bowl of sprouted barley

Amylase is an enzyme, from germinated barley, used in bread making.

Amylase

Also known as Alpha Amylase


What is Amylase?

Amylase is an enzyme that hydrolyzes starch into simple sugars. It is used in breadmaking to increase volume, texture and flavor, and to retard bread staling.

Origin

Amylase exists in humans’ salivary glands and pancreas. It also exists in sprouted grains. It is the main enzyme in malt. Amylase on the market is produced from fungal or bacterial fermentation.

Function

There are three main kinds of amylase:1

  1. α-amylase is endoamylase. It randomly hydrolyzes the α-1,4 linkages of starch, yielding low molecular-weight sugars and dextrins. It is optimally active at pH 5.3.
  2. β-amylase attacks the second linkage from the non-reducing end of the straight segments of starch molecules and produces maltose. Its optimal pH is approximately 5.5.
  3. Glucoamylase hydrolyzes α-1,4 linkages from the non-reducing ends of starch molecules and releases glucose. It also has low activity on α-1,6 linkages of starch; therefore, it can completely convert starch to glucose. Both β-amylase and glucoamylase are exo-amylases.

Unsprouted wheat flour has β-amylase. Its quantity is inadequate to enhance bread qualities. Therefore, fungal amylase, which is usually α-amylase, is added,2 because amylase degrades starch into simple sugars. The increased sugar content has several benefits. First, it provides enough carbohydrates for yeast fermentation.

More yeast fermentation increases bread volume and produces better flavor. Second, less starch remaining means the chance for starch recrystallization is decreased. Starch recrystallization is known to be the main reason for bread staling, so adding amylase  prevents recrystallization and bread staling. Third, bread crust color is created by Maillard reaction between simple reducing sugar and protein. More simple sugar will result in faster color development.

Overdose of amylase will result in sticky bread, because too many short starch segments decrease the water-holding capacity of the starch.

Application

Amylase is mixed with other dry ingredients during dough making. Its recommended level is 0.002-0.006% of the flour weight.3 Amylase, like other enzymes, is sensitive to pH, temperature, moisture, ions and ionic strength, shearing and pressure. Amylase functions best in the range of 30°C to 40°C (86°F to 104°F) and is usually destroyed at temperatures above 45°C (113°F).

FDA regulation

One amylase is regulated GRAS by the FDA in GRN No.79. It is produced by Novozymes.4 Amylase need not be labelled when used in baking, because it is denatured after baking, according to article 21CFR101.100 in the Code of Federal Regulations.5

References

  1. Delcour, J.A., and R.C. Hoseney. “Chapter 2 Starch.” Principles of Cereal Science and Technology, 3rd ed., AACC International Inc., 2010, pp. 39–42.
  2. Curic, D., et al. “The Influence of Fungal Alpha-Amylase Supplementation on Amylolytic Activity and Baking Quality of Flour.” International Journal of Food Science and Technology, vol. 37, no. 6, 2002, pp. 673–680, doi:10.1046/j.1365-2621.2002.00598.x.
  3. Smith, J., and L. Hong-Shum. “Part 5 Enzymes.” Food Additive Data Book, Blackwell Science Ltd., 2003, pp. 39–40.
  4. U.S. Food & Drug Administration. “GRAS Notices.” Accessdata.fda.gov, 14 Aug. 2017, www.accessdata.fda.gov/scripts/fdcc/?set=GRASNotices&id=79&sort=GRN_No&order=DESC&startrow=1&type=column&search=Intended Use%C2%A4VARCHAR%C2%A4amylase.
  5. U.S. Food & Drug Administration. “21CFR101.100 – Code of Federal Regulations Title 21.” Accessdata.fda.gov, 14 Aug. 2017, www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=101.100.