Biologically active peptides are small protein fragments that have a positive impact on health. Bioactive peptides are derived from proteins found in nature, such as plants, animals, fungi and microbes, or in industrially manufactured foods. They are primarily 3-20 amino acid residues in length and remain inactive while they are kept within the parent protein.
The release of peptides from the parent protein occurs during food processing and/or gastrointestinal digestion, in vitro hydrolysis with proteolytic enzymes, or fermentation by bacteria. The peptides released by the digestive system are often absorbed into the bloodstream and exert specific, beneficial biological effects on the human body.
Functional foods and nutraceuticals containing bioactive peptides are gaining popularity as consumers seek to prevent or treat chronic diseases. The search for bioactive peptides in natural and synthetic foods has become an important field of research.
Despite the potential of generating bioactive peptides, there are some limitations. Firstly, the generation of bioactive peptides from food requires optimal processing conditions to maintain their biological activity and stability during gastrointestinal digestion. Furthermore, a bioactive peptide’s molecular weight must be well controlled in order to achieve the desired function.
For example, peptides with low molecular weight (MW) are easier to isolate and can be purified using size-exclusion chromatography and RP-HPLC. However, the MW distribution of the obtained peptides can be affected by the type of membrane used in the ultrafiltration process.
Moreover, some peptides can enhance their bioactivity by binding to calcium (Ca) and phosphorus (P) ions. The ability of a particular peptide to bind Ca and P ions may help the molecule cross the intestinal barrier and reach the bloodstream. The binding ability of peptides to minerals is also thought to influence their anti-inflammatory, antioxidant, antimicrobial, antidiabetic and other biological activities.