Effects of Zein and Chitosan Coatings Containing Essential Oils on Physicochemical and Organoleptic Characteristics of Mazafati Date Fruits

Use of natural coatings with various capabilities provides the opportunity to produce healthier and more acceptable materials, especially for higher value-added products such as dates. The objective of this study was to investigate effects of date coatings on the fruit various characteristics for the purpose of a longer shelf-life.

Mazafati dates were coated with natural polymers (zein, chitosan and pimpernel essential oil). Effects of coating on various characteristics of dates, including moisture content, total soluble solids, acidity, sugar content, pH and sensory characteristics (color, taste, firmness and brightness), were assessed at 4 and -18 oC for the first year and at 10 oC for the second year. Data were analyzed using factorial experiment in a completely randomized design. Comparisons of the means were carried out using Duncan method.

In organoleptic characteristics, the highest color score belonged to the fruits with chitosan after three months of storage and the lowest color score belonged to chitosan and oil and to control and oil treatments after 12 and 9 months of storage, respectively. Zein and chitosan treatments included better tastes and textures, compared to those other treatments did. In chemical assessments, zein treatments include the highest and chitosan treatments included the lowest moisture contents. The lowest sugar contents were reported in control. No significant differences were seen in acidity and pH contents of the treatments.

Based on the results of sensory and physicochemical assessments, use of the highlighted coating treatments to preserve physicochemical characteristics of the fruit dates as well as chitosan coating to minimize color and zein coating to minimize flavor changes in dates are recommended.