In vitro gastrointestinal digestion simulation screening of novel ACEI peptides from broccoli: mechanism in high glucose-induced VSMCs dysfunction

Many natural angiotensin-converting enzyme inhibitory (ACEI) peptides have been widely studied. However, their stability in vivo is poor in most cases. In this study, peptides were initially digested from broccoli in vitro, and absorption was simulated by Caco2 cells transport and then analyzed by Peptideomics and molecular docking. Subsequently, the mechanisms were verified using a high glucose-induced vascular smooth muscle cells (VSMCs) dysfunction model. Results showed that ACEI activity of broccoli crude peptide increased by 70.73 ± 1.42% after digestion. The enzymatic hydrolysates of crude broccoli peptides before and after digestion were detected by HPLC. The digested crude peptides were highly stable (with a stability level > 90%) in the intestine and possessed a strong absorptive potential. Five peptides with high stability and strong permeability were first identified, including HLEVR, LTEVR, LEHGF, HLVNK, and LLDGR, which exhibited high activity with IC50 values of 3.19 ± 0.23 mM, 17.07 ± 1.37 mM, 0.64 ± 0.02 mM, 0.06 ± 0.01 mM, and 2.81 ± 0.12 mM, respectively. When the VSMCs model was exposed to Ang II, the expressions of PCNA, MMP2, and Bcl2 were increased, while the expression of BAX was inhibited. When the VSMCs was exposed to high glucose (HG), the Ang II concentration significantly increased. This indicates that HG elevated Ang II levels. Finally, five peptides significantly attenuated Ang II-induced VSMCs proliferation and migration by down-regulating AT1R expression and inhibiting ERK and p38 MAPK phosphorylation. Notably, in exploring VSMCs dysfunction on a high glucose-induced model, ACEI peptides resulted in down-regulation of ACE and up-regulation of ACE2 expression. Therefore, it can be further referenced for the functional food against hypertension and cardiovascular diseases.

Structural and functional properties of fava bean albumin, globulin and glutelin protein fractions

This study reports a comparative evaluation of the physicochemical and functional properties of fava bean albumin, globulin and glutelin proteins. The fava bean globulins had significantly (p < 0.05) higher protein content (88.49 %) than the albumin (83.47 %) and glutelin (86.71 %). Far-UV circular dichroism results indicate low contents of α-helix, but high levels of unordered and β-sheet structures in the albumin and globulin. Higher surface hydrophobicity of the globulins was directly related to formation of oil-in-water emulsions with smaller oil droplet sizes, and better foaming capacity than the albumin and glutelin. The albumin had a broad range (32-92 %) of protein solubility that covers acidic and alkaline pH while glutelin exhibited significantly higher in vitro protein digestibility (77.33 %) when compared to the 75.34 and 71.73 % for globulin and albumin, respectively. We conclude that each fava bean protein fraction may find specific uses as ingredients for the formulation of various food products.

Preparation and nutritional characterisation of protein concentrate prepared from foxtail millet (Setaria italica)

Plant-based protein sources as a sustainable alternative to animal sources are highly relevant for food and dietary supplements industries. Plant proteins are becoming popular as an eco-friendly source for meeting global protein requirements due to their importance in nutrition, management of metabolic diseases, biological activities, functionality in processed food products and their low carbon footprints. We applied biochemical protein extraction protocol and prepared protein concentrate from an underutilised cereal, foxtail millet, with plausible applications in foods and supplements. Herein efforts were utilised to obtain foxtail millet protein (FMP) concentrate by means of standardisation of processes of extraction cum isolation. The conditions including flour to solvent ratio, extraction-precipitation pH, dissolution time, etc. were optimised to significantly improve protein yield and recovery. The FMP concentrate prepared was also analysed for nutritional composition, bioactive compounds, amino acid content and digestion properties in comparison to packaged brown rice protein concentrate. The protein concentrate prepared was found to have high digestibility, rich in essential amino acids with good phenolic and flavonoid content, thereby making it a potential sensory and antioxidant additive for food/pharmaceutical applications.

A comparative evaluation of the structure, functionality and volatile profiles of Trichosanthes kirilowii seed protein isolates based on different extraction methods

In the present study, we hypothesised that Trichosanthes kirilowii seed protein isolate (TPI) obtained by different extraction methods have distinct structure, functional attributes and volatile profiles. Alkaline-extracted isolate (AE-TPI) exhibited lower protein content and a darker colour than the other two isolates because more polyphenols and pigments were coextracted. Salt-extracted isolate (SE-TPI) and AE-TPI had higher in vitro protein digestibility than reverse micelle-extracted isolate (RME-TPI) due to higher degrees of denaturation, which enabled them to be more susceptible to proteolysis. The SE-TPI gel resulted in a stronger gel network and greater hardness than the other two isolate gels. In the volatile profile, SE-TPI (22) yielded the largest number of volatile compounds, followed by AE-TPI (20) and RME-TPI (15). The current results indicated that the structure, functional properties and volatile profiles of TPI are largely influenced by the extraction technique.

