Role of the Soluble and Micelle-Bound Heat-Induced Protein Aggregates on Network Formation in Acid Skim Milk Gels

Guyomarc’H, Fanny; Queguiner, Claire; Law, Andrew J. R.; Horne, David S.; Dalgleish, Douglas G.

doi:10.1021/jf030201x

Cited by 92 publications

(79 citation statements)

References 32 publications

(55 reference statements)

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“…The impact of heat-induced whey protein denaturation on gel firmness is still a subject of intensive discussion. [43][44][45][46] The bonds involved are either covalent disulfide bonds or hydrophobic interactions. Some researchers 44,47 reported that addition of a thiol-blocking agent caused a considerable decrease in G′, indicating the importance of disulfide bonds on gel firmness.…”

Section: Effects Of Concentration and Incubation Timementioning

confidence: 99%

Small and Large Deformation Rheology of Acid Gels from Transglutaminase Treated Milks

et al. 2006

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The purpose of this study was to evaluate the effects of microbial transglutaminase on the rheological and mechanical properties of gels from a commercial UHT milk made by acidification with D-gluconic-acid-δ-lactone. Although further heating of UHT milk, primarily carried out to inactivate the enzyme, showed a significant impact on gel firmness, we observed no enzyme-related effects at small deformation. The impact of the additional thermal treatment was also evident in large deformation measurements. In these experiments, gels from enzyme-treated milk revealed much higher elasticity and rupture force. Prolonged incubation time or increased enzyme concentration resulted in lower gel firmness (small deformation), indicating a reduced number of total bonds as a result of the restriction of proper rearrangements during acidification. Large deformation measurements revealed a heat-induced amplification of this effect, i.e., lower rupture forces at almost constant elasticity levels. In gels from milk, which was not subjected to thermal enzyme inactivation, we observed a further increase in both parameters. This is presumably caused by a combination of residual enzyme activity and of additional substrate, liberated during acidification.

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Section: Effects Of Concentration and Incubation Timementioning

confidence: 99%

Small and Large Deformation Rheology of Acid Gels from Transglutaminase Treated Milks

et al. 2006

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“…Indeed, it has been shown that heat treatment of milk induces the formation of κ-casein-β-lactoglobulin complexes that are responsible for a higher value of the gelation pH [10,17,28]. For higher levels of mineral depletions, the pH of milk before heat treatment and the heat-induced κ-casein dissociation no longer increased.…”

Section: Discussionmentioning

confidence: 99%

Acid gelation of colloidal calcium phosphate-depleted preheated milk

Famelart

Gauvin

Pâquet

et al. 2009

Dairy Sci. Technol.

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-This study aimed at understanding the role of colloidal calcium phosphate (CCP) in acid gelation of milk. Milks were depleted in Calcium (Ca) by dialysis against milk permeate containing a cation-exchange resin. Dialysed milks were then heated (90°C-10 min) and acidgelled at 42°C with a yoghurt culture. Minerals, total and soluble protein contents, pH and optical density were measured in unheated and heated dialysed milk, together with diameters and ζ-potentials of particles. Dialysis of milk led to a dissociation of 45% total Ca and 30% total phosphorus, to an increase in sodium content and pH of milk, to lower turbidity and ξ-potential, but did not change the casein particle size. Soluble Ca and casein-bound Ca were removed from milk, CCP being removed increasingly, while Ca removed from the phosphoserine residues increased very little during the dialysis experiments. Maximal dissociation of α s1 -and α s2 -casein was 20%, while that of β-and κ-casein was 35-40% of total at the end of dialysis, and it increased after heating, especially for κ-casein. The pH value at which the milk sample begins to gel increased for low mineral depletion rates but decreased for higher depletion levels. This was due to the increase in the pH value of milk and in the κ-casein dissociation. The elastic modulus decreased in samples at the lowest depletion and then levelled off, which suggested that the phosphoserine-bound Ca played a critical role in the formation of acid gels.colloidal calcium phosphate / CCP / acid milk gel / dialysis Article published by EDP SciencesRésumé -Gélification acide de lait déplétés en phosphate de calcium et chauffés. Cette étude a pour objectif de comprendre le rôle du phosphate de calcium colloïdal (CCP) dans la gélification acide du lait. Dans ce but, les micelles de caséines ont été déplétées en CCP par dialyse de lait contre un perméat de lait contenant une résine échangeuse de cations. Les laits dialysés étaient ensuite chauffés (90°C-10 min) et gélifiés à 42°C par acidification avec une culture bactérienne de yaourt. Les minéraux, les protéines totales et solubles, le pH et la blancheur ont été mesurés dans les laits dialysés chauffés et non chauffés, ainsi que le diamètre et le potentiel ζ des particules. La dialyse a entraîné une solubilisation maximale de 45 % du calcium total et de 30 % du phosphore total, une augmentation des teneurs en sodium et du pH, une densité optique réduite des laits et de plus faibles potentiels ζ, mais n'a pas eu d'effet sur la taille des particules. Le Ca soluble et le Ca lié à la caséine diminuaient dans le lait, le CCP diminuant régulièrement, tandis que le Ca lié aux phosphosérines diminuait peu, au fil de la dialyse. La dissociation de la caséine s′élevait à 20 % (caséines α s1 et α s2 ) et 35-40 % (caséines β et κ) dans le lait en fin de dialyse et augmentait après le traitement thermique, particulièrement pour la caséine κ. Le pH de gélification augmentait pour de faibles déplétions minérales et diminuait pour des plus fortes déplétions. Ceci s′ex...

