Preparation of phycocyanin microcapsules and its properties

Comprehensive analysis of the effects of fresh Spirulina microcapsules on protein cross-linking and structural changes in wheat noodles

Fresh spirulina microcapsules (SP-MICs) are a viable strategy to prolong the preservation of fresh spirulina. This study aims to investigate the effects of SP-MICs on noodle quality, focusing on physicochemical properties and wheat gluten structures. Compared to the control group, the addition of 3 % SP-MICs significantly improved the sensory and textural properties of the noodles. Chewiness and hardness increased by 14.40 % and 32.36 %, respectively. In terms of glutenin subunits, HMS and B/C-LMS contents increased by 6.10 % and 5.39 %, respectively. Additionally, the gliadin-to-glutenin ratio reached its lowest at 1.19. Surface hydrophobicity decreased by 6.41 %, disulfide bond content increased by 31.60 %, and non-covalent interactions (hydrogen bond and hydrophobic interactions) were enhanced. The secondary structure of gluten protein became more ordered, with a 6.86 % increase in β-sheet content and a 1.10 % decrease in random coil content. SEM and CLSM results showed that 3 % SP-MICs significantly reinforced the gluten network and protein-starch cross-linking.

Enhancing the stability and functionality of phycobiliproteins as natural food colourants through microparticle formulation

The food industry is increasingly turning to microalgae pigments as natural functional colourants to replace potentially harmful synthetic dyes. Among those, phycobiliproteins offer deep and vibrant colours with bioactivities, showing to be a promising alternative. However, incorporating them into a food matrix can be challenging due to their inherent instability, low bioavailability, and off-flavours. Accordingly, the present work aimed to prepare microparticles of phycocyanin (PCMP) and of an ultrasound-assisted phycoerythrin-rich extract from Porphyridium purpureum (PEMP) to improve these natural colourants' stability and functional properties. The microparticles were prepared by Nano spray-drying using inulin and gum Arabic as coating materials, resulting in particles with high yield, encapsulation efficiency (from 69 % to 80 %), solubility, and colour retention. Combining inulin and gum Arabic allowed the formation of smaller and more homogeneous particles with increased antioxidant potential when compared to using inulin alone. Moreover, gum Arabic improved the bioaccessibility of PEMP from 35 % to 51 %, demonstrating the potential of this microparticle formulation to enhance the stability and functionality of phycobiliproteins.

The study on preparation, stability and anti-allergic efficacy of phycocyanin microcapsules

The study aimed to investigate the stability and anti-allergic efficacy of phycocyanin through the construction of microcapsules. Phycocyanin (PC), a blue pigment found in microalgae, has attracted significant attention due to its anti-allergic properties. However, it is susceptible to instability when exposed to light, heat, and changes in pH. To address this issue, phycocyanin microcapsules were prepared using sodium alginate (SA), calcium chloride and chitosan (CS) as wall materials. The structures of microcapsules were carried out using scanning electron microscopy (SEM), fourier transform infrared spectroscopy, and particle size measurements that confirmed the successful encapsulation of PC within the microcapsules. The optimal effect was achieved when the mass ratio of PC to SA was 1:3, resulting in an embedding rate of 70.92 %. Stability studies shown that phycocyanin microcapsules exhibited the highest pigment retention rate under conditions of pH 6, darkness and a temperature of 37 °C. Furthermore, in vivo testing on mouse revealed a strong anti-allergic effect. These findings indicate that microcapsules prepared with phycocyanin as the core material exhibit high stability and a favorable anti-allergic effect, suggesting significant potential. This study serves as a reference for the further development of anti-allergic foods that can effectively prevent or alleviate food allergies.

Impact of pH and protein/polysaccharide ratio on phycocyanin-okra polysaccharides complex

Phycocyanin is a natural blue pigment that tends to denature and lose its color in acidic solutions. In response to this problem, the complexes of phycocyanin (PC) with okra polysaccharides (OP) were prepared by ultrasonic processing at different pH conditions, and the molecular interactions of the complexes were characterized. The results showed that there were significant differences in the color, functional groups, and surface morphology of the complexes formed at different pH conditions. By colorimetry and particle size tester, it was demonstrated that the complex solution showed a steady blue color at pH 3.4. The highest fluorescence intensity (1.55 × 107 a.u.) and the significant red-shift of the complexes were observed at 0.4 % m/v polysaccharides addition. Infrared spectroscopy test further demonstrated that OP induced the formation of higher-order trimers of PC, which kept the color stable. Molecular dynamics simulations showed that the binding energy of PC/OP complex was -42.21 ± 2.61 kcal/mol, indicating that the binding affinity was very strong. Overall, this study suggests that this complex stabilizes the structure of PC, which in turn exerts a biological effect and will facilitate the use of PC as an artificial color substitute in food or beverage applications.

