Protein Enrichment of Wheat Bread with Microalgae: Microchloropsis gaditana, Tetraselmis chui and Chlorella vulgaris

Microwave-assisted extraction of proteins from Pseudochlorella pringsheimii: Optimization and application in fortified high-protein buns

For optimizing the process of protein extraction through microalga Pseudochlorella pringsheimii, microwave-assisted extraction (MAE) was selected. After model validation and verification, the optimized values obtained for biomass concentration, microwave power and microwave time was 3.15 %, 200 W and 116 s, respectively. The extracted microalgae protein concentrates (MPC) were utilized for developing fortified high-protein buns. Comparative analysis of buns formulated by incorporating microalgae protein concentrate (MPC) and decolorized microalgae biomass (DMB) was carried out for nutritional, textural, and colour characteristics. The results revealed that fortification of buns with MPC significantly increased the protein content as compared to DMB fortified and control buns. The current work opens a new door for food industrialists to formulate products in such a way that can potentially enhance the nutritive properties (especially protein content) without adversely affecting its other desired characteristics.

Effects of black soybean peel anthocyanins on the structural and functional properties of wheat gluten

BACKGROUND

Wheat gluten (WG) is a crucial cereal protein commonly utilized in the food, biological and pharmaceutical industries. However, WG is poorly soluble in water, resulting in poor functional properties, which restrict its application in the food industry. As a result, there is an urgent need for improving the properties of WG.

RESULTS

This study was conducted to examine the functional properties of WG after binding with black soybean peel anthocyanin extract (BAE). Results showed that BAE enhanced the solubility, water-holding and antioxidant capacity, foaming properties and emulsifying activity of WG, while decreasing the emulsion stability. The degree of hydrolysis of WG and retention rate of BAE became higher in the digested WG-BAE complex than in the control groups. Additionally, an analysis was conducted on the mechanism of interaction between cyanidin-3-O-glucoside (C3G) and WG/gliadin (Gli)/glutenin (Glu). The secondary structure of WG/Gli/Glu was altered after adding C3G. C3G had high affinity for WG/Gli/Glu since their binding constants were greater than 104 L mol-1. The primary binding forces between C3G and WG/Gli were hydrophobic interactions, whereas the main interaction forces between C3G and Glu were hydrogen bonding and van der Waals forces. Moreover, C3G increased the thermal stability and changed the network structure of WG/Gli/Glu.

CONCLUSION

This study revealed that BAE effectively enhanced a range of functional properties of WG. The interaction between WG and BAE also improved the bioavailability and nutritional value of them. Furthermore, the interaction mode between BAE and WG was investigated. These findings lay a foundation for utilizing gluten-anthocyanins in the food sector. © 2024 Society of Chemical Industry.

Modulation of Gut Microbiota and Short-Chain Fatty Acid Production by Simulated Gastrointestinal Digests from Microalga Chlorella vulgaris

Chlorella vulgaris is a source of potential bioactive compounds that can reach the large intestine and interact with colonic microbiota. However, the effects of consumption of this microalga on gastrointestinal function have scarcely been studied. This paper simulates, for the first time, the passage of C. vulgaris through the gastrointestinal tract, combining the INFOGEST method and in vitro colonic fermentation to evaluate potential effects on the human colonic microbiota composition by 16S rRNA gene sequencing and its metabolic functionality. The results show that the presence of this microalga increased the release of short-chain fatty acids (SCFAs), such as acetic, propionic, butyric, and isobutyric fatty acids, after 48 h colonic fermentation, being indicators of gut health. In correlation with the release of SCFAs, a significant reduction in bacterial groups causing intestinal imbalance, such as Enterobacteriaceae, Enterococcus spp., and Staphylococcus spp., was observed. In addition, digests from C. vulgaris favored intestinal health-related taxa, such as Akkermansia and Lactobacillus. C. vulgaris is, therefore, a promising food ingredient for good intestinal health and the maintenance of a balanced colonic microbiota.