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“…On the other hand, by decreasing the casein to whey protein ratio of milk blends, Guyomarc'h et al (2003a), Puvanenthiran et al (2002) or Beaulieu et al (1999) increased the size of complexes up to fivefold and obtained acid gels with proportionally increased final G' values. In model whey protein systems, higher protein concentration also promotes formation of larger complexes Ju and Kilara 1998b;Le Bon et al 1999).…”

Section: Possible Methods To Modify the Size Of The Heat-induced Wheymentioning

confidence: 99%

“…Disulphide covalent bonds have also been evidenced to sustain the acid gels' network (Hinrichs and Keim 2007) as a result of the formation of heat-induced whey protein/κ-casein complexes on heating the milk. Covalent bonds are thought to account for the increased elastic modulus G' and lower tanδ of acid gels made with heated milk (Guyomarc'h et al 2003a). Vasbinder et al (2004) further showed that thiol/disulphide exchanges occur throughout acidification of milk where heatinduced complexes are present and evidenced that disulphide bonds contribute to the increase in G' on gel formation.…”

Section: Structure and Mechanical Properties Of Acid Dairy Gelsmentioning

confidence: 99%

“…As the casein micelles loosen and rearrange throughout acidification (Gastaldi et al 1996), the exact nature of the casein "micelles" that eventually form the particulate gel is not known, which sensibly challenges modelling (Horne 2003). In heated milk, the presence of heat-induced whey protein/κ-casein complexes increases the pH at which gelation onsets from pH~4.8 to~5.4 (Graveland- Bikker and Anema 2003;Guyomarc'h et al 2003a;Heertje et al 1985;Lucey et al 1997a). It is hypothesized that the complexes modify the surface properties of casein micelles as to increase net colloidal attraction, hence decreasing the threshold for acid destabilisation (Donato and Guyomarc'h 2009).…”

Section: Introductionmentioning

confidence: 99%

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How to tailor heat-induced whey protein/κ-casein complexes as a means to investigate the acid gelation of milk—a review

Morand

Guyomarc’H

Famelart

2011

Dairy Science & Technol.

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The heat treatment of milk greatly improves the acid gelation of milk and is therefore largely applied in yoghurt manufacture. During the heat treatment, soluble and micelle-bound whey protein/κ-casein complexes are produced in milk. The complexes and their physico-chemical properties have been held responsible for the early gelation point, the increased final firmness and for the serum retention capacity of the acid gels made of heated milk. They are suspected to bring new functionalities to the casein micelles and to help the formation of interactions when building the gel network. In order to investigate the type of interactions that the complexes can affect throughout the acid gelation of milk, an original strategy would be to control the physico-chemical properties of the whey protein/κ-casein soluble complexes and to use them as vectors to modify the possible interactions in the milk. In that perspective, the different physico-chemical properties of the whey protein/κ-casein soluble complexes that are thought to significantly affect the acid gelation behaviour of the casein micelles are listed. Then, the physical, chemical and biological means that could possibly be applied to the formation of complexes in order to modulate each of the targeted property are reviewed and evaluated. In order to open a large choice for future investigation, these methods were found in a larger literature resource than milk, including other protein systems like model whey protein solutions or non-dairy globular protein systems. The food-compatible

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Role of the Soluble and Micelle-Bound Heat-Induced Protein Aggregates on Network Formation in Acid Skim Milk Gels

Cited by 92 publications

References 32 publications

Small and Large Deformation Rheology of Acid Gels from Transglutaminase Treated Milks

Small and Large Deformation Rheology of Acid Gels from Transglutaminase Treated Milks

Acid gelation of colloidal calcium phosphate-depleted preheated milk

How to tailor heat-induced whey protein/κ-casein complexes as a means to investigate the acid gelation of milk—a review

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