Effects of Aloe-pectin coatings and osmotic dehydration on storage stability of mango slices

Abstract

Mango (Mangifera indica L.) is one of the most important tropical fruits with inimitable taste, unique flavor, fragrance, and therapeutic traits. It is the national fruit of Pakistan and is commonly called the king of fruits, however, it is very challenging to protect the keeping quality of the fruit. To enhance the shelf life and overcome the microbial count, edible biodegradable (aloe-pectin) coatings were applied on minimally processed (osmotically treated) fresh-cut mango slices. Pre-treatment of Osmotic Dehydration (OD) was performed at 45 °C for 3 hours by 55 °Brix solutions of sucrose and glucose, respectively. The coating solution was made by aloe vera gel with combination of 0.2% CaCl2 (w/v) and 0.5% pectin (w/v). Total Fungal Count (TFC) (yeast and mold growth), Moisture Contents (MC), and Total Soluble Solids (TSS) of minimally processed (osmo-coated) mango slices were analyzed during 15 days of storage at 5 °C. A minimum increase in Total Fungal Count (TFC) from 1.00 to 2.53 Log CFU/g, TSS from 25.30 to 27.16 °Brix, and a decrease in moisture contents from 62.43 to 60.65% was observed in double-coated with osmo-sucrose treated (osmotic dehydration in 55°Brx sucrose solution before coating) samples from 0 to 15 days respectively. However, significant changes in the TFC, moisture contents, and TSS, were observed in double-coated with osmo-glucose treated (osmotic dehydration in 55 °Brix glucose solution before coating) samples after 10 days of storage. According to the results of the current study, the aloe-pectin coating can significantly reduce the TFC, decrease the TSS, and minimize the moisture loss during storage, when used after osmo-sucrose pretreatment.