Use of the Reflectance Spectra as a Non-Destructive Indicator of Quality, i.e., Color, and Maturity, i.e., Pigment Content, of Mango Fruit

Appearance is the primary factor in quality judgments of fruits and vegetables. Poor coloration of mango peel is an important factor in grade and commercial value reduction. Furthermore, fruit quality is highly dependent to its maturity stage at harvest, which is more related to chlorophyll content in the peel rather than epidermis coloration because mangoes are generally harvested before any visible color changes. Reflectance spectra in the visible range let to access both pigment contents and color coordinates. Therefore, this study proposes a methodology to estimate, from visible spectra of mango peel, an indicator of external fruit quality, the fruit color, and an indicator of the fruit maturity stage, the chlorophyll content in the peel. This methodology was applied to three cultivars: 'Tommy Atkins', 'Kent' and 'Nam Doc Mai'. Our results showed that mango cultivars had heterogeneous peel color which can be differentiated using the distribution of the hue angle values as criteria. In addition, the peel chlorophyll content was accurately estimated from reflectance indices using a partial least square regression (R2 > 0.98). Significant differences in the peel chlorophyll contents were established between cultivars. This study suggested that reflectance measurements in the visible region could be a practical tool to assess non-destructively the peel color and the mango maturity stage. (Resume d'auteur)