Precision formulation, a new concept to improve dietary amino acid absorption based on the study of cationic amino acid transporters

Amino acid (AA) transporters (AAT) control AA cellular fluxes across membranes, contributing to maintain cellular homeostasis. In this study, we took advantage of rainbow trout metabolic feature, which highly relies on dietary AA, to explore the cellular and physiological consequences of unbalanced diets on AAT dysregulations with a particular focus on cationic AAs (CAA), frequently underrepresented in plant-based diets. Results evidenced that 24 different CAAT are expressed in various trout tissues, part of which being subjected to AA- and CAA-dependent regulations, with y+LAT2 exchanger being prone to the strongest dysregulations. Moreover, CAA were shown to control two major AA-dependent activation pathways (namely mTOR and GCN2) but at different strength according to the CAA considered. A new feed formulation strategy has been put forward to improve specifically the CAA supplemented absorption in fish together with their growth performance. Such "precision formulation" strategy reveals high potential for nutrition practices, especially in aquaculture.

Potential antihypertensive activity of novel peptides from green basil leaves

Hypertension is among the risk factors of death globally. Novel antihypertensive peptides are alternative choices of antihypertensive assistance. This study aimed to discover novel antihypertensive peptides from green basil leaves. Two bioactive peptides with high angiotensin-converting enzyme inhibition (Asp-Leu-Ser-Ser-Ala-Pro; peptide 1) and antioxidant (Asp-Ser-Val-Ser-Ala-Ser-Pro; peptide 2) activities were gavaged to male Wistar rats induced with NG-nitro-l-arginine methyl-ester (L-NAME). L-NAME-treated rats (HT) had decreased body weights and levels of nitrite and nitrate, which are metabolites of nitric oxide. The levels of their glucose and liver function indicators increased as compared to normal rats. HT rats receiving antihypertensive drugs (HTD) showed higher low-density lipoprotein and low-density lipoprotein/high-density lipoprotein levels than HT rats. Peptide 1 seems to benefit the rat lipid profiles, liver functions, antioxidant, nitrite, nitrate, and angiotensin II peptide levels but not peptide 2. In conclusion, our findings indicate the antihypertensive potential related to vasodilation of peptides from green basil leaves.

Recovery of Protein from Industrial Hemp Waste (Cannabis sativa, L.) Using High-Pressure Processing and Ultrasound Technologies

Hemp seeds are currently used mainly for oil extraction, generating waste that could be potentially exploited further as a source of proteins and other bioactives. This study aims to valorise hemp waste (Cannabis sativa, L.) from previous oil extraction as a source of protein by analysing the effect of high-pressure processing (HPP) pre-treatments (0-600 MPa; 4-8 min) combined with conventional or ultrasound-assisted extraction (UAE) methods on protein recovery/purity, amino acid composition, and protein structure. Overall, maximum protein recovery (≈62%) was achieved with HPP (200 MPa, 8 min) with UAE. The highest protein purity (≈76%) was achieved with HPP (200 MPa, 4 min) with UAE. Overall, UAE improved the extraction of all amino acids compared to conventional extraction independently of HPP pre-treatments. Arg/Lys ratios of the protein isolates ranged between 3.78 and 5.34, higher than other vegetable protein sources. SDS-PAGE did not show visible differences amongst the protein isolates. These results seem to indicate the advantages of the use of UAE for protein recovery in the food industry and the need for further studies to optimise HPP/UAE for an accurate estimation of processing costs and their effects on the composition and structure of proteins to contribute further to the circular economy.

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

The search for bioactive components for the development of functional foods and nutraceuticals has received tremendous attention. This is due to the increasing awareness of their therapeutic potentials, such as antioxidant, anti-inflammatory, antihypertensive, anti-cancer properties, etc. Food proteins, well known for their nutritional importance and their roles in growth and development, are also sources of peptide sequences with bioactive properties and physiological implications. Cereal and legume grains are important staples that are processed and consumed in various forms worldwide. However, they have received little attention compared to other foods. This review therefore is geared towards surveying the literature for an appraisal of research conducted on bioactive peptides in cereal and legume grains in order to identify what the knowledge gaps are. Studies on bioactive peptides from cereal and legume grains are still quite limited when compared to other food items and most of the research already carried out have been done without identifying the sequence of the bioactive peptides. However, the reports on the antioxidative, anticancer/inflammatory, antihypertensive, antidiabetic properties show there is much prospect of obtaining potent bioactive peptides from cereal and legume grains which could be utilized in the development of functional foods and nutraceuticals.

