Nondestructive assessment of fruit biological age in Brazilian mangoes by time-resolved reflectance spectroscopy in the 540-900 nm spectral range

Time-resolved Reflectance Spectroscopy (TRS) in the 540–900 nm spectral range has been tested in order to assess nondestructively the biological age of Brazilian mangoes. To this purpose a TRS set-up has been used to measure absorption and scattering coefficients of 60 intact mango fruits (cultivar ‘Haden’), harvested in Minas Gerais, Brazil, and transported by plane to Milan, Italy. Flesh firmness, pulp color, and absorbance spectra by reflectance were determined on the same fruit, while ethylene and CO2 production rates, and respiratory quotient were determined on a subsample of the same fruit. Absorption spectra of intact fruit showed high variability at 540–600 nm, near carotenoids absorption and in the 630– 690 nm range, near chlorophyll-a absorption, in agreement with the reflectance measurements on the pulp. Firmness ranged from 5 to 108 N, but the majority of the fruit was less firm than 20 N. The pulp color showed a greenish yellow hue in less mature fruit, and an orange hue in more mature fruit. Good correlations (R2>0.8) were found between the ethylene production rate and the ratio of the absorption coefficient at 540 nm to any of the absorption coefficients at 630, 650, 670, 690 nm, as well as between color parameters and µa540. Our results underline that TRS in the 540–900 nm range can be a useful tool to assess nondestructively the biological age of Brazilian mangoes.