Properties of Plums during Cold Storage

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 degrees C followed by a shelf life period of 5d at 20 degrees 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