Dairy Ingredients: Milk's Magic
July 01, 2009
by Donna Berry
Dairy ingredients such as nonfat dry milk, lactose and whey have long been used invisibly in many baked food applications. Today’s innovative bakers are learning how modified versions of these standard dairy ingredients can assist in the manufacture of baked foods ranging from artisan breads and scones to nutrition bars and whole-grain snack cakes.
At the 2009 IFT Annual Meeting + Food Expo in June in Anaheim, CA, Hilmar Ingredients, Hilmar, CA, showcased an 80% whey protein concentrate (WPC) in an Italian herb biscotti. This specific 80% WPC is designed to improve texture in bakery products by controlling moisture, maintaining volume and emulsifying fat. The dairy ingredient also reduces dough stickiness, enhancing the processing and/or handling characteristics of high-protein bakery formulations. This particular prototype contained 11 g of carbohydrates, 3.5 g of fat and 8 g of protein in a single 35-g serving.
Hilmar also offers an innovative whey protein hydroylsate (WPH) for use in bar applications. The hydroylsate has the ability to modify the texture of nutrition bars, making them softer and more pliable. WPH is derived from fresh, sweet whey (the by-product of making rennetcoagulated cheeses such as Cheddar and Swiss) produced using a special cross-filtration process. The concentrate is then enzymatically hydrolyzed to produce a mixture of peptides and free amino acids with enhanced functional and nutritional benefits, according to the company.
New Zealand-based Fonterra, with US offices in Rosemont, IL, launched a new range of concentrated dairy proteins for the nutrition bar market. The company claims these ingredients solve the discoloration, texture and shelflife issues associated with traditional proteins. The problem with high-protein bars is that the protein absorbs moisture from the rest of the bar, and over time, the bars get hard and sometimes turn an undesirable brown color. The texture can also be chalky and powdery.
The range includes a WPC and milk protein concentrate (MPC) designed to replace ingredients such as calcium caseinate, WPH and total milk proteins. The company said that unlike these traditional proteins, the new ingredients have a less chewy texture and do not harden or become brown over time.
MPCs are produced from skim milk by a series of processes that includes ultrafiltration, evaporation and drying. MPC contains undenatured forms of both milk proteins: casein and whey. The level of protein, lactose and minerals present varies depending on the degree of protein concentration, which can be modified by the mem- branes used during ultrafiltration. Although ultrafiltration is the preferred method for extracting MPC, it also can be produced by precipitating the proteins out of milk or by dry-blending the milk proteins with other milk components. Depending on how MPC is produced, costs may vary and, more important, functionality may differ.
Commercially, MPCs, which are white to light-cream-colored dry powders, range in protein levels starting at about 42% and going to 85%. As the protein content of MPCs increases, the lactose level decreases. For example, MPC42 is 42% protein and 46% lactose. MPC80 contains 80% protein and 5% lactose. For comparison, skim milk powder (SMP) contains about 35% protein and 52% lactose. Although they share similar form and function, MPC and SMP act differently depending on the application.
As mentioned, whey is the by-product of cheesemaking and has long been viewed simply as something that was disposed. Whey has come a long way, and in some instances, cheese is produced for the sake of making whey.
Today, whey is processed into a number of food-grade ingredients. Its valuable protein components are isolated and used for both functional and nutritional fortification of all types of foods, including baked foods.
Now a new by-product is gaining recognition in the baking world — whey permeate — or, what is left over after whey has been processed into specialty protein ingredients such as WPC, which ranges in protein content from 34 to 90%, and whey protein isolate (WPI), which provides 90% or more protein.
During ultrafiltration and diafiltration, whey proteins are retained by the filtering membrane because of their larger size and processed into WPC and WPI. Lower molecular weight whey components, such as lactose and various minerals including calcium and phosphorus, pass through the membrane 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 any residual protein is removed from this powder, along with a small amount of lactose and minerals, the remaining powder is whey permeate.
“Whey permeate can deliver enhanced functionality and organoleptic characteristics that make it a useful and versatile bakery performer,” said K.J. Burrington, dairy ingredient applications coordinator at the Center for Dairy Research at the University of Wisconsin, Madison, WI.
The composition of whey permeate varies by milk source, cheese type and processing conditions. Permeate contains only trace amounts of protein; however, many commercial specifications list protein content around 3.5 to 5%. This discrepancy is due to the dairy industry’s tradition of calculating protein contents by testing for total nitrogen, which, in the case of permeate, is largely non-protein nitrogen rather than true protein.
“The main component of whey permeate is lactose,” Ms. Burrington said. “This lactose contributes to an enhanced surface browning in many baked foods.”
Lactose, a reducing sugar, enters into browning reactions with amino acids (Maillard browning). It also caramelizes readily under the influence of oven heat. Although a sugar, lactose is not very sweet. In fact, it has a sweetening power of only 16 compared to 100 for sucrose in a 1% aqueous solution.
Lactose is also less soluble than either glucose or sucrose, and crystallizes more readily than either of these sugars. It is unfermentable by yeast and thus survives the dough fermentation unchanged and undiminished. Bakers have long added small amounts of lactose to doughs and batters, either directly or indirectly through the addition of dairy ingredients. Now whey permeate is another one of those indirect options.
“We are also discovering that the minerals in whey permeate provide a salty perception, while only contributing a minute amount of sodium,” she said.
Permeate contains less than 1% sodium and, thus, can positively influence the Nutritional Facts label.“In fact, in some baked foods, it has been possible to not add any salt to the application and still have a tasty product,” Ms. Burrington pointed out.
Further, whey permeate provides a cost savings when it substitutes for more expensive ingredients. Research shows that a significant amount of permeate (5 to 8%) can be used in muffins, scones or cookies, resulting in products of similar or superior quality to those formulated using nonfat dry milk. For example, in chocolate chip cookies, flour and egg are kept constant, but using 6% whey permeate allows for a reduction in more expensive ingredients such as sugar and shortening. 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 with comparable benefits.
Because whey permeate contains very little protein, in applications such as traditional cakes and quick breads where protein is critical to the structure of the finished product, permeate is not a good substitute for other more costly ingredients. However, there are opportunities for permeate in low-fat or whole-grain cakes or quick breads, especially those containing high amounts of fiber.
“In one prototype, almost 8% whey permeate was added, which allowed for a reduction of more expensive ingredients across the formula in proportion,” Ms. Burrington said.
Denmark-based Arla Foods, with Arla Food Ingredients offices in Basking Ridge, NJ, has a new range of whey permeates that provide a mild sweet, dairy flavor and have low hygroscopy (absorption of water). These free-flow permeates have a 96% lactose content, which is responsible for the favorable flavor profile. The high lactose content also allows for higher dosage levels than other permeates, which often have an off-taste at high levels.
Being able to use more permeate can provide additional cost savings, as it can replace other fillers that are more expensive, such as pure lactose, whey powder, maltodextrin and dextrose. The low-hygroscopy attribute makes it easier to handle on the production line because it does not clump and accumulate inside the machinery, thus reducing the need for cleaning.
Arla sees permeate as gaining more importance in the food industry, given the battle against high raw material prices. As demand has grown for whey permeates, Arla has sourced more raw materials through external partnerships. For example, Arla has an agreement with Norwegian dairy firm TINE to expand its capacity of WPCs. TINE had previously sold the whey generated by its cheese operations as animal feed. But a new plant refines it into WPC for the food and nutrition industry, which commands a higher price.
The dairy ingredient industry continues to invest in technologies to enhance product performance and to position dairy ingredients as an economical formulating tool for bakers.