Utilization of Microalgae and Duckweed as Sustainable Protein Sources for Food and Feed: Nutritional Potential and Functional Applications

Aquatic biomass, particularly microalgae and duckweed, presents a promising and sustainable alternative source of plant-based protein and bioactive compounds for food and feed applications. This review highlights the nutritional potential of these aquatic species, focusing on their high protein content, rapid growth rates, and adaptability to nonarable environments. Microalgae, such as Chlorella and Arthrospira spp., and duckweed, such as Lemna minor, are evaluated for their functional food applications, including their roles as protein supplements, bioactive components, antioxidants, and emulsifiers in food formulations. The study also examines their environmental benefits, including wastewater bioremediation, nutrient recycling, and greenhouse gas mitigation, which contribute to a more sustainable agricultural system. Technological advancements in the cultivation, harvesting, and processing of microalgae and duckweed are discussed to enhance their scalability and economic feasibility in food and feed production. The findings suggest that integrating microalgae and duckweed into agricultural and food systems can significantly improve food security, nutritional outcomes, and sustainability. Future research should focus on optimizing cultivation efficiencies, advancing protein extraction techniques, and expanding the applications of aquatic biomass in various food products.

Wheat Bread Supplemented with Egg Albumin: Structural Features, and In Vitro Starch and Protein Digestibility

This study aimed to explore the effects of egg albumin protein addition (5, 15 and 20 g/100 g db) on the textural characteristics, as well as in the in vitro digestibility of protein and starch of wheat bread. Egg albumin addition resulted in smoother bread loaves as compared to traditional wheat bread. Reduced hardness and increased cohesiveness were correlated to the protein secondary structure, mainly with the content of β-sheets. The in vitro protein digestibility decreased with the albumin addition, suggesting the mediation of protein-starch interactions. The in vitro starch digestibility was also decreased, reflected in a huge decrease of the slowly digestible starch fraction, but with non-significant changes in the rapidly digestible starch fraction. The supplemented albumin can form a physical barrier around the starch granules, which hampers the access of the amylolytic enzymes to the starch chains. Overall, the results of this study suggest that the addition of egg albumin is a viable alternative for producing wheat bread with reduced glycemic index and improved nutritional properties.

Exploring Tetraselmis chui microbiomes-functional metagenomics for novel catalases and superoxide dismutases

The focus on microalgae for applications in several fields, e.g. resources for biofuel, the food industry, cosmetics, nutraceuticals, biotechnology, and healthcare, has gained increasing attention over the last decades. In this study, we investigate the microbiome of the cultured microalga Tetraselmis chui (T. chui) to highlight their potential for health benefits. In this context, biomolecules like antioxidants play a crucial role in the well-being of living organisms as they metabolise harmful reactive oxygen species (ROS) to reduce oxidative stress. Impaired processing of ROS leads to damaged cells and increases the risk of cancer, inflammatory diseases, and diabetes, among others. Here, we identify, characterise, and test bacterial antioxidants derived from the T. chui microbiome metagenome dataset. We identified 258 genes coding for proteins with potential antioxidant activity. Of those, four novel enzymes are expressed and identified as two superoxide dismutases (SOD), TcJM_SOD2 and TcIK_SOD3, and two catalases (CAT), TcJM_CAT2 and TcIK_CAT3. Extensive analyses characterised all implemented enzymes as active even in concentrations down to 25 ng*ml-1 for the SODs and 15 ng*ml-1 for the CATs. Furthermore, sequence-based analyses assign TcJM_SOD2 and TcIK_SOD3 to iron superoxide dismutases (Fe SODs) and TcJM_CAT2 and TcIK_CAT3 to heme-containing catalases. These candidates are phylogenetically classified within the phylum Pseudomonadota. Regarding the biotechnological potential, a toxicity assay did not indicate any harmful effects. The introduced enzymes may benefit medical applications and expand the potential of microalgae microbiomes. KEY POINTS: • Omics-based discoveries of antioxidant enzymes from Tetraselmis chui microbiome • Two superoxide dismutases and two catalases are identified and tested for activity • Enzyme sensitivity highlights biotechnological potential of microalgae microbiomes.

