Thermal and pH stability of spray-dried encapsulated astaxanthin oleoresin from Haematococcus pluvialis using several encapsulation wall materials

Microencapsulation of natural products using spray drying; an overview

AIMS

This study examines microencapsulation as a method to enhance the stability of natural compounds, which typically suffer from inherent instability under environmental conditions, aiming to extend their application in the pharmaceutical industry.

METHODS

We explore and compare various microencapsulation techniques, including spray drying, freeze drying, and coacervation, with a focus on spray drying due to its noted advantages.

RESULTS

The analysis reveals that microencapsulation, especially via spray drying, significantly improves natural compounds' stability, offering varied morphologies, sizes, and efficiencies in encapsulation. These advancements facilitate controlled release, taste modification, protection from degradation, and extended shelf life of pharmaceutical products.

CONCLUSION

Microencapsulation, particularly through spray drying, presents a viable solution to the instability of natural compounds, broadening their application in pharmaceuticals by enhancing protection and shelf life.

Impact of thermal processing and emulsification methods on spice oleoresin blending: Insights for flavor release and emulsion stability

This study investigated the effect of heat treatments on the pungency and aroma profiles of a spice oleoresin blend, and the emulsion stability with different surfactants, encapsulating agents, and homogenization mechanisms. Total pungency increased with heat until 120 °C and drastically reduced at 150 °C. Thermal processing induced aroma release, and 46 compounds were identified at 90 °C, predominantly comprising sesquiterpenes. Tween 80 dispersed the highest oleoresin mass (6.21 ± 0.31 mg/mL) and reported the maximum emulsion stability index. The oleoresin percentage significantly influenced the emulsion stability, with 1% oleoresin producing the most stable emulsion. High-pressure homogenization applied on gum Arabic resulted in a greater encapsulation efficiency, exceeding 86%, and the lowest creaming index (4.70 ± 0.06%), while Hi-Cap 100 produced the best flow properties. The findings provide insights into incorporating lipophilic spice oleoresin blends in aqueous food systems and understanding the release of flavor compounds during thermal food processing.

Comparison of milk protein concentrate, micellar casein, and whey protein isolate in loading astaxanthin after the treatment of ultrasound-assisted pH shifting

Milk proteins can be used as encapsulation walls to increase the bioavailability of active compounds because they can bind hydrophobic, hydrophilic, and charged compounds. The objective of this study was to investigate the effects of astaxanthin (ASTA) encapsulation and the functional properties of milk protein and ASTA nanocomposites by an ultrasound-assisted pH-shifting treatment of different milk proteins, including milk protein concentrate (MPC), micellar casein (MCC), and whey protein isolate (WPI). The ultrasound-assisted pH-shifting treatment of milk protein helped to improve the encapsulation rate of ASTA. Therein, MCC showed great improvement of encapsulating ASTA after co-treatment with the raised encapsulated rate of 5.11%, followed by WPI and MPC. Furthermore, the nanocomposites of ASTA with milk protein exhibit improved bioavailability, antioxidant capacity, and storage stability. By comparison, MCC-encapsulated ASTA has the best storage stability, followed by MPC, and WPI-encapsulated ASTA has the least stability over a 28-d storage period. The results of intrinsic fluorescence and surface hydrophobicity showed that milk protein underwent fluorescence quenching after binding to ASTA, which was due to the hydrophobic sites of the protein being occupied by ASTA. In general, the nanocomposites of milk protein and ASTA fabricated by using an ultrasound-assisted pH-shifting treatment have the potential to be better nano-delivery systems for ASTA in functional foods, especially MCC, which showed excellent performance in encapsulation after treatment technique.

