Phenolase activity in tomato fruit in relation to growth and to various ripening disorders

An efficient method for the extraction of phenolase from tomato fruit is described. It has indicated that phenolase activity increases towards maturity and then decreases somewhat during normal ripening. The red area of fruit which showed a physiological ripening disorder known as ‘blotch’ contained an abnormally high activity while the green areas contained an even higher activity. Tomatoes exhibiting ‘blossom‐end’ rot also contained enhanced activity, especially in the affected region. Levels of phenolase in tomato species other than Lycopersicon esculentum have also been examined. The browning symptoms associated with specific physiological ripening disorders are discussed in relation to phenolase activity and the availability of phenolic substrates.