The use of polysaccharide-based edible coatings enriched with essential oils to improve shelf-life of strawberries

Edible coating formulations have been developed to increase shelf-life of some horticultural products. The objective of this research was to study the effect of edible coatings based on sodium alginate (AL) and pectin (PE) enriched with essential oils constituents (citral and eugenol) on the shelf-life extension of strawberries. AL and PE were tested at 1 and 2% (w/v) and were enriched with eugenol (Eug) at 0.1 and 0.2% and citral (Cit) at 0.15 and 0.3%. Strawberries were dipped in those solutions for 2 min, then stored at 0.5 °C. Measurements of color CIE (L*, a*, b*, h°, C*), firmness, soluble solids content (SSC), weight loss, trolox equivalent antioxidant capacity (TEAC), microbial growth and taste panels were accomplished at 0, 7 and 14 d storage. With those quality characteristics, hierarchical cluster analysis formed 3 groups either for AL or PE based edible coatings. Taking into account the mean closest values to the one at harvest for color, higher value for firmness, SSC and antioxidant activity, and lower value for weight loss and microbial spoilage, the best group was selected. From the selected groups, the 2 edible coating formulations which had higher score on taste panels were considered the best for preserving quality through shelf-life of strawberries. Those edible coatings were for AL the AL 2% + Eug 0.1%; AL 2% + Cit 0.15% + Eug 0.1% and for PE the PE 2% + Eug 0.1%; PE 2% + Cit 0.15%.