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- The effect of nanocoatings enriched with essential oils on ‘Rocha’ pear long storagePublication . Gago, Custódia; Antão, Rui; Dores, Cristino; Guerreiro, Adriana; G, Miguel; Faleiro, Maria Leonor; Figueiredo, Ana Cristina; Antunes, Maria DulceThe effect of coating 'Rocha' pears with alginate-based nanoemulsions enriched with lemongrass essential oil (LG) or citral (Cit) was investigated. Fruit were treated with the nanoemulsions: sodium alginate 2% (w/w) + citral 1% (w/w) (Cit1%); sodium alginate 2% (w/w) + citral 2% (w/w) (Cit2%); sodium alginate 2% (w/w) + lemongrass 1.25% (w/w) (LG1.25%); sodium alginate 2% (w/w) + lemongrass 2.5% (w/w) (LG2.5%). Then, fruit were stored at 0 °C and at 95% relative humidity, for six months. Fruit samples were taken after two, four and six months, and then placed at 22 °C. Upon removal and after 7 d shelf-life, fruit were evaluated for colour CIE (L*, h◦), firmness, soluble solids content (SSC), titratable acidity (TA), weight loss, electrolytic leakage, microbial growth, symptoms of superficial scald and internal browning. All nanoemulsions had droplets in the nano range <500 nm, showed uniformity of particle size and stable dispersion. Cit-nanoemulsions had lower droplet size and higher stability than LG. No nanoemulsion showed cytotoxicity. Coatings reduced fruit colour evolution and preserved better firmness than control. After shelf-life, better firmness was found in LG-coated fruit. Coatings did not affect SSC and TA. Microbial growth was below the safety limits in all treatments. Fruit treated with LG-nanoemulsions did not show scald symptoms and panelists preferred LG1.25% coated fruit. Cit2% treated fruit showed the highest scald and internal browning symptoms, while LG1.25% did not show any disorders. This study suggests that LG-nanocoatings have the potential for preserving the quality of 'Rocha' pear.
- Innovative edible coatings to improve storage of small fruits and fresh-cutPublication . Guerreiro, Adriana Cavaco; Antunes, Maria Dulce; Miguel, Maria Graça; Faleiro, LeonorEdible coatings enriched with essential oils or their constituents have been studied for their effect on increasing food storage life. The objective of the present study was to find the best edible coating formulations based on polysaccharides enriched with essential oils compounds to increase storage life of small fruit and fresh-cut. In the first year of this study, edible coating formulations based on alginate and pectin enriched with citral and eugenol were tested on Arbutus unedo berries, strawberries, raspberries and fresh-cut „Bravo de Esmolfe‟apples. General quality parameters [color CIE (L*hºC*), firmness, soluble solids content (SSC), weight loss, trolox equivalent antioxidant capacity (TEAC), microbial growth and taste panels] were evaluated through cold storage. From them, two edible coatings which better preserved shelf-life for each polysaccharide (alginate and pectin) were chosen. The previous selected edible coatings were tested for cytotoxicity, then applied to the same fruit for studying their effect on nutritional and sensory parameters [color CIE (L*hºC*), firmness, soluble solids content, weight loss, microbial growth, taste panels, phenol compounds (total phenols, flavonoids, anthocyanins), sugars, organic acids, antioxidant activity (TEAC, ORAC (oxygen radical absorbance capacity) and DPPH (1,1-diphenyl-2-picrylhydrazyl) and taste panels]. Ethylene and CO2 production as well as ethanol and acetaldehyde were also measured. The edible coating which better preserved fruit quality while increasing storage life was selected for commercial recommendation. Those were for arbutus berries alginate 1% + eugenol 0.1% + citral 0.15%, for fresh-cut „Bravo de Esmolfe‟ apple was alginate 2% + eugenol 0.1% plus dip in ascorbic acid, strawberries was alginate 2% + citral 0.15 % + eugenol 0.1% and for raspberrieswas pectin 1% + citral 0.15%+ eugenol 0.1%.