Pure strains of Saccharomyces cerevisiae species are used as bread yeast.
1. Pure culture :
Pure yeast cultures are produced at ABF’s Research and Development Center located at North Ryde, Sydney, Australia. Fresh sub-pure cultures are regularly distributed to ABF factories across the world in order to be used for production of bread yeast. Pure culture used in bread yeast fermantation is called inoculum. Tons of bread yeast can be produced by using a small amount of this culture.
The sugar required for the growth of yeast cultures is derived from molasses. Molasses is sterilized with steam after having undergone thorough processes for clearing out debris.
Pure culture is first prepared by reproduction in laboratory conditions.
2. Production of the seed culture :
Pure culture is inoculated into seed fermentor containing sterile molasses syrup as well as other nutrition. Pure culture is transferred to the main fermentor after it transforms into yeast cells at the desired level. Pure culture growth in the main fermantor then becomes seed yeast.
3. Fermentation :
To the seed yeast which has been transferred to the main fermentor is added molasses syrup and nutritive in a controlled manner in order to ensure high quality reproduction. Simultaneously, the fermentor is provided with a high dose of sterile air and oxygen that is needed for fast cell growth.
4. Separation and Washing :
The yeast that builds at the main fermentor is collected at the end of the commercial fermentation process. This collection process is carried out via centrifugal separators, and a cream-colored "Liquid Yeast" is obtained by repeatedly washing the yeast cells with water.
5. Packaging and Warehousing :
Liquid Yeast is kept in stainless steel tanks at 0-4 degrees in order to ensure that it preserves its activity and durability. The liquid yeast is transferred to vacuum filters, and it is dehydrated and finally scraped off the filters by using knives. It is pressed into 1 kg or 0.5 kg packs by mixers, or packaged into 25 kg packs in crumbled Granular form. It is warehoused in clean rooms with a high air circulation, and then delivered in refrigerated vehicles.
PACKAGING AND TRACEABILITY:
The products are pressed into 1 kg and 0.5 kg blocks and packaged inside While Sulfite paper and BOPP/Cellophane films with Mauri and Marmara brand names, and party numbers, production and expiration dates printed on packages.
Crumbled fresh yeast is packaged inside Kraft sacks of 25 kg, and party number, production/expiration dates are printed on the packages.
YEAST ACTION ON DOUGH:
Yeast has three actions on dough:
1. It produces carbon dioxide which gives the dough the desired volume and provides it with its spongy texture once baked.
2. It nourishes and reinforces the dough via the fermentation activity in its gluten structure.
3. It adds a flavor to the dough by producing complex chemical compounds as byproducts of the fermentation process.
