Heat Inactivation of Pectinesterase in Orange Juice Pulp

摘要

ABSTRACTHeat inactivation of pectinesterase in juice pulp was nonlinear suggesting the presence of fractions of pectinesterase with differing heat stabilities. The residual activity rapidly decreased to 4 upon heating for 19 sec at 80°C and decreased very little upon subsequent heating for up to 180 sec at 80°C. The D values (time to inactivate 90 of the enzyme) at 90°C of the heat sensitive and heat stable fractions were estimated to be 0.225 and 32 sec, respectively. The Z values (change in temperature to achieve a 10‐fold change in time of inactivation) were estimated to be 10.8°C and 6.5°C for the sensitive and stable fractions, respec