Author Topic: Article: Advancements in Yeasts  (Read 4543 times)

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Article: Advancements in Yeasts
« on: July 17, 2009, 05:19:52 PM »
I have copied and pasted below a recent article from the BakingBusiness.com website on recent advances in yeast products used for baking applications:

Accounting for Choices
Bakers yeast improves its delivery modes and performance characteristics.

(Baking & Snack, July 01, 2009)
by Laurie Gorton 

This is not your father’s bakers yeast. Two big changes in this ingredient characterize what’s now available to producers of grain-based foods — not changes in the single-celled organism responsible for fermenting doughs, but in the way it is delivered and in the expanding palette of strain characteristics from which to choose.

"The days of providing a generic ‘off the shelf’ fermentation solution are long gone," said Steve Bright, technology manager, AB Mauri Fleischmann’s, Chesterfield, MO.

CREAM OF THE CROP. In the decade since its introduction, cream yeast now dominates in wholesale production of bread. Dean Modglin, director of sales, wholesale bakeries, Red Star Yeast Co. LLC, Lesaffre Yeast Corp., Milwaukee, WI, estimated that cream yeast accounts for 75% of yeast sold by the company and for good reason. "Cream yeast is consistent," he said. "Its gassing activity is adjusted at load-out from the manufacturing plant, so it shows increased consistency compared with crumbled or block yeast.

"Cream yeast is a necessity for the big bakers," Mr. Modglin continued. "It enables them to use a closed-loop ingredient handling system with automatic delivery of the yeast directly to drop points at the mixers." Sanitation, always a concern with yeast, improves because cream yeast is handled in the bakery by a tank system with automatic clean-in-place capacity, and there are no bags to open and discard.

The huge jump in usage of cream yeast by larger bakers was also noted by Scott Miller, National Yeast, St. Louis, MO. (National Yeast is partnered with Minn-Dak Yeast Co., Wahpeton, ND, and USA Yeast Co., Hattiesburg, MS.) "Most of the automated bakeries now use cream yeast," Mr. Miller said. "Most are conversions, but nearly every new bread bakery is built with automated ingredient handling capability, and that includes cream yeast."

DRIVING CHOICE. "Yeast doesn’t always get its due respect," Mr. Miller said. He noted a current big push to differentiate bakers yeast products by increasing their value to the customer and gave as examples the highly specific needs for yeasts suitable for frozen dough or high-sugar breads. "Such characteristics are driving the changes in baker yeast products," he stated.

Mr. Bright reported, "Our customers are becoming more sophisticated and their needs more specialized, and our R&D experts spend a considerable amount of time and effort to provide for the bakers’ needs."

"The proliferation of choices for bakers yeast results mainly from a compromise between the costs (in use) and the benefits of differentiation," said Jan Van Eijk, PhD, research director, Lallemand, Montreal, QC.

Lean-dough yeast strains, cited by Dr. Van Eijk as an example, perform better than regular bakers yeast in formulations low in sugar and without mold inhibitors, while high-sugar strains suit high-sugar products that also contain calcium propionate. "Most fresh yeast used in North America is a compromise between lean and sweet dough performance using a single yeast strain," Dr. Van Eijk observed. Additionally, the company supplies Eagle VitaD bakers yeast, an active yeast that is also a natural source of vitamin D, which he described as "a true nutritional benefit for the baker to provide to the consumer."

Why are there so many bakers yeast choices? Arnaud Deniaud, director, technical services, Red Star Yeast/Lesaffre, answered, "Bakers started to realize yeast could be adapted to specific applications. The choices now answer needs in terms of formulation and production needs such as osmo- and sugar-tolerant styles. The stresses on bakers yeast are not the same when viewed in light of the baking formula and process, fresh versus frozen, sugar-free versus high-sugar, preservative-free versus preservative included."

For example, sugar tolerance is a quality needed in the Hispanic market, particularly for production of sugar-rich conchas, the signature bread offered by most panaderias. "You can use regular bakers yeast, but you’ll get more consistent results with a sugar-tolerant variety," Mr. Deniaud said.

Flavor plays a role, too. Mary Fitzpatrick, director of sales, bakery and food service, Red Star Yeast Co., said that customers in the fresh pizza market prefer the yeasty flavor contributed by active dry yeast (ADY). Because of the way ADY is made, it contains a percentage of dead yeast cells. "These give the yeasty flavor that is so highly desired by that customer base," she said.

The newest style is an instant active dry yeast (IADY) with improved gassing powers, SAF-Instant Premium, introduced a few weeks ago. Ms. Fitzpatrick explained that the product is a new strain of bakers yeast that allows the baker to use about 30% less yeast than other IADY products yet achieve proper fermentation and leavening action.

