Bioactive peptides

Bioactive peptides#

Bioactive peptides are a group of biological molecules that are normally buried in the structure of parent proteins and that become active after microbial fermentation. They can have a wide range of applications, such as antimicrobial, antihypertensive, antioxidant activities, blood-lipid-lowering effect, opioid role, antiobesity, ability to bind minerals, antidiabetic, and antiaging effects (Akbarian et al., 2022).

Bioactive peptides represent a promising strategy to enhance the quality of human life, with applications in medicine, cosmetics, and nutrition (Bhandari et al, 2020). These peptides, typically containing fewer than 50 amino acid residues, exert specific functions in living organisms, often residing within the structures of larger protein molecules (Daliri et al, 2017). Proline, arginine, lysine, and hydrophobic residues are commonly found in the amino acid composition of bioactive peptides.

Bioactive peptides offer advantages in terms of therapeutic production. They exhibit specialized activities with minimal toxic effects, even at low concentrations, making them effective in treating chronic diseases. Unlike traditional drugs, bioactive peptides do not accumulate in the body, facilitating easy excretion and degradation, which is beneficial for avoiding long-term environmental impact and adverse side effects (Akbarian et al., 2022).

From a nutritional standpoint, bioactive peptides demonstrate higher bioavailability compared to proteins, and their smaller size reduces allergenic effects (Lemaire at al., 2021).

Production of bioactive peptides through microbial fermentation#

Bioactive peptides can be efficiently generated through microbial fermentation, a process that involves the use of bacterial hydrolases to break down proteins into smaller peptides. This method, an integral part of enzymatic hydrolysis utilizing bacteria, is notably effective when employing industrially utilized primer cultures with high proteolytic potency. Both primer and nonprimer bacteria in fermented food products contribute to the production of bioactive peptides (Chai at al., 2020).

Lactobacillales, a diverse group of beneficial bacteria found in nature and the human digestive system, play a pivotal role in this peptide production. Their involvement extends beyond physiological effects, encompassing technological significance in shaping the texture and taste of fermented products.

The proteolytic systems of specific Lactobacillales, including Lactococcus lactis, Lactobacillus helveticus, and Lactobacillus delbrueckii of the bulgaricus subspecies, are well-understood. These systems comprise various proteins attached to the cell wall and intracellular proteins. Combining multiple fermentations and enzymatic hydrolysis has been shown to enhance bioactive peptide production (Song at al., 2017; Griffiths at al., 2013; John at al., 2006; Sasaki at al., 1995).

Notably, microbial fermentation stands out as a cost-effective method for peptide production. Microorganisms serve as economical sources of proteases, known for their safety. The low cost of bacterial cultures, attributed to minimal nutrient requirements and short growth times, further contributes to the economic feasibility of microbial fermentation. Additionally, the expression of Lactobacillales proteases on the cell wall simplifies extraction protocols, making them relatively easy and inexpensive (Raj at al., 2021).

Functional applications of bioactive peptides obtained from milk fermentation#

Fermented milk products with a mixed culture primer containing five strains of Lactobacillales demonstrated an antihypertensive effect with increased ACE inhibitory activity in hypertensive animal models (Jäkälä at al., 2010).

Studies report high inhibitory activity against radicals, such as 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH), in fermented camel milk with Leuconostoc lactis. Beyond the use of living microorganisms, proteolytic enzymes isolated from Lactobacillales have successfully been employed to generate bioactive peptides from milk proteins (Soleymanzadeh at al., 2016).

Section references#

Akbarian M, Khani A, Eghbalpour S, Uversky VN. Bioactive Peptides: Synthesis, Sources, Applications, and Proposed Mechanisms of Action. Int J Mol Sci. 2022 Jan 27;23(3):1445. doi: 10.3390/ijms23031445. PMID: 35163367; PMCID: PMC8836030.

Bhandari D., Rafiq S., Gat Y., Gat P., Waghmare R., Kumar V. A review on bioactive peptides: Physiological functions, bioavailability and safety. Int. J. Pept. Res. Ther. 2020;26:139–150. doi: 10.1007/s10989-019-09823-5.

Daliri E.B.-M., Oh D.H., Lee B.H. Bioactive peptides. Foods. 2017;6:32. doi: 10.3390/foods6050032.

Lemaire M., Ménard O., Cahu A., Nogret I., Briard-Bion V., Cudennec B., Cuinet I., Le Ruyet P., Baudry C., Dupont D. Addition of dairy lipids and probiotic L. fermentum in infant formulas modulates proteolysis and lipolysis with moderate consequences on gut physiology and metabolism in Yucatan piglets. Front. Nutr. 2021;8:20. doi: 10.3389/fnut.2021.615248

Chai K.F., Voo A.Y.H., Chen W.N. Bioactive peptides from food fermentation: A comprehensive review of their sources, bioactivities, applications, and future development. Compr. Rev. Food Sci. Food Saf. 2020;19:3825–3885. doi: 10.1111/1541-4337.12651

Song A.A.-L., In L.L., Lim S.H.E., Rahim R.A. A review on Lactococcus lactis: From food to factory. Microb. Cell Factories. 2017;16:1–15.

Griffiths M.W., Tellez A.M. Lactobacillus helveticus: The proteolytic system. Front. Microbiol. 2013;4:30. doi: 10.3389/fmicb.2013.00030.

John R.P., Nampoothiri K.M., Pandey A. Solid-state fermentation for L-lactic acid production from agro wastes using Lactobacillus delbrueckii. Process Biochem. 2006;41:759–763. doi: 10.1016/j.procbio.2005.09.013.

Sasaki M., Bosman B.W., Tan P.S. Comparison of proteolytic activities in various lactobacilli. J. Dairy Res. 1995;62:601–610. doi: 10.1017/S0022029900031332.

Raj T., Chandrasekhar K., Kumar A.N., Kim S.-H. Recent biotechnological trends in lactic acid bacterial fermentation for food processing industries. Syst. Microbiol. Biomanuf. 2021;2:14–40. doi: 10.1007/s43393-021-00044-w.

Jäkälä P., Vapaatalo H. Antihypertensive peptides from milk proteins. Pharmaceuticals. 2010;3:251–272. doi: 10.3390/ph3010251.

Soleymanzadeh N., Mirdamadi S., Kianirad M. Antioxidant activity of camel and bovine milk fermented by lactic acid bacteria isolated from traditional fermented camel milk (Chal) Dairy Sci. Technol. 2016;96:443–457. doi: 10.1007/s13594-016-0278-1.