Lactose-Free Milk Still a Work-in-Progress

It's easy to find descriptions of lactose-free milk telling you that it's exactly like regular milk except without the lactose.

That's true. With an asterisk.

The differences between lactose-free and regular milks are tiny. Lactase is used to remove the lactose, breaking it down into the simpler sugars glucose and galactose. Because of a quirk in sugar chemistry - though some would say sugar chemistry is all quirks - each of the simpler sugars individually is sweeter than lactose. As a result, lactose-free milk itself is slightly sweeter than regular milk (although it has the same number of calories). Good for getting kids to drink their milk, less good for adults and for certain recipes.

The other change is more of an issue in the U.S. than elsewhere. Regular milk doesn't sit in the dairy case for very long. Turnover is extremely high, so dairies can afford to use regular pasteurization rather than what is called UHT (Ultra High Temperature) pasteurization or just plain UP. UHT milks last much longer without going bad. They're the norm in many places of the world but not in America. Although techniques keep getting better, regular milk drinkers might notice a slight "cooked" taste to lactose-free milk.

And they do. A study, Sensory characteristics of commercial lactose-free milks manufactured in the United States, Koushik Adhikari et al. in the journal LWT - Food Science and Technology, used both a specialist and a consumer panel to check the differences.

This study determined the sensory characteristics of ultrapasteurized (UP) lactose-free milk of different fat contents, and compared them with regular milk. Nine milk samples (six UP lactose-free and three regular) containing 0, 2 or 3 g milkfat/100 mL were tested by a descriptive panel. A consumer test with three UP lactose-free milk and three regular samples was also conducted. The skim milks were found to be lacking in freshness and the dairy notes were lower compared to the higher-fat-content milks. The UP lactose-free milks were different from the regular milk because of higher intensities of cooked, processed, and sweet attributes. UP lactose-free milks tended to score higher than the regular milks at the same fat content for dairy-related attributes, but this difference was not significant for the reduced-fat milks. Although majority of the consumers in the present study were aware that UP lactose-free milks existed in the market, only few had tasted them before. The higher intensities of cooked and sweet flavor attributes in the UP lactose-free milks might be a hindrance to their consumption by the lactose-intolerant population. More efforts are needed from the dairy industry to develop better lactose-free products and to educate consumers about lactose-free dairy products.

An article by Caroline Scott-Thomas on the study in the Dairy Reporter gave more bad news.

The lactose-free varieties were also described as having more chalkiness, less freshness, more cooked flavors and higher viscosity.

Scott-Thomas says the market for lactose-free milk has increased 20% since 1997. While that may sound good, it falls far short of the explosion in other specialty foods, like gluten-free. It's not clear whether the problem is that most adults with lactose intolerance don't drink any milk at all, whether they settle for regular milk with or without lactase tablets, or whether they would buy more if lactose-free milk tasted as good as regular milk. Making it better certainly couldn't hurt. That's a goal for the food scientists to aim for.