Authors Eur. Kittur, F.S.; Saroja, N.; Tharanathan, R.N.
The effects of four different composite coating formulations based on polysaccharides on maintaining quality and an extended shelf-life of banana and mango at 27±2 “C were investigated and compared with commercial Waxol-coated and uncoated fruits. The formulations consisted of modified starch, cellulose, and chitosan, blended with a suitable lipid component and a wet-ting agent. Quality parameters measured included firmness, total soluble solids, and titratable acidity. Physio-logical parameters measured were CO2evolved and weight loss due to respiration and transpiration. The polysaccharide-based coatings displayed retarded colour development, lower acidity and greater firmness values compared to Waxol and control. CO2evolution and losing weight were also reduced significantly. The data were also subjected to PCA, to differentiate the characteristics of the five types of films. Chitosan-based coatings were much superior in prolonging the shelf-life and quality of banana and mango of time. The predominant methods used to preserve fresh fruits during handling and subsequent marketing include controlled atmosphere and modified atmosphere packaging (MAP) techniques in conjunction with refrigerated storage. MAP reduces respiration due to the change in the concentration of O2and CO2in the fruit surroundings, and delays senescence. Though economical, MAPis more difficult to implement because of rather complicated interactions between the product and the packaging material. Also, polymeric films with a wide range of permeability characteristics are rather limited in number. Another limitation involved is environmental concern about using plastic materials. A recent approach has been the use of a coating that is edible and semipermeable to CO2and O2, edible coating mixture composed of sucrose fatty acid ester (SFE) and sodium carboxymethylcellulose (TAL-Prolong) would produce, after application, a semipermeable modified atmosphere within fresh fruits. SFEs have been tested extensively on banana; changes in the internal concentrations of CO2, O2and ethylene, and delay of ripening have been noted. Delayed ripening was also reported in pears and apples coated with Nutri-Save (N,O-carboxymethyl chitosan) reported increases in firmness and titratable acidity with reduced CO2production in straw-berries after treatment with chitosan. Encouraging results were also obtained when Nutri-Save was applied to tomato, pepper, squash, cauliflower, sprouts and broccoli, however, reported that neither Nu-tri-Save nor Semperfresh (an improved form of TAL-Prolong) was effective in extending the post-harvest shelf-life of bell pepper or long green pepper stored at 21 “C. reported that a post-harvest application of TAL-Prolong delayed ripening in banana; however, the colour and texture were inferior com-pared to the control. Such contrasting results were attributed to differences in maturity of the fruit and cultivar and permeability of the coatings per se. The objectives of this study were to optimize and evaluate edible coat