Electrospray-Assisted Fabrication of Dextran-Whey Protein Isolation Microcapsules for the Encapsulation of Selenium-Enriched Peptide

Selenium-enriched peptide (SP, selenopeptide) is an excellent organic selenium supplement that has attracted increasing attention due to its superior physiological effects. In this study, dextran-whey protein isolation-SP (DX-WPI-SP) microcapsules were fabricated via high-voltage electrospraying technology. The results of preparation process optimization showed that the optimized preparation process parameters were 6% DX (w/v), feeding rate Q = 1 mL/h, voltage U = 15 kV, and receiving distance H = 15 cm. When the content of WPI (w/v) was 4-8%, the average diameter of the as-prepared microcapsules was no more than 45 μm, and the loading rate for SP ranged from ~46% to ~37%. The DX-WPI-SP microcapsules displayed excellent antioxidant capacity. The thermal stability of the microencapsulated SP was improved, which was attributed to the protective effects of the wall materials for SP. The release performance was investigated to disclose the sustained-release capacity of the carrier under different pH values and an in-vitro-simulated digestion environment. The digested microcapsule solution showed negligible influence on the cellular cytotoxicity of Caco-2 cells. Overall, our work provides a facile strategy of electrospraying microcapsules for the functional encapsulation of SP and witnesses a broad prospect that the DX-WPI-SP microcapsules can exhibit great potential in the food processing field.

Complexation of anthocyanins, betalains and carotenoids with biopolymers: An approach to complexation techniques and evaluation of binding parameters

Natural pigments are bioactive compounds that can present health-promoting bioactivities in the human body. Due to their strong coloring properties, these compounds have been widely used as color additives as an alternative to artificial colorants. However, since these pigments are unstable under certain conditions, such as the presence of light, oxygen, and heat, the use of complexation and encapsulation techniques with biopolymers is in demand. Moreover, some functional properties can be achieved by using natural pigments-biopolymers complexes in food matrices. The complexation and encapsulation of natural pigments with biopolymers consist of forming a complex with the aim to make these compounds less susceptible to oxidative and degrading agents, and can also be used to improve their solubility in different media. This review aims to discuss different techniques that have been used over the last years to create natural pigment-biopolymers complexes, as well as the recent advances, limitations, effects, and possible applications of these complexes in foods. Moreover, the understanding of thermodynamic parameters between natural pigments and biopolymers is very important regarding the complex formation and their use in food systems. In this sense, thermodynamic techniques that can be used to determine binding parameters between natural pigments and potential wall materials, as well as their applications, advantages, and limitations are presented in this work. Several studies have shown an improvement in many aspects regarding the use of these complexes, including increased thermal and storage stability. Nonetheless, data regarding the biological effects on the human body and the sensory acceptance of natural pigments-biopolymers complexes in food systems are scarce in the literature.

Property and Stability of Astaxanthin Emulsion Based on Pickering Emulsion Templating with Zein and Sodium Alginate as Stabilizer

Astaxanthin loaded Pickering emulsion with zein/sodium alginate (SA) as a stabilizer (named as APEs) was developed, and its structure and stability were characterized. The encapsulation efficiency of astaxanthin (Asta) in APEs was up to 86.7 ± 3.8%, with a mean particle size of 4.763 μm. Freeze-dried APEs showed particles stacked together under scanning electronic microscope; whereas dispersed spherical nanoparticles were observed in APEs dilution under transmission electron microscope images. Confocal laser scanning microscope images indicated that zein particles loaded with Asta were aggregated with SA coating. X-ray diffraction patterns and Fourier transform infrared spectra results showed that intermolecular hydrogen bonding, electrostatic attraction and hydrophobic effect were involved in APEs formation. APEs demonstrated non-Newtonian shear-thinning behavior and fit well to the Cross model. Compared to bare Asta extract, APEs maintained high Asta retention and antioxidant activity when heated from 50 to 10 °C. APEs showed different stability at pH (3.0-11.0) and Na+, K+, Ca2+, Cu2+ and Fe2+ conditions by visual, zeta potential and polydispersity index measurements. Additionally, the first order kinetics fit well to describe APEs degradation at pH 3.0 to 9.0, Na+, and K+ conditions. Our results suggest the potential application of Asta-loaded Pickering emulsion in food systems as a fortified additive.

