The raw materials of empty capsules can generally be divided into gelatin capsules and vegetarian capsules. Gelatin is a white or light yellow, translucent, micro-glossy sheet or powder that is degraded by collagen in connective tissue such as animal skin, bone, and sarcolemma. It is a hydrophilic colloid of macromolecules and is a low-calorie health food with high nutritional value. Another large class of capsules are plant capsules. The outer shell of a plant capsule is generally prepared from a material such as starch, HPMC, Pullulan.