Evaluating the Potential of the Defatted By-Product of Aurantiochytrium sp. Industrial Cultivation as a Functional Food

While Aurantiochytrium sp. is an increasingly popular source of polyunsaturated fatty acids (PUFAs), its extraction generates high amounts of waste, including the spent, defatted residue. The composition and bioactivities of this by-product could prove to be a major part of the sustainable valorisation of this organism within the framework of a circular economy. In this study, the defatted biomass of commercial Aurantiochytrium sp. was nutritionally characterised, and its amino acid profile was detailed. Additionally, the antioxidant and prebiotic potentials of an enzymatically digested sample of defatted Aurantiochytrium sp. were evaluated under a set of miniaturised in vitro assays. The nutritional profile of the spent Aurantiochytrium biomass revealed a protein and dietary-fibre rich product, with values reaching 26.7% and 31.0% for each, respectively. It also held high concentrations of glutamic and aspartic acid, as well as a favourable lysine/arginine ratio of 3.73. The digested samples demonstrated significant Weissela cibaria and Bifidobacterium bifidum growth-enhancing potential. Residual ferric reducing antioxidant power (FRAP) activity was likely attributed to antioxidant amino acids or peptides. The study demonstrated that some of the nutritional and functional potential that reside in the defatted Aurantiochytrium sp. waste encourages additional studies and the development of food supplements employing this resource's by-products under a biorefinery framework.

Functional foods and bioactive ingredients harnessed from the ocean: current status and future perspectives

With an increase in life expectancy and decrease of quality-of-life couple with the high prevalence of diseases, diet is expected to play a key function in sustaining human health. Nutritionists, food technologists and medical experts are working in synergy to cater for the increasing demand of food with associated therapeutic benefits, commonly known as functional food, that may improve well-being and reduce the risk of diseases. Interestingly, the marine ecosystem, due to its abundant and phenomenal biodiversity of marine organisms, constitutes a vital source of a panoply of healthy foods supply for the thriving functional food industry. Marine organisms such as seaweeds, sea cucumbers, sponges, and mollusks amongst others are sources of thousands of biologically active metabolites with antioxidant, anti-parasitic, antiviral, anti-inflammatory and anticancer properties. Given the growing number of research and interest to probe into the therapeutic roles of marine products, this review was designed to provide a comprehensive summary of the therapeutic properties of marine organisms (macroalgae, sea cucumbers and fish among others) which are consumed worldwide, in addition to their potentials and as sources of functional ingredients for developing novel food and fostering wellness. The gap between research development and actual commercialization, and future prospects of marine-based products also summarized to some extent.

Dietary L-citrulline supplementation modulates nitric oxide synthesis and anti-oxidant status of laying hens during summer season

Background

L-citrulline (L-Cit), a non-protein amino acid, has been implicated in several physiological functions including anti-inflammatory, anti-oxidative, and hypothermic roles, however, there is a paucity of information with regards to its potential in poultry production.

Methods

This study was designed to investigate the effects of dietary L-Cit supplementation on the production performance, nitric oxide production, and antioxidant status of laying hens during summer period. Hy-Line Brown laying hens (n = 288, 34 weeks old) were allotted to four treatment, 6 replicates of 12 chickens each. Dietary treatments of control (basal diets), 0.25%, 0.50% and 1.00% L-Cit supplementation were fed to chickens for eight (8) weeks. Production performance, free amino acid profiles, nitric oxide production, and antioxidant properties were measured. Blood samples were collected at the 4^th and 8^th weeks of the experiment.

Results

Air temperature monitoring indicated an average daily minimum and maximum temperatures of 25.02 °C and 31.01 °C respectively. Dietary supplementation with L-Cit did not influence (P > 0.05) the production performance, and rectal temperature of laying hens. Egg shape index was increased (P < 0.05) with increasing levels of L-Cit. Serum-free content of arginine, citrulline, ornithine, tryptophan, histidine, GABA, and cystathionine were elevated, but taurine declined with L-Cit diets. Plasma nitric oxide (NO_x) concentration was highest at 1% L-Cit. Likewise, nitric oxide synthase (NOS) activity for total NOS (tNOS) and inducible NOS (iNOS) were upregulated with increasing L-Cit levels, although, tNOS was not affected at the 4^th week. Anti-oxidant enzymes including catalase and superoxide dismutase (SOD) were increased with L-Cit supplementation, however, SOD activity was unchanged at 4^th week, while total anti-oxidant capacity increased at the 8^th week. L-Cit supplementation attenuated the extent of lipid peroxidation, and also inhibited glutathione peroxidase activity.

