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Thermal inactivation and variability of γ-glutamyltransferase and α-L-fucosidase enzymatic activity in sheep milk

Piga, Carlo and Urgeghe, Pietro Paolo and Piredda, Giovanni and Scintu, Maria Francesca and Di Salvo, Riccardo and Sanna, Gavino (2013) Thermal inactivation and variability of γ-glutamyltransferase and α-L-fucosidase enzymatic activity in sheep milk. LWT - Food Science and Technology, Vol. 54 (1), p. 152-156. ISSN 0023-6438. Article.

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DOI: 10.1016/j.lwt.2013.05.018

Abstract

We present a study of the thermal inactivation and variation of activity of two enzymes in sheep milk: γ-glutamyltransferase and α-L-fucosidase. We find that the thermal treatment of milk causes inactivation of α-L-fucosidase between 57 °C and 68 °C, and γ-glutamyltransferase between 68 °C and 80 °C. In untreated sheep milk, the highest level of enzymatic activity (EA) for these two enzymes is in the pH range 5.5–6.0 and 8.0–8.5, respectively. Skimming treatment causes the loss of 35% of the activity of γ-glutamyltransferase. No differences in the EA were ascribable to the diets evaluated in this study. We observed EAs of α-L-fucosidase and γ-glutamyltransferase over the entire lactation cycle, noting that the EA of the former increased from 81 to 207 U mL−1 (average 159 ± 30 U mL−1) while the EA of the latter from 3.12 to 4.89 U mL−1 (average 3.83 ± 0.34 U mL−1). Relationships between both enzymes and selected milk parameters (lipids, proteins, lactose, urea and somatic cells) are highlighted by Principal Component Analysis.

Item Type:Article
ID Code:9221
Status:Published
Refereed:Yes
Uncontrolled Keywords:γ-glutamyltransferase, α-L-fucosidase, thermal inactivation, variability, sheep milk
Subjects:Area 03 - Scienze chimiche > CHIM/01 Chimica analitica
Area 07 - Scienze agrarie e veterinarie > AGR/15 Scienze e tecnologie alimentari
Divisions:002 Altri enti e centri di ricerca del Nord Sardegna > AGRIS Sardegna, Olmedo > Dipartimento per la ricerca nelle produzioni animali
001 Università di Sassari > 01-a Nuovi Dipartimenti dal 2012 > Agraria
001 Università di Sassari > 01-a Nuovi Dipartimenti dal 2012 > Chimica e Farmacia
Publisher:Elsevier
ISSN:0023-6438
Deposited On:01 Oct 2013 09:48

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