Construction of a pectin/sodium alginate composite hydrogel delivery system for improving the bioaccessibility of phycocyanin

In this study, different concentrations of sodium alginate were compounded with pectin and phycocyanin to co-prepare composite hydrogel spheres (HP-PC-SA 0.2 %, 0.6 %, 1.0 %, 1.4 %) to evaluate the potential of the composite hydrogel spheres for the application as phycocyanin delivery carriers. The hydrogel spheres' physicochemical properties and bioaccessibility were assessed through scanning electron microscopy, textural analysis, drug-carrying properties evaluation, and in vitro and in vivo controlled release analysis in the gastrointestinal environment. Results indicated that higher sodium alginate concentrations led to smaller pore sizes and denser networks on the surface of hydrogel spheres. The textural properties of hydrogel spheres improved, and their water-holding capacity increased from 93.01 % to 97.97 %. The HP-PC-SA (1.0 %) formulation achieved the highest encapsulation rate and drug loading capacity, at 96.87 % and 6.22 %, respectively. Within the gastrointestinal tract, the composite hydrogel's structure significantly enhanced and protected the phycocyanin's digestibility, achieving a bioaccessibility of up to 88.03 %. In conclusion, our findings offer new insights into improving functionality and the effective use of phycocyanin via pectin-based hydrogel spheres.

Porous Polylactide Microparticles as Effective Fillers for Hydrogels

High-strength composite hydrogels based on collagen or chitosan-genipin were obtained via mixing using highly porous polylactide (PLA) microparticles with diameters of 50-75 µm and porosity values of over 98%. The elastic modulus of hydrogels depended on the filler concentration. The modulus increased from 80 kPa to 400-600 kPa at a concentration of porous particles of 12-15 wt.% and up to 1.8 MPa at a filling of 20-25 wt.% for collagen hydrogels. The elastic modulus of the chitosan-genipin hydrogel increases from 75 kPa to 900 kPa at a fraction of particles of 20 wt.%. These elastic modulus values cover a range of strength properties from connective tissue to cartilage tissue. It is important to note that the increase in strength in this case is accompanied by a decrease in the density of the material, that is, an increase in porosity. PLA particles were loaded with C-phycocyanin and showed an advanced release profile up to 48 h. Thus, composite hydrogels mimic the structure, biomechanics and release of biomolecules in the tissues of a living organism.

Controlled Release of Phycocyanin in Simulated Gastrointestinal Conditions Using Alginate-Agavins-Polysaccharide Beads

C-phycocyanin (CPC) is an antioxidant protein that, when purified, is photosensitive and can be affected by environmental and gastrointestinal conditions. This can impact its biological activity, requiring an increase in the effective amount to achieve a therapeutic effect. Therefore, the aim of this study was to develop a microencapsulate of a complex matrix, as a strategy to protect and establish a matrix for the controlled release of CPC based on polysaccharides such as agavins (AGV) using ionic gelation. Four matrices were formulated: M1 (alginate: ALG), M2 (ALG and AGV), M3 (ALG, AGV, and κ-carrageenan: CGN), and M4 (ALG, AGV, CGN, and carboxymethylcellulose: CMC) with increasing concentrations of CPC. The retention and diffusion capacities of C-phycocyanin provided by each matrix were evaluated, as well as their stability under simulated gastrointestinal conditions. The results showed that the encapsulation efficiency of the matrix-type encapsulates with complex composites increased as more components were added to the mixtures. CMC increased the retention due to the hydrophobicity that it provides by being in the polysaccharide matrix; CGN enabled the controlled diffusive release; and AGV provided protection of the CPC beads under simulated gastrointestinal conditions. Therefore, matrix M4 exhibited an encapsulation efficiency for CPC of 98% and a bioaccessibility of 10.65 ± 0.65% after the passage of encapsulates through in vitro digestion.

Chitosan Sponges for Efficient Accumulation and Controlled Release of C-Phycocyanin

The paper proposed a new porous material for wound healing based on chitosan and C-phycocyanin (C-PC). In this work, C-PC was extracted from the cyanobacteria Arthrospira platensis biomass and purified through ammonium sulfate precipitation. The obtained C-PC with a purity index (PI) of 3.36 ± 0.24 was loaded into a chitosan sponge from aqueous solutions of various concentrations (250, 500, and 1000 mg/L). According to the FTIR study, chitosan did not form new bonds with C-PC, but acted as a carrier. The encapsulation efficiency value exceeded 90%, and the maximum loading capacity was 172.67 ± 0.47 mg/g. The release of C-PC from the polymer matrix into the saline medium was estimated, and it was found 50% of C-PC was released in the first hour and the maximum concentration was reached in 5-7 h after the sponge immersion. The PI of the released C-PC was 3.79 and 4.43 depending on the concentration of the initial solution.

