SUPERFICIAL SCALD A FUNCTIONAL DISORDER OF STORED APPLES .3. CONCENTRATION OF DIPHENYLAMINE IN FRUIT AFTER TREATMENT

After treatment of apples with diphenylamine most of it was found in the peelings (1 mm thick) and was distributed approximately as follows: 60 % in the cuticle, 20 % in the epidermis, and 20 % in the hypodermis and cortex (assumed to be predominantly in the hypodermis). Treated apples lost 95 % or more of the original diphenylamine during 30 weeks' storage at 1°. A concentration in the peelings of about 0.2 μg/cm2 appeared to be the minimum required to inhibit scald‐inducing reactions. Concentrations of diphenylamine immediately after treatment and the minimum effective concentrations were estimated in the cuticle, epidermis, and hypodermis. It appeared that the concentration needed to inhibit the scald‐inducing reactions was appreciably less than that required for inhibiting respiration, phosphorylation, or the oxidation of carotene. Copyright © 1968 John Wiley & Sons, Ltd