A non-destructive method for monitoring the ripening of tomatoes based on their induction of chlorophyll fluorescence

Abstract

Maturity is one of the most important factors associated with assessing the quality of tomatoes. The aim of this study is to develop a new device to measure the degree of ripeness of tomato fruits based on chlorophyll fluorescence. The results of this method, chlorophyll fluorescence, were compared with those of the widely used colorimeter for this purpose. Botanical variety of tomatoes “Alkazar” was used with different stages of maturity: green, breakers, turning, pink, light red, and red. The results indicated that specific parameters of the slow induction of chlorophyll fluorescence, such as the maximum chlorophyll fluorescence (Fm) and the coefficient of specific photosynthetic activity (Rfd), can be used to classify tomato fruits according to their maturity stage, as efficiently as the hue angle parameter of the color measurements. A correlation coefficient between the hue angle and the slow induction of chlorophyll fluorescence parameters was 0.96 with Fm, and 0.97 with Rfd. Using the hue angle or Fm, the fruits of all six-maturity stages were accurately classified. In conclusion, the developed device method is a non-destructive, innovative, convenient, and less time-consuming than the color-based method.