Microalgae: A Promising Source of Bioactive Phycobiliproteins

Phycobiliproteins are photosynthetic light-harvesting pigments isolated from microalgae with fluorescent, colorimetric and biological properties, making them a potential commodity in the pharmaceutical, cosmetic and food industries. Hence, improving their metabolic yield is of great interest. In this regard, the present review aimed, first, to provide a detailed and thorough overview of the optimization of culture media elements, as well as various physical parameters, to improve the large-scale manufacturing of such bioactive molecules. The second section of the review offers systematic, deep and detailed data about the current main features of phycobiliproteins. In the ultimate section, the health and nutritional claims related to these bioactive pigments, explaining their noticeable potential for biotechnological uses in various fields, are examined.

Enhancing phycocyanin solubility via complexation with fucoidan or κ-carrageenan and improving phycocyanin color stability by encapsulation in alginate-pregelatinized corn starch composite gel beads

Phycocyanin (PC), as a pigment-protein complex, aggregates and precipitates in acidic environments. In this context, complex formation with anionic polysaccharides is a strategy to enhance protein solubility. Besides, acidic conditions negatively affect the inherent blue color of PC, which can be prevented by encapsulation. Thereupon, in the present study, two different biopolymer-based systems, namely complexes and hydrogel beads, were prepared to increase PC solubility and its color stability under acidic conditions, respectively. Fucoidan and κ-carrageenan (KC) were separately utilized to make a complex with PC. Calcium alginate-pregelatinized corn starch (PCS) composite gel beads were used to encapsulate PC. The prepared samples were added into model systems simulating acidic conditions and then characterized during storage at 4 and 25 °C under dark conditions. Appropriate colloidal stabilities were observed for fucoidan/PC and KC/PC model systems. The color of the samples remained stable at 4 °C. As well, the bead carriers (i.e. alginate-PCS) properly protected PC against low pH conditions over time at 4 °C. Thereupon, the blue color of the beads satisfactorily remained stable at this temperature. The findings showed that complexation with fucoidan or KC and encapsulation in mixed hydrogel beads are promising routes for improving PC solubility and its color stability, respectively.

Comparison of Alginate Mixtures as Wall Materials of Schizochytrium Oil Microcapsules Formed by Coaxial Electrospray

This work evaluated maltodextrin/alginate and β-glucan/alginate mixtures in the food industry as wall materials for the microencapsulation of Schizochytrium sp. oil, an important source of the omega-3 fatty acid DHA (docosahexaenoic acid). Results showed that both mixtures display a shear-thinning behavior, although the viscosity is higher in β-glucan/alginate mixtures than in maltodextrin/alginate. Scanning electron microscopy was used to assess the morphology of the microcapsules, which appeared more homogeneous for maltodextrin/alginate. In addition, oil-encapsulation efficiency was higher in maltodextrin/alginate mixtures (90%) than in β-glucan/alginate mixtures (80%). Finally, evaluating the microcapsules' stability by FTIR when exposed to high temperature (80 °C) showed that maltodextrin/alginate microcapsules were not degraded contrary to the β-glucan/alginate microcapsules. Thus, although high oil-encapsulation efficiency was obtained with both mixtures, the microcapsules' morphology and prolonged stability suggest that maltodextrin/alginate is a suitable wall material for microencapsulation of Schizochytrium sp. oil.

Phycobiliproteins from algae: Current updates in sustainable production and applications in food and health

Phycobiliproteins are light-harvesting complexes found mainly in cyanobacteria and red algae, playing a key role in photosynthesis. They are extensively applied in food, cosmetics, and biomedical industry due to bright color, unique fluorescence characteristics and diverse physiological activities. They have received much attention in the past few decades because of their green and sustainable production, safe application, and functional diversity. This work aimed to provide a comprehensive summary of parameters affecting the whole bioprocess with a special focus on the extraction and purification, which directly determines the application of phycobiliproteins. Food grade phycobiliproteins are easy to prepare, whereas analytical grade phycobiliproteins are extremely complex and costly to produce. Most phycobiliproteins are denatured and inactivated at high temperatures, severely limiting their application. Inspired by recent advances, future perspectives are put forward, including (1) the mutagenesis and screening of algal strains for higher phycobiliprotein productivity, (2) the application of omics and genetic engineering for stronger phycobiliprotein stability, and (3) the utilization of synthetic biology and heterologous expression systems for easier phycobiliprotein isolation. This review will give a reference for exploring more phycobiliproteins for food and health application development.

