Dairy Byproduct Enhances Cream Cheese Formulation

As the popularity of Greek yogurt has grown, so has the dairy industry’s acid whey problem. Da Chen, an assistant professor in the Department of Food Science at Purdue University, learned about the acid whey problem when he visited a local dairy company. “They produced a lot of acid whey and didn’t know what to do with it,” Chen says.

The company offered it to local farmers at no cost. Some used it as feed for cows, or as fertilizer. The structure of the acid whey makes it difficult to find uses for it, and it’s also a pollutant when it gets into ground water.

Sweet whey, another common dairy byproduct, is normally used to produce whey powder supplements, Chen explains. “But for the acid whey, it’s been a very big challenge for the dairy industry,” he says.

Chen led research into using an acid whey protein–based fat replacer that could replace whey protein isolate in cream cheese formulations. The researchers thought that concentrating the acid whey’s calcium and proteins could yield a soft, creamy cheese that required less heat to produce than conventional cream cheese. The research was funded in part by the U.S. Department of Agriculture (USDA).

Fat in cream cheese provides multiple benefits. It gives the cream cheese flavor and a smooth texture, and it increases yield. In addition, fat creates the internal structure of cream cheese and is the reason it melts when heated. The fat content of cream cheese is 30% or more.

Cream cheese is particularly popular in Europe, which makes about 10 million tons each year, and in the United States, which makes almost 6 million tons.

An Inexpensive Addition

The researchers obtained acid whey from a dairy and filtered it to concentrate the protein and calcium content. They heated it up so aggregates formed, which they collected and added to skim milk. They then followed the regular steps for making cream cheese by adding starters and rennet, which produced curd. They added salt and mixed it in.

They made a fat-free cheese with 1% acid whey. Full-fat, low-fat, and skim milk batches were made as comparison cheeses. The researchers made at least two batches of each sample. Because the acid whey has a high calcium content, which helps the cheese thicken, the mix required heating for just 15 minutes at 85°C.

The resulting cheeses were analyzed for moisture content and rheological qualities. And while the researchers didn’t try their cheese because it wasn’t food grade, they did use tribology tests to assess its smoothness. “Tribology actually mimics the frictions of food,” explains Chen.

They found that adding only 1% acid whey into skim milk created a creamy, smooth cream cheese similar to low-fat cream cheese. “[It’s] not as great as full fat, but we are a little bit better than the low-fat,” says Chen.

Chen’s lab is working on another project funded by the USDA’s National Institute of Food and Agriculture. It involves investigating the use of plant proteins to make fat replacers, similar to the work with acid whey.

The cream cheese findings are useful for the dairy industry, Chen says, because the methods the researchers used are simple and inexpensive to scale up to commercial levels. Their methods can increase yield and make a healthier cream cheese with a low fat content and increased calcium and protein content while putting an inexpensive, surplus ingredient to good use, thus also contributing to more sustainable food production.ft