Editing Gelatin (section)

===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>