Formation of bioactive peptides during simulated gastrointestinal digestion is affected by αs1-casein polymorphism in buffalo milk

Enzymatic hydrolysis of buffalo casein enhances DPP-4 inhibition: Structural modifications and bioactive peptide identification

Dipeptidyl peptidase-4 (DPP-4), the enzyme responsible for the rapid degradation of incretin hormones, plays a pivotal role in blood glucose regulation, and its inhibition serves as an effective strategy for maintaining glucose homeostasis. The aim of this study was to investigate the effect of enzymatic hydrolysis on the structure of buffalo casein and its DPP-4 inhibitory activity. Results demonstrated that Flavorzyme effectively hydrolyzed buffalo casein, as evidenced by scanning electron microscopy and electrophoretic analysis, with the degree of hydrolysis reaching its maximum value (20.05 ± 0.14%) after 3 h. The results of circular dichroism spectra, as well as endogenous and exogenous fluorescence spectra, indicated marked alterations in the secondary and tertiary structures of buffalo casein following enzymatic hydrolysis. Additionally, the DPP-4 inhibitory effect of buffalo casein was found to increase with longer hydrolysis times. The hydrolysate obtained after 3 h of hydrolysis demonstrated the highest level of inhibition, with a half-maximal inhibitory concentration (IC50) value of 1.04 mg/mL. The DPP-4 inhibitory peptide YPFPGPIPN, with an IC50 value of 0.88 mg/mL, was identified in the 1 to 3 kDa fraction of the 3-h hydrolysate. This peptide interacted with the active site of DPP-4 via hydrogen bonds, hydrophobic interactions, salt bridges, and π-cation interactions. This study offers a novel scientific foundation for the development of functional antidiabetic foods derived from buffalo casein.

Exploring structural features of sleep-enhancing peptides derived from casein hydrolysates by chemometrics and random forest methodology

Milk casein is regarded as source to release potential sleep-enhancing peptides. Although various casein hydrolysates exhibited sleep-enhancing activity, the underlying reason remains unclear. This study firstly revealed the structural features of potential sleep-enhancing peptides from casein hydrolysates analyzed through peptidomics and multivariate analysis. Additionally, a random forest model and a potential Tyr-based peptide library were established, and then those peptides were quantified to facilitate rapidly-screening. Our findings indicated that YP-, YI/L, and YQ-type peptides with 4-10 amino acids contributed more to higher sleep-enhancing activity of casein hydrolysates, due to their crucial structural features and abundant numbers. Furthermore, three novel strong sleep-enhancing peptides, YQKFPQY, YPFPGPIPN, and YIPIQY were screened, and their activities were validated in vivo. Molecular docking results elucidated the importance of the YP/I/L/Q- structure at the N-terminus of casein peptides in forming crucial hydrogen bond and π-alkyl interactions with His-102 and Asn-60, respectively in the GABAA receptor for activation.

Influence of bile salts on the gastrointestinal digestion of agar-casein hybrid systems and the nanoassembly of their digestion products

This manuscript reports on the effect of different bile salts concentration on the gastrointestinal digestion of casein and casein-agar hybrid systems and evaluates the effect on the nanostructural assembly of the digestion products through the application of advanced small angle X-ray scattering analysis (SAXS). The results showed that bile salts promote the hydrolysis of micellar casein upon in vitro gastrointestinal digestions. It is noteworthy that in the presence of agar, bile salts interact with the polysaccharide, leading to a reduction in their proteolytic activity. While structured agar-casein hydrogels were shown to be able to limit the proteolysis during the gastric phase, increasing concentrations of bile salts promoted the diffusion of casein from the gel network during the intestinal phase, hence leading to higher degree of hydrolysis. The released digestion products were seen to interact with bile salts, forming ordered lamellar/micellar nanostructures. In particular, the presence of solubilized agar in the digesta was seen to promote the formation of these nanostructures. These nanostructures were formed at 10 mM bile salts for the hydrogels, and across all concentrations for agar-casein blends. Thus, this work demonstrates the great relevance of bile salts in the nanostructural assembly of protein digestion products, which is expected to have a great relevance in bioavailability and metabolic responses induced by protein-rich foods.

