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the void space around LAB in yogurt

Printed From: Dairy Science and Food Technology
Category: Starter cultures
Forum Name: Starter cultures
Forum Description: Discussion about the microorganisms used in the manufacture of cultured products
URL: https://www.dairyscience.info/forum/forum_posts.asp?TID=151
Printed Date: 29 Mar 2024 at 6:35am
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Topic: the void space around LAB in yogurt
Posted By: Guests
Subject: the void space around LAB in yogurt
Date Posted: 22 Mar 2010 at 11:35pm
M.Kalab had pointed out the void spaces around LAB in set-style yogurt.I do not know if it is the first time,but Iread from this reprint :M.Kalab,Development of microstructure in set-style nonfat yogurt-a review, Food Mirostructure,Vol.2(1983),pp.51-66.

there some different hypothesis:

(1)the void space is resulted from the proteolytic activity of LAB.but F.L.Davies point out that "S.thermophilus has little or no proteolytic activity...but the void spaces are equally evident around the non-proteolytic streptococci as around the strongly proteolytic lactobacilli.

(2)Olyson's hypothesis:
because of the local concentrations of lactic acid, the milk around LAB form a gel earlier,and then the gel separate from the LAB.but no explain on how gel separate from LAB.

(3)or the void space is artificial product when prepare sample.



Replies:
Posted By: Guests
Date Posted: 22 Mar 2010 at 11:36pm
"but the void spaces is obtained as if subjected to some stress"which phenomenon support the Olyson's hypothesis(local concentrations of lactic acid)


Posted By: Guests
Date Posted: 22 Mar 2010 at 11:36pm
what is the mechanism of the healing of curd (after cutting) ?
and the mechanism of shrink of curds when cooking?

may the same mechanism result in the void spaces around LAB?both proteolytic activity and the "interior tension"cause the void spaces and make them as if subjected to some stress?

but I do not know the mechanisim of healing and shrink,could some person talk about this? 
Diagram explaining curd shrinkage 


Posted By: Guests
Date Posted: 22 Mar 2010 at 11:36pm
Re healing of curd and curd shrinkage. While not totally understood there has been a lot of work in this area. If you do a search using Goggle scholar you will get a good overview of what has been done.


Posted By: Guests
Date Posted: 22 Mar 2010 at 11:36pm
thank you

in fact,I am not doing research...

I am just curious about these problems.


PS:I have used google scholar,it did find LOTS of papers!!



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