Influence of colloidal calcium phosphate level on the microstructure and rheological properties of rennet-induced skim milk gels

TY - JOUR

T1 - Influence of colloidal calcium phosphate level on the microstructure and rheological properties of rennet-induced skim milk gels

AU - Koutina, Glykeria

AU - Knudsen, Jes Christian

AU - Andersen, Ulf

AU - Skibsted, Leif Horsfelt

PY - 2015/9/1

Y1 - 2015/9/1

N2 - Colloidal calcium phosphate is an essential part of casein micelles and being responsible for their stability. Different mineralization of casein micelles was obtained by acidification of skim milk to pH 6.5, 6.0 or 5.5, followed by a dialysis method, using simulated milk ultrafiltrate without lactose, to obtain varying levels of micellar calcium and phosphorus but constant value of pH, serum and free calcium, and serum phosphorus. Bovine chymosin was added to the skim milk samples after dialysis and microstructural and rheological properties during gel formation were recorded at 30°C. Samples after dialysis needed approximately 30min after the addition of chymosin to form rennet gels. In addition, low micellar calcium and phosphorus values were both found to correlate with slightly less time for the gels to be formed. This information highlights the importance of CCP in the primary phase of rennet gel formation. The protein network of rennet gels after dialysis was more compact with many aggregates as demineralization decreased. The small protein particles are able to increase the potential connection points among proteins, support particle fusion and cause a compact structure.

AB - Colloidal calcium phosphate is an essential part of casein micelles and being responsible for their stability. Different mineralization of casein micelles was obtained by acidification of skim milk to pH 6.5, 6.0 or 5.5, followed by a dialysis method, using simulated milk ultrafiltrate without lactose, to obtain varying levels of micellar calcium and phosphorus but constant value of pH, serum and free calcium, and serum phosphorus. Bovine chymosin was added to the skim milk samples after dialysis and microstructural and rheological properties during gel formation were recorded at 30°C. Samples after dialysis needed approximately 30min after the addition of chymosin to form rennet gels. In addition, low micellar calcium and phosphorus values were both found to correlate with slightly less time for the gels to be formed. This information highlights the importance of CCP in the primary phase of rennet gel formation. The protein network of rennet gels after dialysis was more compact with many aggregates as demineralization decreased. The small protein particles are able to increase the potential connection points among proteins, support particle fusion and cause a compact structure.

KW - Colloidal calcium phosphate

KW - Microscopy

KW - Rennet gel

KW - Rheology

U2 - 10.1016/j.lwt.2015.03.035

DO - 10.1016/j.lwt.2015.03.035

M3 - Journal article

SN - 0023-6438

VL - 63

SP - 654

EP - 659

JO - L W T- Food Science and Technology

JF - L W T- Food Science and Technology

IS - 1

ER -