The effect of alginate-based edible coatings enriched with essential oils constituents on Arbutus unedo L. fresh fruit storage

• Alginate edible coatings enriched with citral and eugenol have good antimicrobial and antioxidant activity.
• MIC's for citral and eugenol were of 0.15 and 0.1%.
• Citral and eugenol at MIC concentrations are suitable for prolonging storage life of arbutus berries.
• The best formulations were Alginate (AL) 1% + Eugenol 0.2% and AL 1% + Citral 0.15% + Eugenol 0.1%.

The effect of coating Arbutus unedo fresh fruit with alginate-based edible coatings enriched with the essential oils compounds (EOC) eugenol (Eug) and citral (Cit) was studied. The minimum inhibitory concentrations (MIC) against the main postharvest pathogens were determined for Eug and Cit giving values of 0.10 and 0.15 (w/v), respectively. Twelve formulations of edible coatings were used: sodium alginate (AL) was tested at 1 and 2% (w/v) with incorporation of Eug and Cit at MIC and double MIC or their combination at MIC. Arbutus berries were dipped in those solutions for 2 min, and then stored at 0.5 °C. Control consisted of uncoated fruit. On days 0, 14 and 28, samples were taken to perform physicochemical and biochemical analysis [color CIE (L*, h°), firmness, soluble solids content (SSC), weight Loss, trolox equivalent antioxidant capacity (TEAC), microbial growth and taste panels]. Results showed that edible coatings of 1% AL were the best to maintain most quality attributes of the commodity through storage at 0.5 °C. The incorporation of Cit and Eug into the alginate edible coatings improved the coatings in most cases, AL 1% + Eug 0.20% and AL 1% + Cit 0.15% + Eug 0.10% being those that better preserved sensory and nutritional attributes and reduced microbial spoilage. Thus, these coatings may be useful for improving postharvest quality and storage life of fresh arbutus fruit.