How Seasonal Variations In Cow’s Milk Affects Whey Protein

From time to time, a client will question why their whey protein seems “different.”  This has to do with source of cheese that the whey was derived from, and the associated method utilized in cheese production. Another reason they whey can be "different" has to do with the diet of the cows during lactation.

The science behind transforming milk to cheese is a complex chemical process. Cow's milk is rich in a wide range of chemical compounds that can be processed into various dairy products such as cheese, butter, and yogurt.

Specifically, the milk component involved in cheese production is a soluble protein called casein. The enzyme rennet can be used to catalyze the conversion of casein in milk to para-casein by removing a glycopeptide from the soluble casein. Para-casein further coagulates, in the presence of calcium ions to form white, creamy lumps called the curd, leaving behind the supernatant called the whey.

There is no standard method of cheese making; limitless variations exist for all stages of the process: pre-ripening, curdling, addition of artificial ingredients and salt for flavor, and aging. This variation in processing accounts for the wide range of cheeses commercially available, differing in texture and flavor. The curd can also be processed with other techniques to make a variety of desserts. However, all processes have one thing in common: the separation of the curd from the whey.

Commercially, there are two main approaches for preparing milk for curdling:

1.  Curdling via microorganisms or...
2.  Using a strong acid such as hydrochloric acid.

The differences in these methods affects the resulting quality of the final cheese. The variations and different types of starting cultures, amount, and process time are what leads to more sophisticated types of gourmet cheeses. The efficiency related with using a strong acid will generate a commercial grade cheese without much complexity.

Regardless of the process utilized to prepare cheese curds, whether it is high end or economy cheese, the resulting supernatant, or phase separated liquid, is where we derive whey protein that is ultra-filtered several times and spray dried before becoming the rich, high quality protein supplement known for its benefits in the bodybuilding and general health industries.

Since whey is the byproduct of an organic raw material-aka cheese (I use the word organic meaning “natural” not certifying a commercial farming method), there are times that whey protein will be “different” from batch to batch regardless if it made using the same exact formulation.  In addition to the cheese curling method, the diet of the cows will affect the whey protein color as well.

Sometimes whey has a more yellow/orange hue, as opposed to a light cream/white color. Cheese manufacturers compensate for this variation by adding a food grade titanium dioxide pigment (very common with mozzarella cheese production).

Cheeses, and whey for that matter, that have a more yellow/orange color have the same protein quality. The cows were fed a diet that contained small amounts of beta carotene, which contain annatto pigment. This is the same natural pigment that gives carrots it orange color.

Pasture fed cows that consume fresh grass produce whey with a higher beta carotene content. During the winter, a cow’s diet consists primary of hay. Hay contains less beta carotene, which results in a “whiter” whey.

At the end of the day, the nutritional quality is the same of whey regardless of the color. However, there is a perception that the lighter colored whey is higher quality, when in fact it only means that the cows had less beta-carotene in their diet at the time.