Some Remarks on Colloid Stability: Selected Examples Taken from the Milk Chain for Food Prepares

Abstract

Different forces play key roles in the stability of food colloid dispersions. The focus here is on those controlling attraction and/or repulsion, which concur to stabilization, phase separation, coagulation and are quite evident in water-based systems. The combination of attractive and repulsive forces favors or hinders the association of colloid entities; such processes are often met in food technology. The above processes depend on the forces at work and colloid concentration in the medium (i.e., on interparticle distance). Worked examples deal with milk manipulation procedures, ending in cheese formation. The whole milk sequence is controlled by the combination of forces leading to aggregation and phase separation of casein and other milk components. Thereafter, one gets either fresh, for prompt consumption, or aged cheeses. The combination of attractive (van der Waals, vdW, and depletion) with repulsive (double layer, DL, but also steric) forces results in the dominance of aggregation versus dispersion modes in the milk transformation chain, which depends on the distance among colloid particles, on the amplitude of the mentioned forces, and on their decay. The combined role of double layer and van der Waals (vdW) forces is at the basis of the DLVO theory on colloid stability, which is properly modified when these forces overlap with steric stabilization and, eventually, with depletion. Steric effects are dispersive, and depletion ones favor colloid nucleation in a single phase. The milk manipulation chain is a worked example of the intriguing association features controlled by the mentioned forces (and of ancillary ones, as well), and indicates which forces favor the formation of products such as parmesan or mozzarella cheese but are not alien to the preparation of many other dairy products.

On Concept of Hybrid in Colloid Sciences

“…Today, efforts proceed on the same line, trying to get products with superior quality in terms of safety and with significant yields, too. English [107], Italian [108], and Dutch [109] universities are worldwide recognized for taking care of the above field and to go ahead with a series of important initiatives in the field of colloid-based formulations used in the food industry.…”

Proteomics Analysis in Dairy Products: Cheese, a Review

“…In the ripened cheeses, a critical role for the final product is played by the ripening conditions such as temperature, relative humidity, and rates of O 2 , CO 2 , and NH 3 , that affect the character and diversity of cheese microflora. The traits of these microorganisms and activity contribute to the final characteristics of the product, such as flavor and quality [1][2][3]. The latter are attributed to the complex dynamics and interactions developed among the microorganisms, growth substrates and proteins in milk and the environment.…”

“…During cheese making the most uncontrollable step is the one linked with the microflora growth and their interactions [1,2,7]. The traditional method for improving the quality characteristics of cheese is the "vaccination" with bacterial strains isolated from high quality aged cheeses [8].…”