Promoting the Growth of Haematococcus lacustris under High Light Intensity through the Combination of Light/Dark Cycle and Light Color

The unicellular microalgae Haematococcus lacustris is an astaxanthin-rich organism that is widely used for commercial cultivation, but its main limitation is its relatively low biomass yield. It is widely accepted that the use of appropriate high light intensity could promote algal growth; however, H. lacustris is very sensitive to high-intensity light, and its growth can be readily arrested by inappropriate illumination. To exploit the growth-promoting benefit of higher light intensities while avoiding growth arrestment, we examined the growth of H. lacustris under high light intensities using various light profiles, including different light colors and light/dark cycles. The results show that light color treatments could not alleviate cellular stress under high light intensities; however, it was interesting to find that red light was favored the most by cells out of all the colors. In terms of the light/dark cycle, the 2/2 h light/dark cycle treatment was shown to lead to the highest specific growth rate, which was 46% higher than that achieved in the control treatment (18 μmol/m2·s light intensity, white light). Therefore, in further experiments, the 2/2 h light/dark cycle with red-light treatment was examined. The results show that this combination enabled a significantly higher specific growth rate, which was 66.5% higher than that achieved in the control treatment (18 μmol/m2·s light intensity, white light). These findings offer new strategies for the optimization of illumination for the growth of H. lacustris and lay the foundations for more reasonable lighting utilization for the cultivation of commercially valuable algal species.

The spatial arrangement of astaxanthin in bilayers greatly influenced the structural stability of DPPC liposomes

Liposomes are regarded as the ideal nanocarrier for concurrent or separate delivery of nutraceuticals in the food industries. Precise control of the structural stability is essential for the processing, storage, and nutrition delivery of liposomes. Astaxanthin was found to significantly affect the membrane stability of liposomes by inserting into the phospholipid bilayers in a similar way to cholesterol. Compared with cholesterol, astaxanthin could significantly improve the phase transition temperature, membrane fluidity, and membrane compactness of liposomes. Additionally, the membrane stability was well modulated by controlling the distribution patterns of astaxanthin (monomers, H- and J-aggregates) in bilayers. For instance, astaxanthin H-aggregates could endow the liposomal membrane with highest rigidity and compactness. Additionally, astaxanthin aggregates, especially J-aggregates could greatly improve storage stability of liposomes, thus providing a novel strategy to regulate and optimize the stability of liposomes for their diversified applications.

Encapsulation of Capsaicin in Whey Protein and OSA-Modified Starch Using Spray-Drying: Physicochemical Properties and Its Stability

The poor water-solubility and stability of capsaicin limits its widespread application in the industry. Spray-dried capsaicin microcapsules were fabricated using whey protein (WP) and octenyl-succinic-anhydride-modified starch (OS) as wall materials in this study. The aim is to investigate the impact of protein/starch ratio on microcapsules’ physicochemical characteristics and stability. SEM images showed that microcapsule granules were uneven in size, and irregular, with some wrinkles and dents. FTIR illustrated a chemical interaction between capsaicin and composite wall materials. XRD showed that the spray-dried powders were mainly in amorphous form. As the whey protein content decreased, the yield (9.32–68.18%), encapsulation efficiency (49.91–94.57%), wettability (158.87–232.63 s), and solubility (74.99–96.57%) of samples decreased, but the mean particle size (3.22–26.03 μm), apparent viscosity, and shear stress tended to increase. Besides, DSC revealed that the glass transition temperatures (Tg) of samples were at around 85 °C. Capsaicin microcapsules with WP:OS at the ratio of 7:3 possessed the highest Tg, and the best storage stability. Based on our research, microencapsulation significantly improved the stability and the water-solubility of capsaicin. A small amount of OSA-starch mixed with whey protein as a promising carrier for capsaicin would greatly promote the application of capsaicin in the food industry.

Microencapsulation as a Noble Technique for the Application of Bioactive Compounds in the Food Industry: A Comprehensive Review

The use of natural food ingredients has been increased in recent years due to the negative health implications of synthetic ingredients. Natural bioactive compounds are important for the development of health-oriented functional food products with better quality attributes. The natural bioactive compounds possess different types of bioactivities, e.g., antioxidative, antimicrobial, antihypertensive, and antiobesity activities. The most common method for the development of functional food is the fortification of these bioactive compounds during food product manufacturing. However, many of these natural bioactive compounds are heat-labile and less stable. Therefore, the industry and researchers proposed the microencapsulation of natural bioactive compounds, which may improve the stability of these compounds during processing and storage conditions. It may also help in controlling and sustaining the release of natural compounds in the food product matrices, thus, providing bioactivity for a longer duration. In this regard, several advanced techniques have been explored in recent years for microencapsulation of bioactive compounds, e.g., essential oils, healthy oils, phenolic compounds, flavonoids, flavoring compounds, enzymes, and vitamins. The efficiency of microencapsulation depends on various factors which are related to natural compounds, encapsulating materials, and encapsulation process. This review provides an in-depth discussion on recent advances in microencapsulation processes as well as their application in food systems.

