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SOLUBILITY AND EMULSIFYING PROPERTIES OF KAPPA CASEIN AND ITS CASEINOMACROPEPTIDE
Author(s) -
CHOBERT JEANMARC,
TOUATI ABDELMADJID,
BERTRANDHARB CATHERINE,
DALGALARRONDO MICHÈLE,
NICOLAS MARIEGEORGETTE
Publication year - 1989
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.1989.tb00413.x
Subject(s) - casein , solubility , chemistry , emulsion , chromatography , food science , biochemistry , organic chemistry
Kappa‐casein A was treated with chymosin in order to isolate the caseino‐macropeptide corresponding to the C‐terminal 106–169 residues of K‐casein. Whole casein, K‐casein and the caseinomacropeptide (CMP) were studied for their water solubility and emulsifying activity. The CMP was soluble over the range of pH from 1 to 10, with a “minimum” solubility (88%) in the range of pH 1–5 and a “maximum” solubility (98%) in the range of pH 5–10. For whole casein and K‐casein, at pH values above 5.5, the emulsifying activity increased when pH increased and the maximum value was obtained for very alkaline solutions; for pH values below 4.5, the increase in emulsifying activity was much more pronounced at pH 2.5; below pH 2.5, emulsifying activity decreased. For CMP, the increase in emulsifying activity was much more pronounced in the acidic range than in the alkaline range. After 24 h storage and heating of the emulsion, a large pH‐dependant decrease of emulsifying activity (22–60%) was observed for CMP for pH values below 4.0; under the same conditions, the emulsifying activity of whole casein and K‐casein showed a 5–19% and a 1–21% decrease, respectively. For pH values above 6.0, a 22–59% decrease was observed for CMP as compared to a 1–12% and a 4–17% decrease with whole casein and K‐casein, respectively.