Authors Radi, E. Firouzi, H. Akhavan, S. Amiri,
In order to preserve freshness and to control spoilage and pathogenic bacteria growth, it is recommended to use edible coatings on fresh-cut fruit to extend their shelf life. For this purpose, natural polysaccharides, proteins, and antioxidants are used as raw materials for edible coatings and films. Edible coatings can also be used as carriers of antimicrobials, antioxidants, anti-browning, flavoring, and coloring agents that improve the nutritional, sensorial, and microbiological properties of fresh-cut fruit. A dip treatment of fresh-cut fruit in organic acids (such as citric acid and ascorbic acids) and calcium salts as an alternative to sulphites were used to prevent enzymatic browning after fruits peeling and/or cutting. Also, calcium treatments can maintain or improve the tissue firmness and crispness. In this regards, edible coatings containing Aloe vera and green tea extracts are well documented in the literature. Aloe vera gel and gelatin have been used as edible coatings in fruit storage technology . The barrier properties of Aloe gel coatings towards respiratory gases, as well as its antimicrobial functions in coated fruit and fresh-cut fruit are reported. Besides, gelatin coatings show good barrier characteristics against oxygen and aroma transfers at low and intermediate relative humidity. However, gelatin has poor barrier properties against water vapour transfer due to its hydrophilic nature. In recent years, the Aloe vera gel has been used as an edible coating for sweet cherries, mangoes, apples, papayas, fresh-cut kiwifruit, and fresh-cut orange. Besides, the effect of Aloe vera coating, containing anti-browning solution, on apples slices has been published in literature. Furthermore, tea (Camellia sinensis), is a good source of polyphenolic compounds, which have strong antioxidant properties. The high antioxidant capacity and overall antimicrobial activity of green tea have been attributed to catechins and their oxidized condensation products. Coating with gelatin incorporated with green tea extract successfully retarded the microbial growth and therefore extended the shelf life of fresh-cut orange during cold storage. Such properties made us use green tea as our coating alternative. The aim of the present study was to investigate the combined effects of edible coatings containing gelatin, calcium chloride, ascorbic acid, and citric acid as well as various concentrations of Aloe vera and green tea extracts on physicochemical and microbial characteristics of fresh-cut apples during storage.