Microalgae Xanthophylls: From Biosynthesis Pathway and Production Techniques to Encapsulation Development

In the last 20 years, xanthophylls from microalgae have gained increased scientific and industrial interests. This review highlights the essential issues that concern this class of high value compounds. Firstly, their chemical diversity as the producer microorganisms was detailed. Then, the use of conventional and innovative extraction techniques was discussed. Upgraded knowledge on the biosynthetic pathway of the main xanthophylls produced by photosynthetic microorganisms was reviewed in depth, providing new insightful ideas, clarifying the function of these active biomolecules. In addition, the recent advances in encapsulation techniques of astaxanthin and fucoxanthin, such as spray and freeze drying, gelation, emulsification and coacervation were updated. Providing information about these topics and their applications and advances could be a help to students and young researchers who are interested in chemical and metabolic engineering, chemistry and natural products communities to approach the complex thematic of xanthophylls.

Recent research advances in astaxanthin delivery systems: Fabrication technologies, comparisons and applications

Astaxanthin (AST) is classified as a kind of carotenoid with bright red color, powerful antioxidant activity as well as a range of health benefits. AST-based functional foods present a new thought of healthy diets with both the enhancement of food color and incorporation of nutrients. However, the poor water solubility, easy oxidation, light instability, thermal instability and peculiar smell excessively restrict its application in the food industry. In this review, common bio-based materials for various AST delivery systems suitable for different food products are highlighted. Moreover, characteristics of different delivery systems and current applications in food products are also compared and summarized. This review provides some ideas on the research trends and applications of AST delivery systems in food. The joint use of two or more materials can significantly enhance the stability of delivery systems. All of the encapsulation systems slow down the degradation of AST to a certain extent and can be applied to different food systems. However, studies and applications are still focused on emulsions and microcapsules with unsatisfactory odor masking effects. In the future, diverse AST-loaded delivery systems with high encapsulation efficacy, good stability, odor masking effects and cost-effective preparation technologies will be the major research trends.

Production of a rich-carotenoid colorant from pumpkin peels using oil-in-water emulsion followed by spray drying

Peels and seeds are byproducts generated during the processing of fruits and vegetables that have been cut off or rejected in the food industry. Pumpkin peels are an example of products that provide valuable nutritional aspects but that have low commercial value. This work aimed at recovering carotenoids from pumpkin peels to produce valuable powders. The pumpkin peel flour was obtained from convective drying and milling processes. Liquid-solid extraction produced the ethanol raw extract with a high carotenoid content. Carotenoid extract and Arabic gum suspensions were mixed in proportions of 1:2, 1:3, or 1:4 w/w. Emulsions produced via Ultra-Turrax (UT) and Ultra-Turrax plus high pressure (UTHP) were evaluated and spray dried. The particles carotenoid concentrations varied from 159.1 to 304.6 µg/g and from 104.3 to 346.2 µg/g for samples primarily produced via UT and UTHP, respectively. UTHP 1:3 particles showed the lowest degradation of carotenoids during 90 days of storage, with a retention index of 79%. The homogenization and spray drying techniques were proven to be suitable steps to preserve the carotenoids recovered from the byproduct studied. Microparticles can be used as a natural dye with potential use in food, pharmaceuticals, and cosmetics.

Green Extraction by Ultrasound, Microencapsulation by Spray Drying and Antioxidant Activity of the Tucuma Coproduct (Astrocaryum vulgare Mart.) Almonds

