Peptide-metal complexes: obtention and role in increasing bioavailability and decreasing the pro-oxidant effect of minerals

Abstract

Bioactive peptides derived from food protein sources have been widely studied in the last years, and scientific researchers have been proving their role in human health, beyond their nutritional value. Several bioactivities have been attributed to these peptides, such as immunomodulatory, antimicrobial, antioxidant, antihypertensive, and opioid. Among them, metal-binding capacity has gained prominence. Mineral chelating peptides have shown potential to be applied in food products so as to decrease mineral deficiencies since peptide-metal complexes could enhance their bioavailability. Furthermore, many studies have been investigating their potential to decrease the Fe pro-oxidant effect by forming a stable structure with the metal and avoiding its interaction with other food constituents. These complexes can be formed during gastrointestinal digestion or can be synthesized prior to intake, with the aim to protect the mineral through the gastrointestinal tract. This review addresses: (i) the amino acid residues for metal-binding peptides and their main protein sources, (ii) peptide-metal complexation prior to or during gastrointestinal digestion, (iii) the function of metal (especially Fe, Ca, and Zn)-binding peptides on the metal bioavailability and (iv) their reactivity and possible pro-oxidant and side effects.

Peptide–Mineral Complexes: Understanding Their Chemical Interactions, Bioavailability, and Potential Application in Mitigating Micronutrient Deficiency

“…Zinc deficiency is prevalent in developing countries and has been implicated in the growth retardation of up to two billion people, as well as approximately 800,000 child deaths per year [ 6 , 11 ]. Calcium is the most abundant mineral in the body and accounts for 1.5–2.2% of total body weight; it is involved in skeletal strength maintenance, muscle contraction, neurotransmission, and blood coagulation [ 5 , 12 , 13 ]. Calcium deficiency results in a reduction in bone mass and bone-related illnesses, such as osteoporosis and rickets, especially in children and older adults [ 5 , 13 ].…”

“…Mineral complexation with some organic compounds, such as amino acid chelators, has been used to reduce their interaction with the food matrix [ 5 , 18 ]. For example, ferrous bis-glycinate resulted in four times higher iron absorption than ferrous sulphate, which was possible because bis-glycinate effectively protected iron from the inhibitory effect of phytate in maize [ 19 ].…”

“…For example, ferrous bis-glycinate resulted in four times higher iron absorption than ferrous sulphate, which was possible because bis-glycinate effectively protected iron from the inhibitory effect of phytate in maize [ 19 ]. Due to the prohibitive cost of amino acids, food protein-derived peptides commonly released in vivo or in vitro by enzymatic proteolysis are promising ligands for complexation with divalent metals towards improving mineral bioavailability and mitigating micronutrient deficiency [ 5 , 20 ]. The mineral-chelating properties of peptides are attributed to the structural diversity of their backbone, which contains both the terminal carboxyl and amino groups, and the side chains of amino acid residues [ 5 , 9 ].…”

“…Due to the prohibitive cost of amino acids, food protein-derived peptides commonly released in vivo or in vitro by enzymatic proteolysis are promising ligands for complexation with divalent metals towards improving mineral bioavailability and mitigating micronutrient deficiency [ 5 , 20 ]. The mineral-chelating properties of peptides are attributed to the structural diversity of their backbone, which contains both the terminal carboxyl and amino groups, and the side chains of amino acid residues [ 5 , 9 ]. To date, a variety of metal-chelating peptides has been generated and identified from different food sources, such as milk, egg, soybean and sea cucumber [ 21 , 22 , 23 , 24 ].…”

“…Recently, the potential of food-derived peptides as transition metal ligands to enhance iron or calcium absorption was extensively discussed [ 2 ]. Another excellent review had a special emphasis on the role of peptide–metal complexes in decreasing the pro-oxidant effect of minerals [ 5 ]. Compared to the published works, this review highlights the potential of using peptide–mineral complexes as functional food ingredients towards the mitigation of micronutrient deficiency, with focus on their solubility, gastrointestinal digestion, absorption and bioavailability.…”