Heat-Induced Aggregation of β-Lactoglobulin as a Function of pH

Hoffmann, Marion; Mil, P.J.J.M. van

doi:10.1021/jf980886e

Cited by 154 publications

(147 citation statements)

References 23 publications

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“…The increase of temperature causes a reversible unfolding of the monomer followed by an irreversible aggregation. Association between these aggregates forms larger aggregates with different characteristics depending on the heat treatment and pH values (HOFFMANN & VAN MIL, 1999). The increased size of aggregates induces the increased particles volume fraction resulting in a more viscous solution (VARDHANABHUTI & FOEGEDING, 1999).…”

Section: Resultsmentioning

confidence: 99%

The effect of the addition of selected phenolic acids on the rheological properties of heated solutions of whey proteins

Szwajgier¹,

Gustaw²

2015

Acta Alimentaria

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This study measured the fl ow behaviour of whey protein isolate mixtures with cinnamic or ferulic acids. Samples were heated in a vacuum (80 C, -0.9 atm, 280 r.p.m., 0.5 h). The fl ow curves of all samples showed a nonNewtonian shear thinning fl ow and the viscoelastic properties were typical for weak gel systems. At pH 6.0, 6.7, and 8.0, the highest shear stress values were obtained with 20, 40, and 40 mg of cinnamic acid g -1 protein, respectively. At pH 6.0, the use of ferulic acid (20 mg g -1 protein) resulted in the elevation of shear stress values, but at pH 8.0, ferulic acid caused a decrease in shear stress values in comparison to cinnamic acid. The thixotropic area (A T ) was increased in mixtures containing 20-40 mg cinnamic acid g -1 protein (at pH 6.7) and 20 mg of cinnamic acid g -1 protein (at pH 6.0). Similarly, the addition of ferulic acid (40 and 20 mg g -1 protein at pH 6.7 and 6.0, respectively) caused a signifi cant increase in A T . At pH 8.0, no signifi cant differences in A T values were observed between samples. Such systems can be applied with reference to health promoting foods such as WPI-based desserts.

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Section: Resultsmentioning

confidence: 99%

The effect of the addition of selected phenolic acids on the rheological properties of heated solutions of whey proteins

Szwajgier¹,

Gustaw²

2015

Acta Alimentaria

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“…As a result, the conversion of thiols into disulphide bonds increased with pH up to at least 6.9 [163] or up to pH 11 [113], as did the contribution of intermolecular disulphide bonds in the formation of heatinduced protein aggregates of β-lactoglobulin [67] or of κ-casein and whey protein in milk [57]. Conversely, the contribution of electrostatic interactions decreased as pH increased, as a result of the increased negative charge of the β-lactoglobulin (isoelectric pH ~ 5.4) [67].…”

Section: Disulphide Bonds Number and Size Of The Heat-induced Proteimentioning

confidence: 95%

Formation of heat-induced protein aggregates in milk as a means to recover the whey protein fraction in cheese manufacture, and potential of heat-treating milk at alkaline pH values in order to keep its rennet coagulation properties. A review

