Assessing the heat induced changes in major cow and non-cow whey proteins conformation on kinetic and thermodynamic basis

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• 作者：Loredana Dumitra?cu^a ; Ekaterini Moschopoulou^b ; Iuliana Aprodu^a ; Silvius Stanciu^a ; Gabriela Râ ; peanu^a ; Nicoleta St?nciuc^a ; ^{Nicoleta.Sava@ugal.ro} ;
• 关键词：¦Â-Lactoglobulin ; ¦Á-Lactalbumin ; Conformational changes ; Thermal denaturation ; Goat milk ; Sheep milk
• 刊名：Small Ruminant Research
• 出版年：2013
• 出版时间：April, 2013
• 年：2013
• 卷：111
• 期：1-3
• 页码：129-138
• 全文大小：546 K

文摘

In this study, the RP-HPLC technique was used as the main analytical method to measure the residual native ¦Â-lactoglobulin and ¦Á-lactalbumin concentration after heat treatment in raw milk from three different species (goat, sheep and cow). Further, a detailed comparative kinetic study of ¦Â-lactoglobulin and ¦Á-lactalbumin denaturation was carried out at temperature ranging from 72.5 to 90 ¡ãC.

Kinetic studies showed that the thermal denaturation of ¦Â-lactoglobulin followed biphasic behavior, resulting in activation energy of 91.68 ¡À 13.18 kJ mol^?1, 137.13 ¡À 25.25 kJ mol^?1 and 62.11 ¡À 3.26 kJ mol^?1 for the denaturated fraction in goat, sheep and cow milk and 307.91 ¡À 61.29 kJ mol^?1, 158.99 ¡À 23.64 kJ mol^?1 and 170.18 ¡À 43.61 kJ mol^?1 for the native fraction in milk samples. ¦Á-Lactalbumin denaturation followed the first-order kinetics, resulting in activation energy values of 202.65 ¡À 1.42 kJ mol^?1, 155.56 ¡À 5.53 kJ mol^?1 and 140.44¡À 6.14 kJ mol^?1 respectively in goat, sheep and cow milk. The heat-induced changes in protein structure were outlined after running molecular dynamics simulations at different temperatures, supporting the experimental observations. These experiments were conducted only for cow and goat ¦Á-lactalbumin and were limited by the lack of protein structures from databases.