Physiological activities and bioactive compound from laver (Pyropia yezoensis) hydrolysates by using subcritical water hydrolysis

Assessing and optimizing the bioactivities of diverse enzyme-derived protein hydrolysates from Porphyra yezoensis: unlocking the health potential

The interest in algae-derived bioactive compounds has grown due to their potential therapeutic efficacy against a range of diseases. These compounds, derived from proteins, exhibit diverse functions and profound pharmacological effects. Recent research has highlighted the extensive health benefits of algae-derived bioactive compounds, positioning them as potential natural antioxidants in the food, pharmaceutical, and cosmetic industries. This study focuses on extracting proteins from Porphyra yezoensis using innovative physical pre-treatment methods such as stirring, ball milling, and homogenization, under various acidic and alkaline conditions. Enzymatic hydrolysis, employing commercial enzymes at optimal temperature, pH, and enzyme-substrate ratios, produced distinct fractions according to molecular weight. Pepsin demonstrated the highest hydrolysis rate, with the fraction above 10 kDa identified as the most bioactive hydrolysate. Antioxidant activity was evaluated through DPPH, ABTS, ferrous ion chelation, and reducing power assays, demonstrating high antioxidant potential and the ability to mitigate oxidative stress. The 10 kDa fraction of pepsin hydrolysate exhibited 82.6% DPPH activity, 77.5% ABTS activity, 88.4% ferrous ion chelation activity, and higher reducing power potential (0.84 absorbance at 700 nm). Further exploration of mechanisms, amino acid profiles, and potential in vivo benefits is essential to fully exploit the medicinal potential of these algae-derived hydrolysates.

Subcritical Water Extraction of Undaria pinnatifida: Comparative Study of the Chemical Properties and Biological Activities across Different Parts

The subcritical water extraction of Undaria pinnatifida (blade, sporophyll, and root) was evaluated to determine its chemical properties and biological activities. The extraction was conducted at 180 °C and 3 MPa. Root extracts exhibited the highest phenolic content (43.32 ± 0.19 mg phloroglucinol/g) and flavonoid content (31.54 ± 1.63 mg quercetin/g). Sporophyll extracts had the highest total sugar, reducing sugar, and protein content, with 97.35 ± 4.23 mg glucose/g, 56.44 ± 3.10 mg glucose/g, and 84.93 ± 2.82 mg bovine serum albumin (BSA)/g, respectively. The sporophyll contained the highest fucose (41.99%) and mannose (10.37%), whereas the blade had the highest galactose (48.57%) and glucose (17.27%) content. Sporophyll had the highest sulfate content (7.76%). Key compounds included sorbitol, glycerol, L-fucose, and palmitic acid. Root extracts contained the highest antioxidant activity, with IC50 values of 1.51 mg/mL (DPPH), 3.31 mg/mL (ABTS+), and 2.23 mg/mL (FRAP). The root extract exhibited significant α-glucosidase inhibitory activity with an IC50 of 5.07 mg/mL, indicating strong antidiabetic potential. The blade extract showed notable antihypertensive activity with an IC50 of 0.62 mg/mL. Hence, subcritical water extraction to obtain bioactive compounds from U. pinnatifida, supporting their use in functional foods, cosmetics, and pharmaceuticals is highlighted. This study uniquely demonstrates the variation in bioactive compound composition and bioactivities across different parts of U. pinnatifida, providing deeper insights. Significant correlations between chemical properties and biological activities emphasize the use of U. pinnatifida extracts for chronic conditions.

Potential of Subcritical Water Hydrolysis to Valorize Low-Valued Ray-Finned Fish (Labeobarbus nedgia): Effects of Hydrolysis Temperature and Pressurization Agent

Subcritical water (SCW) hydrolysis was applied to valorize the low-valued ray-finned fish (Labeobarbus nedgia) into valuable protein hydrolysates, employing N2 and CO2 as pressurization agents at varying temperatures (140, 160, 180, and 200 °C). The degree of hydrolysis (DH) and total free amino acid content increased with temperature for both pressurizing agents. The highest DH (54.5 ± 0.4%) and total free amino acid content (210 ± 1 mg/gprot) were observed at 200 °C when CO2 gas was used as the pressurizing agent. Predominantly, glycine and alanine were released for both pressurizing agents. The antioxidant activity, evaluated through three different assays, increased with temperature and was found to be the highest at 200 °C. This study illustrated the advantages of the intensified SCW technology by using CO2 as a pressurization agent in valorizing low-valued ray-finned fish (Labeobarbus nedgia), as animal residue rich in proteins, for the production of valuable protein hydrolysates with a high fraction of valuable free amino acids, which could offer potential applications as a functional ingredient in the food industry.

