title: Behavior of Heat-Denatured Whey: Buttermilk Protein Aggregates during the Yogurt-Making Process and Their Influence on Set-Type Yogurt Properties.
abstract: The objective of this study was to assess the impact of using heat-denatured whey:buttermilk protein aggregate in acid-set type yogurt production. Whey and buttermilk (25:75) protein concentrate was adjusted to pH 4.6, heated at 90 °C for 5 min, homogenized and freeze-dried. Set-type yogurts were prepared from skim milk standardized to 15% (w/v) total solids and 4.2% (w/v) protein using different levels of powdered skim milk or freeze-dried protein aggregate. The use of the protein aggregate significantly modified yogurt texture, but did not affect the water-holding capacity of the gel. Confocal laser-scanning microscope images showed the presence of large particles in milk enriched with protein aggregate, which directly affected the homogeneity of the clusters within the protein matrix. Thiol groups were freed during heating of the protein aggregate suspended in water, suggesting that the aggregates could interact with milk proteins during heating.
authors.affiliation: STELA Dairy Research Center, Institute of Nutrition and Functional Foods (INAF), Laval University, Quebec City, QC, G1V 0A6, Canada. maxime.saffon.1@ulaval.ca.
authors.forename: Maxime
authors.initials: M
authors.lastname: Saffon
authors.affiliation: STELA Dairy Research Center, Institute of Nutrition and Functional Foods (INAF), Laval University, Quebec City, QC, G1V 0A6, Canada. veronique.richard@fsaa.ulaval.ca.
authors.forename: Véronique
authors.initials: V
authors.lastname: Richard
authors.affiliation: Dairy Products Technology Center (DPTC), California Polytechnic State University, San Luis Obispo, CA 93405, USA. rjimenez@calpoly.edu.
authors.forename: Rafael
authors.initials: R
authors.lastname: Jiménez-Flores
authors.affiliation: STELA Dairy Research Center, Institute of Nutrition and Functional Foods (INAF), Laval University, Quebec City, QC, G1V 0A6, Canada. sylvie.gauthier@fsaa.ulaval.ca.
authors.forename: Sylvie F
authors.initials: SF
authors.lastname: Gauthier
authors.affiliation: Food Research and Development Center (FRDC), Agriculture and Agri-Food Canada, St-Hyacinthe, QC, J2S 8E3, Canada. Michel.britten@agr.gc.ca.
authors.forename: Michel
authors.initials: M
authors.lastname: Britten
authors.affiliation: STELA Dairy Research Center, Institute of Nutrition and Functional Foods (INAF), Laval University, Quebec City, QC, G1V 0A6, Canada. yves.pouliot@inaf.ulaval.ca.
authors.forename: Yves
authors.initials: Y
authors.lastname: Pouliot
keywords: buttermilk; protein aggregates; texture properties; yogurt