Application of Antiviral, Antioxidant and Antibacterial Glycyrrhiza glabra L., Trifolium pratense L. Extracts and Myristica fragrans Houtt. Essential Oil in Microcapsules

Viruses and bacteria can disrupt normal human functions; therefore, ways to use the beneficial properties of plants to promote health are constantly being researched. Plant materials that accumulate biologically active compounds can be used to create a new pharmaceutical form. This study aimed to investigate the biological activity of selected plant extracts and essential oil and to produce microcapsules. The main compounds in extracts and essential oil were determined using chromatographic methods, antioxidant activity was evaluated spectrophotometrically, antimicrobial activity was assessed by monitoring the growth of nine pathogens, and the antiviral effect on infected bird cells with coronavirus was evaluated. Trifolium pratense L. extract had the highest antioxidant (26.27 ± 0.31 and 638.55 ± 9.14 µg TE/g dw by the DPPH and ABTS methods, respectively) and antiviral activity (56 times decreased titre of virus). Liquorice extract expressed antibacterial activity against Gram-positive pathogens and the highest antioxidant activity using the FRAP method (675.71 ± 4.61 mg FS/g dw). Emulsion stability depended on excipients and their amount. Microcapsules with extracts and essential oil were 1.87 mm in diameter, and their diameter after swelling was increased more than two times in intestinal media, while less than 0.5 times in gastric media.

A Review on a Hidden Gem: Phycoerythrin from Blue-Green Algae

Phycoerythrin (PE) is a pink/red-colored pigment found in rhodophytes, cryptophytes, and blue-green algae (cyanobacteria). The interest in PE is emerging from its role in delivering health benefits. Unfortunately, the current cyanobacterial-PE (C-PE) knowledge is still in the infant stage. It is essential to acquire a more comprehensive understanding of C-PE. This study aimed to review the C-PE structure, up and downstream processes of C-PE, application of C-PE, and strategies to enhance its stability and market value. In addition, this study also presented a strengths, weaknesses, opportunities, and threats (SWOT) analysis on C-PE. Cyanobacteria appeared to be the more promising PE producers compared to rhodophytes, cryptophytes, and macroalgae. Green/blue light is preferred to accumulate higher PE content in cyanobacteria. Currently, the prominent C-PE extraction method is repeated freezing-thawing. A combination of precipitation and chromatography approaches is proposed to obtain greater purity of C-PE. C-PE has been widely exploited in various fields, such as nutraceuticals, pharmaceuticals, therapeutics, cosmetics, biotechnology, food, and feed, owing to its bioactivities and fluorescent properties. This review provides insight into the state-of-art nature of C-PE and advances a step further in commercializing this prospective pigment.

A review of recent strategies to improve the physical stability of phycocyanin

There is an increasing demand for more healthy and sustainable diets, which led to an interest in replacing synthetic colors with natural plant-based ones. Phycocyanin, which is commonly extracted from Spirulina platensis, has been explored as a natural blue pigment for application in the food industry. It is also used as a nutraceutical in food, cosmetic, and pharmaceutical products because of its potentially beneficial biological properties, such as radical scavenging, immune modulating, and lipid peroxidase activities. The biggest challenges to the widespread application of phycocyanin for this purpose are its high sensitivity to chemical degradation when exposed to heat, light, acids, high pressure, heavy metal cations, and denaturants. Consequently, it is of considerable importance to improve its chemical stability, which requires a thorough knowledge of the relationship between the structure, environment, and chemical reactivity of phycocyanin. To increase the application of this natural pigment and nutraceutical within foods and other products, the structure, biological activities, and factors affecting its stability are reviewed, as well as strategies that have been developed to improve its stability. The information contained in this article is intended to stimulate further studies on the development of effective strategies to improve phycocyanin stability and performance.

