Effect of water content on the thermal inactivation kinetics of horseradish peroxidase freeze-dried from alkaline pH

M. Adilia Lemos, Jorge C. Oliveira, Jorge A. Saraiva

Research output: Contribution to journalArticle

Abstract

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.
Original languageEnglish
Pages (from-to)393-398
Number of pages6
JournalFood Science and Technology International
Volume7
Issue number5
DOIs
StatePublished - 2001

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Horseradish Peroxidase
Hot Temperature
Water
Water content
Enzymes
water content
enzymes
Kinetics
heat inactivation
peroxidase
kinetics
water
Phosphorus
Temperature
Acetanilides
Bibliography of Medicine
Anthralin
phosphorus pentoxide
water activity
temperature

Cite this

Lemos, M. Adilia; Oliveira, Jorge C.; Saraiva, Jorge A. / Effect of water content on the thermal inactivation kinetics of horseradish peroxidase freeze-dried from alkaline pH.

In: Food Science and Technology International, Vol. 7, No. 5, 2001, p. 393-398.

Research output: Contribution to journalArticle

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abstract = "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.",
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Effect of water content on the thermal inactivation kinetics of horseradish peroxidase freeze-dried from alkaline pH. / Lemos, M. Adilia; Oliveira, Jorge C.; Saraiva, Jorge A.

In: Food Science and Technology International, Vol. 7, No. 5, 2001, p. 393-398.

Research output: Contribution to journalArticle

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

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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.

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