Extraction:
Partially purified collagen is converted into gelatin by extraction with either water or acid solutions at appropriate temperatures.
All industrial processes are based on neutral or acid pH values because though 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 is usually increased in later extraction steps, which ensures minimum thermal degradation of the extracted gelatin.