Guyomarc’H

2006

Lait

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-The heat-treatment of cheese milk, or whey, to denature the whey proteins has long been the most applied means of recovering these proteins, either directly in the cheese curd, or as added to the cheese milk prior to renneting. In heat-treated milk, the interaction of the denatured whey proteins with the casein micelles, however, limits the primary phase of the enzymatic reaction, and prevents fusion of the casein micelles. Cheeses containing heat-denatured whey proteins also exhibit excessive moisture, a crumbly and soft texture, and poor meltability. Various technological means to reduce these drawbacks are reviewed. Especially, it is generally accepted that the heat-treatment of skim milk at alkaline pH generates aggregates of denatured whey proteins and κ-casein in the serum phase of milk, rather than on the surface of the casein micelles. As a consequence, the casein micelles are depleted in κ-casein, and free of denatured whey proteins. However, the attempts made to exploit this interesting protein distribution in cheese-making remain scarce, despite their promising results. Résumé -Récupération des protéines sériques du lait dans le caillé fromager au moyen de la formation d'agrégats thermo-induits, et intérêt de chauffer le lait à pH alcalin dans le but de conserver son aptitude à la coagulation présure. Revue. Le traitement thermique du lait ou de lactosérum est un des moyens les plus utilisés pour incorporer les protéines sériques ainsi dénatu-rées, soit directement dans le caillé, soit sous forme d'ingrédient ajouté au lait fromager. Cependant, l'interaction entre les protéines sériques dénaturées et les micelles de caséines, due au chauffage du lait, a pour effet de limiter la phase primaire de la coagulation par la présure, ainsi que la fusion des micelles déstabilisées. Les fromages obtenus à partir de lait chauffé sont aussi plus humides, plus mous, plus granuleux et moins aptes à la fonte que les fromages standards. Les moyens technologiques de pallier ces inconvénients sont rappelés. En particulier, il est connu que le traitement thermique du lait à pH alcalin favorise la formation d'agrégats de protéines sériques dénaturées et de caséine κ dans la phase soluble du lait, plutôt qu'en surface des micelles de caséines. En consé-quence, la teneur en caséine κ des micelles est réduite et celles-ci ne sont pas recouvertes de protéi-nes sériques dénaturées. Cependant, peu d'études ont tenté d'exploiter ces caractéristiques du lait chauffé à pH alcalin en technologie fromagère, malgré des résultats prometteurs. coagulation présure / traitement thermique / protéine sérique / fromage

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“…The disulfide bridges are known to be a key factor that affects the gel strength (Hoffmann and Van Mil, 1999;Creamer et al, 2004) and the aggregation process through the polymerization of monomers to form large polymer chains. However, there is only limited availability of the bonds to be formed and hence excessively longer heating time may not be effective anymore.…”

Section: Effect Of Heating Time On Hiwpg Dissolutionmentioning

confidence: 99%

Influence of Run Time and Aging on Fouling and Cleaning of Whey Protein Deposits on Heat Exchanger Surface

Fickak¹,

Hatfield

Chen

2012

JFR

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In the cleaning operations of heat exchange surfaces in dairy processing plants, the effect of heating/run time (HT) and aging on the fouling/cleaning of heat exchangers is not well understood. Longer heating time of the same deposit is expected to result in the formation of stronger and perhaps more cleaning resistant deposit. In this study, the phenomenon of heating and aging on the formation and cleaning of dairy fouling is investigated using the heat induced whey protein gels (HIWPG) produced in laboratory. The processes were also investigated with the whey protein deposits formed in pilot-scale plant trails.The HIWPGs were produced in tubular capsules for various heating (or run) times (60, 120, 240, 1440 and 2880 min respectively) and then dissolved in aqueous sodium hydroxide (0.5 wt %). The heating process here would have been of 'pure' aging. The dissolution rate was calculated based on the previously established UV Spectrophotometer analysis. The structure and texture of the gels were analysed using Scanning Electron Microscope (SEM) and texture analyser. In the pilot-scale plant study, whey protein fouling layers were generated by recirculating whey protein solution (6 wt %) for various heating periods (30, 60, and 90 min respectively). The deposit layers were then removed by recirculating aqueous sodium hydroxide (0.5 wt %) and the cleaning efficiency was monitored in the form of the recovery of heat transfer coefficient while both fluid electric conductivity and turbidity were recorded as indications of cleaning completion. It was found that increasing the HIWPG heating time significantly increased the gel hardness and dissolution time, implicating the difficulty in cleaning. Similarly to these results on gels, increasing the pilot-scale plant heating/run time increased the extent of fouling. The fouling layer formed next to the metal surface experienced the longest period of aging and the slope of the heat transfer coefficient increase seen at the final cleaning stage is related to this aging effect. The rate of cleaning for deposits formed initially on the metal surface is lower indicating a 'pure' aging effect of the deposit near surface.

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Heat-Induced Aggregation of β-Lactoglobulin as a Function of pH

Cited by 154 publications

References 23 publications

The effect of the addition of selected phenolic acids on the rheological properties of heated solutions of whey proteins

The effect of the addition of selected phenolic acids on the rheological properties of heated solutions of whey proteins

Formation of heat-induced protein aggregates in milk as a means to recover the whey protein fraction in cheese manufacture, and potential of heat-treating milk at alkaline pH values in order to keep its rennet coagulation properties. A review

Influence of Run Time and Aging on Fouling and Cleaning of Whey Protein Deposits on Heat Exchanger Surface

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