Changes in organic acids in chilled tomato fruit (Lycopersicon esculentum Mill)

Mature green tomatoes cv Calypso were stored at 5, 7,12 or 19oC for 0,3,9, 12 or 21 days, then ripened at 19oC for 3 or 6 days before analysis for organic acids, pH and acidity. Citric acid concentration increased after storage at 5 or 7oC and decreased at 19oC. Malic acid decreased at all temperatures with the greatest decrease occurring at 19oC. The malic/citric acid ratio was 0.32 at 19o C and 0.36 at 12oC. The rate of acetic acid accumulation increased as the storage temperature was reduced. Oxalic acid concentration decreased with time but was greatest at 12oC and lowest at 19oC. Fumaric acid concentration showed similar but erratic trends. Changes in pH were variable, but greater in chilled than unchilled fruit. Titratable and total acidities increased with storage time at chilling temperatures, but decreased at 19oC. Bound acidity initially decreased with time but subsequently increased. Significant differences were found between organic acid concentrations and pH in chill‐damaged and undamaged tissue.