Exploring Extremotolerant and Extremophilic Microalgae: New Frontiers in Sustainable Biotechnological Applications

Exploring extremotolerant and extremophilic microalgae opens new frontiers in sustainable biotechnological applications. These microorganisms thrive in extreme environments and exhibit specialized metabolic pathways, making them valuable for various industries. The study focuses on the ecological adaptation and biotechnological potential of these microalgae, highlighting their ability to produce bioactive compounds under stress conditions. The literature reveals that extremophilic microalgae can significantly enhance biomass production, reduce contamination risks in large-scale systems, and produce valuable biomolecules such as carotenoids, lipids, and proteins. These insights suggest that extremophilic microalgae have promising applications in food, pharmaceutical, cosmetic, and biofuel industries, offering sustainable and efficient alternatives to traditional resources. The review concludes that further exploration and utilization of these unique microorganisms can lead to innovative and environmentally friendly solutions in biotechnology.

Effects of Chlorich®EnergyBoost on Enhancing Physical Performance and Anti-Fatigue Properties in Mice

Chlorich®EnergyBoost, a water extract obtained from Chlorella sorokiniana, has been proposed to enhance physical performance and provide anti-fatigue effects. This study assessed the impact of Chlorich®EnergyBoost supplementation on physical performance and its anti-fatigue properties. Twenty-four mice were allocated into four groups: (1) the control group receiving only water,;(2) the 1X group (49.2 mg/kg/day); (3) the 2X group (98.4 g/kg/day); and (4) the 5X group (246 g/kg/day). All groups were orally administered the supplements for four consecutive weeks. The evaluation included grip strength, swimming endurance, an exhaustion test, and serum biochemistry analysis. Additionally, the study examined the bioactive peptides through matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) and conducted bacterial reverse mutation and acute oral toxicity tests for safety assessment. The findings indicated that Chlorich®EnergyBoost supplementation led to a significant reduction in serum lactate levels by 14.08% to 22.54% and blood urea nitrogen levels by 12.23% to 16.76%, an increase in the lactate clearance rate by 0.28 to 0.35, an enhancement of muscle glycogen storage by 1.10 to 1.44-fold, and hepatic glycogen storage by 1.41 to 1.47-fold. These results demonstrated dose-dependent effects. MALDI-TOF analysis revealed the expression of dihydrolipoamide dehydrogenase and superoxide dismutase. Both the bacterial reverse mutation and acute oral toxicity tests showed no adverse effects.

Recent developments and challenges in algal protein and peptide extraction strategies, functional and technological properties, bioaccessibility, and commercial applications

The burgeoning demand for protein, exacerbated by population growth and recent disruptions in the food supply chain, has prompted a rapid exploration of sustainable protein alternatives. Among these alternatives, algae stand out for their environmental benefits, rapid growth, and rich protein content. However, the widespread adoption of algae-derived proteins faces significant challenges. These include issues related to harvesting, safety, scalability, high cost, standardization, commercialization, and regulatory hurdles. Particularly daunting is the efficient extraction of algal proteins, as their resilient cell walls contain approximately 70% of the protein content, with conventional methods accessing only a fraction of this. Overcoming this challenge necessitates the development of cost-effective, scalable, and environmentally friendly cell disruption techniques capable of breaking down these rigid cell walls, often laden with viscous polysaccharides. Various approaches, including physical, chemical, and enzymatic methods, offer potential solutions, albeit with varying efficacy depending on the specific algal strain and energy transfer efficiency. Moreover, there remains a pressing need for further research to elucidate the functional, technological, and bioaccessible properties of algal proteins and peptides, along with exploring their diverse commercial applications. Despite these obstacles, algae hold considerable promise as a sustainable protein source, offering a pathway to meet the escalating nutritional demands of a growing global population. This review highlights the nutritional, technological, and functional aspects of algal proteins and peptides while underscoring the challenges hindering their widespread adoption. It emphasizes the critical importance of establishing a sustainable trajectory for food production, with algae playing a pivotal role in this endeavor.

