TY - JOUR
T1 - Effect of water content on the thermal inactivation kinetics of horseradish peroxidase freeze-dried from alkaline pH
AU - Lemos, M. Adilia
AU - Oliveira, Jorge C.
AU - Saraiva, Jorge A.
PY - 2001
Y1 - 2001
N2 - The thermal inactivation of horseradish peroxidase freeze-dried from solutions of different pH (8, 10 and 11.5,
measured at 25 C) and equilibrated to different water contents was studied in the temperature range from 110 to
150 C. The water contents studied (0.0, 1.4, 16.2 and 25.6 g water per 100 g of dry enzyme) corresponded to
water activities of 0.0, 0.11, 0.76 and 0.88 at 4 C. The kinetics were well described by a double exponential
model. The enzyme was generally more stable the lower the pH of the original solution, and for all pH values, the
maximum stability was obtained at 1.4 g water/100 g dry enzyme. Values of z were generally independent of
water content and of the pH of the original solution, and in the range of 15–25 °C, usually found in neutral
conditions, with the exception of the enzyme freeze dried from pH 11.5 and equilibrated with phosphorus
pentoxide, where a z-value of the stable fraction close to 10 C was found.
AB - The thermal inactivation of horseradish peroxidase freeze-dried from solutions of different pH (8, 10 and 11.5,
measured at 25 C) and equilibrated to different water contents was studied in the temperature range from 110 to
150 C. The water contents studied (0.0, 1.4, 16.2 and 25.6 g water per 100 g of dry enzyme) corresponded to
water activities of 0.0, 0.11, 0.76 and 0.88 at 4 C. The kinetics were well described by a double exponential
model. The enzyme was generally more stable the lower the pH of the original solution, and for all pH values, the
maximum stability was obtained at 1.4 g water/100 g dry enzyme. Values of z were generally independent of
water content and of the pH of the original solution, and in the range of 15–25 °C, usually found in neutral
conditions, with the exception of the enzyme freeze dried from pH 11.5 and equilibrated with phosphorus
pentoxide, where a z-value of the stable fraction close to 10 C was found.
U2 - 10.1106/E9NW-1TB4-KU4W-8X7M
DO - 10.1106/E9NW-1TB4-KU4W-8X7M
M3 - Article
VL - 7
SP - 393
EP - 398
JO - Food Science and Technology International
JF - Food Science and Technology International
SN - 1082-0132
IS - 5
ER -