The industrial processing amazon fruits, like tucuma, generates a large amount of coproducts with large nutritional potential. Thus, this work obtained the oily extract of the tucuma almonds coproducts by green extraction using palm oil by the ultrasound method and then microencapsulated by atomization and verification of its antioxidant activity. Thermogravimetric techniques, infrared spectroscopy, scanning electron microscopy, moisture content, water activity were applied to characterize the microparticles. Total carotenoids were determined by UV spectroscopy and antioxidant activity was measured by 2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid and co-oxidation in the system β-carotene/linoleic acid. The oily extract and microparticle had total carotenoid contents of 3.305 mg/100 g ± 0.01 and 2.559 mg/100 g ± 0.01, respectively. The antioxidant activity assessed through the 2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid value was 584.75 μM/trolox ± 0.01 (oily extract) and 537.12 μM/trolox ± 0.01 (microparticle) were determined. In the system β-carotene/linoleic acid showed oxidation of 49.9% ± 1.8 lipophilic extract and 43.3% ± 2.3 microparticle. The results showed that the oily extract of the tucuma almond coproduct can be used as a carotenoid-rich source and microencapsuled with possible application for functional foods production.

Effect of Interfacial Ionic Layers on the Food-Grade O/W Emulsion Physical Stability and Astaxanthin Retention during Spray-Drying

The utilization of astaxanthin in food processing is considered to be narrow because of its substandard solubility in aqueous matrices and the instability of chemical compounds during the processing of food and the instability of chemical compounds during the processing of food. The investigation sought to evaluate multilayer emulsions stabilized by ionic interfacial layers of lupin protein isolate (LPI), ι-carrageenan (CA), and chitosan (CHI) on the physical stability of the emulsion as well as the retention of astaxanthin during the spray drying process. Primary emulsion (Pr-E) was prepared by adding LPI on oil droplet surfaces containing astaxanthin. The homogenization pressure and cycles to obtain the Pr-E were investigated. The secondary emulsion (Se-E) and tertiary emulsion (Te-E) were elaborated by mixing CA/Pr-E and CHI/Se-E, respectively. Emulsion stability was assessed under different environmental stresses (pH and NaCl). Astaxanthin retention of emulsions was determined immediately after finishing the spray-drying process. The results showed that Pr-E was stabilized with 1.0% (w/v) of LPI at 50 MPa and three cycles. Se-E and Te-E were obtained with CA/Pr-E and Se-E/CHI of 70/30 and 50/50% (w/w), respectively. The Se-E was the most stable compared to the Pr-E and Te-E when subjected to different pHs; nevertheless, once the NaCl concentration rose, no variations in the ζ-potential of all emulsions studied or destabilization were observed. The Se-E and Te-E derived provided higher astaxanthin retention (>95%) during the spray-drying process compared to Pr-E (around 88%). The results indicated that these astaxanthin multilayer emulsions show considerable potential as a functional ingredient in food products.

Spectroscopic, mineral, and antioxidant characteristics of blue colored powders prepared from cornflower aqueous extracts

The present study aimed to prepare blue colored powders from an aqueous extract of cornflower petals. Low temperature (4 °C) aqueous extraction (1:20) and microencapsulation by freeze-drying were performed. A mixture of stabilizers (maltodextrin, guar gum, and lecithin) in a proportion of 10% to the amount of extract was used. The results indicated that the addition of 2% and 4% guar gum to maltodextrin (8-6%) significantly increased the efficiency of the process, but 4% guar gum caused the formation of amorphous particles; therefore, 2% guar gum addition was found to be the most optimal. The FT-IR and FT-Raman band characteristics for guar gum, lecithin, and maltodextrin dominated over those for anthocyanins contained in the powders made from cornflower petals. The blue powders had total phenolic content of 19.5-26.6 mg GAE/g DW. The antioxidant activity of the prepared powders measured by ABTS, CHEL, OH, and RED was high.

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.

Influence of molecular structure of astaxanthin esters on their stability and bioavailability

The stability and bioavailability of fourteen astaxanthin esters (Asta-Es) with different molecular structures were investigated using in vitro and in vivo digestion models. The results demonstrated that Asta-E with long-chain and saturated fatty acids were more stable than other types of Asta-E. Astaxanthin diester (Asta-DE) was better than astaxanthin monoester (Asta-ME) and free astaxanthin (F-Asta), as determined based on the degradation rate constant at 60 °C. The absorbability of Asta-Es with different molecular structures was evaluated through the serum concentrations of astaxanthin (Asta). The results indicated that Asta-E with short-chain fatty acids had higher bioavailability than Asta-Es with long-chain fatty acids, whereas Asta-E with high-unsaturation fatty acids had higher bioavailability than Asta-E with low-unsaturation fatty acids. Asta-ME had significantly increased bioavailability compared with Asta-DE. We concluded that the molecular structure of Asta-E could significantly affect their stability and bioavailability.

