Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2007
Publication Date: N/A
Technical Abstract: Edible coatings with antimicrobial agents provide a novel way to improve the safety and shelf-life of fresh-cut fruit. The effect of lemongrass, oregano oil and vanillin, incorporated in apple puree-alginate edible coatings, on the shelf-life of fresh-cut Fuji apples, was investigated. Coated apples were packed in air filled polypropylene trays and wrapped with polypropylene film. Changes in headspace atmosphere, color, firmness, sensory quality and microbial growth were measured during 21 days storage at 4 ºC. A significant reduction in the rates of O2 depletion and CO2 production was observed in samples containing high concentrations of essential oils. Ethylene concentration in the coated apples with essential oils remained below 50 l l-1 in the headspace atmosphere, while it increased continuously in either uncoated apples or those coated without essential oils during storage. Significant amounts of ethanol and acetaldehyde were found in the packaged headspace of coated apples beyond the first week storage. Coatings with calcium chloride and N-acetylcysteine helped to maintain firmness and color, while coatings containing lemongrass induced severe softening. Coatings containing vanillin (0.3% w/w) exhibited the highest sensorial quality after two weeks of storage. All antimicrobial coatings significantly inhibited the growth of psychrophilic aerobes, yeasts and molds. The antimicrobial effect of essential oils against L. innocua inoculated into apple pieces was also examined. Coatings containing lemongrass (1.0 and 1.5% w/w) and oregano oil (0.5% w/w) exhibited the strongest antimicrobial activity against L. innocua (4 log reduction). Alginate-apple puree edible coatings were successfully formulated with the addition of essential oils and resulted in beneficial effects on the shelf-life of fresh-cut Fuji apples.