Baking&Snack - July 2012 - 54

ENZYMES

How enzymes work

Basically, enzymes speed up chemical reactions. This special class of proteins catalyzes such activity by bringing reactants together rather than relying on the natural pace of a chance meeting of molecules. To do this, a specific enzyme complexes with a specific substrate, much as a key fits into a lock. After the desired reaction occurs, the enzyme is released unchanged along with the altered substrate. The enzyme continues to function in this manner until it is deactivated, or denatured. Such a shutdown can occur from exposure to heat, as in baking, or by a forced chemical alteration, as when pH changes.

Emerging enzymes enable high-speed production of bread while eliminating chemicals from the ingredient listing.
DuPont Nutrition and Health

Addition of lipase improves the stabilizing functions of lipids, allowing them to act as natural emulsifiers.
Lallemand

organisms themselves,” said Jan van Eijk, PhD, research director, baking ingredients, Lallemand, Montreal, QC. They occur naturally in many bakery ingredients. But often, bakers find it most beneficial to supplement a batter or dough’s native enzymes content to maximize their functionality in a specific application. “Each enzyme functions best at its own pH and temperature range, and the progress of the chemical reaction depends on these conditions along with time and concentration,” Dr. van Eijk added. “Most commercial enzymes are produced from

microorganisms and are standardized for specific activities.” Enzymes come from many sources. “The enzymes sold commercially are painstakingly selected from libraries of organisms collected from anywhere on earth,” Dr. Boutte said. Criteria include the enzyme’s ability to work well under baking conditions. They should also be easy to produce in high quantities and have few, if any, side activities. “It is also desirable to produce enzymes that are unaffected by naturally occurring enzyme inhibitors or by common bakery ingredients,” he said, citing certain enzymes that do not work well in the presence of sugar and shortening. These proteins enjoy special status from a labeling standpoint. “Since enzymes modify dough properties during processing but are rendered inactive by the oven’s heat, they are present in the baked food only at insignificant levels,” said Michael Beavan, project manager, Watson Inc., West Haven, CT. “Therefore, enzymes fit the definition of a processing aid and are exempt from being identified on finished product ingredient legends.” However, many bakers do list them, because consumers percieve enzymes positively.

In a bakers’ basket
Six basic categories of enzymes are available to bakers: amylase, asparaginase, lipase, oxidase, protease and xylanase (also called hemicellulose and pentosanase). “There are enzymes that break down macromolecules such as protein and starch, and there are those that build up these same macromolecules,” Mr. Beavan said. “The first type is responsible for the extensible properties of dough, which allow it to flow, while the second type is responsible for the elasticity or strength of the dough.” Alpha-amylases were the first enzymes used in the baking industry. Naturally occurring in malt as well as industrially produced through microbial fermentations, alphaamylases are added to wheat flour to standardize natural amylase activity. “Addition assures a certain minimal production of sugar for fermentation during baking,” Dr. Boutte said. Alpha-amylase degrades the starch in wheat flour into small dextrins, which allows yeast to work throughout dough fermentation, proofing and the early stage of baking. Bread volume and crumb texture thus improve. Also, the small sugars released by alpha-amylase

/ Baking & Snack / July 2012

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Baking&Snack - July 2012

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