processing_fermentation

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PROCESSING METHODS:

FERMENTATION

Fermentation is the conversion of organic substances to simpler substances, by the action of enzymes or living organisms such as bacteria or microorganisms, including yeasts, moulds and fungi. Fermentation changes the quality of products. Some food products are more edible, more nutritious and more tasty after fermentation

Legislation

Scale of processing:

small

medium

large

Fermentation takes place for

set, long-life set yoghurt takes place in the final container
- incubated for 3-4 h at 40-44°C (until pH 4,6-4.7)
- water baths or tanks for small - medium scale processing
  - water level is maintained to just below the neck of the container
- cabinets for small - medium - large scale processing - insulated chambers with forced air circulation can be used for 250-7500 litres capacity
- medium - large scale processing: yoghurt is fermented in a continuous system
  - tunnel which consists of two section
    - warm air circulation in the incubation section of the tunnel where the speed is regulated to ensure contact time required to reach the required acidity
    - cooling section where cooled/chilled air is circulated around the product
stirred, long-life stirred, frozen and drinking yoghurt
- in the jacketed vessel used for heating and cooling for small-medium scale processors

or in a suitable container which can be sealed and heated
in fermentation tanks (medium - large scale )

fermentation tanks
- are insulated ensure an even temperature is maintained during the incubation.
- cone-shape tanks will ease the removal of the coagulum
- warm milk is pumped into the fermentation tanks
- milk and starter culture mixture is agitated to ensure even dispersion of the culture in the milk
- incubated for 3-4 h until the pH is 4.2-4,6.
(Graphics courtesy of Tetra Pak Procesing Systems)

Figure: A fermentation tank with agitator