Effects of maturity on chlorophyll-related absorption in nectarines, measured by non-destructive time-resolved reflectance spectroscopy

The ripening of fruits like nectarines and peaches is characterised by the decrease in chlorophyll content or colour of the fruit flesh. However, measuring the colour of fruit flesh is usually not conducted, as there is a lack of suitable techniques. Time-Resolved Reflectance Spectroscopy (TRS) is a novel technique that can measure the light absorbed by the fruit flesh. Using a laser light beam at 670 nm, the chlorophyll content of the fruit flesh is assessed without disrupting the natural structure of the fruit. Data on individual fruits of different maturity at harvest were analysed based on a deterministic model using mixed effect non-linear regression. The results indicate that an analysis of data combined from pre- and post-harvest is possible. Using the theory of Biological Shift Factor, an explained part of 97% is obtained at 20°C and 85% at 10°C.