Impact of 3D printing materials on mircoalga Chlorella vulgaris

3D printing represents a key enabling technology in designing photobioreactors. It allows rapid prototyping of complex geometries at an affordable price. Yet, no study dealt with the biocompatibility of 3D printing material with microalgae. Thus microalga Chlorella vulgaris was cultivated in contact with different 3D printing materials (Acrylonitrile Butadiene Styren - ABS, PolyCarbonate Blend - PC-Blend, PolyLactic acid - PLA, and acrylate methacrylate resin). Cell status was analyzed using flow cytometry, fluorometry, and pigment profiling. Results revealed that acrylate methacrylate resin material inhibits growth, a constant rise in intracellular reactive oxygen species, and a decrease in photosynthetic apparatus functioning. On the contrary, ABS, PC-Blend, and PLA led to nominal perfromances. Nevertheless, PLA was the only material that did not induce an early onset of intracellular reactive oxygen species. Therefore, resin can be ruled out as photobioreactor material, ABS and PC-Blend could be used after a curation period, and PLA induces no detectable perturbations by the means used in this study.

The utility of algae as sources of high value nutritional ingredients, particularly for alternative/complementary proteins to improve human health

As the global population continues to grow, the demand for dietary protein is rapidly increasing, necessitating the exploration of sustainable and nutritious protein sources. Algae has emerged as a promising food source due to their high value ingredients such as proteins, as well as for their environmental sustainability and abundance. However, knowledge gaps surrounding dietary recommendations and food applications restrict algae's utilization as a viable protein source. This review aims to address these gaps by assessing the suitability of both microalgae and macroalgae as alternative/complementary protein sources and exploring their potential applications in food products. The first section examines the potential suitability of algae as a major food source by analyzing the composition and bioavailability of key components in algal biomass, including proteins, lipids, dietary fiber, and micronutrients. Secondly, the biological effects of algae, particularly their impact on metabolic health are investigated with an emphasis on available clinical evidence. While evidence reveals protective effects of algae on glucose and lipid homeostasis as well as anti-inflammatory properties, further research is required to understand the longer-term impact of consuming algal protein, protein isolates, and concentrates on metabolic health, including protein metabolism. The review then explores the potential of algal proteins in food applications, including ways to overcome their sensory limitations, such as their dark pigmentation, taste, and odor, in order to improve consumer acceptance. To maximize algae's potential as a valuable protein source in the food sector, future research should prioritize the production of more acceptable algal biomass and explore new advances in food sciences and technology for improved consumer acceptance. Overall, this paper supports the potential utility of algae as a sustainable and healthy ingredient source for widespread use in future food production.

Protein Quality and Protein Digestibility of Vegetable Creams Reformulated with Microalgae Inclusion

Microalgae are considered a valuable source of proteins that are used to enhance the nutritional value of foods. In this study, a standard vegetable cream recipe was reformulated through the addition of single-cell ingredients from Arthrospira platensis (spirulina), Chlorella vulgaris, Tetraselmis chui, or Nannochloropsis oceanica at two levels of addition (1.5% and 3.0%). The impact of microalgae species and an addition level on the amino acid profile and protein in vitro digestibility of the vegetable creams was investigated. The addition of microalgae to vegetable creams improved the protein content and the amino acid nutritional profile of vegetable creams, whereas no significant differences were observed in protein digestibility, regardless of the species and level of addition, indicating a similar degree of protein digestibility in microalgae species despite differences in their protein content and amino acid profile. This study indicates that the incorporation of microalgae is a feasible strategy to increase the protein content and nutritional quality of foods.