"This yeast has more activity, more gassing power," Mr. Deniaud added. "With it, we have tried to solve some of the issues with IADY, one of these being sensitivity to cold water." In making doughs that will be retarded or refrigerated to make items such as Danishes and croissants, bakers want to use the coldest water possible, opting for ice-cold temperatures. The strain chosen for the new product shows more resistance to cold than regular bakers yeast, including other IADY and active dry yeast forms.

Tolerance of bakers yeast to the presence of mold inhibitors takes on increasing importance. "The baking industry is increasingly raising the bar of shelf-life expectance," Mr. Bright said. "As a result, we have seen higher levels of preservatives being used, and it is critical that the yeast activity is constant, regardless of preservation levels."

BENEFITS SOUGHT. "Consistency is key," Mr. Miller stated. "Desired performance level can be customer-specific, but the common thread is consistency."

"The industry expects consistency," Mr. Bright said. "This has never been more true than today where tolerance and timing are critical."

Consistency starts with the manufacturing process, and managers at Lesaffre called attention to a significant change in their company’s methods. "The greatest move to achieving improved consistency from our Red Star products happened when we switched to corn sugar as a pure source of carbohydrates at our Cedar Rapids plant," Mr. Deniaud said. "Molasses is a raw material that varies a lot. At our other plants, we use a blend of cane, beet and corn sugars, but Cedar Rapids is 100% corn sugar. Because that raw material is very consistent, it allows us to make a consistent product."

Consistency also refers to how the yeast handles at the bakery, as Dr. Van Eijk observed, noting that compressed yeast must be easily crumbled without being gummy and that all forms of yeast must be easily dissolved in water without leaving grit or producing foam. Other desired characteristics depend on application and include stability in refrigerated storage as well as in dry mixes, expected taste and flavor, cryo-resistance in frozen doughs, dough relaxing effect and nutritional benefit. With so many qualities sought, no wonder there are so many styles of bakers yeast available today.

All yeast suppliers work diligently to assure consistent performance from their products. As Mr. Bright explained, "Globally, we developed a proprietary testing system that allows us to look at the gassing activity under very controlled conditions. Our plants all over the world take part in audits whereby each plant tests a standard sample of flour, yeast, salt and sugar for analysis and comparison."


The Good Performer

Saccharomyces cerevisiae‘s broad genetic diversity sets the stage for it to play many roles in grain-based foods. The strains selected for use as bakers yeast must demonstrate their benefits not only in wheat flour doughs but also in the yeast manufacturer’s production process.

How do manufacturers choose the strains to propagate for bakery use? "Commercial potential matters the most," said Scott Miller, National Yeast, St. Louis, MO. "The product has to be versatile and accommodate a broad range of applications. And it needs to be viable throughout the process, which includes our manufacturing plants as well as the bakery customers."

Lesaffre supports a global R&D group that meets during the year to assess "field intelligence" — "The things we hear from our customers and the hands-on experience we have with our products as they are used by our customers, who range from small pizza shops to large wholesalers," said Mary Fitzpatrick, director of sales, bakery and food service, Red Star Yeast Co., Milwaukee, WI. "We evaluate the opportunities based on the size of the markets and their needs to determine which of our projects will get top priority."

"Providing value for our customers is our mantra," said Steve Bright, technology manager, AB Mauri Fleischmann’s, Chesterfield, MO. "Strain development and screening is an arduous and expensive proposition." A new strain’s potential must first be identified in the lab along with its ability to be commercially propagated. "It is very rare when we are able to identify a strain that gives both good commercial propagation qualities for the yeast manufacturer and fermentation characteristics for the baker."

Source and breeding matter, too. "The US and European baking industry have spoken loud and clear against genetically modified yeast," Mr. Bright observed, "so our research is always focused on using classic methods of strain discovery and screening."

Specific values that guide the screening process include, according to Jan Van Eijk, PhD, research director, Lallemand, Montreal, QC, high, but consistent, gassing activity and tolerance to sugar, propionate, cool temperatures and freezing conditions as well as efficient manufacturing capability (no special nutritional needs, high yields, ease of filtering) at the yeast processor.

"But as a first consideration, research and selection are driven by the market needs," said Arnaud Deniaud, director, technical services, Red Star Yeast/Lesaffre.

In recent years, bakery customers challenged their yeast suppliers to innovate along a number of interesting vectors. Mr. Deniaud noted that whole-grain formulations was "a different story for us." He reported development work with a cool-start yeast, another with greater gassing power and a yeast that would remain stable when blended directly with other dry ingredients in bakery mixes.

"It takes a long time — up to 10 years — to develop a new yeast from strain to commercial product," Ms. Fitzpatrick said.