An Overview of the Occurrence of Bioactive Peptides in Different Types of Cheeses

The search for improvements in quality of life has increasingly involved changes in the diet, especially the consumption of foods which, in addition to having good nutritional value, are characterized by offering health benefits. Among the molecules that trigger several beneficial responses are peptides, which are specific fragments of proteins known to produce positive effects on the human body. This review aimed to discuss the bioactive potential of peptides from cheeses. Studies show that the protein composition of some cheese varieties exhibits a potential for the release of bioactive peptides. The production of these peptides can be promoted by some technological procedures that affect the milk structure and constituents. The cheese maturation process stands out for producing bioactive peptides due to the action of enzymes produced by lactic acid bacteria. Thus, in addition to being proteins with high biological value due to their excellent amino acid profile, peptides from some types of cheeses are endowed with functional properties such as anti-hypertensive, antimicrobial, antioxidant, anticarcinogenic, opioid, and zinc-binding activities.

Food-derived bioactive peptides as momentous food components: Can functional peptides passed through the PI3K/Akt/mTOR pathway and NF-κB pathway to repair and protect the skeletal muscle injury?

Muscle injury is defined as an overuse injury or traumatic distraction of a muscle, which is latent in any sport event, from amateur to large events. Based on previous numbers of muscle injuries and time spent to the athletes' recovery, the use of dietary functional factors intervention strategies is essential to enhance the recovery process and health. In recent years, there has been increasing evidence that biologically active peptides played an important role in sports nutrition and muscle injure recovery. Food-derived bioactive peptides were physiologically active peptides mostly derived from proteins following hydrolysis, which could be resorbed in intact form to reduce muscle damage following exercise and induce beneficial adaptions within the connective tissue. However, the complexity of the histoarchitectural considerations for skeletal muscle injuries and the repair mechanism of damaged skeletal muscle were not well known. In the following overview, the potential mechanisms and possible limitations regarding the damaged skeletal muscle metabolism were summarized, which aimed to present an overview of the nutritional strategies and recommendations after a muscular sports injury, emphasizing the use of main bioactive peptides. In addition, this review will provide implications for the studies of dietary bioactive peptides in the future.

Conventional and in silico approaches to select promising food-derived bioactive peptides: A review

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Seaweed and edible insects are considered new sources of bioactive peptides.

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Conventional approaches are necessary to validate the bioactivity of peptides.

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Bioinformatics tools accelerate the obtaining of bioactive peptides.

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The integrated approach is a promising strategy to obtain bioactive peptides.

The interest for food-derived bioactive peptides, either from common or unconventional sources, has increased due to their potential therapeutic effect against a wide range of diseases. The study of such bioactive peptides using conventional methods is a long journey, expensive and time-consuming. Hence, bioinformatic approaches, which can not only help to predict the formation of bioactive peptides from any known protein source, but also to analyze the protein structure/function relationship, have gained a new meaning in this scientific field. Therefore, this review aims to provides an overview of conventional characterization methods and the most recent advances in the field of in silico approaches for predicting and screening promising food-derived bioactive peptides.

Bioactive peptides from foods: production, function, and application

Bioactive peptides are a class of peptides with special physiological functions and have potential applications in human health and disease prevention. Bioactive peptides have gained much research attention because they affect the cardiovascular, endocrine, immune, and nervous systems. Recent research has reported that bioactive peptides are of great value for physiological function regulation, including antioxidation, anti-hypertension, antithrombosis, antibacterial properties, anti-cancer, anti-inflammation, anti-diabetic, anti-obesity, cholesterol-lowering, immunoregulation, mineral binding and opioid activities. The production of food-derived bioactive peptides is mainly through the hydrolysis of digestive enzymes and proteolytic enzymes or microbial fermentation. The purpose of this review is to introduce the production, function, application, challenges, and prospects of food-derived bioactive peptides.

Identification of bioactive peptides released from in vitro gastrointestinal digestion of yam proteins (Dioscorea cayennensis)

Bioactive peptides have been broadly studied for their contribution to human health. This study aimed to identify bioactive peptides generated by in vitro gastrointestinal digestion of yam proteins. Yam protein concentrate (YPC) was submitted to simulated digestion. Gastric phase hydrolysate (GPH) and total gastrointestinal phase hydrolysate (GIPH) had their peptides identified by nanoLC-ESI-MS/MS. Peptide sequences were subjected to a database-driven (BIOPEP) bioactivity search. In vitro tests included: Antioxidant activity, DNA damage protection, ACE-inhibitory activity and antibacterial activity against the bacteria Escherichia coli, Salmonella sp. and Lysteria monocytogenes. Simulated digestion generated small peptides (mostly MW < 3500 Da), several of them with potential bioactive sequences predicted in silico. In both GPH and GIPH biological activities were detected, although GIPH displayed stronger DNA damage protection and antibacterial activity against Escherichia coli. The digestion of yam proteins releases promising biologically active peptides which can contribute to the prevention of bacterial infection and chronic degenerative diseases, with beneficial effects to human health.