharvest quality of cold-stored cherry tomatoes

Edible composite coatings based on hydroxypropyl methylcellulose (HPMC), beeswax (BW), and food preservatives with antifungal properties were formulated and evaluated on cherry tomatoes during cold storage. Selected food preservatives included: sodium methyl paraben (SMP), sodium ethyl paraben (SEP) and sodium benzoate (SB). Cherry tomatoes artificially inoculated with Alternaria alternata were coated and stored up to 21 d at 5 degrees C followed by 4 d of shelf-life at 20 degrees C. All antifungal coatings reduced the incidence and severity of alternaria black spot on inoculated cherry tomatoes, being the SB-based coating the most effective. Analytical and sensory fruit quality was evaluated on intact and cold-stored tomatoes. In contrast to coatings containing SMP or SEP, the SB-based coating was effective to reduce weight loss and respiration rate and maintain the firmness of coated cherry tomatoes. Peel color, ethanol and acetaldehyde content of the juice, sensory flavor, off-flavors, and fruit appearance were not adversely affected by the application of the antifungal coatings. In conclusion, HPMC-BW coatings containing the food additive SB at 2% showed potential for industrial application, including the production and commercialization of organic cherry tomatoes. (C) 2015 Elsevier B.V. All rights reserved.