Which animals or plants are the main sources of raw materials for gelatin hollow capsules?

1. Animal source:
The preparation of gelatin relies on collagen in animal tissues. According to multiple pieces of evidence, its main raw materials are fresh cow bones, cowhide, pigskin, as well as tendons and ligaments from healthy animals. These raw materials undergo acid hydrolysis, alkaline hydrolysis, or enzymatic degradation to extract collagen and purify it into gelatin. For example:
Beef bones and cowhide are the main sources of gelatin production, especially widely used in regions such as the European Union.
Pig skin is also commonly used in gelatin preparation, especially in the Asian market.

2. Substitutes for plant capsules:
Plant capsules (such as HPMC, pullulan polysaccharides, starch, etc.) are alternatives to gelatin capsules, but their raw material sources are completely different. The raw materials for plant capsules are plant cellulose or natural polysaccharides, such as hydroxypropyl methylcellulose (HPMC) derived from etherification products of wood or cotton fibers, and pullulan polysaccharides obtained through microbial fermentation