Maturation-Associated Physiological and Biochemical Transitions in Carob (Ceratonia siliqua L.): Optimizing Harvest Timing Toward Functional Valorization of Fruits.

Carob fruit (Ceratonia siliqua L.) undergoes numerous physicochemical and biochemical transformations during its ripening; however, these changes have not previously been characterized in a temporal sequence that describes the states of maturity of carob fruit, limiting the potential to determine periods of harvest that can maximize both nutrient-dense value and yield. In the current study, physical, colorimetric, and biochemical measurements were conducted that assessed the changes that occurred in unripe carob pods over five different carob pod ages (T1-T5). Physical traits including pod length, width, thickness, and mass all increased consistently throughout immature stages, reaching their maximum at T5. Brix and pH remained consistent until the early stages of maturity but began to decline beginning at T4, with Brix being the most impacted of the measurements. Total sugars varied across stages, with a minimum of 1616 mg measured in T2 and a maximum of 2198 mg measured in T3. The biochemical results showed that total phenolics, flavonoids, condensed tannins, and even their antioxidant activity were all highest at T2, declining at all other maturity periods. These findings indicate that immature carob fruits experience various developmental phases, with the T2-T3 gap recognized as a critical period marked by heightened amounts of bioactive chemicals. This crucial period presents advantageous prospects for focused enhancement in food and pharmaceutical sectors. This study addresses a significant gap in the literature by clarifying the dynamic changes throughout the immature stage, so establishing a scientific foundation for the efficient utilization of immature carob pods and ensuring their sustained functional and agronomic value.