Comparative evaluation of postharvest treatment efficacy in trimmed coconuts using citric acid, sodium chloride, and peroxyacetic acid

The shelf life of trimmed aromatic coconuts is limited by enzymatic browning and microbial growth after husk removal. Although chemical treatments can delay these deteriorative processes, their application in fresh produce is constrained by regulatory and consumer safety considerations. This study evaluated and compared the effects of citric acid (CA), sodium chloride (NaCl), and peroxyacetic acid (PAA) on the quality and microbial stability of trimmed coconuts during 15 days into the storage room at 5-8°C. Before packaging, coconuts were immersed for 5 minutes in CA solutions (10% and 20%), NaCl solutions (10% and 20%), and PAA solution (80 ppm), while untreated samples served as the control. Throughout the storage period, visual quality and color parameters (L*, a*, b*) were assessed. Additionally, the total soluble solids (TSS), pH, titratable acidity (TA), total plate count, and yeast and mold count of the homogenized coconut water and meat mixture were analyzed to evaluate changes in chemical composition and microbial quality. Treatments with 20% CA and 20% NaCl significantly (P < 0.05) reduced microbial growth and effectively maintained visual quality and color throughout storage. In contrast, PAA treatment exhibited only short-term antimicrobial effects (up to six days) and led to rapid discoloration thereafter. These results indicate that citric acid, particularly at 20%, is the most effective among the tested treatments for preserving the visual, physicochemical, and microbiological quality of trimmed coconuts under refrigerated conditions.