Van Slyke

Category: Cheese yield
Forum Name: Cheese yield
Forum Description: Discussion of cheese yield
URL: https://www.dairyscience.info/forum/forum_posts.asp?TID=50
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Topic: Van Slyke
Posted By: Guests
Subject: Van Slyke
Date Posted: 19 Mar 2010 at 9:19pm
 Why does the Van Slyke yield equation overestimate yield? Can it be used for spanish cheeses? Thank you

Replies:
Posted By: Guests
Date Posted: 19 Mar 2010 at 9:20pm
 When the Van Slyke yield equation was published in 1949, the Kjeldahl total nitrogen (TN) factor for converting TN to protein was 6.25. The factor currently used is 6.38. Using the 6.38 conversion factor gives protein, and hence casein, concentrations some 1.021 times higher than those obtained using the 6.25 conversion factor. The actual effect on the yield of Cheddar cheese can be calculated by determining the casein concentration in cheese milk using both conversion factors and substituting the values for casein into the Van Slyke equation. This is shown below for milk containing 2.5 % (w/v) casein-TN factor of 6.38-, 3% fat (w/v) and a cheese moisture content of 37 % (w/v). Using y (cheese yield , kg )=(milk casein-0.1+ milk fat x 0.93) x 109/100-moisture content of cheese, milk containing 2.5 % casein gives a yield of 9%. If the casein concentration is reduced by 1/1.021 this gives a value of 2.45 % casein and a Van Slyke cheese yield of 8.9%. In the example given above, present day yields, calculated with the Van Slyke yield equation are 0.1/9 x100, =1.1%, approximately 1% higher than intended by Van Slyke. The Van Slyke yield equation was developed for calculating the yield of Cheddar cheese only. Carlos if you wish to post future questions please include your E-mail address.

Posted By: Guests
Date Posted: 19 Mar 2010 at 9:20pm
 How are other cheese types affected by this? We produce cheddar, muenster, colby, mont jack, baby swiss, emek, syrian, jerusalem. Most of our production is P/S mozz W/M Mozz and Fresh Mozz. Is the a standardization formulation spread sheet in excel to cover the bulk of these items? We use Raw milk, skim, and skim condensed to 20-25%. We also use back in our whole milk vats some whey cream. We are having problems with consistancy issues with our pressed cheeses. I think it is because we have messed with and not accounted for the change to the f/p. We have increased the fat but have not increased the protein. Can you offer any assistance, would be very much appreciated.

Posted By: Guests
Date Posted: 19 Mar 2010 at 9:20pm
 This is a holding response. I will respond in more detail later. Consistent manufacture of virtually all cheese requires correct standardisation of the starting 'milk'. A standardisation spreadsheet in Excel can certainly be used. I am only familiar with some of the cheeses used but the information necessary to produce the spread sheet is freely available. Regards Mike

Posted By: Guests
Date Posted: 19 Mar 2010 at 9:21pm
 I have created a separate thread for the posting on Munester and other cheeses by Ed Ayers. Plaese see section on 'Posting on Munester and other cheeses by Ed Ayers'

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