Methods of measuring green colour and chlorophyll content of apple fruit

Summary The change in colour from green to yellow during ripening of apples depends essentially upon disappearance of chlorophyll. Chlorophyll concentration in the fruit peel can be estimated by extraction and spectrophotometry or in terms of the reflectance of the apple surface at 675 nm. The reflectance and chlorophyll concentration data do not conform to the Kubelka‐Munk equation. Reflectance at 675 nm is highly correlated with colour descriptions derived from reflectance spectra. Although a reflectance spectrophotometer gave the most precise reflectance measurements, a simple colorimetric device was modified to give nearly equivalent results.