Design of an active edible coating: Antimicrobial, physical, and sensory properties of sodium caseinate-guar gum blends enriched in essential oils

This work aimed to develop an essential oil (EO) emulsion coating for strawberries and pears based on a sodium caseinate-guar gum blend. Autochthonous microbiota of the fruits combined with physical and sensory evaluation of the blends were studied to design the coatings. Microbial populations were isolated from pears and strawberries to select the best EOs among lemon, thyme, peppermint, fennel, and orange. Thyme EO showed the highest and widest antimicrobial activity followed by peppermint and lemon EOs. Coarse and stable emulsified blends were obtained using these EOs at 1.5 % in the blend (D4,3 from 50 to 72 µm; ζ-potential > −30 mV). Coatings were slightly or moderately liked, although the coating/fruit pair influenced the likeness. Only lemon EO-based coating was considered appropriate for both fruits. In conclusion, lemon and thyme EOs could be combined to develop an acceptable antimicrobial coating for strawberries and pears.