Microalgae-Sustainable Source for Alternative Proteins and Functional Ingredients Promoting Gut and Liver Health

Dietary proteins derived from animal sources, although containing well-balanced profiles of essential amino acids, have considerable environmental and adverse health effects associated with the intake of some animal protein-based products. Consuming foods based on animal proteins carries a higher risk of developing non-communicable diseases such as cancer, heart disease, non-alcoholic fatty liver disease (NAFLD), and inflammatory bowel disease (IBD). Moreover, dietary protein consumption is increasing due to population growth, posing a supply challenge. There is, therefore, growing interest in discovering novel alternative protein sources. In this context, microalgae have been recognized as strategic crops that can provide a sustainable source of protein. Compared to conventional high-protein crops, using microalgal biomass for protein production presents several advantages in food and feed in terms of productivity, sustainability, and nutritional value. Moreover, microalgae positively impact the environment by not exploiting land or causing water pollution. Many studies have revealed the potential of microalgae as an alternative protein source with the added value of positive effects on human health due to their anti-inflammatory, antioxidant, and anti-cancer properties. The main emphasis of this review is on the potential health-promoting applications of microalgae-based proteins, peptides, and bioactive substances for IBD and NAFLD.

Exposure to oxyfluorfen-induced hematobiochemical alterations, oxidative stress, genotoxicity, and disruption of sex hormones in male African catfish and the potential to confront by Chlorella vulgaris

The present study evaluated the effect of chronic exposure to oxyfluorfen (OXY) on different physiological responses of male African catfish, Clarias gariepinus, and the ameliorative effect of Chlorella vulgaris. The fish (160 ± 5.10 g) were exposed to 1/20 LC₅₀ of OXY (0.58 mg/L) for 60 consecutive days with or without co-administration of C. vulgaris (25 g/kg diet) in triplicate groups. The results revealed that chronic exposure to a sublethal level of OXY induced severe anemia and leukopenia. OXY-exposed fish experienced hypoproteinemia, marked lower AchE levels, and a significant increase in glucose, liver, and kidney function biomarkers. The DNA fragmentation of the liver increased by 15 % in fish compared to the control. On the other hand, lipid peroxidation, superoxide dismutase, and catalase activities were markedly increased in the liver and testes homogenates of the OXY-exposed fish. Meanwhile, total antioxidant capacity and glutathione S-transferase levels declined in the same tissues. Exposure to OXY induced a significant reduction in testosterone and luteinizing hormone levels and a significant increase in follicle stimulating hormone and estradiol. Meanwhile, C. vulgaris dietary supplementation succeeded in alleviating the negative impact of OXY on hematobiochemical parameters and restoring the antioxidant balance in the liver and testes. Furthermore, it ameliorated endocrine disruption and repaired sex hormone levels. In conclusion, exposure to OXY could induce systemic stress, oxidative stress, and endocrine disruption in male C. gariepinus. The dietary supplementation of C. vulgaris could be a potential protective strategy against the toxicity of OXY.

Microalgae protein digestibility: How to crack open the black box?

Microalgae are booming as a sustainable protein source for human nutrition and animal feed. Nevertheless, certain strains were reported to have robust cell walls limiting protein digestibility. There are several disruption approaches to break down the cell integrity and increase digestive enzyme accessibility. This review's intent is to discuss the digestibility of microalgae proteins in intact cells and after their disruption. In intact single cells, the extent of protein digestibility is chiefly related to cell wall structural properties (differing among strains) as well as digestion method and when added to food or feed protein digestibility changes depending on the matrix's composition. The degree of effectiveness of the disruption method varies among studies, and it is complicated to compare them due to variabilities in digestibility models, strains, disruption method/conditions and their consequent impact on the microalgae cell structure. More exhaustive studies are still required to fill knowledge gaps on the structure of microalgal cell walls and to find efficient and cost-effective disruption technologies to increase proteins availability without hindering their quality.

