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9 points to eliminate serum in yogurt

Some Theory …

9 points to eliminate serum in yogurt 3The yoghurt structure consists of a three-dimensional network forming by casein micelles. This network is ”alive”.

Depending on the practice I use when making yogurt, deficiencies may be created when the 3-D network is formed. This means that the 3-D network is weak and unstable.

Two critical factors: temperature changes and pH change cause rearrangement of the 3-D network. This rearrangement or shrinking, in general, is called syneresis.

9 points to eliminate serum in yogurt  4The rearrangement rate firstly, and how perfect the 3-D network is will determine the whey outlet from the gel, or as it is called, the serum expulsion.

Let us start:

caseins

So whenever I have milk with a few caseins percentage, then we start already with serum expulsion in yoghurt. In this case the 3-dimensional network is weak.

homogenised milk or not

9 points to eliminate serum in yogurt 6In homogenised milk yoghurt, the new fat globules resulting from homogenization have a much smaller size that can approximate that of caseins and have also protein features. They participate more effectively in the three-dimensional network.  In this case the 3-dimensional network is more powerful.

In yogurt from non-homogenized milk, the fat globules interrupt the 3-dimensional network, weakening it. In this case, the 3-dimensional network has imperfections.

heat treatment

I want intense heat treatment [high T for a sufficient amount of time] to evaporate water, i.e. to increase 9 points to eliminate serum in yogurt 7the casein content.

Intense heat treatment also results in denaturation of whey proteins. Serum proteins change structure, interact with caseins and enhance the 3 dimensional network. In this case the 3-dimensional network is more powerful.

slow rate of acidification

At a fast rate of acidification [pH drop], the 3-dimensional network can not smoothly be rearranged. In this case the 3-dimensional network will have imperfections.

9 points to eliminate serum in yogurt  8what time I should remove the yogurt from the oven [how acidic it should be]

Ideal pH value is 4.50.  A pH value of 4.40 to 4.60 is satisfactory. pH values ​​below 4.40 or above 4.60 result in defects in the 3-D network.

slow cooling rate

The temperature from 42-43 degrees should be decreased to 4 degrees. Fast temperature rate change causes abnormal rearrangement of the 3-dimensional network. In this case the 3-dimensional network will have imperfections.

any mechanical disorder

Even a shake, since from the point yogurt has formed the 1st gel structure [calculate after 1.5 hours in the oven] can cause a crack in the 3-dimensional network.

dimensions of the manufacturing container

If you use cups with a small cross-sectional area and a high height will serum elimination will be promoted. Whey expulsion is also promoted whenever the yoghurt is half-consumed and then stored with a large area of ​​exposure.

when the lids will be placed in cups

Lids onto the cups should be placed when the yoghurt has a low temperature, i.e., when the yoghurt is in the refrigerator and has reached a temperature of 4 degrees Celsius. Otherwise, moisture concentration on the surface of yoghurt, due to condensation, will promote serum excretion.

 

You tube: Athanasios Kouris

https://www.youtube.com/channel/UCfh1gAHj-6BKNGPKYSvscJA

fb: Traditional Homemade Dairy Products Manufacture

 

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