Editing Gelatin (section)

==Production==
[[File:Materials Used in Gelatin Production.svg|280px|thumb|{{Citation needed|date=December 2017}}]]
In 2019, the worldwide demand of gelatin was about {{convert|620000|tonne|e9lb|lk=in|abbr=}}.<ref>{{Cite web|title=Gelatin Market Size, Analysis {{!}} Industry Trends Report, 2020-2027|url=https://www.grandviewresearch.com/industry-analysis/gelatin-market-analysis|access-date=2020-10-17|website=www.grandviewresearch.com|language=en}}</ref> On a commercial scale, gelatin is made from [[by-product]]s of the [[meat]] and [[leather]] industries.
Most gelatin is derived from pork skins, pork and cattle bones, or split cattle hides.<ref name="gc">{{cite web|date=12 June 2013|title=Natural Health Products Ingredients Database: Hydrolyzed Collagen|url=http://webprod.hc-sc.gc.ca/nhpid-bdipsn/atReq.do?atid=hydrolized.collagen|url-status=live|archive-url=https://web.archive.org/web/20160512222007/http://webprod.hc-sc.gc.ca/nhpid-bdipsn/atReq.do?atid=hydrolized.collagen|archive-date=12 May 2016|access-date=9 May 2016|publisher=Government of Canada, Health Canada, Health Products and Food Branch, Natural Health Products Directorate|df=dmy-all}}</ref> Gelatin made from fish by-products avoids some of the religious objections to gelatin consumption.<ref name="Cole2" /> The raw materials are prepared by different curing, acid, and alkali processes that are employed to extract the dried collagen hydrolysate. These processes may take several weeks, and differences in such processes have great effects on the properties of the final gelatin products.

Gelatin also can be prepared at home. Boiling certain cartilaginous cuts of meat or bones results in gelatin being dissolved into the water. Depending on the concentration, the resulting stock (when cooled) will form a jelly or gel naturally. This process is used for [[aspic]].

While many processes exist whereby collagen may be converted to gelatin, they all have several factors in common. The intermolecular and intramolecular bonds that stabilize insoluble collagen must be broken, and also, the hydrogen bonds that stabilize the collagen [[helix]] must be broken.<ref name="Ward2" /> The manufacturing processes of gelatin consists of several main stages:
# Pretreatments to make the raw materials ready for the main extraction step and to remove impurities that may have negative effects on physicochemical properties of the final gelatin product.
# [[Hydrolysis]] of collagen into gelatin.
# Extraction of gelatin from the hydrolysis mixture, which usually is done with hot water or dilute acid solutions as a multistage process.
# The refining and recovering treatments including filtration, clarification, evaporation, sterilization, drying, rutting, grinding, and sifting to remove the water from the gelatin solution, to blend the gelatin extracted, and to obtain dried, blended, ground final product.

===Pretreatments===
If the raw material used in the production of the gelatin is derived from [[bone]]s, dilute [[acid]] solutions are used to remove [[calcium]] and other salts. Hot water or several solvents may be used to reduce the fat content, which should not exceed 1% before the main extraction step. If the raw material consists of [[hide (skin)|hides]] and skin, then size reduction, washing, hair removal, and degreasing are necessary to prepare the materials for the hydrolysis step.

===Hydrolysis===
After preparation of the raw material, i.e., removing some of the impurities such as fat and salts, partially purified collagen is converted into gelatin through hydrolysis. Collagen hydrolysis is performed by one of three different methods: [[acid hydrolysis|acid]]-, [[base hydrolysis|alkali]]-, and [[enzymatic hydrolysis]]. Acid treatment is especially suitable for less fully [[cross-link]]ed materials such as pig skin collagen and normally requires 10 to 48 hours. Alkali treatment is suitable for more complex collagen such as that found in [[bovine]] hides and requires more time, normally several weeks. The purpose of the alkali treatment is to destroy certain chemical crosslinks still present in collagen. Within the gelatin industry, the gelatin obtained from acid-treated raw material has been called type-A gelatin and the gelatin obtained from alkali-treated raw material is referred to as type-B gelatin.<ref>{{cite web|url= http://www.vyse.com/about_gelatin_process.html|title= Type A & B Process Definition|date= 26 October 2009|access-date= 16 July 2014|publisher= Vyse Gelatin Company|archive-url= https://web.archive.org/web/20150301224019/http://www.vyse.com/about_gelatin_process.html|archive-date= 1 March 2015|df= dmy-all}}</ref>

Advances are occurring to optimize the yield of gelatin using enzymatic hydrolysis of collagen. The treatment time is shorter than that required for alkali treatment, and results in almost complete conversion to the pure product. The physical properties of the final gelatin product are considered better.<ref>{{cite journal|title=Recent advances on the role of process variables affecting gelatin yield and characteristics with special reference to enzymatic extraction: A review|journal=Food Hydrocolloids|date=February 2017|volume=63|pages=85–96|doi=10.1016/j.foodhyd.2016.08.007|last1=Ahmad|first1=Tanbir|last2=Ismail|first2=Amin|last3=Ahmad|first3=Siti Aqlima|last4=Khalil|first4=Khalilah A.|last5=Kumar|first5=Yogesh|last6=Adeyemi|first6=Kazeem D.|last7=Sazili|first7=Awis Q.}}</ref>

===Extraction===
Extraction is performed with either water or acid solutions at appropriate temperatures. All industrial processes are based on neutral or acid pH values because although alkali treatments speed up conversion, they also promote degradation processes. Acidic extraction conditions are extensively used in the industry, but the degree of acid varies with different processes. This extraction step is a multistage process, and the extraction temperature usually is increased in later extraction steps, which ensures minimum thermal degradation of the extracted gelatin.

===Recovery===
This process includes several steps such as filtration, evaporation, drying, grinding, and sifting. These operations are concentration-dependent and also dependent on the particular gelatin used. Gelatin degradation should be avoided and minimized, so the lowest temperature possible is used for the recovery process. Most recoveries are rapid, with all of the processes being done in several stages to avoid extensive deterioration of the peptide structure. A deteriorated peptide structure would result in a low gel strength, which is not generally desired.