Therapeutic Efficacy of Natural Product 'C-Phycocyanin' in Alleviating Streptozotocin-Induced Diabetes via the Inhibition of Glycation Reaction in Rats

Diabetes is a long-term metabolic disorder characterized by persistently elevated blood sugar levels. Chronic hyperglycemia enhances glucose-protein interactions, leading to the formation of advanced glycation end products (AGEs), which form irreversible cross-links with a wide variety of macromolecules, and accumulate rapidly in the body tissues. Thus, the objective of this study was to assess the therapeutic properties of C-phycocyanin (C-PC) obtained from Plectonema species against oxidative stress, glycation, and type 2 diabetes mellitus (T2DM) in a streptozotocin (STZ)-induced diabetic Wistar rat. Forty-five days of C-PC administration decreased levels of triglycerides (TGs), blood glucose, glycosylated hemoglobin, (HbA1c), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), liver and kidney function indices, and raised body weight in diabetic rats. C-PC suppressed biochemical glycation markers, as well as serum carboxymethyllysine (CML) and fluorescent AGEs. Additionally, C-PC maintained the redox state by lowering lipid peroxidation and protein-bound carbonyl content (CC), enhancing the activity of high-density lipoprotein cholesterol (HDL-C) and renal antioxidant enzymes, and preserving retinal and renal histopathological characteristics. Thus, we infer that C-PC possesses antidiabetic and antiglycation effects in diabetic rats. C-PC may also act as an antidiabetic and antiglycation agent in vivo that may reduce the risk of secondary diabetic complications.

Phycobiliproteins, the pigment-protein complex form of natural food colorants and bioactive ingredients

Currently, the use of synthetic pigments in foods is restricted since synthetic pigments are proven and suspected to be harmful to human health. Phycobiliproteins (PBPs), existed in phycobilisomes (PBSs) of algae, are a kind of pigment-proteins with intense color. The specific color of PBPs (red and blue) is given by the water-soluble open-chained tetrapyrrole chromophore (phycobilin) that covalently attaches to the apo-protein via thioether linkages to cysteine residues. According to the spectral characteristics of PBPs, they can be categorized as phycoerythrins (PEs), phycocyanins (PCs), allophycocyanins (APCs), and phycoerythrocyanins (PECs). PBPs can be used as natural food colorants, fluorescent substances, and bioactive ingredients in food applications owing to their color characteristics and physiological activities. This paper mainly summarizes the extraction and purification methods of the PBPs and reviews their characteristics and applications. Moreover, the use of several strategies such as additives, microencapsulation, electrospray, and cross-linking to improve the stability and bioavailability of PBPs as well as the future outlooks of PBPs as natural colorants in food commercialization are elucidated.

Progress of Microencapsulated Phycocyanin in Food and Pharma Industries: A Review

Phycocyanin is a blue fluorescent protein with multi-bioactive functions. However, the multi-bioactivities and spectral stability of phycocyanin are susceptible to external environmental conditions, which limit its wide application. Here, the structure, properties, and biological activity of phycocyanin were discussed. This review highlights the significance of the microcapsules' wall materials which commonly protect phycocyanin from environmental interference and summarizes the current preparation principles and characteristics of microcapsules in food and pharma industries, including spray drying, electrospinning, electrospraying, liposome delivery, sharp-hole coagulation baths, and ion gelation. Moreover, the major technical challenge and corresponding countermeasures of phycocyanin microencapsulation are also appraised, providing insights for the broader application of phycocyanin.

Fabrication and characterization of phycocyanin-alginate-pregelatinized corn starch composite gel beads: Effects of carriers on kinetic stability of phycocyanin

Composite gel beads using calcium alginate and different concentrations of pregelatinized corn starch (PCS) were produced to encapsulate phycocyanin (PC). Rheological properties of different sodium alginate/PCS/PC mixtures, structural and morphological properties of beads, and kinetic stability of encapsulated PC (upon heating at various time-temperature combinations) were then assessed. Rheological properties of the mixtures exhibited shear thinning behaviors. Aquagram revealed that the PC-containing beads had more water structure with weak‑hydrogen bonds. Morphological images represented less subsidence in the structures of composite gel beads, unlike PCS-free beads. Kinetic study showed that degradation rate constant values of PC encapsulated in composite gel beads (1.08-3.45 × 10^-4, 3.38-4.43 × 10^-4, and 5.57-15.32 × 10^-4 s^-1) were lower than those in PCS-free alginate gel beads (4.45 × 10^-4, 9.20 × 10^-4, and 18.04 × 10^-4 s^-1) at 40, 50, and 60 °C, respectively. This study suggests that the composite gel beads can improve PC stability.

