A team of UW-Madison researchers have culminated over a decade of work with the discovery of the enzyme responsible for reducing the bitterness in cheese.
The process of cheesemaking really begins when \starter"" bacteria cultures are added to warm milk to help flavor and age the cheese. Often, the bacterium Lactobacillus helveticus is added to reduce bitterness and enhance flavor.
Using a novel technique to single out specific genetic traits, Jim Steele and his UW-Madison colleagues have identified the enzyme in Lactobacillus responsible for avoiding the development of bitter flavor. During this process, Steele's group sequenced almost all of the 2,400 genes in Lactobacillus.
Steele, a food scientist with the UW College of Agricultural and Life Sciences, and his group designed numerous so-called ""knockout bacteria,"" identical to the original strain except the gene needed to produce a particular enzyme. They tested and compared the strains, until found the ""bitterness"" enzyme that had been knocked out. For makers of cheese, this is a crucial development.
""If the bacteria in the starter culture produced this enzyme cheesemakers would save money and ensure a more consistent product,"" Steele said. ""Food processors need to be able to produce a consistent product--that's why they are very discerning of quality, much more so than consumers buying cheese.""
Mark Johnson, senior scientist at the Wisconsin Center for Dairy Research and team member, said this new discovery will reduce one of the major expenses in cheesemaking: the cost of storing cheeses. Cheddar takes six months to a year to age, some cheeses like Parmesan can take even longer and can turn bitter as they're aging. Producers are always looking for ways to increase their quality, but reduce the time their product is sitting around.
""Bitter-producing cultures tend to be fast acid producers. Slower cultures are less likely to produce bitterness,"" Johnson said. ""Economics dictate that cheesemakers need to make cheese fast, so what they need is a fast acid producer that does not produce bitterness.""
The discovery is music to any business' ears, much less cheesemakers--more time to create a better product. Noting that it takes at least a year to produce sharp aged cheddar, Johnson said, ""I can envision that one day cheese makers will be able to consistently produce any desirable flavor in any cheese and in a much shorter
period of time.""
According to Johnson, this same technique will be used in the near future to select various characteristics that can be singled out and eliminated for use. ""I'm really excited about the potential--before it was a trial and error process, now it will be a directed approach,"" Johnson said. ""Once they can be identified, [Steele] can find the enzymes that produce the flavor. It may lead us to identify a flavor component that we have missed or knew nothing about.""
""Using microarray technology, we will put the bacteria under cheese-like conditions and study which genes make proteins,"" Steele said. ""That will allow us to narrow down the number of genes involved in flavor production by at least ten-fold.""
Steele noted that much has changed in the 12 years he has been tracking down this enzyme.
""It's been a long tour to get where we're at,"" Steele said. ""It really is amazing how time changes, how scientific advancements have very rapidly changed. It's been fun to try to pick the needle out of the haystack.""
Steele credits UW-Madison's ""extraordinary environment,"" which allowed him to collaborate with other experts, such as Johnson, in this area of cross-disciplinary research.
""If you take a look at the expertise here related to dairy food and genomics, it's a fairly unique situation,"" Steele said. ""There's no other facility I can think of that would have all the resources we have.""
Steele said that once this technology becomes available to area cheese producers, they will immediately benefit from a product that is more consistent and can be stored for less time, keeping their advantage in a highly competitive global food market.
""In Wisconsin, it's important that we maintain an ecological edge in the area of cheese,"" Steele said. ""It's important that we make sure the technology here is as good as any place in the world.""
The group will soon be applying for a patent, and both researchers anticipate their new starter culture to be commercially available within two years.
If we have to wait that long for a brick of sharp cheddar, it's probably not too much to ask.