Process optimization and characterization of hydrolysate from underutilized brown macroalgae (Padina tetrastromatica) after fucoidan extraction through subcritical water hydrolysis

The growing demand for macroalgal biomass as a source of proteins, peptides, and amino acids is garnering attention for their biological and functional properties. This study depicts the use of emerging green techniques, i.e. subcritical water, to hydrolyze protein from Padina tetrastromatica. The biomass was treated with subcritical water at varying temperatures between 100 and 220 °C for 10-40 min at a biomass to water proportion of 1:50 (w/v) and pressure of 4.0 MPa. The optimum conditions for recovering the maximum protein (127.2 ± 1.1 mg g-1), free amino acids (58.4 ± 1.0 mg g-1), highest degree of hydrolysis (58.8 ± 1.2 %) and low molecular weight peptides (<650 Da) were found to be 220 °C for 10 min. The amino acid profiling of the hydrolysate revealed that it contains 45 % essential amino acids, with the highest concentration of methionine (0.18 %), isoleucine (0.12 %) and leucine (0.10 %). It was found that the hydrolysate contains phenolics (23.9 ± 1.4 mg GAE g-1) and flavonoids (1.23 ± 0.1 mg QE g-1), which are largely responsible for antioxidant activity. The hydrolysate effectively inhibits acetylcholinesterase and α-amylase in vitro, with IC50 values of 17.9 ± 0.1 mg mL-1 and 16.0 ± 0.5 %, respectively, which can help prevent Alzheimer's disease and diabetes mellitus. Consequently, this study reveals that utilizing eco-friendly subcritical water hydrolysis method, 79 % of the protein was recovered from P. tetrastromatica, which might be an effective source of bioactive peptides in various nutraceutical, pharmaceutical and cosmeceutical applications.

Plant-based proteins: advanced extraction technologies, interactions, physicochemical and functional properties, food and related applications, and health benefits

Even though plant proteins are more plentiful and affordable than animal proteins in comparison, direct usage of plant-based proteins (PBPs) is still limited because PBPs are fed to animals as feed to produce animal-based proteins. Thus, this work has comprehensively reviewed the effects of various factors such as pH, temperature, pressure, and ionic strength on PBP properties, as well as describes the protein interactions, and extraction methods to know the optimal conditions for preparing PBP-based products with high functional properties and health benefits. According to the cited studies in the current work, the environmental factors, particularly pH and ionic strength significantly affected on physicochemical and functional properties of PBPs, especially solubility was 76.0% to 83.9% at pH = 2, while at pH = 5.0 reduced from 5.3% to 9.6%, emulsifying ability was the lowest at pH = 5.8 and the highest at pH 8.0, and foaming capacity was lowest at pH 5.0 and the highest at pH = 7.0. Electrostatic interactions are the main way for protein interactions, which can be used to create protein/polysaccharide complexes for food industrial purposes. The extraction yield of proteins can be reached up to 86-95% with high functional properties using sustainable and efficient routes, including enzymatic, ultrasound-, microwave-, pulsed electric field-, and high-pressure-assisted extraction. Nondairy alternative products, especially yogurt, 3D food printing and meat analogs, synthesis of nanoparticles, and bioplastics and packaging films are the best available PBPs-based products. Moreover, PBPs particularly those that contain pigments and their products showed good bioactivities, especially antioxidants, antidiabetic, and antimicrobial.

Exploring Bioactive Compounds in Brown Seaweeds Using Subcritical Water: A Comprehensive Analysis

In this study, we characterized the bioactive properties of three important brown seaweed species, Sargassum thunbergii, Undaria pinnatifida, and Saccharina japonica, by subcritical water extraction (SWE), as these species are well known for their beneficial health effects. Their physiochemical properties, including potential antioxidant, antihypertensive, and α-glucosidase inhibitory activity, and the antibacterial activity of the hydroysates were also analyzed. The highest total phlorotannin, total sugar content, and reducing sugar content in the S. thunbergii hydrolysates were 38.82 ± 0.17 mg PGE/g, 116.66 ± 0.19 mg glucose/g dry sample, and 53.27 ± 1.57 mg glucose/g dry sample, respectively. The highest ABTS⁺ and DPPH antioxidant activities were obtained in the S. japonica hydrolysates (124.77 ± 2.47 and 46.35 ± 0.01 mg Trolox equivalent/g, respectively) and the highest FRAP activity was obtained in the S. thunbergii hydrolysates (34.47 ± 0.49 mg Trolox equivalent/g seaweed). In addition, the seaweed extracts showed antihypertensive (≤59.77 ± 0.14%) and α-glucosidase inhibitory activity (≤68.05 ± 1.15%), as well as activity against foodborne pathogens. The present findings provide evidence of the biological activity of brown seaweed extracts for potential application in the food, pharmaceutical, and cosmetic sectors.

