Investigation of the Colloidal Interactions at Play in Combined Acidification and Rennet of Different Heat-Treated Milks

Abstract

The properties of gels obtained by combined acidification and rennet were investigated for milks heated at different temperature-time regimes using a high temperature short time (HTST) pilot plant system. Increasing amounts of heat-induced whey protein complexes were found in the soluble phase as a function of heating time/temperature, and only in the most extensively heated milk (i.e., 85 degrees C/300 s), these complexes were in quantities comparable to those reported in previous studies. Two levels of rennet were studied, and at the gelation pH, the amount of CMP released was 11 +/- 1% and 26 +/- 5% in the low and high rennet experiments, respectively. These two levels of rennet caused profound changes in the gelation behavior and in the structure development of the network. When a small amount of rennet was used, different heating temperature-time regimes did not affect the first stage of renneting. Increasing the extent of milk heat treatment and/or the level of rennet increased the pH of gelation and the stiffness of the gels. This work is the first to compare the effect of heating (using a pilot plant setup) and amount of rennet on the destabilization and interaction of casein micelles during aggregation by combined rennet and acidification.

Fabrication of Delivery Gels with Micellar Casein Concentrates (MCC) Using Microfiltration Embedding Lactobacillus Rhamnosus GG (LGG): Effect of Temperature on Structure, Rheological Behavior, and Texture

“…The high macromolecule protein formed might be attributed to some new chemical bonds like disulfide covalent bonds and noncovalent bonds produced by cross-linking and aggregation in the protein–protein amino acid chain during heat treatment . The results were in agreement with Cooper, Corredig, and Alexander, who studied colloidal interactions at combined acidification and rennet with different heat-treated milks and obtained a result that gels treated at 80 °C for 300 s possessing some more macromolecule stripes than those treated at 80 °C for 20 s …”

Probe Mobility in Native Phosphocaseinate Suspensions and in a Concentrated Rennet Gel: Effects of Probe Flexibility and Size

“…The coagulation induced by chymosin action is generally broken into three phases: enzyme action, aggregation, and gel aging. − First, the enzyme specifically splits off the κ-casein located at the surface of the supramolecular edifice. This reduces the steric and electrostatic repulsion between casein particles, and the suspension becomes unstable.…”

Rheological and structural properties of differently acidified and renneted milk gels

“…It has also been successfully used in soya milk and skim milk gels (Lin et al, 2012). Because it is an enzyme-and acid-induced process, the gelation behavior is quite complicated and largely depends on coagulation processes (Castillo et al, 2006a;Le Feunteun and Mariette, 2008;Cooper et al, 2010;Salvatore et al, 2011).…”