Culture Splash: Fermented Dairy Beverages

By Kimberly J. Decker, Contributing Editor

The list of global fermented dairy drinks runs to dozens of entries from at least as many countries, taxing the pronunciation skills of even the most multilingual among us. Danish kærnemælk and Polish zsiadle mleko sidle up against Rwandas ikivuguto and Irans doogh. Meanwhile, Scottish blaand leaves one wondering whether its name reflects its Viking origins or stands as a commentary on the fermented whey beverages flavor.

That so many cultures across so many generations could embrace so many variations on spoiled" milkand that they continue to do so long after refrigeration and GMPs brought spoilage under controltestifies not only to the universality of these beverages, but to the palates ability to adapt to what nature (and lactic-acid bacteria) throw its way.

And though todays fermented dairy drinks are a far cry from their ancestors in everything from flavor profile to processing, product developers still build upon time-tested traditions in their formulations. Get the details right and these 21st-century cultured beverages will stand the test of time, too.

Come a long whey

To grasp just how diverse the world of cultured dairy drinks is, consider the difference between, say, a Danimals Rockin Raspberry smoothie and Central Asias beloved kumis: The former is sweet, fruity and designed to pacify Juniors taste buds; the latter is alcoholic, fizzy and made from mares milk. What more need we say?

To be sure, notes Mukul Juneja, product manager, Givaudan, Cincinnati, Outside the United States, most traditional drinks are not as sweet" as the yogurt beverages common in our own supermarkets. But even this distinction may evaporate as more cultured dairy products drift toward a generalized Western-style sweetness.

A case in point is Indian lassi, which Juneja says is traditionally tart like yogurt and prepared simply with salt, pepper and maybe some cumin." But, he continues, The more modern versions have more sugar added. And now the most popular versions are fruitier."

Cultured dairy drinks have evolved in other ways, too. On the plus side, theyre more consistent. One of the necessities of mass production for recognizable commercial brands, as opposed to traditional homemade or cottage industry, is consistency," Juneja says. That is probably one of the most significant areas of improvement."

We can trace a good chunk of that improvement to the widespread use of specially selected and cultured fermentative strains that replace the starters" small-scale producers would harvest from one days production for use in the next. Now we have companies dedicated to developing proprietary strains of microbial cultures designed to be stable in modern manufacturing facilities," Juneja says.

Theyre also fine-tuned to enhance in the drinkable-dairy medium. According to Jonathan Hopkinson, Ph.D., senior applications scientist, DuPont Nutrition & Health, New Century, KS: Generally, lower-viscosity cultures are used. They make acid and flavor, but produce fewer exopolysaccharides," which are the large polymers that can overwhelm the texture of a drinkable product. With fewer exopolysaccharides, you get a decrease in viscosity, and your drinkable yogurt stays drinkable.

Standard time

As for which cultures were actually allowed to use in yogurt drinks, the Code of Federal Regulations (CFR), surprisingly enough, has nothing to say. In fact, the CFR doesnt specify standards of identity for yogurt drinks, at alllet alone for smoothies." But dont go taking that as a signal to label liberally, as the yogurt portion of any yogurt drink" labeled as such must fit the federal definition of yogurt.

That means it must contain the lactic acid-producing bacteria Lactobacillus bulgaricus and Streptococcus thermophilus, and a minimum of 3.25% milkfat, 8.25% milk solids not fat and 0.9% titratable acidity (expressed as lactic acid) prior to the addition of bulky flavors. These standards, laid out in greater detail in 21 CFR 131.200, also apply to yogurt-and-juice-based smoothies, while milk-and-juice blends are permitted to contain any directly acidified milk product.

This still leaves manufacturers substantial room to differentiate their products. As Kimberlee (K.J.) Burrington, dairy ingredient applications coordinator, Wisconsin Center for Dairy Research (WCDR), University of Wisconsin-Madison, says, You can find levels of fat ranging from nonfat to full fat, but protein levels dont vary a lot." Sugar levels are lower in light" beverages, she continues, but higher in meal-replacement types; as for total solids content in drinkable yogurt, its lower than in spoonable.

Furthermore, according to the article Culturally Speaking: Making Yogurt Drinkable" published in the June 2004 issue of Dairy Foods, fruit content can rise as high as 30% in these products. While flavor levels vary, natural fruit flavors usually come in at between 8% and 15%. And, given the variety of stabilizer options and functionalities, their levels also fluctuate, with a spread from 0.01% to 0.5% not uncommon.

Keeping it together

Stabilizers might just be the linchpin to the industrys ability to produce reliable, acceptable, consistent drinkable yogurts; like streamlined cultures, they represent a technology leap that has boosted cultured dairy to a more advanced stage of maturity.

The appearance of the traditional product often included considerable whey on top of a casein layer," Hopkinson says. "With the advent of stabilizers, this separation is a thing of the past." To make sure it stays a thing of the past, formulators can use negatively charged hydrocolloid stabilizers, like high-methoxy pectin, which interacts with the positively charged casein proteins to keep them from aggregating and squeezing out the whey.

Hopkinson stresses the importance of dispersing the pectin thoroughly during the homogenization of the yogurt masswhich is the one step in drinkable yogurt production that most diverges from that of its spoonable cousin. While the goal with cup-set yogurt is to protect the coagulated mass, yogurt drinks go through a final homogenization that reduces their particle size and distributes their stabilizer systems.

The greatest challenge in manufacturing drinkable yogurt, Hopkinson says, is getting people to add the slurry of pectin and sugar at the proper timeafter fermentationand then homogenize with the right shear."

