Title: Effects of different edible coatings on polyphenol oxidase activity and colour of fresh-cut apple during cold storage

Authors: Charlotte Bertrand; Maria Filomena De Jesus Raposo; Rui Manuel Santos Costa De Morais; Alcina Maria Miranda Bernardo De Morais

Addresses: CBQF – Centro de Biotecnologia e Química Fina – Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal ' CBQF – Centro de Biotecnologia e Química Fina – Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal ' CBQF – Centro de Biotecnologia e Química Fina – Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal ' CBQF – Centro de Biotecnologia e Química Fina – Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal

Abstract: Fresh-cut fruits are highly susceptible to enzymatic browning. The aim of this study was to evaluate the effects of different coatings on polyphenol oxidase (PPO) activity and colour of 'Royal Gala' apple cubes during storage at 4°C. The main constituents (polysaccharides) of the coatings used were carrageenan, alginate, the exopolysaccharide (EPS) from the marine microalga Porphyridium cruentum, pectin, and carboxymethyl cellulose (CMC). When PPO activity increased, the apple cubes became browner (L* values decreased, and/or a* and/or b* values increased) for pectin, carrageenan, EPS 5 g.L⁻¹ and CMC coatings. EPS coated apple cubes, in particular, did not present the best results in order to prevent the colour changes and to lower down PPO activity, but the results obtained were very similar to those of alginate. The coating based on pectin was the most recommended to preserve fresh-cut 'Royal Gala' apple closely followed by CMC.

Keywords: edible coatings; carrageenan; alginate; exopolysaccharide; EPS; Porphyridium cruentum; pectin; carboxymethyl cellulose; CMC; PPO activity; fresh-cut apples; Royal Gala; postharvest technology; refrigerated storage; polyphenol oxidase activity; apple colour; cold storage; fresh-cut fruits; enzymatic browning.

DOI: 10.1504/IJPTI.2015.074313

International Journal of Postharvest Technology and Innovation, 2015 Vol.5 No.2, pp.91 - 104

Received: 25 Feb 2015
Accepted: 05 Jun 2015
Published online: 22 Jan 2016 *

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