Firstly it depend on the source of gelatin. for example fish gelatin like Cod fish gelatin extraction pattern is different from bovine gelatine.

secondly , yes the pH of extraction solution is directly affects the clarifying process of gelatin. So work on a little about pH of solution and ionic strength of them

Finally which bloom of gelatin do you consider?

i an currently doing research with tilapia fish skin, so normally the Bloom is closed to mammalian gelatin. i observed that the limpidity of gelatine increase when pH of extraction increase, is it means that that amount of acid used can influence the quantities of impurities removed during pretraitement? And by the way, is deminelisation helps to improve the Bloom of gelatin?

Dear Zei

Bloom is also variant as application comes in mind, for example Bloom 170 is widely used in dairy products as stabilizer bu bloom more than 240 is used for gelling and products like pastille...

The visual method of determining clarity using a 6.67% solution of gelatine against a reference standard is widely used.

Clarity can be determined with a nephelometer or spectrophotometer

using a 6.67% solution at a wavelength of 620 nm.

Color can be determined in a spectrophotometer at 450 nm using a 6.67% solution.

both values should be determined at the same time. Deionized water is the standard of choice when determining color and clarity

using an instrument.

Ash or dissolved salts exert an influence on most of the physical properties of

gelatine which worsen with increasing salt content – as well as on the sensory

parameters..so demineralisaztion by meanas of UF or even ion exchangers is necessary...among this salt sulphur salt mainly affects clarity...

Why do you think that sulphuric acid has the most important effect on the clarity of gelatin?

so by eliminating the content of salt, we can improve the clarity of gelatin? and Ehsan, do you know why does the isoelectric point of gelatin type A is always higher than gelatin type B?

You cant eliminate salts but you can reduce it.

In the case of alkaline-conditioned type B (basic) gelatine, both asparagine and glutamine are almost completely converted to aspartic and glutamic acids respectively. The amino acid composition of collagen and an acid-conditioned type A (acid) gelatine hardly differ. This explains the different

iso-electric points (IEP) typical of types A and B gelatine. For gelatine of type A, this corresponds to collagen at about pH 8–9 and for type B at pH 4.8–5.5.

Please do not hesitate to contact me if you had any questions...

Good Luck

thank you very much, Ehsan.

So it means that during extraction on type B ( hide), we should keep water PH between 4.8-5.5 and heat temperature around 60 degrees to get high bloom?

However, during extraction of type B ( hide), we have seen that since Water PH is around 8 and HIDE ( boil PH 5.5), it takes few hours before water PH goes down between 6-6.5. Since PH is higher (5.5), extraction ( cooking) takes 7-11 hours before we get 5% concentrated Liquor ( quantity of extraction load is 6 TON of Hide + water). in such cases, we add small does of sulfuric acid or Acetic Acid to bring down water PH. But I heard that these acids effects gelatin bloom a lot.

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