African Journal of
Food Science

  • Abbreviation: Afr. J. Food Sci.
  • Language: English
  • ISSN: 1996-0794
  • DOI: 10.5897/AJFS
  • Start Year: 2007
  • Published Articles: 766

Full Length Research Paper

Enhancing the retention of β-carotene and vitamin C in dried mango using alternative blanching processes

Isabel I. R. Guiamba
  • Isabel I. R. Guiamba
  • Departamento de Engenharia Química, Faculdade de Engenharia, Universidade Eduardo Mondlane, Maputo, Moçambique.
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Lilia Ahrne
  • Lilia Ahrne
  • Department of Food Science, University of Copenhagen, Copenhagen, Denmark.
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Ulf Svanberg
  • Ulf Svanberg
  • Department of Biology and Biological Engineering/Food and Nutrition Science, Chalmers University of Technology, Gothenburg, Sweden.
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  •  Received: 09 August 2017
  •  Accepted: 25 September 2017
  •  Published: 31 July 2018

Abstract

The effects of microwave (MW) dry blanching of mango in comparison with conventional water blanching and blanching in closed plastic bags prior to hot air drying (70°C) were evaluated on the retention of vitamin C and β-carotene and on the activity of polyphenol oxidase (PPO) and ascorbic acid oxidase (AAO) enzymes. Blanching conditions for MW and water blanching were 2 min at 90°C high temperature and short time (HTST) or for 10 min at 70°C low temperature and low time (LTLT). PPO was completely inactivated by the blanching treatments, while low AAO activity remained. High retentions (~100%) of vitamin C were found in dried mango after blanching treatments HTST with MW and blanching in closed plastic bags, while lower retention was observed after LTLT with MW (81.8 ± 4.5%), and conventional water blanching 86.7 ± 2.6% (HTST) and 78.6 ± 2.5% (LTLT). Blanching resulted in partial oxidation of L-AA into dehydroascorbic acid (DHAA). Lower retention of all-trans-β-carotene was obtained in MW and HTST water blanched dried mango (82 to 90%) compared with LTLT water blanched dried mango (~100%). In all dried blanched mango samples the levels of 13-cis-β-carotene isomer increased. A slight darkening of colour was observed only in conventional blanched mango samples.
 
Key words: Microwave heating, mango, β-carotene, vitamin C, ascorbic acid oxidase.