Analysis of chitosan treatment on white and black sweet cherry

Abstract

Bicolor (Rosaline) and black (Regina) sweet cherry cultivars were treated with chitosan-Ca-lactate and chitosan-alginate solutions. The chitosan coating is biocompatible, nontoxic and possesses antimicrobial activity. The sample series (five replicates of thirty pieces from each variety and each treatment, and a control) were refrigerated at 4 °C for 21 and 28 d, to the end of shelf-life. Physical (visual sorting, weight loss and texture of intact fruit), physicochemical (TSS, antioxidant activity, and pH of the pulp), and microbiological properties (total number of microorganisms, Escherichia coli, fungi and yeasts) were investigated weekly. For the last week only the Regina cultivar had acceptable appearance, the other cultivar was discarded after 21 d. The chitosan-alginate treatment preserved the texture, showed smaller weight loss, higher antioxidant preservation and smaller microbial contamination than the samples with chitosan-Ca-lactate on both cultivars. Based on the results, the edible coating can help to preserve the nutritional value of fresh fruit and this technology can be useful in preparing the ready-to-eat fruit salads or in decoration of confectionery products.