Food Peptides for the Nutricosmetic Industry

In recent years, numerous reports have described bioactive peptides (biopeptides)/hydrolysates produced from various food sources. Biopeptides are considered interesting for industrial application since they show numerous functional properties (e.g., anti-aging, antioxidant, anti-inflammatory, and antimicrobial properties) and technological properties (e.g., solubility, emulsifying, and foaming). Moreover, they have fewer side effects than synthetic drugs. Nevertheless, some challenges must be overcome before their administration via the oral route. The gastric, pancreatic, and small intestinal enzymes and acidic stomach conditions can affect their bioavailability and the levels that can reach the site of action. Some delivery systems have been studied to avoid these problems (e.g., microemulsions, liposomes, solid lipid particles). This paper summarizes the results of studies conducted on biopeptides isolated from plants, marine organisms, animals, and biowaste by-products, discusses their potential application in the nutricosmetic industry, and considers potential delivery systems that could maintain their bioactivity. Our results show that food peptides are environmentally sustainable products that can be used as antioxidant, antimicrobial, anti-aging, and anti-inflammatory agents in nutricosmetic formulations. Biopeptide production from biowaste requires expertise in analytical procedures and good manufacturing practice. It is hoped that new analytical procedures can be developed to simplify large-scale production and that the authorities adopt and regulate use of appropriate testing standards to guarantee the population's safety.

Subcritical Water Treatment for Valorization of the Red Algae Residue after Agar Extraction: Scale-Up from Laboratory to Pilot Plant

The feasibility of industrial subcritical water treatment on Gelidium sesquipedale residue through scaling up from the lab to pilot system in discontinuous mode (geometric scale-up factor = 50), at 130 and 175 °C (5% biomass), was investigated. The maximum volumes of the reactors were 500 mL at the lab-scale and 5 L at the pilot-scale system. At 175 °C, faster extraction/hydrolysis was observed for the pilot plant, but maximum yields were similar: 71.4 and 78.6% for galactans, 9.8 and 10.4% for glucans, and 92.7 and 86.1% for arabinans in pilot scale and lab scale, respectively, while the yields for proteins accounted nearly 40%. The highest yields for amino acids were observed for the smallest ones, while lower yields were determined for polar amino acids. The total phenolic content and color intensity progressively increased along time at lab scale, while a plateau was reached at the pilot level. Lower extraction yields but reproducible results were obtained at 130 °C. Finally, the pilot scale was essayed at a higher biomass loading (15%), and successful results were obtained, supporting the feasibility of the scaling-up process.

Hydrothermal Degradation of Amino Acids

Within the past years, hydrothermal processes have gathered much attention as promising conversion technologies for especially wet biomass. Amino acids are an integral component of biomass, zoo biomass in particular. However, what happens to them during hydrothermal treatment? Reviewing the available literature going back to the mid of the 20th century revealed an astonishing, but still fragmentary view. In fact, two universal degradation reactions could be identified (i. e., deamination and decarboxylation), competing with each other. Thereby, small structural differences may obviously have huge impacts on the fate of individual amino acids. Nevertheless, the amount of available experimental data is relatively scarce in many cases. In this work, the available knowledge about the degradation of 20 proteinogenic amino acids under hydrothermal conditions was presented and discussed critically. The hydrothermal conversion of proteinaceus biomass as well as the Maillard reaction, both extensively reviewed elsewhere, were only touched on.

Protein Hydrolysis by Subcritical Water: A New Perspective on Obtaining Bioactive Peptides

The importance of bioactive peptides lies in their diverse applications in the pharmaceutical and food industries. In addition, they have been projected as allies in the control and prevention of certain diseases due to their associated antioxidant, antihypertensive, or hypoglycemic activities, just to mention a few. Obtaining these peptides has been performed traditionally by fermentation processes or enzymatic hydrolysis. In recent years, the use of supercritical fluid technology, specifically subcritical water (SW), has been positioned as an efficient and sustainable alternative to obtain peptides from various protein sources. This review presents and discusses updated research reports on the use of subcritical water to obtain bioactive peptides, its hydrolysis mechanism, and the experimental designs used for the study of effects from factors involved in the hydrolysis process. The aim was to promote obtaining peptides by green technology and to clarify perspectives that still need to be explored in the use of subcritical water in protein hydrolysis.

