Although fat is the source of much delight in decadent dairy creations, it can harm our health. Thankfully, growing consumer demand for reduced-fat versions of our favorites is being met with rapidly expanding options to lower fat without losing flavor and mouthfeel. At 9 calories per gram, fat more than doubles the 4 calories per gram of protein and carbohydrates. Milkfat is a key factor in organoleptic characteristics, including texture, structure, bite and mouthfeel.
Texture is a combination of factors related to “structure,” including viscosity, gel strength and character (elastic vs. brittle); bite (resistance to shear by the teeth); and “mouthfeel” (creaminess and lubricity).
Structure affects a product’s physical characteristics. “Ice creams are less stable as they have more water that needs to be controlled, thus higher levels of stabilizer are added, resulting in higher viscosity during processing,” says Joe Klemaszewski, dairy applications food scientist, Cargill Texturizing Solutions, Minneapolis. “Higher levels of protein are sometimes present in reduced-fat sour creams. These products also have higher processing viscosity.”
Not only does mouthfeel affect our perception of the product and its flavors. Klemaszewski also notes that increased protein in sour cream, which leads to higher viscosity, also causes a higher buffering capacity. “This can adversely affect flavor, as the product is perceived as being more tart,” he says.
Fat acts as a carrier for fat-soluble flavors. Many flavors have different perception thresholds in fat and water media, so fat removal can dramatically reduce or increase the flavor amount required to deliver the desired impact. Butyric acid, a crucial component of butter flavor, requires 7 ppm to be detected in water, yet only 0.6 ppm in oil.
Fat’s mouth-coating effect delay or prolong flavor release. Fats may also mask flavors or delay release due to variations in evaporation coefficients for flavor compounds in oil and water. In both cases, fat removal can lead to major imbalances in flavor, plus it can lead to a sudden burst of flavor, replacing the slow and steady release in the full-fat version.
On the level
Whole milk has 3.35% fat. Dairy products, however, exhibit a far greater range. Federal guidelines require that ice cream contain a minimum 10% milkfat. Typical products range from 10% to 17% fat, while premium products may contain 20% fat.
Yogurt made from whole milk is at least 3.25% milkfat. “Low-fat yogurt” with low-fat or part-skim milk ranges from 0.5% to 2.0% milkfat. “Nonfat yogurt” is made from skim milk, delivering less than 0.5% milkfat.