Blood oranges are valued for their color and nutritional properties, thriving in Mediterranean climates where temperature variations enhance anthocyanin (ACN) synthesis. Climate change threatens this process. This study evaluated six foliar applications of sorbitol (2 %, 5 %) and sorbitol-Ca (2 % + 0.7 %) from early fruit development to harvest. All treatments enhanced peel and pulp redness, particularly sorbitol-Ca, as confirmed by lower hue angle and higher color index. Treated fruits had higher total soluble solids (TSS), with 11.07 % in 2 % sorbitol-treated fruits versus 9.63 % in controls. Sorbitol-Ca reduced respiration rates (15.63 vs. 21.57 mg CO₂ kg^-1 h^-1) and increased firmness (9.72 vs. 8.89 Nmm^-1). Phenolic content, antioxidant activity, and bound calcium levels improved fruit quality. ACN content increased over 20 % and 40 % in sorbitol- and sorbitol-Ca-treated fruits, mainly due to Cyanidin derivatives. Sorbitol-based treatments offer a strategy to enhance blood orange resilience to climate change, improving functional and commercial value.

Cv ‘Doña María’ table grape is a high-quality table grape variety included in the Protected Designation of Origin (PDO) of the European Union “The bagged grape of the Vinalopó”. The PDO stipulates that grape clusters must be protected with paper bags from inclement weather and insects, which helps enhance the final grape quality. However, ‘Doña María’ is a variety prone to high shattering in the late stages of ripening on the vine and during postharvest. Inorganic calcium treatments are one of the most commonly used tools to reduce this disorder, but the translocation of this mineral from veraison onward has been questioned. In this study, five applications were performed, from veraison to harvest, using sorbitol-chelated calcium (0.7% + 1.0%), Ca(NO₃)₂ (Ca) at 0.7% and sorbitol at 1%. It was observed that bagged grapes (not wetted with the solutions) only increased the concentration of total and bound calcium when treated with sorbitol–Ca. This resulted in reduced berry drop during cultivation and postharvest and improved fruit firmness. Additionally, it reduced grape metabolism indicators such as respiration rate, weight loss, malic acid degradation, prevented abscisic acid (ABA) and malondialdehyde (MDA) accumulation, and favored the accumulation of secondary metabolites such as total polyphenols, increased antioxidant activity, and sugar content. The application of sorbitol-chelated calcium is an effective and safe tool that enhances fruit quality and prevents losses due to shattering during postharvest.

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.

'Cv 'Doña María' table grape is a high-quality table grape variety included in the Protected Designation of Origin (PDO) of the European Union "The bagged grape of the Vinalopó." The PDO stipulates that grape clusters must be protected with paper bags from inclement weather and insects, which helps enhance the final grape quality. However, 'Doña María' is a variety prone to high shattering in the late stages of ripening on the vine and during postharvest. Inorganic calcium treatments are one of the most commonly used tools to reduce this disorder, but the translocation of this mineral from veraison onward has been questioned. In this study, five applications were performed, from veraison to harvest, using sorbitol-chelated calcium (0.7 % + 1.0 %), Ca(NO3)2 (Ca) at 0.7% and sorbitol at 1%. It was observed that bagged grapes (not wetted with the solutions) only increased the concentration of total and bound calcium when treated with Sorbitol-Ca. This resulted in reduced berry drop during cultivation and postharvest and improved fruit firmness. Additionally, it reduced grape metabolism indicators such as respiration rate, weight loss, malic acid degradation, prevented abscisic acid (ABA) and malondialdehyde (MDA) accumulation, and favored the accumulation of secondary metabolites such as total polyphenols, increased antioxidant activity, and sugar content. The application of sorbitol-chelated calcium is an effective and safe tool that enhances fruit quality and prevents losses due to shattering during postharvest.