Protein adsorption in the food industry
Product quality can be adversely affected if the adsorbed material interferes with processing steps, like pasteurization.
Also, proteins stuck to the heater may cause a burned taste or color in the bulk material.
It is also harmful from a nutritional standpoint: oxalates can decrease absorption of calcium in the body, in addition to increasing risk of kidney stone formation.
[5] Haze-causing proteins can persist in wine due to low settling velocities or charge repulsion on individual particles.
Also, proteinaceous agents such as albumin, casein, or gelatin are used in wine clarification to remove tannins or other phenols.
Microorganisms in biofilms are enclosed in a polymeric matrix consisting of exopolysaccharides, extracellular DNA and proteins.
A biofilm's enclosing polymeric matrix offers protection to its microbes, increasing their resistance to detergents and cleaning agents.
This temperature is high enough to denature the proteins below, lowering the nutritional value of the milk and causing fouling.
Milk is heated to these high temperatures for a short time (15–20 seconds) to reduce the amount of denaturization.
The exposed hydrophobic amino acids decrease the entropy of the water surrounding them, making it favorable for surface adsorption.
As more and more β-lg proteins bind to the casein micelle it forms an aggregate, which will then diffuse to the heat exchanger and/or surface of the container.
A third type of fouling has been discovered that is explained by the chemical interactions of the denatured β-lg proteins.
Researchers have used a Langmuir-type isotherm model to describe experimental values for protein adsorption.
In particular, heat-denatured proteins (such as those found in dairy industry applications) adhere tightly to surfaces and require strong alkaline cleaners for removal.
[16] It is important that cleaning methods are capable of removing both visible and non-visible protein soils.
[16] Generally speaking, highly alkaline cleaners with peptizing and wetting agents are most effective in protein removal on food contact surfaces.
[16] An example of a strong alkaline cleaning agent is sodium hydroxide, also called caustic soda.
[16] Cleaning speed and efficiency is improved due to increased diffusion of the cleaner into the soil matrix, now composed of smaller, more soluble proteins.
[19] Enzyme cleaners are more effective on biofilms since they work as proteases by breaking down proteins at bacterial attachment sites.
