FURTHER STUDIES ON FACTORS AFFECTING EFFLUX OF BETACYANIN FROM BEET ROOT - A NOTE ON THERMAL EFFECTS

As judged by betacyanin efflux, beet root tissue differs in stability toward O2 at low and high temperatures (45–60°C and 60–100°C respectively). The effect of temperature itself can he divided into a high activation energy (93 Kcal mol−1) process in the lower temperature range and a low activation energy process (19 Kcal mor−1) in the higher range (> 60°C). From these data it is suggested that initially, elevating temperatures bring about reversible conformational changes in the membrane. With continuing increase in temperature in the presence of O2, membrane chemical groups susceptible to oxidation are exposed and, upon oxidation, render conformational changes irreversible. Copyright © 1969, Wiley Blackwell. All rights reserved