How Proteins From Milk Are Made

A simple process of pressure and filtration is all it takes to make these powerful complete proteins.

Simple Process. Low Waste. High Yield.

Extracting proteins from milk is simple and relies only on pressure and filtration, which results in minimally processed protein. And unlike many plant-based proteins that are extracted using harsh treatments and added artificial chemicals, most proteins from milk are manufactured mere miles from where the milk was collected, which reduces the carbon footprint of this process.

Extracting proteins from milk is also a low waste process. Milk is 100% edible, whereas a lot of other sources of plant-based proteins may produce yields less than 35%. Simple processing, local manufacturing and modern filtration keeps yields high, which increases the sustainability of making proteins from milk.

Looking for a deeper dive into how different proteins from milk are made? Let’s break it down by type.

Concentrates

To make protein from milk concentrate, whole milk is first separated into cream and skim milk. The skim milk is pasteurized, then fractionated using ultrafiltration to make a skim concentrate that is lactose-reduced.

This process naturally separates milk components according to their molecular size. Milk passes through a membrane that allows some of the lactose, minerals and water to cross through. The casein and whey proteins, however, do not pass through the membrane due to their larger molecular size and are therefore concentrated. The proteins, lactose and minerals that do not go through the membrane are then spray-dried to form a powder.

A similar process is applied to sweet whey (co-product of cheese manufacturing) to obtain whey protein concentrate.

Isolates

Two separation methods are widely used for whey protein isolates. One method utilizes ion exchangers, which extract whey protein from the whey stream (usually a co-product of cheese manufacturing) according to the surface charge characteristics of the molecule.

The second method, membrane filtration (typically a combination of microfiltration and ultrafiltration), uses molecular size as the basis for separating components from the whey stream. In this process, simple pressure is applied across a membrane surface which forces smaller molecules through the membrane while larger molecules are retained.

Both methods yield a very high protein to non-protein product ratio, resulting in protein isolates that are typically at least 90% protein, and contain very low levels of lactose.

Micellar casein and milk whey (“native” whey)

These concentrated milk protein products are produced using microfiltration of skim milk, which modifies the casein-to-whey protein ratio compared to that found in milk. The casein-to-whey protein ratio typically ranges between 82:18 and 95:5 for commercially available micellar casein products. Micellar casein is an ingredient most often found in sports and nutrition products.

The whey-enriched stream alternatively is called milk whey or “native” whey. This ingredient is also used in sports products and has potential in infant nutrition. It can be found in blends of whey proteins as well.

Casein and caseinates

Casein (acid) is obtained by coagulating skim milk, followed by separating, washing and drying steps. Rennet casein, an ingredient used in some cheeses, is made using enzymes. To facilitate applications in food products and drinks, casein may be further processed into caseinates (sodium, calcium, etc.).

Caseinates are found in a myriad of products where they act as natural emulsifiers, providing body and “creaminess.” Because they are lactose-free, caseinates are often used in non-dairy creamers, for example.

Milk Powders

Milk powders are simply made from whole or skim milk, concentrated by evaporation, then spray-dried.

They are used worldwide as an ingredient in all food categories, and can be used when fluid milk is not available, or to fortify products for nutritional or functional reasons.