Yeast is a single-celled living organism that is widely used in baking, brewing, winemaking and other industries.

Yeast

Also known as bakers’ yeast or Saccharomyces cerevisiae


What is Yeast?

Yeast is a single-celled living organism widely used in baking, brewing, winemaking and other industries.

Saccharomyces cerevisiae can ferment and metabolize a variety of sugars under anaerobic conditions with preference for glucose, fructose and maltose. As a result, it produces carbon dioxide, ethanol and other organic compounds.1,2 In baking, the most common forms used are:

  • Compressed
  • Cream
  • Active or Inactive Dry

Origin

Various classes of yeasts can be found in many ecosystems and food processing environments. They can be isolated from the nectar of flowers, skins of fruits, honey, surfaces of leaves and plants. In addition, they occur in the soil or can be found in the air.

Function

This ingredient serves many functions in bakery products. However, the two most pronounced ones are:3,4

  1. Dough rising: Carbon dioxide production, which essential for dough rising to build bread volume and improve crumb grain and overall texture.
  2. Dough maturation and flavor development: The production of ethanol and small amounts of organic compounds, such as ketones and aldehydes. This is responsible for mellowing the dough, as well as providing flavors and aromas to bread.

Commercial production

Bakers’ yeast comes in a number of different forms, including compressed, dried/granular, cream or liquid, instant, encapsulated and frozen.

Block diagram for the production of Baker’s yeast

Manufacturers are developing strains that can tolerate and thrive in certain environments. Also, they can perform additional functions that are beneficial to bakers. Here are some examples:

  • Calcium propionate tolerant
  • Freeze-tolerant
  • Osmotolerant
  • High vitamin D
  • Maltase negative
  • Antimicrobial
  • Acrylamide-reducing
  • Aromatic

Application

Yeasts are chosen based on their ability to meet the bakery’s needs, the type of bread to bake, dough system, processing conditions and the equipment. Evaluating the suitability of this ingredient is based on:

  • Gassing power
  • Vitality
  • Shelf-life
  • Form (dry or liquid)
  • Operational conditions at bakery

Forms used in bakeries:

Form Water content (%) Solids content* (%) Handling and application
Compressed 70.0 30.0
  • Shelf-life: 2–3 weeks at refrigeration temperature
  • Can be added directly to mixer
  • Application: medium-sized and high-speed bakeries
  • Activity: high although lower than cream yeast
Cream 85.0 15.0
  • Shelf-life: 2–3 weeks under...

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