Hydrolyzed collagen (HC) can be extracted from different sources and tissues, it can be extracted from bovine Achilles tendon by using different enzymes such as alcalase, pepsin, trypsin, and collagenase produced by Penicillium aurantiogriseum. It shows antihypertensive, antioxidant, and antimicrobial activity. HC from bovine lung showed antioxidant and anti-inflammatory activity. HC from the nuchal ligament of bovine by papain action can be used as a promising precursor of angiotensin-I-converting enzyme (ACE)-inhibitory peptides.
Another traditional source of HC is porcine skin. It presents a low molecular weight around 1–10 KDa. It is produced by a hydrothermal process and fractionated by ultra-filtration membranes; showing antioxidant, anti-aging, skin permeation properties, and ACE-inhibitory potency. HC from porcine skin contains functional peptides commonly used in dietary supplements. HC porcine extraction can be carried out by treatments that include high temperature (150–250 °C) and pressure (350–3900 KPa). These parameters of extraction generate peptides with lower molecular weight than 15 KDa.