Recent Advances in Astaxanthin Micro/Nanoencapsulation to Improve Its Stability and Functionality as a Food Ingredient

Astaxanthin is a carotenoid produced by different organisms and microorganisms such as microalgae, bacteria, yeasts, protists, and plants, and it is also accumulated in aquatic animals such as fish and crustaceans. Astaxanthin and astaxanthin-containing lipid extracts obtained from these sources present an intense red color and a remarkable antioxidant activity, providing great potential to be employed as food ingredients with both technological and bioactive functions. However, their use is hindered by: their instability in the presence of high temperatures, acidic pH, oxygen or light; their low water solubility, bioaccessibility and bioavailability; their intense odor/flavor. The present paper reviews recent advances in the micro/nanoencapsulation of astaxanthin and astaxanthin-containing lipid extracts, developed to improve their stability, bioactivity and technological functionality for use as food ingredients. The use of diverse micro/nanoencapsulation techniques using wall materials of a different nature to improve water solubility and dispersibility in foods, masking undesirable odor and flavor, is firstly discussed, followed by a discussion of the importance of the encapsulation to retard astaxanthin release, protecting it from degradation in the gastrointestinal tract. The nanoencapsulation of astaxanthin to improve its bioaccessibility, bioavailability and bioactivity is further reviewed. Finally, the main limitations and future trends on the topic are discussed.

Encapsulation of Active Ingredients in Food Industry by Spray-Drying and Nano Spray-Drying Technologies

Since its invention in 1872 by Samuel Percy, the spray drying of food products has been widely used, whether in products consumed by babies in milk formulations, powdered sweets and cocoa soluble in milk for children, or food supplements rich in proteins, vitamins, and minerals for adults. All of these products were first formulated in solution and then converted into powders to facilitate the transport and preservation of the properties during storage. In recent years, novel technologies such as nano spray drying have emerged for the development of food formulations with high-cost active ingredients. The aim of the present work is to present a review of the literature reported in the last 10 years related to these technologies. The basis of the spray-drying technologies i.e., conventional and nano, are described and compared, emphasizing the instrumental processing conditions for achieving a desired product. Examples of some unwanted reactions presented during the encapsulation of active ingredients are provided.

Food-grade Pickering emulsion as a novel astaxanthin encapsulation system for making powder-based products: Evaluation of astaxanthin stability during processing, storage, and its bioaccessibility

The use of astaxanthin as a food ingredient is limited due to its poor water solubility in aqueous matrices and highly susceptibility to oxidation; hence microencapsulation of this carotenoid is an appropriate technique to increase its stability and functionally. In this study, astaxanthin oleoresin was encapsulated using a food-grade Pickering emulsion to enhance its stability during spray-drying and storage and its bioaccessibility. The oil-in-water (O/W) emulsions were stabilized by protein-based aggregates obtained from a lupin protein-rich cultivar (AluProt-CGNA). The emulsions containing the astaxanthin microencapsulated in its oil phase (core material) were submitted to a spray-drying process at 160 °C and 140 °C. For this, blends of these protein-based aggregates (LP-APs) and maltodextrin (at different ratios) were used as wall material. The emulsion stability, microstructure, powder characteristics, oxidative stability and concentration of astaxanthin, encapsulation efficiency and bioaccessibility after spray-drying were investigated. The results showed that LP-APs exhibit a great potential to perform as stabilizers for Pickering emulsions. The formed O/W emulsions were highly stable against creaming at high concentrations of LP-APs. The results also indicated that spray-drying can be applied to prepare stable astaxanthin emulsions into powders with good oxidative stability. The astaxanthin content in dry emulsions under storage conditions (25 and 45 °C for 4 weeks) was higher in powders containing a higher LP-APs concentration. The encapsulation efficiency was higher than 90% with the emulsion stabilized with 6% of LP-APs. The bioaccessebility of reconstituted astaxanthin powder (with 6% LP-APs) was around 80%.

