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Poster De Conférence Année : 2013

Model mixtures evidence the respective roles of whey protein particles and casein micelles during the acid gelation of heated milk

Résumé

Heat-induced whey protein aggregates and casein micelle particles physically organize and assemble to form an acid gel. However, they play a different role in building the gel, depending on their particle numbers in the milk system. The present study was set to evaluate the role of whey protein aggregates and casein micelles by means of changing their ratio in model milk systems. Whey protein aggregates (WPIA) were generated from a whey protein isolate upon controlled heating conditions. Mixtures of Native Micellar Casein (NMC) and WPIA were suspended in a milk permeate at different weight ratios ranging from 0% to 100% NMC. The total protein concentration was set constant to 45 g/kg. Acidification was performed at 35 °C by addition of glucono- -lactone (GDL) to achieve the same final pH of 4.5 in 6 h. Acid-induced gelation of these systems was followed using small deformation rheology as function of pH followed by large deformation test at pH 4.5. Final gels were characterized by texture analysis and whey retention, while their microstructure was investigated using confocal scanning laser microscopy (CSLM) and transmission electron microscopy. The results from this study confirmed that systems with different numbers of each type of protein particles behaved differently during the acid gelation. Increasing the content in WPIA led to an increase in their pH of gelation and final elastic modulus (G’) and a decrease in tan . CSLM shows that increasing WPIA content produced a gel structure with smaller pores which led to a firmer gel as showed by the texture measurements. Furthermore, a more firm gel bound more whey which led to higher whey retention. The results are discussed in terms of interaction between the WPIA and the casein micelles, possibly creating dense clusters or knots in the finer WPIA network.
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Dates et versions

hal-01209418 , version 1 (02-10-2015)

Identifiants

  • HAL Id : hal-01209418 , version 1
  • PRODINRA : 188751

Citer

Robi Andoyo, Fanny Guyomarc'H, Chantal Cauty, Marie-Hélène Famelart. Model mixtures evidence the respective roles of whey protein particles and casein micelles during the acid gelation of heated milk. Insidefood Symposium 2013, Apr 2013, Leuven, Belgium. , 2013. ⟨hal-01209418⟩
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