Effects of Different Edible Coatings on the Shelf Life of Fresh Black Mulberry Fruits (<i>Morus nigra</i> L.)

Abstract

The aim of this study was to evaluate the effects of edible coatings based on gelatine, oils (sunflower and coconut) and beeswax on the physicochemical properties, bioactive compounds (total phenols and monomeric anthocyanin content), antioxidant capacity (DPPH and FRAP assays were used) and sensorial attributes of mulberry fruits during a period of storage (0, 2, 5 and 8 days) at 4 °C. The results showed that, in all samples treated with edible films, the degree of firmness was higher and the deterioration weaker compared to the control at day 8 of storage. Edible coatings significantly reduced the rate of deterioration, in terms of total phenolics and anthocyanins, in mulberry fruits over time, and the gelatine-coated mulberry samples (G_Mn) exhibited the best results. In terms of the antioxidant capacity of the coated mulberry, after 5 and 8 days of storage, only the G_Mn samples maintained significantly high DPPH radical scavenging and FRAP values compared to control. Coating improved the sensorial attributes of the mulberry during storage, and gelatine-coated fruits recorded the highest score, followed by layer-by-layer samples (O+W_G_Mn). All edible coatings used to cover black mulberry in this study extended the shelf life of the fruits, while maintaining high levels of bioactive compounds and, consequently, high antioxidant capacity, along with improved sensory qualities, during cold storage.

Keywords

• mulberry
• coconut oil
• sunflower oil
• gelatine
• beeswax
• total phenols