Effect of Hydroxypropyl Methylcellulose-Beeswax Composite Edible Coatings Formulated with or without Antifungal Agents on Physicochemical Properties of Plums during Cold Storage

Abstract

The influence of hydroxypropyl methylcellulose-(HPMC-) beeswax (BW) composite edible coatings formulated with or without food additives with antifungal properties on physicochemical and sensory properties of plums (Prunus salicina) cv. "Friar" stored for 11 and 22 d at 1 ∘ C followed by a shelf life period of 5 d at 20 ∘ C was evaluated. Food preservatives selected from previous research included potassium sorbate (PS), sodium methyl paraben (SMP), and sodium ethyl paraben (SEP). Emulsions had 7% of total solid content and were prepared with glycerol and stearic acid as plasticizer and emulsifier, respectively. All the coatings reduced plum weight and firmness loss and coated fruit showed higher titratable acidity, soluble solids content, and hue angle values at the end of the storage period. In addition, physiological disorders such as flesh browning and bleeding were reduced in coated samples compared to uncoated controls. Paraben-based coatings were the most effective in controlling weight loss and the SMP-based coating was the most effective in maintaining plum firmness. Respiration rate, sensory flavor, off-flavors, and fruit appearance were not adversely affected by the application of antifungal coatings. Overall, these results demonstrated the potential of selected edible coatings containing antifungal food additives to extend the postharvest life of plums, although further studies should focus on improving some properties of the coatings to enhance gas barrier properties and further increase storability.

Edible Coatings Formulated with Antifungal GRAS Salts to Control Citrus Anthracnose Caused by Colletotrichum gloeosporioides and Preserve Postharvest Fruit Quality

“…Edible coatings can have the capacity to modify the internal gas composition of fresh fruit in terms of O 2 and CO 2 concentrations [18]. The effect of edible coatings on the delay of changes related to fruit ripening (softening, color change, decrease in acidity, appearance of some physiological disorders, etc.)…”

“…The main advantages of using GRAS salts include their availability, relatively low cost and high solubility in water [17]. In previous works at the IVIA CTP, we have developed and characterized hydroxypropyl methylcellulose (HPMC)-lipid edible coatings containing GRAS salts with activity against fungal pathogens causing postharvest diseases of plums [18,19] or cherry tomatoes [20,21]. Furthermore, on citrus fruits, this type of coatings has also been effective against green and blue molds [10,[22][23][24][25] and Lasiodiplodia stem-end rot [26].…”

Postharvest Treatments with GRAS Salts to Control Fresh Fruit Decay

“…Similarly, among a wide variety of antifungal GRAS salts tested as ingredients of HPMC-beeswax edible coatings, paraben salts and potassium sorbate were found to be the best for effective control of brown rot caused by M. fructicola on artificially inoculated plums [43]. These coatings also effectively reduced weight loss and maintained firmness and overall quality of coated plums during prolonged cold storage [40].…”

“…Fresh fruit samples are selected, washed, artificially inoculated with the target pathogen, and, after about 24 h (curative activity), coated with the different coating treatments and allowed to dry on a mesh screen. Coatings are usually applied by fruit immersion for brief periods (10-30 s) [39], but they can also be applied by pipetting a small amount of the emulsion (0.1-0.5 mL, depending on the commodity) onto each fruit and rubbing manually with gloved hands to mimic coating application in industrial packing line roller conveyors [40]. Control fruits are inoculated, but are uncoated or treated with coatings formulated without GRAS salts.…”

Edible coatings based on sodium alginate and ascorbic acid for application on fresh-cut pineapple (Ananas comosus (L.) Merr)

“…Several polymers of natural origin have been used for the fabrication of food-edible coatings including starch (Praseptiangga et al, 2017), alginate (Mannozzi et al, 2017), chitosan (Mannozzi et al, 2018), pectin (Mannozzi et al, 2017), cellulose derivatives (Gunaydin et al, 2017), etc. Among these polymers, sodium alginate is well-known for its excellent film-forming properties and functionalities (López Córdoba et al, 2013;Mannozzi et al, 2017).…”