DYNAMICS OF FIRMNESS AND COLOUR OF THAI MANGO CULTIVAR 'NAM DOK MAI SI-THONG'

Firmness and colour of Thai mango (‘Nam Dok Mai Si-Thong’) were assessed (firmness at two opposite sides) at regular intervals during storage at 13°C for 14 days, followed by storage at 28°C for another 8 days. The mangoes were individually labelled and the obtained data were analysed using a logistic decay for firmness and all colour attributes (L*, a*, and b*), including the biological variation within in a batch. The variation in maturity was expressed as biological shift factor. Explained parts of around 90% were obtained for all variables. The biological shift factors are normally distributed. No major difference was found for firmness between both sides of the mangoes. Hardly any relation was found between the biological shift factors of the colour attributes with that of firmness. That confirms that (skin) colour cannot be used to assess the maturity status of firmness in this cultivar. As expected, a pronounced effect of temperature was found, but only on the rate constant of the softening and colour decay process. At 28°C, softening was almost 1.65 times faster and colour development 5 times faster for a* and b* colour aspects than at 13°C. The other model parameters and the model structure were, however, not affected by temperature. That means that in the supply chain, the same model can be used to assess and predict the behaviour of colour and firmness in the entire chain.