Gelatin Hydrolysis Tests are used to find out whether there is any presence of Gelatinases within a certain solution.
Gelatinases are secreted by bacteria whenever they come into contact with gelatin and help to make it easier to digest.

Digesting gelatin is also often referred to as “Hydrolyzing”, so what exactly is involved in the process of Gelatin hydrolysis? What are its principles, and what is it often used for?
If you’ve ever found yourself pondering on any of these deep questions, then you will want to read on below, because we are going to find some of the answers you have been searching for!
What Are The Principles Of The Gelatin Hydrolysis Test?
A gelatin hydrolysis test put simply, is used to find out whether a particular organism is able to produce gelatinase, which can then be used to digest gelatin.
When the test is carried out, gelatin is slowly introduced to the organism, and the observers check to see whether gelatinase goes into production.
Observers of the test will look out for two unique steps that occur.
First, the gelatin that is introduced to the organism will begin to be hydrolyzed, which converts the gelatin into polypeptides, which are linear chains of amino acids.
Those same amino acids will then be used by the cells of the organism for the purposes of metabolism.
The second step of gelatin hydrolysis involves detecting just how much gelatinase has been secreted by the organism.
In order to do this, the observers will use a gelatin medium, which will begin to grow when the gelatinase reacts with the gelatin present within the medium.
This gives researchers a clear picture of just how much gelatinase a certain organism excretes!
What Is The Method Of A Gelatin Hydrolysis Test?
There are actually numerous methods that are utilized to determine the amount of gelatinase in an organism, but one particular method stands on top as one of the most popular.
To start off, this method involves placing some gelatin deep within a shallow pool of a broth culture, which will contain the desired organism.
Once the gelatin has been placed, the solution is then left to incubate at temperatures of around 35 to 37 degrees celsius for around 14 days.
This will cause the organism to interact with the gelatin, which will also cause it to excrete gelatinase if it has any.
Over the course of that 14-day period, observers will remove the solution from the incubator daily to check to see the progress of the test and to see how much gelatinase has already been excreted.
After the 14-day period has passed, the solution will then be placed within a refrigerator to cool.
However, it will also be placed alongside a solution that does not contain any gelatin. This solution is referred to as the control, and once it hardens, the test is finally finished.
Performing such a test will allow observers to determine whether an organism excretes gelatinase, and how much it excretes if it does.
An organism is considered to excrete gelatinase if it causes the solution that it is placed within to liquefy, after having been refrigerated.
This is because, if gelatin were still left undigested and then placed in the refrigerator, it would harden.
Thus, if the observer removes the solution from the refrigerator alongside the control and finds that they have both hardened, then it can be concluded that the organism does not excrete gelatinase!
These are the most common interpretations that observers of gelatin hydrolysis encounter, and thus it is what many observers make a point of looking out for.
What Are The Uses Of A Gelatin Hydrolysis Test?
The most basic use of a gelatin hydrolysis test, of course, is to find out whether an organism excretes gelatinase, but there are also many other uses for such a test.
Gelatin hydrolysis can also be used to identify different species of Serratia, Protus, Bacillus, and Clostridium, amongst others.
Staphylococcus is gelatinase-positive, while non-pathogenic epidermidis is gelatinase-negative.
Finally, such tests can also be used to differentiate Serratia and Proteus species from all other members of the Enterobacteriaceae family, as they tend to be gelatinase-positive, while all other members of the family tend not to be.
Frequently Asked Questions
What Causes Gelatin To Liquify
Gelatin is a truly unique substance, because, when heated up to around body temperature, it becomes a liquid, but when it is cooler, it is slightly closer to a solid but is still incredibly flexible.
This is why gelatin is used in all sorts of soft foods and desserts, to give them a slight springiness. These include desserts such as Jello!
Does Gelatin Dissolve In Water?
Gelatin is a protein that is derived from the skin, bones, and ligaments of animals and is completely edible.
One of the properties of gelatin is that it will dissolve in water. Gelatin is actually used in a larger number of foods, as it helps to give the foods a sense of softness.
Why Do We Need To Chill Gelatin After Being Cold?
The reason that we chill gelatin, especially when using it to make foods such as Jello, is because the act of cooling causes the bonds between the molecules of gelatin to bond together more strongly, which gives the final product more firmness.
This is why you are often advised to place a Jello product directly into the fridge right after you have made it.
To Wrap Up
Gelatin hydrolysis tests are used to determine what organisms excrete gelatinase, which is used by all manner of organisms to digest gelatin and use it for metabolism.
The basic procedure of gelatin hydrolysis is incredibly simple and can be done by just about anyone with enough requisite experience.
It is also easy to interpret the results of the test thanks to the common results that many prior hydrolysis tests have yielded.
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