The physicochemical parameters during dry heating strongly influence the gelling properties of whey proteins
Résumé
In this study we determined the composition (proportion of native proteins, soluble and insoluble aggregates)and quantified the gelling properties (gel strength and water holding capacity) of pre-texturizedwhey proteins by dry heating under controlled physicochemical conditions. For this purpose, a commercialwhey protein isolate was dry heated at 80 C (up to 6 days), 100 C (up to 24 h) and 120 C (up to 3 h)under controlled pH (2.5, 4.5 or 6.5) and water activity (0.23, 0.32, or 0.52). Gelling properties were quantifiedon heat-set gels prepared from reconstituted pre-texturized proteins at 10% and pH 7.0. The formationof dry-heat soluble aggregates enhanced the gelling properties of whey proteins. The maximalgelling properties was achieved earlier by increasing pH and water activity of powders subjected todry heating. An optimized combination of the dry heating parameters will help to achieve better gellingproperties for dry heated whey proteins.