Impact of in vitro gastrointestinal digestion on peptide profile and bioactivity of cooked and non-cooked oat protein concentrates

Abstract

Oat ( Avena sativa ) is one of the most cultivated and consumed cereals worldwide. Recognized among cereals for its high protein content (12%–24%), it makes it an excellent source of bioactive peptides, which could be modified during processes such as heating and gastrointestinal digestion (GID). This work aims to evaluate the impact of heat treatment on the proteolysis of oat proteins and on the evolution of antioxidant peptide released during in vitro static GID, in terms of comparative analysis between cooked oat protein concentrate (COPC) and non-heated oat protein concentrate (OPC) samples. The protein extraction method and cooking procedure used showed no detrimental effects on protein quality. After GID, the proportion of free amino acids/dipeptides (<0.2 ​kDa) reached >40% for both samples (OPC and COPC), thus producing peptides with low molecular weight and enhanced bioactivity. Furthermore, during GID, the amino acid profile showed an increase in essential, positively-charged, hydrophobic and aromatic amino acids. At the end of GID, the reducing power of OPC and COPC increased >0.3 and 8-fold, respectively, in comparison to the non-digested samples; while ABTS •+ and DPPH • showed a >20-fold increase. Fe 2+ chelating capacity of OPC and COPC was enhanced >4 times; similarly, Cu 2+ chelation showed a >19-fold enhancement for OPC and >10 for COPC. β-carotene bleaching activity was improved 0.8 times in OPC and >9 times in COPC; the oxygen radical antioxidant capacity assay increased 2 times in OPC and >4.7 times in COPC, respectively. This study suggests that OPC after cooking and GID positively influenced the nutritional and bioactive properties of oat peptides. Thus, COPC could be used as a functional food ingredient with health-promoting effects, as hydrothermal treatment is frequently used for this type of cereals.

Isolation and evaluation of quinoa (Chenopodium quinoa Willd.) protein fractions. A nutritional and bio-functional approach to the globulin fraction

“…In addition to the nutritional aspects, proteins are recognized for their bio-functional properties, with potential to release bioactive peptides ( Sánchez-Velázquez et al, 2021 ; Han et al, 2021 ). Hydrolyzed globulins were tested for their antioxidant activity and ACE inhibitory capacity, and the results are shown in Fig.…”

Production, health‐promoting properties and characterization of bioactive peptides from cereal and legume grains

“…For instance, fermented pea seeds were subjected to in IGD and the samples evaluated for ACE inhibitory potential, 45 the authors found out that only the in vitro‐digested samples had ACE inhibition. In another study evaluating the impact of IGD on peptide profile and bioactivity of cooked and non‐cooked oat protein concentrates, the ability of IGD to produce peptides was very apparent as the digestates had significantly higher antioxidant properties when compared to the non‐digested samples 46 …”

Integrated Technology for Cereal Bran Valorization: Perspectives for a Sustainable Industrial Approach

“…Proteins are well-known for their daily diet significance. Proteins, according to recent studies, are a rich source of biologically active peptides, such as Tyr-Ser-Lys, SSYYPFK, LQAFEPLR, and EFLLAGNNK [ 33 , 34 , 35 ]. Bioactive peptides are specific protein fragments formed by short-chain amino acids with health benefits in the human body beyond their essential nutritional value [ 36 ].…”

“…Oats are grown and consumed worldwide, and their high protein content makes them an excellent source of bioactive peptides (12–24%). Globulins constitute the majority of bioactive protein and have the highest concentration of bioactive peptides, such as SSYYPFK from oat globulin hydrolysates, which can reduce systolic and diastolic blood pressure [ 34 ], and Tyr-Ser-Lys from RB powder, which had an antihypertensive effect [ 33 , 42 ]. Feng Wang and colleagues have identified 22 peptides of oat globulin from the tryptic hydrolysates [ 35 ].…”