Improving the Thermal and Oxidative Stability of Food-Grade Phycocyanin from Arthrospira platensis by Addition of Saccharides and Sugar Alcohols

The water-soluble pigment protein phycocyanin (C-PC) from cyanobacteria Arthrospira sp. is an excellent natural food colorant and nutritional supplement with a brilliant blue color. However, C-PC is highly unstable, especially at high temperatures and when exposed to oxidative stress. The lack of simple and economical methods for improving the stability of C-PC greatly limits the application of this functional protein in the food industry. This study investigated the effect of adding saccharides (glucose, mannose, galactose, and maltose) and sugar alcohols (mannitol and maltitol) on the stability of food-grade C-PC extracted from Arthrospira platensis; the relevant reaction kinetics were also analyzed. The results revealed that glucose, mannose, mannitol, galactose, and maltose could effectively improve the thermal stability of C-PC. This improvement was positively correlated with the concentration of the additives and decreased sharply when the temperature exceeded 60 °C. Furthermore, the results also revealed the instability of C-PC when subjected to oxidative stress and the effectiveness of glucose, mannose, mannitol, and maltose in preventing the oxidative degradation of C-PC. In general, this study demonstrates that glucose, mannose, mannitol, and maltose are promising compounds for promoting the thermal and oxidative stability of C-PC, providing an economical and effective method for C-PC preservation.

Technological and Sensory Aspects of Macaroni with Free or Encapsulated Azolla Fern Powder

Azolla might be considered an alternative and promising dietary ingredient for antioxidants. There have not been any reports on the incorporation of free Azolla fern powder (FAP) or its microcapsules in foods, especially fresh pasta, yet. Microencapsulation was used to mask the undesirable taste and odour of Azolla, as well as to preserve its antioxidant potential. The current study concentrated on two major goals. The first goal was to use alginate as a wall material for FAP encapsulation, as well as to characterise the FAP microcapsule for its encapsulation efficiency, solubility, and thermal stability. The second goal was to assess the impact of integrating FAP or its microcapsules into fresh macaroni on its colour parameters, cooking quality, texture properties, and sensory characteristics. The microspheres had a high encapsulation efficiency (88.19%) and a low water solubility (85.23 g/kg), making them suitable for use in foods that require cooking in water. When compared to free Azolla powder, encapsulation reduced the antioxidant activity loss rate by 67.73%. All the cooking and textural properties of fresh macaroni were not significantly affected, except for water absorption and weight gain, but the overall acceptability index (85.13%) was not affected by microcapsule incorporation.

Physicochemical degradation of phycocyanin and means to improve its stability: A short review

The cyanobacterium Arthrospira platensis, spirulina, is a source of pigments such as phycobiliprotein and phycocyanin. Phycocyanin is used in the food, cosmetics, and pharmaceutical industries because of its antioxidant, anti-inflammatory, and anticancer properties. The different steps involved in extraction and purification of this protein can alter the final properties. In this review, the stability of phycocyanin (pH, temperature, and light) is discussed, considering the physicochemical parameters of kinetic modeling. The optimal working pH range for phycocyanin is between 5.5 and 6.0 and it remains stable up to 45 °C; however, exposure to relatively high temperatures or acidic pH decreases its half-life and increases the degradation kinetic constant. Phycobiliproteins are sensitive to light; preservatives such as mono- and di-saccharides, citric acid, or sodium chloride appear to be effective stabilizing agents. Encapsulation within nano- or micro-structured materials such as nanofibers, microparticles, or nanoparticles, can also preserve or enhance its stability.

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Phycocyanin is in great demand for industrial application.

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Phycocyanin is sensitive to pH, temperature, and light.

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Optimal stability occurs between pH 5.5–6.0 and at temperatures <45 °C in the dark.

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The use of preservatives or its encapsulation with polymers enhances its stability.

Simultaneous Application of Mixotrophic Culture and Magnetic Fields as a Strategy to Improve Spirulina sp. LEB 18 Phycocyanin Synthesis

Spirulina is a filamentous microalga which is considered a promising alternative source of essential nutrients and active biomolecules. High production cost and the space required to install a photobioreactor are two of the greatest challenges in the industrial application of microalga-based products. Thus, this study aimed to improve Spirulina sp. LEB 18 biomass and phycocyanin content by combining the application of mixotrophic culture and magnetic fields (MF). Zarrouk medium was modified with 1 and 3 g/L liquid molasses and the application of 30 mT for 1·h/d was investigated. Mixotrophic culture with 1 g/L molasses showed the highest biomass concentration (1.62 g/L), carbohydrate content (25.6%), and lipid contents (8.7%) after 15 days. Although the combination of 30 mT and 1 g/L liquid molasses decreased biomass production (1.44 g/L), there was increase in protein yield (76.9%) and protein productivity (73.8 mg/L·d). The proposed method increased phycocyanin production by 145% and its purity from 0.584 in the control culture to 0.627. Data described by this study show that the combination of mixotrophic culture and MF application is a promising alternative to increase microalga protein and phycocyanin production.

