Stability parameters for β-lactoglobulin thermal dissociation and unfolding in phosphate buffer at pH 7.0

Owusu‐Apenten, Richard; Khokhar, S.; Galani, Despina

doi:10.1016/s0268-005x(01)00067-4

Cited by 34 publications

(37 citation statements)

References 42 publications

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“…Isolated lac is considered one of the least heat-stable of the milk proteins; however, denaturation at relatively high temperatures can be substantially reversible, thus accounting for its apparently high thermal stability observed in bovine milk (Anema & McKenna, 1996;Larson & Rolleri, 1955;Lin et al, 2010). However, there are also studies showing that dimeric lg possesses a high stabilization free energy at neutral pH in phosphate buffer, which can explain the higher heat stability of lg against lac (Apenten, Khokhar, & Galani, 2002). Results also have shown that lgB was irreversibly denatured to a greater extent than lgA variant e in agreement with previous results from RP-HPLC.…”

Section: Whey Protein Denaturationmentioning

confidence: 99%

Influence of moderate electric fields on gelation of whey protein isolate

et al. 2015

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Proteins are one of the food constituents most affected by heating, and some of the changes involve their unfolding, denaturation and gelation. Ohmic heating has often been claimed to improve the quality of foodstuffs due to its uniform heating and (putative) presence of a moderate electric field (MEF). However, this is still subject to discussion, so it is important to determine the effect of ohmic heating and of its MEF upon food constituents. Hence, the aim of this work was to evaluate the effects of MEF on denaturation, aggregation and viscoelastic properties of whey protein isolate (WPI), and compare them with those obtained via conventional heating under identical treatment conditions (up to 30 min at 85 o C). Results have shown that MEF interferes with whey protein unfolding and aggregation pathways at relatively high temperatures. MEF treatments have resulted in WPI solutions possessing more 8 and 10% of native Lactoglobulin and Lactalbumin, respectively, after 30 s of heating at 85 o C, when compared with a conventional heating method. Protein aggregates from MEF-treated WPI solutions presented a maximum increase in size of 78 nm, whereas conventional heating produced an increase of 86 nm. Unlike in conventional heating, aggregation of whey proteins during MEF was not sufficiently strong to form a true elastic gel network, since decreases in both storage and loss modulus were observed following MEF treatment. Our results suggest that MEF may provide a novel method for production of a whey protein matrix with distinctive gel-forming properties.2

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Section: Whey Protein Denaturationmentioning

confidence: 99%

Influence of moderate electric fields on gelation of whey protein isolate

et al. 2015

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“…Reference IV (Apenten et al, 2002). Protein solutions (0.4-4 mg mL À1 in 50 mM buffer phosphate at pH 7.0) were equilibrated 10 min at each selected temperature.…”

Section: Analysis Of Data Obtained In Previous Workmentioning

confidence: 99%

“…Apenten et al (2002) prepared b-LG AB by ammonium sulfate precipitation from milk and purified it by preparative scale gel filtration.…”

Section: Analysis Of Data Obtained In Previous Workmentioning

confidence: 99%

“…Ultraviolet spectrophotometry is a fast, accurate, quantitative and nondestructive technique used in studies of protein structure and function when more specialized instrumentation is not readily available. A number of studies have described in detail the experimental considerations for b-LG thermal unfolding followed by this optical method (Apenten, Khokhar, & Galani, 2002;Kella & Kinsella, 1988;Poklar, Vesnaver, & Lapanje, 1993). In these works, the difference in absorbance at 293 nm (which is a measure of the exposure of Trp residues from the protein interior upon unfolding) was recorded and plotted as a function of temperature from 20°C to below 90°C.…”

Section: Introductionmentioning

confidence: 99%

“…The native protein (reference state) for a DCU reaction is D n (Neet & Timms, 1994). Recently (Apenten et al, 2002;, it was considered that b-LG dimer denature via a three-state DCU process involving the dissociation into monomers (N) which then unfold in accordance with the following equation:…”

Section: Introductionmentioning

confidence: 99%

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