Natural Preservation of Fresh-Cut Lemons Using Manna Extracted from Fraxinus Angustifolia: A Study on Shelf Life and Sensory Acceptance

The growing demand for fresh-cut fruit requires innovative preservation strategies to counteract rapid quality deterioration, particularly in lemon (Citrus limon (L.) Burm. f.), which is highly susceptible to flesh browning and loss of sensory traits. Manna, a natural exudate obtained from Fraxinus angustifolia, is traditionally used in the Mediterranean area and is known to be rich in bioactive compounds such as polyphenols, minerals (e.g., calcium), and antioxidants. This study aimed to evaluate the effectiveness of manna as a natural preservative on fresh-cut lemon slices (cv. Zagara Bianca) from two different flowerings, primofiore (yellow fruit) and verdello (green fruit), harvested at the same time. Treatments with different manna solutions (5%, 10%, and 15%) were applied, and physicochemical parameters, nutraceutical content, and sensory traits (flavor and acidity perception) were evaluated at harvest and after 3, 6, and 12 days of storage at 5 degrees C with 85% RH. The results showed distinct effects depending on the maturity stage, but in all cases, manna treatments modulated the respiration rate, reduced weight loss, modified acidity perception, and improved nutraceutical content. In green lemon slices, treatment with 15% manna helped to maintain nutraceutical stability, sustained antioxidant activity, and reduced quality degradation, ensuring a balanced lemon flavor perception. In yellow lemon slices, treatment with 15% manna led to an increase in total soluble solids and a modified taste perception, resulting in a less pronounced freshness compared with the control. Overall, manna proved to be a natural coadjuvant capable of limiting oxidative processes and slowing tissue senescence, while simultaneously enhancing the nutraceutical properties of fresh-cut lemon slices.