Enhancing Calcium Transport in Table Grapes Using Sorbitol: A Sustainable Strategy for Promoting Fruit Quality

Table grapes suffer significant losses due to issues such as fungal infections, cracking, and berry shattering, which affect them both in the vineyard during ripening and throughout postharvest storage. Current control methods, such as sulfur dioxide (SO2) treatments, are increasingly constrained by potential fruit damage and regulatory limitations, prompting a search for sustainable alternatives. This comprehensive review synthesizes the current scientific understanding and recent studies regarding calcium dynamics and proposes sorbitol as an innovative preharvest solution to enhance table grape quality through improved calcium (Ca) transport. Ca is a vital macronutrient for cell wall integrity and fruit resistance; however, its inherent low mobility in the phloem restricts its effective delivery to developing fruits, particularly after the veraison stage. This review thoroughly discusses the mechanistic hypotheses by which sorbitol, a naturally occurring sugar-alcohol, acts as a “vector” by forming stable, soluble complexes with Ca, thereby facilitating its crucial translocation to fruit tissues. Preharvest foliar applications of these calcium-sorbitol complexes have demonstrated numerous benefits, improving fruit firmness, reducing the incidence of cracking and shattering, mitigating fungal decay, and boosting antioxidant activity. These effects collectively enhance overall fruit quality and extend storability. Finally, we outline future directions for investigation, aiming to further clarify the molecular mechanisms involved and explore the potential of sorbitol to form complexes with other poorly mobile nutrients and plant elicitors, opening new avenues for sustainable crop management.