Stability of casein micelles cross-linked with genipin: A physicochemical study as a function of pH

• Published in: International dairy journal Vol. 68; pp. 70 - 74
• Main Authors: Casanova, Federico, Nogueira Silva, Naaman F., Gaucheron, Frédéric, Nogueira, Márcio H., Teixeira, Alvaro V.N.C., Perrone, Italo Tuler, Alves, Maura Pinhero, Fidelis, Priscila Cardoso, Carvalho, AntÔnio F. de
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2017; Elsevier
• Subjects: Food and Nutrition; Food engineering; Life Sciences; protéine du lait; technologie laitière; chemical stability; méthode de précipitation à l'éthanol; produit laitier; précipitation; stabilité chimique; micelle de caséine; génipine; propriété physicochimique du lait; stabilité; milk protein
• ISSN: 0958-6946; 1879-0143
• DOI: 10.1016/j.idairyj.2016.12.006

Chemical or enzymatic cross-linking of casein micelles (CMs) increases their stability against dissociating agents. In this paper, a comparative study of stability between native CMs and CMs cross-linked with genipin (CMs-GP) as a function of pH is described. Stability to temperature and ethanol were investigated in the pH range 2.0–7.0. The size and the charge (ζ-potential) of the particles were determined by dynamic light scattering. Native CMs precipitated below pH 5.5; CMs-GP precipitated from pH 3.5 to 4.5, whereas no precipitation was observed at pH 2.0–3.0 or pH 4.5–7.0. The isoelectric point of CMs-GP was determined to be pH 3.7. Highest stability against heat and ethanol was observed for CMs-GP at pH 2, where visible coagulation was determined only after 800 s at 140 °C or 87.5% (v/v) of ethanol. These results confirmed the hypothesis that cross-linking by GP increased the stability of CMs.