Microalgae Encapsulation Systems for Food, Pharmaceutical and Cosmetics Applications

Microalgae are microorganisms with a singular biochemical composition, including several biologically active compounds with proven pharmacological activities, such as anticancer, antioxidant and anti-inflammatory activities, among others. These properties make microalgae an interesting natural resource to be used as a functional ingredient, as well as in the prevention and treatment of diseases, or cosmetic formulations. Nevertheless, natural bioactives often possess inherent chemical instability and/or poor solubility, which are usually associated with low bioavailability. As such, their industrial potential as a health-promoting substance might be severely compromised. In this context, encapsulation systems are considered as a promising and emerging strategy to overcome these shortcomings due to the presence of a surrounding protective layer. Diverse systems have already been reported in the literature for natural bioactives, where some of them have been successfully applied to microalgae compounds. Therefore, this review focuses on exploring encapsulation systems for microalgae biomass, their extracts, or purified bioactives for food, pharmaceutical, and cosmetic purposes. Moreover, this work also covers the most common encapsulation techniques and types of coating materials used, along with the main findings regarding the beneficial effects of these systems.

Extraction Methods for Obtaining Natural Blue Colorants

Background:

Blue is a color not often present in food. Even so, it is especially attractive to children. Today, most blue coloring agents used by the food industry are synthetic. With increasing health issues concern by the scientific community and the general population, there is a trend to look for natural alternatives to most synthetic products. There only exist few natural blue colorants, which are presented in a literature survey, along with the methods currently used for their recovery from natural sources. The best extraction methods and process parameters for the extraction of blue anthocyanins, iridoids and phycocyanin are discussed.

Methods:

A literature survey was conducted to detect the main sources of blue colorants found in nature. The focus was on the extraction methods used to recover such molecules, with the objective of finding efficient and environmentally safe techniques for application at industrial level, and, thus, allowing the production of natural blue colorants at scale high enough for food industry consumption.

Results:

The main natural blue colorants found in literature are anthocyanins, phycocyanin, and genipin. While anthocyanins can be recovered from a variety of plants, the source of phycocyanin are algae, and genipin can be obtained specifically from Gardenia jasminoides Ellis and Genipa americana L. Several extraction techniques have been applied to recover blue colorants from such sources, from classical methods using organic solvents, to more sophisticated technologies as ultrasoundassisted extraction, supercritical fluid extraction, pressurized liquid extraction, high-pressure extraction, and enzyme-assisted extraction.

Conclusion:

There is great potential for anthocyanins, phycocyanin and genipin use as natural food additives with health benefits, besides imparting color. However, the technologies for the colorants recovery and application are not mature enough. Therefore, this area is still developing, and it is necessary to evaluate the economic feasibility of the proposed extraction processes, along with the safety and acceptance of colored food using these additives.

Encapsulation of tartary buckwheat flavonoids and application to yoghurt

Aims: The present work investigates the effect of tartary buckwheat flavonoid (TBF) capsules on the physical and chemical properties of yoghurt using polymeric whey protein (PWP) as a wall material.Methods: PWP was prepared by thermal polymerisation. TBF was encapsulated using PWP as the wall material via the pore-coagulation bath method. The physicochemical properties of the TBF capsules, such as the entrapment yield, moisture, average particle size, particle size distribution, surface morphology, molecular interactions, and thermal stability were investigated, in addition to the release of TBF in simulated gastric and intestinal juices. Yoghurt formulation was carried out using encapsulated TBF (3%, w/w), blank PWP beads (2.7%, w/w), and unencapsulated TBF (0.3%, w/w). A control yoghurt sample was prepared without these ingredients. The effects of encapsulated TBF on the chemical composition, acidity, texture, synaeresis, sensory properties, number of Streptococcus thermophilus and Lactobacillus, and other physical and chemical properties of the yoghurt were investigated.Results: TBF capsules were found to be sphere-shaped with porous surfaces, an average particle size of 1728.67 μm, an encapsulation yield of 92.85 ± 1.98% (w/w), and a glass transition temperature of 152.06 °C. When the TBF capsules were exposed to simulated gastric fluid for 4 h, the TBF release rate was 15.75% (w/w), while in simulated intestinal fluid, the TBF release rate reached 65.99% (w/w) after 1 h. After 5-6 h in simulated intestinal fluid, the TBF release rate reached 100% (w/w). The protein content of the yoghurt with encapsulated TBF was 3.57 ± 0.26% (w/w, p < 0.01), and the numbers of Lactobacillus and Streptococcus thermophilus were 2.45 ± 0.98 × 10⁸ (p < 0.01) and 5.43 ± 2.24 × 10⁷ CFU/mL (p < 0.05), respectively, with strong water retention being detected (p < 0.01). Samples containing the encapsulated TBF exhibited a significantly higher acceptability than the unencapsulated TBF (p < 0.01).Conclusions: Encapsulation using PWP effectively delivers TBF to the small intestine through the stomach. It also masks the bitter taste, enhances the colour of TBF-containing yoghurt, and improves the physical and chemical properties of the yoghurt.