Bioactivity and Digestibility of Microalgae Tetraselmis sp. and Nannochloropsis sp. as Basis of Their Potential as Novel Functional Foods

It is estimated that by 2050, the world's population will exceed 10 billion people, which will lead to a deterioration in global food security. To avoid aggravating this problem, FAO and WHO have recommended dietary changes to reduce the intake of animal calories and increase the consumption of sustainable, nutrient-rich, and calorie-efficient products. Moreover, due to the worldwide rising incidence of non-communicable diseases and the demonstrated impact of diet on the risk of these disorders, the current established food pattern is focused on the consumption of foods that have functionality for health. Among promising sources of functional foods, microalgae are gaining worldwide attention because of their richness in high-value compounds with potential health benefits. However, despite the great opportunities to exploit microalgae in functional food industry, their use remains limited by challenges related to species diversity and variations in cultivation factors, changes in functional composition during extraction procedures, and limited evidence on the safety and bioavailability of microalgae bioactives. The aim of this review is to provide an updated and comprehensive discussion on the nutritional value, biological effects, and digestibility of two microalgae genera, Tetraselmis and Nannochloropsis, as basis of their potential as ingredients for the development of functional foods.

Health-Promoting Nutrients and Potential Bioaccessibility of Breads Enriched with Fresh Kale and Spinach

Bread is a staple food and can be a potential product to be enriched with various deficient nutrients. The objective of the study was to characterize the nutritional properties of toasted bread enriched with 10% and 20% of kale and wholemeal bread with 20% and 40% of spinach. The supplementation increased the phenolic content up to 2−3 times in the bread with the addition of 20% spinach and 40% kale. The highest antioxidant properties were noticed in extracts of bread with 20% kale. The in vitro digestion released the hydrophilic and lipophilic antioxidative compounds, leading to higher bioaccessibility of the breads enriched with these selected green vegetables. Even more than a 2-fold increase in folate content was observed in breads with the greatest addition of kale (20%) and spinach (40%), from 18.1 to 45.3 µg/100 g and from 37.2 to 83.2 µg/100 g, respectively, compared to the non-enriched breads. Breads with spinach showed significantly (P < 0.05) higher contents of all of the tested minerals, Cu, Mn, Fe, Zn, Mg, Ca, Na, K, and P, whereas kale enriched breads showed most of them. The results suggest that the addition of fresh green vegetables can enhance the daily supply of micronutrients and significantly increase the bioavailability of bioactive compounds with high antioxidant status.

Improving the Nutritional, Structural, and Sensory Properties of Gluten-Free Bread with Different Species of Microalgae

Microalgae are an enormous source of nutrients that can be utilized to enrich common food of inherently low nutritional value, such as gluten-free (GF) bread. Addition of the algae species: Tetraselmis chuii (Tc), Chlorella vulgaris (Cv), and Nannochloropsis gaditana (Ng) biomass led to a significant increase in proteins, lipids, minerals (Ca, Mg, K, P, S, Fe, Cu, Zn, Mn), and antioxidant activity. Although, a compromise on dough rheology and consequential sensory properties was observed. To address this, ethanol treatment of the biomass was necessary to eliminate pigments and odor compounds, which resulted in the bread receiving a similar score as the control during sensory trials. Ethanol treatment also resulted in increased dough strength depicted by creep/recovery tests. Due to the stronger dough structure, more air bubbles were trapped in the dough resulting in softer breads (23–65%) of high volume (12–27%) vs. the native algae biomass bread. Breads baked with Ng and Cv resulted in higher protein-enrichment than the Tc, while Tc enrichment led to an elevated mineral content, especially the Ca, which was six times higher than the other algae species. Overall, Ng, in combination with ethanol treatment, yielded a highly nutritious bread of improved technological and sensory properties, indicating that this species might be a candidate for functional GF bread development.