Heating of β‐Lactoglobulin A Solution in a Closed System at High Temperatures

Abstract

␤ ␤ ␤ ␤ ␤-Lactoglobulin A solution at pH 6.4 was heated to 180 Њ Њ Њ Њ ЊC at the rate of 6 Њ Њ Њ Њ ЊC/min. By differential scanning calorimetry two independent endothermic peaks were observed. The first peak appeared below 100 Њ Њ Њ Њ ЊC is corresponded to the thermal denaturation of protein. This conformational change led to the aggregation and polymerization of molecules through disulfide linkage, particularly observed above 100 Њ Њ Њ Њ ЊC. The second endothermic peak appeared around 150 Њ Њ Њ Њ ЊC, which was brought by the decomposition of molecules as judged from electrophoresis. Up to 100 Њ Њ Њ Њ ЊC the viscosity of ␤ ␤ ␤ ␤ ␤-lactoglobulin A solution increased by heating, while the viscosity was reduced beyond 113 Њ Њ Њ Њ ЊC, due to change in the size of aggregate and decomposition of ␤ ␤ ␤ ␤ ␤-lactoglobulin A molecules.

Skim acidic milk whey cryoconcentration and assessment of its functional properties: Impact of processing conditions

“…Some studies have been carried out on model β-lactoglobulin solutions (Aymard, Durand, & Nicolai, 1996;Aymard, Nicolai, Durand, & Clark, 1999;Bauer, Carrota, Rischel, & Ogendal, 2000;Gimel, Durand, & Nicolai, 1994;Hoffmann, Roefs, Verheul, van Mil, & Kruif, 1996;Iametti, Cairoli, De Gregori, & Bonomi, 1995;Kitabatake, Wada, & Fujita, 2001;Photchanachai & Kitabatake, 2001. Aqueous β-lactoglobulin and α-lactalbumin mixtures (Dalgleish, Senaratne, & Francois, 1997;Schokker, Singh, & Creamer, 2000) and β-lactoglobulin, α-lactalbumin and bovine serum albumin (Havea, Singh, & Creamer, 2000) were also used to access the functionality of Innovative Food Science and Emerging Technologies 10 (2009) …”

Heating of an Ovalbumin Solution at Neutral pH and High Temperature

“…Heated samples were prepared by the same method as that described elsewhere. 5) Brie‰y, 1.2 ml of an OVA solution (10 mg W ml, pH 7.5) was transferred into glass vials (3.2 cm height; 1.0 cm diameter). Each glass vial was tightly closed with an aluminum cap and heated up to 1809 C in a temperature-regulated oil bath at a rate of 69 C W min.…”

“…4) The authors have recently reported the denaturation, aggregation, and degradation of b-lactoglobulin molecules by heating up to 1809 C in an enclosed moist system. 5) However, there have not been many reports 6) on the eŠects of heating other food proteins, including egg white protein, to temperatures above 1009 C in an enclosed moist system on their functional properties as food ingredients and the changes at the molecular level.…”

Control of heat treatment and storage temperature prevents the formation of visible aggregates in acidic whey dispersions over a 6-month storage period

“…Galani and Owusu (1999) demonstrated that the contribution of non-covalent interactions to the overall aggregation mechanism for b-LG is dominant at temperatures of 90e110 C (Galani & Owusu, 1999). Moreover, Photchanachai and Kitabatake (2001) have shown that heat-denatured b-LG molecules form complexes through hydrophobic amino acid residues when exposed to temperatures of 93e113 C. At temperatures higher than 113 C, the formation of these high-molecular-weight aggregates is decreased (Photchanachai & Kitabatake, 2001). Furthermore, the authors report an increase in viscosity of the b-LG solution induced by heating up to 100 C, but a reduced viscosity at temperatures higher than 113 C, which they attribute to changes in the aggregate size.…”

“…Most studies focusing on heat-treatment of b-LG have been performed at temperatures below 100 C. Studies carried out at temperatures above 100 C have shown that the nature of complex formation of b-LG varies with the heating temperature applied (Galani & Owusu, 1999;Photchanachai & Kitabatake, 2001). Galani and Owusu (1999) demonstrated that the contribution of non-covalent interactions to the overall aggregation mechanism for b-LG is dominant at temperatures of 90e110 C (Galani & Owusu, 1999).…”