One structure, multiple features: The phycocyanin in biotechnology

Phycocyanine (PC) is a water-soluble, non-toxic and bioactive (antioxidant, anti-inflammatory, antitumor, etc.) phycobiliprotein isolated, mainly, from cyanobacteria. Due to its several properties, PC is considered to be a rising biomolecule for Industrial exploitation, and has become an important research axis in order to promote its production, and optimize its biotechnological applications. The aim of this review article was to discuss the basic, and recent properties and applications of PC, and to bring together data on various aspects of PC stabilization, and PC nanopar-ticles formulation. In addition, an overview of the main structural characteristics and process-ses of PC extraction and purification were also discussed. The recent scientific research findings concluded that PC is a promising both functional, and bioactive additive in industry, especially, in food as a dye, in imaging as a fluorescent labeling agent, and in the phar-maceutical and nano-pharmaceutical field as a bioactive molecule and nanopar-ticles, particularly, due to it antitumor capacity. Phycocyanine is, thus, a promising bio-active molecules in pharmacological, and medical fields.

Phycobiliproteins from extreme environments and their potential applications

The light-harvesting phycobilisome complex is an important component of photosynthesis in cyanobacteria and red algae. Phycobilisomes are composed of phycobiliproteins, including the blue phycobiliprotein phycocyanin, that are considered high-value products with applications in several industries. Remarkably, several cyanobacteria and red algal species retain the capacity to harvest light and photosynthesise under highly selective environments such as hot springs, and flourish in extremes of pH and elevated temperatures. These thermophilic organisms produce thermostable phycobiliproteins, which have superior qualities much needed for wider adoption of these natural pigment-proteins in the food, textile, and other industries. Here we review the available literature on the thermostability of phycobilisome components from thermophilic species and discuss how a better appreciation of phycobiliproteins from extreme environments will benefit our fundamental understanding of photosynthetic adaptation and could provide a sustainable resource for several industrial processes.

Development of functional pasta with microencapsulated Spirulina: technological and sensorial effects

BACKGROUND

Spirulina microalgae have been added to food; however, there have been few reports on the methods used to protect the antioxidant potential against process conditions, and the effects on the sensory characteristics of products need to be better described. The aim of this study was to evaluate the influence on the technological properties, sensory profile, and acceptability of the pasta with free or microencapsulated Spirulina biomass added. Pasta formulations included: free Spirulina (FSP), microencapsulated Spirulina (MSP), and empty microspheres (EMP), which were compared with the control pasta (CP).

RESULTS

The microencapsulation protected the antioxidant potential of Spirulina in 37.8% of the pasta cooking conditions. The microspheres presented low solubility in water (86 g.kg^-1 ) and high encapsulation efficiency (87.6%), this being appropriate for addition to products that need cooking in water. The technological properties of pasta (water absorption, weight gain, firmness, and adhesiveness) were affected, but the overall acceptability index (85.13%) was not influenced by the addition of microspheres, despite changes observed in the sensory profile obtained by the CATA (check-all-that-apply).

CONCLUSIONS

Spirulina could be added to pasta even without microencapsulation but the microencapsulation in alginate allows for the protection of the antioxidant potential of the biomass, representing a potential alternative for the bakery industry. © 2019 Society of Chemical Industry.

Operational and economic aspects of Spirulina-based biorefinery

Microalgae biorefinery systems have been extensively studied from the perspective of resources, energy expenditure, biofuel production potential, and high-added value products. The genus Spirulina (Arthrospira) stands out among the microalgae of commercial importance. It accounts for over 30% of biomass produced globally because of high protein concentration and, carotenoid and phycocyanin content. Spirulina cultivation can be used to reduce greenhouse gases and for effluent treatment. Furthermore, its cellular morphology facilitates biomass recovery, which contributes to the process cost reduction. Spirulina biomass is widely applicable in food, feed, cosmetics, biofertilizers, biofuels, and biomaterials. A feasibility analysis of Spirulina biorefinery would provide specific information for the decision-making for the improvement of the Spirulina production process. In that context, this review aimed to present a parameter assessment to contribute to the economic viability of Spirulina production in a biorefinery system.