I. Recio et al., STUDY OF THE FORMATION OF CASEINOMACROPEPTIDES IN STORED ULTRA-HIGH-TEMPERATURE-TREATED MILK BY CAPILLARY ELECTROPHORESIS, Journal of agricultural and food chemistry, 44(12), 1996, pp. 3845-3848
The proteolytic activity of enzymes of psychrotrophic bacteria on case
in and raw and ultra-high-temperature (UHT)-treated mills. was studied
by capillary electrophoresis (CE) in order to characterize the degrad
ation products and evaluate the possibility of distinguishing them fro
m those due to the action of chymosin on kappa-casein. Casein hydrolys
ates with Pseudomonas fluorescens B52 proteinase, milk inoculated with
P. fluorescens, and commercial UHT milks were studied. The degradatio
n products included caseinomacropeptide (CMP), pseudo-caseinomacropept
ide (pseudo-CMP; CMP lacking the 106 Met residue) and an unidentified
third peak. These peaks were already present in some freshly prepared
UHT milk samples, and a progressive increase in peak area was observed
upon storage at 22 degrees C. This might give rise to false positive
results when the presence of rennet whey is investigated by CE. Howeve
r, low area ratios of pseudo-CMP to CMP might allow the presence of re
nnet whey solids to be suspected.