Finding a Whey: How Science Changed the Whey Industry

Last week we learned that whey is one of the byproducts of cheesemaking. To clarify, there are two types of whey, one is called sweet whey and is the byproduct of Cheddar and similar style cheeses. The other is acid whey which is a byproduct of Greek yogurt and cottage cheese. Today, we will be discussing sweet whey, the byproduct of Cheddar-style cheeses.  While the term byproduct might not sound very important, keep in mind that for every 100 pounds of milk, a cheesemaker can expect to get 10 pounds of cheese and 90 pounds of whey. That 90 pounds of whey, which is drained off from the cheese, contains 94 percent water and about 6 percent solids (protein, fat, minerals and lactose). What to do with that large amount of watery whey has long been an issue for the industry but this week we are going to discuss the newly discovered benefits of this versatile dairy derivative.

Liquid whey (Picture provided by Wisconsin whey processing researcher Dr. Karen Smith

                     

Sweet Whey, A Hero in Disguise:

Once upon a time, not so very long ago, cheesemakers were burdened by large amounts of sweet whey. Though it was considered best practice to feed the whey to the pigs or use it on the fields, some cheesemakers were producing so much cheese, and therefore whey, that they were having to pay others to take the whey. All in all, whey was a financial loss for the cheesemakers and a burden to large cheesemaking communities. Along the way, however, farmers began to notice something special about this seemingly burdensome byproduct. It appeared that the pigs ingesting the whey had improved growth rates.  Researchers took over from there and it was discovered that the proteins in whey are some of the most nutritionally complete proteins known to mankind.

A picture of liquid whey provided by Wisconsin whey processing researcher Dr. Karen Smith. On the left is whey from a  cheese without added colorant, on the right is whey from a cheese made with annatto (see last week's article for more on annatto).

             
The Nutrition Factor:

So what does nutritionally complete mean? Well, aside from the 94 percent water, which is now removed during processing, whey contains 6 percent solids. These solids include fat (phospholipids), lactose (milk sugar), minerals such as calcium, phosphorus and potassium and finally protein. While each of the components are important in their own right, the protein is a key part of the nutritionally complete definition. To give a bit of background, proteins are comprised of amino acids. There are generally 22 amino acids present in the body with nine of those falling under the category of essential amino acids, meaning they cannot be produced by the body and must be eaten in the diet. Of these essential amino acids there are some called branch chain amino acids such as isoleucine, valine and leucine. Recent research has shown that these branch chain amino acids are directly linked to muscle synthesis and recovery. What’s most exciting about whey is that it contains the highest amounts of these branch chain amino acids found in food. In particular, a 2007 study from McMaster University showed that as little as 10 grams of whey protein ingested in a recovery drink will aid in muscle protein synthesis (i.e. recovery and growth). This ability to aid in muscle recovery is why you’ve likely heard of athletes drinking whey protein recovery drinks. Keep in mind that whey is not reserved for athletes. In fact, many of the professionals I’ve worked with have said that everyone from growing teens to the elderly can benefits from the complete protein package found in whey.

         A photo of whey after it has been processed. Tera'swhey (shown here) is made in Wisconsin and can be added  to milk, water or smoothies.

So, how is this processed?

After the whey is drained from the cheese any cheese fines are removed and then the whey is cooled per the legal requirements and stored in tanks. When the processor is ready for the whey it will be sent through a pasteurizer and then a membrane separation system that works kind of like a sieve retaining the proteins and letting through the smaller components in the whey.  In order to remove the water from the whey, the remaining components are sent through an evaporator and dried into powder form. This powder is then sold in stores or further processed into drinks and other products. Since the type of membrane separation varies depending on the desired outcome there are several types of whey protein powder including whey protein concentrate (WPC) 34, WPC 80 and whey protein isolate which is higher in protein and lower in fat and minerals than WPC. Depending upon the functional and nutritional needs of the final application, WPC or WPI may be used as each offer slightly different benefits and challenges in terms of food science and diet.

So there you have it, the science of whey! Isn’t it amazing how a little bit of science can take something that was once a waste product and help people transform it into a something that is now a value added product, bring profit to the cheesemaker and great nutrition to the consumer.

Be sure to join us Monday for the final story on the science of dairy.