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

Artikel i vetenskaplig tidskrift, 2018

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.