Conclusion

Dietary L-Cit supplementation modulated systemic arginine metabolism, nitric oxide synthesis, antioxidant defense system, and increased the egg shape index of laying hens during the summer season. 1% L-Cit supplementation proved most effective in potentiating these effects and may be adopted for feed formulation strategies.

Physicochemical Characteristics of Protein Isolated from Thraustochytrid Oilcake

The oil from thraustochytrids, unicellular heterotrophic marine protists, is increasingly used in the food and biotechnological industries as it is rich in omega-3 fatty acids, squalene and a broad spectrum of carotenoids. This study showed that the oilcake, a by-product of oil extraction, is equally valuable as it contained 38% protein/dry mass, and thraustochytrid protein isolate can be obtained with 92% protein content and recovered with 70% efficiency. The highest and lowest solubilities of proteins were observed at pH 12.0 and 4.0, respectively, the latter being its isoelectric point. Aspartic acid, glutamic acid, histidine, and arginine were the most abundant amino acids in proteins. The arginine-to-lysine ratio was higher than one, which is desired in heart-healthy foods. The denaturation temperature of proteins ranged from 167.8–174.5 °C, indicating its high thermal stability. Proteins also showed high emulsion activity (784.1 m²/g) and emulsion stability (209.9 min) indices. The extracted omega-3-rich oil melted in the range of 30–34.6 °C and remained stable up to 163–213 °C. This study shows that thraustochytrids are not only a valuable source of omega 3-, squalene- and carotenoid-containing oils, but are also rich in high-value protein with characteristics similar to those from oilseeds.

Metabolomics Elucidates Dose-Dependent Molecular Beneficial Effects of Hesperidin Supplementation in Rats Fed an Obesogenic Diet

Metabolic syndrome (MetS) is a global epidemic concern. Polyphenols are proposed as good candidates for its prevention, although their mechanisms are not fully understood. The gut microbiota seems to play a key role in polyphenol beneficial effects. Here, we assessed the effects of the citrus polyphenol hesperidin combining an untargeted metabolomics approach, which has an inherent potential to elucidate the host-microbiome interplay, with extensive anthropometric and biochemical characterizations and integrating metabolomics results with our previous 16S rRNA bacterial sequencing data. The rats were fed either a standard or an obesogenic cafeteria diet (CAF) for 17 weeks. After nine weeks, rats were supplemented with vehicle; low- (H1), or high- (H2) hesperidin doses. CAF animals developed MetS features. Hesperidin supplementation in CAF rats decreased the total cholesterol, LDL-C, and free fatty acids. The highest hesperidin dose also ameliorated blood pressure, insulin sensitivity, and decreased markers of arterial stiffness and inflammation. Metabolomics revealed an improvement of the lipidomic profile, decreases in circulating amino acids, and lower excretions of inflammation- and oxidative stress-related metabolites. Bacteroidaceae increases in the CAF-H2 group paralleled higher excretions of microbial-derived metabolites. Overall, our results provide detailed insights into the molecular effects of hesperidin on MetS and suggest that it is a promising prebiotic for the treatment of MetS and related conditions.

Effects of thermal processing on the nutritional and functional properties of defatted conophor nut (Tetracarpidium conophorum) flour and protein isolates

Conophor nut (Tetracarpidium conophorum) was processed using different heat treatments to explore its full potential as food ingredients. The raw, boiled, and toasted nuts were defatted and the proteins isolated by alkaline solubilization and isoelectric precipitation. The variously processed nuts were analyzed for the proximate and amino acid compositions, and functional properties. The protein contents of the isolate ranges between 86.86 g/100g and 87.74 g/100 g, about 1.5-fold higher than those of the defatted flour samples. The essential amino acids of the isolates ranged between 40.57%-41.55%. Glutamic acid, aspartic acid, and arginine were the most predominant amino acids, while methionine and lysine were the first and second limiting amino acids, respectively. The protein efficiency ratio, biological values as well as the functional properties of the proteins were improved with processing. These properties may enhance the potential use of conophor nut protein isolates as high-quality protein ingredient in food systems.