Combined application of calcium lactate and pectin methylesterase maintains strawberry firmness and extends postharvest shelf life

Strawberry is a highly perishable fruit, with limited post-harvest shelf life due to rapid softening and deterioration. This study aimed to evaluate the effectiveness of vacuum infusion of Calcium Lactate (LCa) and Pectin Methylesterase (PME) in maintaining firmness, cell integrity, and quality of strawberries during 12 days of storage at 5°C. The treatments applied were Control (NI), Water (W), PME, LCa, and LCa + PME. Principal Component Analysis (PCA) established the LCa + PME treatment as the most effective, segregating it into the high-quality cluster, positively correlated with firmness and freshness. LCa + PME increased fruit firmness by 48% after 3 days of storage compared to control fruits (W), maintaining it up to 12 days of storage. This stability was attributed to the synergy of the treatment between LCa and exogenous PME, which increases free carboxylic groups, optimizing the formation of Ca-pectate cross-links, resulting in the stabilization of CSP (Sodium Carbonate Soluble Pectin). Additionally, treatments using calcium reduced electrolyte leakage by 22% and limited weight loss to about 2.7% for LCa + PME, resulting in better freshness and lower incidence of damage and contamination. LCa + PME significantly preserved color parameters (L*, C*) and extended shelf life by at least 3 days. It is concluded that vacuum infusion of Calcium Lactate and PME is a promising technology for pectic reinforcement and extension of strawberry post-harvest quality.