Abstract:
The effects of different anti-browning compounds (ascorbic acid, citric acid, L-cysteine and glutathione) on L*-value, hue angle, brown scores and brown pigments of fresh-cut mangoes cv. ‘Nam Dok Mai’ were investigated at four concentrations (0% as control, 0.5%, 1.5% and 2.5%). The browning attributes of treated fresh-cut mangoes were modelled to express the processes and to analyse the data obtained. The results revealed the similar changing tendency of L*-value and hue angle. They decreased in time during storage at 10 °C, while the brown scores and amount of brown pigment increased. All processes were found to follow a first order reaction mechanism of decay or growth. A validation experiment was conducted by dipping fresh-cut mangoes in a different anti-browning solution of ascorbic acid, citric acid, L-cysteine or glutathione at 1.5% concentration and distilled water as control. The estimated values for the browning attributes using proposed models had good agreement with the measured values.
In this validation experiment, other changes namely respiration rate, and enzymes related to browning (polyphenol oxidase (PPO) and peroxidase (POD)) were determined. Treatment with L-cysteine or glutathione was effective in suppressing tissue metabolism and enzyme activity, while citric acid significantly inhibited the growth of microorganisms as indicated by total plate count (TPC) (data not shown).
