Milk is an oil-in-water emulsion in which fat beads are continuously dispersed in the skim milk phase. However, if raw milk remains standing, the fat rises and forms a cream layer. Homogenization is the mechanical processing of fat spheres in milk resulting from high pressure milk passing through a tiny hole; this leads to a decrease in average diameter and an increase in the number of fat spheres and surface area. The result, from a practical point of view, is that the tendency of the fat beads to exfoliate is significantly reduced. Three factors contribute to this stability of homogenized milk: a decrease in the average diameter of fat beads (a factor according to Stokes Law), a size decrease in the size distribution of fat beads (this leads to the fact that the growth rate will be the same for most beads), and the protein membrane an increase in the density of globules due to adsorption (bringing them closer to the continuous phase). At the first inlet of the valve, the fluid velocity is 4 to 6 m / s. It then moves into the space between the valve and the valve seat (see below) and increases its speed to 120 meters per second in about 0.2 milliseconds. While most of the reduction with milk homogenizer in fat spheres occurs in the first stage, clusters tend to accumulate or aggregate in beads with reduced fat content. The second stage valve allows these clusters to be divided into individual oil spheres.
Homogenization Effect
Surface layers There is a natural membrane of amphiphilic molecules with hydrophilic and hydrophobic portions, which are collected during the secretion of the milk fat globules. During homogenization, a large increase in surface area occurs and the membrane of the natural milk fat globule (MFGM) disappears. The raw milk has an interfacial tension of 1-2 mN / m, becomes unstable at 15 mN / m immediately after homogenisation and stabilizes in a short time as a result of protein adsorption (3-4 mN / m). Protein transport is carried out essentially by convection, not by diffusion. Quick coverage is achieved in less than 10 seconds, but milk cream homogenizer can be changed.
Basic Principles Of Milk Homogenization
There is something very controversial about milk cream homogenizer – a few tons of heavy, stationary metal that can pass thousands of liters of milk per hour. On the other hand, they do what they do because of the extremely thin gap in human hair width. Raw milk is an oil-in-water emulsion; this means that the oil (oil) will be dispersed in the water. If left, the oil rises and forms an undesirable layer of cream. The fat content of raw cow’s milk is approximately 3.6% and the average fat sphere size is 3.5 microns. A 300 ml glass contains about 11 ml of pure oil, which can undoubtedly chew a little when you drink it immediately – and chewing is not a tissue that consumers often want to associate with drinking milk. The much smaller fat spheres are now dispersed in water as both pass through a homogenizing device; however, the oil spheres tend to aggregate after this initial homogenization step. To prevent aggregation completely, a second homogenization step may be added to complete the first. The second stage no longer reduces the size of the globules, but milk cream homogenizer of the cluster and prevents further aggregation.
Process Requirements
During homogenisation, the physical state and concentration of the fat phase significantly affects the size and distribution of the fat globules. Homogenisation of cold milk in which the oil hardens is practically ineffective. Processing at temperatures that contribute to the partial hardening of the milk fat (ie below 40 ° C) leads to incomplete dispersion of the milk cream homogenizer.