Stabilizing sensory appeal

Stabilizers arent all about stability, of course. Theyre also tools for achieving proper drinkable yogurt texture. As Donna Klockerman, Ph.D., dairy food scientist, TIC Gums, Belcamp, MD, says, The texture characteristics of drinkable yogurts are controlled by a combination of processing parameters and stabilizer systems."

Harold Nicoll, marketing manager, TIC Gums, believes that such textural manipulation is one way that developers can manage how consumers experience these drinks." He says the company developed a stabilizer to accommodate the single-step processing that some smoothie manufacturers prefer. It allows manufacturers to adjust finished-beverage viscosity toward either the thicker, heavier-bodied smoothies that have emerged as consumer favorites, or the original thin-bodied drinkable yogurts," he says, adding that the stabilizer helps impart the creamy, smooth mouthfeel and texture associated with high-quality drinkable yogurts, and also allows for superior flavor release."

Which underscores another fact: Stabilizers are flavor, as well as textural, tools. As Klockerman explains, they influence the delivery of sweet yogurt and fruit flavors through control of sipping-suction resistance, the texture inside the mouth and the experience following swallowing." She adds that manufacturers can match their drinkable yogurts texture to different flavor combinations of sweet and savory to deliver the desired finished-product characteristics."

How sweet its not

The improvements weve seen in flavor are another area where technology has advanced significantly," says Scott Harris, segment head, Givaudan. He points to the ability of flavor ingredients to deliver a very complex profile that, in some cases, would have been impossible in some parts of the world in the past, especially in areas where weather didn't allow access to a vast variety of fruits."

But flavor may in fact be holding drinkable yogurts back. Despite the strong, uninterrupted growth" the broader yogurt category has enjoyed over the past five years, according to Mintels "Yogurt and Yogurt DrinksUSAugust 2012," 58% of U.S. adults eat yogurt an average of 7.5 times a month. Drinkable yogurts food, drug and mass-merchant sales for 2010 will just surpass $300 million, down one-third from 2006, according to Mintel data," Nicoll notes.

Why? Harris and others postulate that excess sweetness may have something to do with it. Health and convenience certainly attract people to drinkable yogurts," he says, but most of the products in the past have been too sweet and very high in total calories." That may be changing, though, as the acceptance of Greek yogurt and the move in foodservice away from frozen yogurt that tastes like ice cream to that with a more tart yogurt profile means that consumer recognition and demand will change," he says.

Going with the grain

Beyond flavor, product developers are bringing new attention to drinkable dairy via other innovations. For example, Harris raises the banner of health as a strategy that can attract more consumers to drinkable yogurts; after all, its what brought so many to the category in the first place.

Cultured dairy drinks inherently have live bacteria for gut health, but modern technology allows us to advance the benefits to a much higher level, where targeted strains can deliver unique benefits like a boost in immunity," Harris says. Health-focused drinkable products, such as probiotic shots designed to target specific health benefits, may grow in the future as consumers look to food and beverages to fulfill their needs for healthier lifestyles."

Harris praises kefir, in particular, for adding excitement to the drinkable yogurt shelf. But kefir is actually an ancient beverage with a tradition rooted in the herding societies of the North Caucasus. As the story goes, shepherds noticed that the fresh milk they carried in leather pouches would ferment over time and develop a light carbonation. We now know this results from the fermentative action of kefir grains," which are actually not grains at all, but lumpy little clumps of bacteria, yeasts, sugars, proteins and lipids.

Twenty-first century kefir producers eschew the old-fashioned grains and opt instead to use controlled starter cultures that produce the predictable flavor, texture, health benefits and quality that commercial manufacturing requires. Nevertheless, producers like Lifeway Foods, Inc., Morton Grove, IL, stress that their products are still made in the genuine kefir tradition.

 Kefir is cultured for 14 to 16 hours, whereas most yogurts are cultured for just two to three hours," says Fallon Fleyshman Morgan, operations director, Lifeway Foods, Inc. Its that extra time that gives kefir its high probiotic activity count7 to 10 billion CFUs per servingand its delicious effervescent taste."

Fleyshman Morgan says the companys kefir contains 12 different strains of probiotic cultures that may boost the immune system and help the digestive system." The company raises the stakes with a probiotic blend that delivers 20 billion units of probiotic activity in each bottle," per the companys website.

The blends organisms are Bifidobacterium lactis, which can aid immune and digestive health by encouraging a beneficial intestinal microflora, and Lactobacillus reuteri, which in clinical studies has shown the ability to increase the activity of natural cells that kill harmful bacteria and the phagocytic activity of peripheral blood mononucleotides," among other benefits the website lists.

Our top flavors are strawberry, blueberry, plain, pomegranate, peach and raspberry," Fleyshman Morgan says. Pomegranate shot through the rankings when antioxidant and pomegranate research came out as being super-beneficial to the body. The same is now happening with our açaí flavors. We have an organic pomegranate-açaí kefir that is doing very well." Echoing Harris, she notes that public acceptance of Greek yogurt is rubbing off on the companys plain kefir, too, which is becoming hugely powerful. There is no added flavor or sugarjust the cultured milk. Its very tart and tangy and is delicious when mixed with fruit or honey."

Sounds like it might make a good breakfastand, as Burrington points out, thats exactly what kefir often does. Some people put kefir on their cereal instead of milk," she says. Drinkable yogurts are sold in Europe in large cartons for that purpose." Perhaps thats another way to focus consumers radars on the growing, improving range of cultured dairy drinks.

I think you could position a yogurt drink as a breakfast beverage to get your day started right," Burrington says. There are a lot of people who might not drink a glass of milk, but might drink a yogurt."

Kimberly J. Decker, a California-based technical writer, has a B.S. in consumer food science with a minor in English from the University of California, Davis. She lives in the San Francisco Bay Area, where she enjoys eating and writing about food. You can reach her at [email protected].

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