By Kathy Nelson, Wisconsin Center for Dairy Research

This article was adapted from a piece originally appearing in volume 17, number 4, of the Dairy Pipeline newsletter produced by the Wisconsin Center for Dairy Research, University of Wisconsin-Madison.

Whey proteins have risen from obscurity to ordinary use, finding a niche in everything from sports drinks to cake mixes. Can whey permeate find the same success?

It’s possible. Whey permeate offers many benefits to food and beverage manufacturers, including bakers. In items ranging from scones to cakes, whey permeate can deliver enhanced functionality and organoleptic characteristics that make it a useful and versatile bakery performer.

Sources of whey permeate
During ultrafiltration and diafiltration, whey proteins are retained by the filtering membrane due to their larger size. Meanwhile, substances of lower molecular weight, such as lactose and minerals, pass through the filter and become the permeate stream. Once moisture is removed from the liquid permeate stream, an off-white, free-flowing powder with a mild dairy flavor remains. After the protein (plus some lactose and minerals) has been removed from this powder, the remaining collection of substances is called whey permeate. Other names are dairy products solids, deproteinized whey or modified whey.

The main component of whey permeate is lactose. This lactose content dictates permeate’s ability to improve the texture of baked products, affect their appearance and color, extend sweeteners or shortening, and provide such dairy minerals as calcium and phosphorus.

The composition of whey permeate varies by milk source, cheese type and processing conditions. Cow’s milk is typically used for cheesemaking in the United States, and the most common cheeses produced are cultured cheeses, such as Cheddar or mozzarella. Whey from these sources is known as “sweet whey.” Other things that can influence permeate composition include the filtration, evaporation and spray-drying processes used. (Table 1 from the U.S. Dairy Export Council below shows typical composition of food-grade permeate from sweet whey.)

Permeate’s benefits to bakers
In baked products, whey permeate can offer many benefits, such as enhanced surface browning and flavor development, moisture retention and development of a tender crumb structure. Permeate’s naturally salty flavor also means salt can often be reduced or eliminated in a formulation. Permeate does contain about 0.6% sodium and can positively influence the nutritional label. For example, in the scone formulation below (see Example 1), both the nonfat dry milk (NFDM) and permeate offer similar sodium levels. Eliminating the salt can improve the nutritional label by cutting sodium content.

A significant amount of permeate (5% to 8%) can be used in such products as muffins, scones or cookies, resulting in products of similar or superior quality. For instance, in cookies, flour and/or egg are kept constant to supply the needed structure while reducing sugar and fat in the formula. Cookies containing permeate tend to be crispier, with a shorter texture as well as more browning and spread. Other products, such as pie crust, would employ a similar strategy and result in similar benefits.
 
Cakes or quick breads present a greater challenge, since protein is critical to the structure of the finished product and permeate cannot contribute any structural material. For this reason, permeate is most successfully used in lowfat or whole-grain cakes or quick breads, especially those with fiber. The whole-grain snack cake (see Example 3) is one such application. The strategy in this case is to choose a target amount of permeate and replace ingredients across the formula in proportion.



Table 1.

Component                 Sweet Whey Permeate (Powder)(%)

Lactose                          65.0-85.0

Protein*                          3.0-8.0

Ash                                8.0-20.0

Fat                                 <1.5

Moisture                         3.0-5.0

Calcium                          0.75-0.90

Phosphorus                     0.70-0.75

*Please note that permeate contains only trace amounts of protein. Commercial specifications, however, typically list protein content around 3.5% to 5%. The discrepancy is due to dairy industry testing for total nitrogen, a number that is then automatically multiplied by 6.38. The nitrogen found by testing is largely non-protein nitrogen (NPN), rather than true protein. Examples of NPN compounds found in milk and whey include urea, creatine, creatinine, uric acid, orotic acid and ammonia.

Example 1. Permeate in scones

Ingredients	Control Formula (%)	Permeate replacement of NFDM (%)	Permeate replacement of Egg + NFDM (%)
Flour, All-purpose	50.00	50.00	50.00
Water	18.97	18.97	25.86
Butter	10.34	10.34	10.34
Whole Fresh Egg	9.48	9.48	-
Sugar	6.90	6.90	6.90
Whey Permeate	-	2.07	4.66
NFDM	2.07	-	-
Baking Powder	1.72	1.72	1.72
Salt	0.52	0.52	0.52
TOTAL	100.00 %	100.00 %	100.00 %

Ingredients	Control Formula (%)	Permeate Formula (%)
Flour, All-purpose	27.54	27.54
Butter, Unsalted	19.84	16.61
Semi-sweet Chocolate Chips	14.86	14.51
Brown Sugar	14.33	13.11
Granulated White Sugar	12.59	11.36
Whole Fresh Egg	9.62	9.62
Whey Permeate	-	6.03
Salt	0.52	0.52
Bicarbonate of Soda	0.40	0.40
Vanilla	0.30	0.30
TOTAL	100.00 %	100.00 %

Example 3. Permeate in whole grain snack cake

Ingredients	Control Formula (%)	Permeate Formula (%)
Dried Fruit	14.44	13.33
Applesauce	14.07	12.98
Quick Oats	13.69	12.63
Honey	13.32	12.28
Flour, all-purpose	12.58	11.60
Whole Fresh Egg	8.44	7.78
Whey Permeate	-	7.78
Brown Sugar	6.75	6.23
Walnuts, chopped	6.00	5.53
Bran Flakes	4.69	4.32
Canola Oil	4.13	3.80
Sesame Seed	1.50	1.38
Baking Powder	0.28	0.26
Ginger, Ground	0.11	0.11
TOTAL	100.00 %	100.00 %