SUMMARYFour sets of eight tomatoes were subjected to four blanching times of 30, 60, 90, and 120 set at 100°C. Two fruits in each set were also subjected to holding times of 5, 10, 15, and 20 min between the blanching and exhausting operations. Pectic substances were determined as water‐soluble, ammonium‐oxalate‐soluble, and dilute‐hydrochloric‐acid‐soluble fractions. The methoxyl content of each fraction was also determined. Firmness was determined by objective measurements. The 30‐see blanching treatment yielded the firmest tomatoes. These fruits were also characterized by the highest content of ammonium‐oxalate‐soluble pectin. The activity of pectin methylesterase was highest in treatments consisting of 30 see of blanching and a lo‐min holding time. The activity of pectin methylesterase seemed to be greatly suppressed after
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