Mathematical model for detecting tomato ripeness using chlorophyll fluorescence

Abstract

A precise assessment of tomato ripeness is crucial in the harvesting and marketing procedures. Chlorophyll fluorescence is being relied on as a harmless approach for tracking the maturity of tomatoes in postharvest research. In this study, mathematical model is proposed based on measuring the intensity of fast chlorophyll fluorescence of tomatoes depending on their degree of maturity. In the experimental study, four stages of tomato ripening (green, turning, pink, and red) for three varieties (‘Alkazar’, 'Lezginka’, and ‘Rosanchik’) were used. The Fluorescence Intensity (FI) data over time were represented using a third-degree polynomial function and finding its first derivative curve. The FI parameter was obtained as the fluorescence level at the first inflection point on the fluorescence induction curve (at time tI on the first derivative curve). According to the obtained mathematical models, the optimal time for monitoring the degree of ripeness of tomatoes was tI = 129 ± 4 ms. According to the results of experimental studies, there is a general trend, regardless of the variety used, that the FI decreases with tomato maturity. The FI may assist in sorting and grading processes for fresh vegetables and fruits. It can also be used as a system that can be integrated into harvest and post-harvest machinery for agricultural products.