Insolubility, which increased with storage time
and temperature, was attributed to fusion of adjacent powder
particles through proteineprotein interactions during storage of
MPC80 . Insoluble protein material in
reconstituted MPC85 consisted predominantly of casein and the
minor whey proteins . Although MPCs contain less
lactose than other powder milk products (e.g., nonfat dry milk),
lactosylation or the binding of lactose to an amino acid, specifically
lysine, can initiate Maillard browning reactions which contribute to
undesirable color change and loss of nutritional value during
storage. The presence of advanced Maillard browning products may
increase proteineprotein crosslink formation during storage and
can contribute to reduced MPC solubility. Hydrolyzed whey protein concentrate (WPC) had
reduced lysine availability which may suggest decreased Maillard
reactions during storage of hydrolyzed dairy proteins. Protein solubility largely determines
its use in foods, especially in beverage applications, and is
one of the most important factors in determining other functional
properties .
The emulsification and foaming properties of MPCs are reported
to be relatively poorer in comparison with sodium caseinate, WPC,
and whey protein isolate (WPI) which limits their use in coffee
creamers, whipped toppings, soups, and processed meats