Nutritional Value and Biofunctionalities of Two Edible Green Seaweeds (Ulva lactuca and Caulerpa racemosa) from Indonesia by Subcritical Water Hydrolysis

Caulerpa racemosa (sea grapes) and Ulva lactuca (sea lettuces) are edible green seaweeds and good sources of bioactive compounds for future foods, nutraceuticals and cosmeceutical industries. In the present study, we determined nutritional values and investigated the recovery of bioactive compounds from C. racemosa and U. lactuca using hot water extraction (HWE) and subcritical water extraction (SWE) at different extraction temperatures (110 to 230 °C). Besides significantly higher extraction yield, SWE processes also give higher protein, sugar, total phenolic (TPC), saponin (TSC), flavonoid contents (TFC) and antioxidant activities as compared to the conventional HWE process. When SWE process was applied, the highest TPC, TSC and TFC values were obtained from U. lactuca hydrolyzed at reaction temperature 230 °C with the value of 39.82 ± 0.32 GAE mg/g, 13.22 ± 0.33 DE mg/g and 6.5 ± 0.47 QE mg/g, respectively. In addition, it also showed the highest antioxidant activity with values of 5.45 ± 0.11 ascorbic acid equivalents (AAE) mg/g and 8.03 ± 0.06 trolox equivalents (TE) mg/g for ABTS and total antioxidant, respectively. The highest phenolic acids in U. lactuca were gallic acid and vanillic acid. Cytotoxic assays demonstrated that C. racemosa and U. lactuca hydrolysates obtained by HWE and SWE did not show any toxic effect on RAW 264.7 cells at tested concentrations after 24 h and 48 h of treatment (p < 0.05), suggesting that both hydrolysates were safe and non-toxic for application in foods, cosmeceuticals and nutraceuticals products. In addition, the results of this study demonstrated the potential of SWE for the production of high-quality seaweed hydrolysates. Collectively, this study shows the potential of under-exploited tropical green seaweed resources as potential antioxidants in nutraceutical and cosmeceutical products.

A Review on the Extraction and Processing of Natural Source-Derived Proteins through Eco-Innovative Approaches

In addition to their nutritional and physiological role, proteins are recognized as the major compounds responsible for the rheological properties of food products and their stability during manufacture and storage. Furthermore, proteins have been shown to be source of bioactive peptides able to exert beneficial effects on human health. In recent years, scholarly interest has focused on the incorporation of high-quality proteins into the diet. This fact, together with the new trends of consumers directed to avoid the intake of animal proteins, has boosted the search for novel and sustainable protein sources and the development of suitable, cost-affordable, and environmentally friendly technologies to extract high concentrations of valuable proteins incorporated into food products and supplements. In this review, current data on emergent and promising methodologies applied for the extraction of proteins from natural sources are summarized. Moreover, the advantages and disadvantages of these novel methods, compared with conventional methods, are detailed. Additionally, this work describes the combination of these technologies with the enzymatic hydrolysis of extracted proteins as a powerful strategy for releasing bioactive peptides.

Green extraction of proteins, umami and other free amino acids from brown macroalgae Ascophyllum nodosum and Fucus vesiculosus

Seaweeds are a valuable potential source of protein, as well as free amino acids (FAAs) with umami flavour which are in high demand by the food industry. The most commonly used flavouring agents in the food industry are chemically synthesised and therefore are subject to concerns regarding their safety and associated consumer resistance. This study focuses on the effects of extraction time (1 and 2 h) and solvents (0.1 M HCl, 1% citric acid and deionised water) on the extraction of protein and FAAs including umami FAAs from Irish brown seaweeds (Ascophyllum nodosum and Fucus vesiculosus). Extraction yields were influenced by both the extraction solvent and time, and also varied according to the seaweed used. Both seaweeds investigated were found to be good sources of protein, FAAs including umami FAAs, demonstrating potential application as flavouring agents in the food industry. Overall, the use of green solvents (deionised water and citric acid) resulted in higher recoveries of compounds compared to HCl. The results of this study will facilitate the use of more sustainable solvents in industry for the extraction of proteins and flavouring agents from seaweed.

Production and processing of antioxidant bioactive peptides: A driving force for the functional food market

Recently, the demand for functional foods in the global market has increased rapidly due to the increasing occurrences of non-communicable diseases and technological advancement. Antioxidant peptides have been suggested as ingredients used to produce health-promoting foods. These peptides are encrypted from various food derived protein sources by chemical and enzymatic hydrolysis, and microbial fermentation. However, the industrial-scale production of antioxidant peptides is hampered by different problems such as high production cost, and low yield and bioactivity. Accordingly, novel processing technologies, such as high pressure, microwave and pulsed electric field, have been recently emerged to overcome the problems associated with the conventional hydrolysis methods. This particular review, therefore, discussed the current processing technologies used to produce antioxidant peptides. The review also suggested further perspectives that should be addressed in the future.