Edible coatings enriched with essential oils for extending the shelf-life of 'Hayward'fresh-cut kiwifruit

Edible coatings based on sodium alginate at 2% (w/w) enriched with lemongrass 0.5% (w/w), eugenol 0.08% (w/w) + citral 0.2% (w/w) and eugenol 0.16% (w/w) were used to preserve the quality of fresh-cut 'Hayward' kiwifruit. All emulsions were obtained using an ULTRA-TURRAX mixer; one of the two emulsions containing 0.16% eugenol had an additional step in its preparation: it was passed through a high-pressure homogenizer, aiming to reduce its particles to nano dimensions. Cut kiwifruit were dipped in these emulsions for 2 min, and then stored at 4°C in plastic boxes. Control consisted of uncoated fruit. On days 0, 5, 9 and 12, samples were taken to perform analysis of firmness, soluble solids content (SSC), weight loss, microbial growth and appearance. Through storage time, firmness decreased in all edible coatings and control, reaching similar values at day 12. Weight loss was higher in treatments with lemongrass 0.5% and eugenol 0.16% (nano). SSC was higher in uncoated fruit. The fruit treated with lemongrass 0.5% were the first to present appearance impairment at day 5, followed by untreated fruit and eugenol 0.16% at day 9. At the end of the shelf-life, only the fruit covered by eugenol 0.16% (nano) maintained an acceptable appearance (value=4). The hierarchical cluster and PCA analyses showed that eugenol 0.16%, eugenol 0.16% (nano) and eugenol 0.08% + citral 0.2% were the coatings that best preserved fruit quality characteristics through the shelf-life period.