salt determination
Printed From: Dairy Science and Food Technology
Category: General dairy
Forum Name: General dairy
Forum Description: Dairy science and technology matters not covered elsewhere
URL: https://www.dairyscience.info/forum/forum_posts.asp?TID=186
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Topic: salt determination
Posted By: Guests
Subject: salt determination
Date Posted: 23 Mar 2010 at 10:22pm
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which is the quickest method for determinig the amount of salt in cheese? Gravimetric determination or what?
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Replies:
Posted By: Guests
Date Posted: 23 Mar 2010 at 10:23pm
Measuring NaCl in an aqueous solution is easy! Getting representative samples from cheese and interperting your results is somewhat more difficult.
There are several methods using titration with silver nitrate. I would recomend that you determine salt potentiometrically.
You can also look up the Volhard titration for an alternative to a potentiometric titration.
Note at the IDF, ISO and AOAC websites for updates on standards. The IDF site is listed in the links section. cAUTION: I have listed some details of the iDF and AOAC standards below. Not sure how up to date these are!
AOAC official method 983.14 and 971.27, IDF Standard 88A:1988 and ISO 5943:1988.
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Posted By: Guests
Date Posted: 23 Mar 2010 at 10:23pm
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How long after manufacture can you test for salt? R Scott says 3-4 days. I tried that but after 6 weeks I get totally different results. What causes salt in moisture to vary from one month to the next if the quantity salt added stays the same?
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Posted By: Guests
Date Posted: 23 Mar 2010 at 10:23pm
Your question is deceptively simple!
Consider for a moment a dry salted cheese like Cheddar for example. It is possible to visualise a ‘freshly’ produced block of cheese as comprising a multitude of small ‘cheese islands’ or ‘mini cheeses’ formed from the compression of individual curd particles.
It can be calculated that salt equilibrium in an individual cheese island or mini-cheese takes around 24 hours.
It is possible, although sometimes difficult in practice, to obtain precise and consistent control of salt in dry-salted milled curd. In controlled pilot scale Cheddar cheese making it is possible to get to within ± 0.1-0.15% of the target salt concentration.
Under these conditions, where essentially uniform distribution of salt has been obtained, an accurate representation of salt concentration in the cheese can be obtained by sampling cheese 24 hours after manufacture.
If the curd has not been salted uniformly then things get much more complicated!
Under these circumstances, one can visualise pockets of curd of varying salt concentration in the vat. After pressing, there will be a multitude of mini-cheese of widely differing salt concentrations. Under these circumstances, a block of cheese will consist initially of areas of low, intermediate and high salt concentration. While an overall equilibrium value for salt in the finished cheese will eventually obtained, significant variation in salt concentration through a block of this cheese will be apparent for a considerable time.
What then is the answer to the problem? Again deceptively simple, firstly adjust cheese manufacturing conditions to obtain a uniform distribution of salt in the cheese. Then consider your approach to sampling, salt determination and data analysis!
The above is a simple non-mathematical explanation of a complex issue. I have not touched on the factors influencing salt uptake by curd or the difusion of salt in cheese or mellowing. If you want to know more I suggest you look at Professor P F Fox’s work in this area.
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