ENZYMIC BROWNING AND FREE TYROSINE IN POTATOES AS AFFECTED BY PENTACHLORONITROBENZENE

Two potato varieties, Pungo and Irish Cobbler, grown in soil treated with pentachloronitrobenzene (PCNB) at 50 pounds per acre were lower in free tyrosine content than were control potatoes. PCNB lowered total phenolic content of Irish Cobblers, but not that of Pungos. The PCNB treatment did not significantly affect tyrosinase activity. The amount of free tyrosine was related to enzymic browning. The results indicate that PCNB, when used as a soil fungicide, tended to decrease tyrosine content of two potato varieties and may also decrease enzymic browning. Storage for 1 month at 70°F. generally increased tyrosine content. © 1968, American Chemical Society. All rights reserved.