New Process May Improve Taste of Lactose-Free Milk

Lactose-free milk comes in just about every variety that regular milk does - fat-free, 1% lowfat, 2% lowfat, whole, calcium-fortified, chocolate. You can use lactose-free milk as a straight one-for-one substitute for regular milk in any recipe. It's real milk, straight from the cow.

But there are two differences that affect the taste.

The first is that the lactose, the milk sugar, is split into two simpler sugars, glucose and galactose. By an oddity of chemistry each of the two simple sugars is sweeter than lactose is. Therefore lactose-free milk is slightly sweeter than regular milk.

The second is that lactose-free milk is made using a type of UHT pasteurization instead of regular pasteurization. UHT - Ultra-High Temperature - pasteurization cooks the milk at a higher temperature for a shorter period of time than regular pasteurization. The advantage is that UHT milk lasts longer before going sour than regular milk. Lactose-free milk doesn't sell in the same phenomenal quantities that regular milk does so it needs a longer shelf period. Some people, unfortunately, detect a slightly "cooked" taste in the lactose-free milk because of this.

Food researchers at Oregon State University (OSU) have developed a new food processing technique that provides the same long life without the "cooked" taste, according to the Research Notebook at the Portland Oregonian web site.

Michael C. Qian and his OSU co-workers say that ultrahigh-temperature pasteurization, or UHT, produces milk that stays fresh at room temperature for six months. However, UHT leaves a "cooked" flavor in milk.

The scientists describe how a new food processing technique affects milk taste. Called high hydrostatic pressure processing, it involves putting foods under pressures that crush and kill bacteria while leaving food with a fresh, uncooked taste.

"Milk processed at a pressure of about 85,000 pounds per square inch for five minutes, and lower temperatures than used in commercial pasteurization, causes minimal production of chemical compounds responsible for the cooked flavor," they said. "The processing gives milk a shelf life at refrigerated temperature of at least 45 days."

Their report will be in the Nov. 29 issue of the Journal of Agricultural and Food Chemistry.

When or if this technique makes it to store shelves remains unknown, but it's something to look forward to.