Addition of norbixin microcapsules obtained by spray drying in an isotonic tangerine soft drink as a natural dye

Annatto seeds (Bixa orellana L.) are a natural source of norbixin, a carotenoid with antioxidant activity and an intense yellow-orange color which is a commonly used food and beverage colorant. However, it is susceptible to environmental factors such as light, oxygen, and temperature. Microencapsulation presents an alternative for improving the bioactive compound's stability. In this study, norbixin microcapsules (MCN) were added to isotonic tangerine soft drinks in a quantity not exceeding food additive regulations. The final concentration was 2.86 ± 0.02 µg norbixin/mL, and according to the CIELab system, the beverage acquired the expected orange tonality. The addition of MCN favorably affects beverage stability during storage under accelerated conditions (heat and light), and the half-life time was more significant (29.71 days) than when non-encapsulated norbixin was used (393.39 min). In conclusion, MCN should be considered as an additive with potential use in processed beverage industries instead of synthetic dyes.

Effect of Membrane Surface Modification Using Chitosan Hydrochloride and Lactoferrin on the Properties of Astaxanthin-Loaded Liposomes

Astaxanthin-loaded liposomes were prepared by a thin-film ultrasonic method, and the effects of the different membrane surface modifiers chitosan hydrochloride (CH) and lactoferrin (LF) on the physicochemical stability of the liposomes and bioaccessibility of astaxanthin were studied. Based on the negative charge characteristics of egg yolk lecithin, LF and CH with positive charge were assembled on the surface of liposomes by an electrostatic deposition method. The optimal concentrations of modifiers were determined by particle size, zeta potential and encapsulation efficiency. The interaction between the liposomes and the coatings was characterized by Fourier Transform infrared spectroscopy. The stability of astaxanthin in different systems (suspension and liposomes) was investigated, and its antioxidant capacity and bioaccessibility were determined. The results showed that both membrane surface modifications could interact with liposomes and protect astaxanthin from oxidation or heat degradation and enhance the antioxidant activity of the liposome, therefore membrane surface modification played an important role in stabilizing the lipid bilayer. At the same time, the encapsulated astaxanthin exhibited higher in vitro bioaccessibility than the free astaxanthin. CH and LF modified liposomes can be developed as formulations for encapsulation and delivery of functional ingredients, providing a theoretical basis for the development of new astaxanthin series products.

Enzyme-assisted extraction of astaxanthin from Haematococcus pluvialis and its stability and antioxidant activity

The release of bioactive pigments could be potentially improved by enzyme degradation of plant cell wall polysaccharides. In this study, the objective was to evaluate enzyme type (cellulase and pectinase), pH values, hydrolysis temperature and time on the release of astaxanthin from Haematococcus pluvialis (H. pluvialis). The results showed that pre-treated H. pluvialis with enzymes could improve the separation yield of astaxanthin. Pectinase release rate of astaxanthin from H. pluvialis was significantly higher than cellulase (p < 0.05), and enzyme hydrolysis time was also shorter. The stability study of astaxanthin oleoresin and microcapsule during storage at different temperature, oxygen and illumination was found that the degradation rate of astaxanthin rose with increasing temperature and illumination time, and the retention in oxygen environment decreased. The stability of astaxanthin microcapsules was better than astaxanthin oleoresin.

Development and Characterization of Astaxanthin-Containing Whey Protein-Based Nanoparticles

Astaxanthin (ASX) is a carotenoid of great interest due to its potential health benefits. However, its use in the food, feed, and pharmaceutical fields is limited due to low bioavailability, poor stability during thermochemical treatments, susceptibility to oxidation, and poor organoleptic characteristics. The aim of this work was to develop a method to stabilize astaxanthin extracted from the microalgae Haematococcus pluvialis (H.p.) and to improve its nutritional and functional properties through nanoencapsulation. Nanoparticles (NPs) were produced by emulsification–solvent evaporation technique starting from H.p. oleoresin using whey proteins concentrate (WPC) as stabilizer. The efficiency of encapsulation was 96%. The particle size (Z-average) was in the range of 80–130 nm and the superficial charge (measured as zeta-potential) was negative (−20 to −30 mV). The stability of the NPs upon resuspension in water was assayed through a panel of stress tests, i.e., extreme pH, UV radiation, Fe³⁺ exposition, and heating at 65 °C, that always showed a superior performance of encapsulated ASX in comparison to oleoresin, even if NPs tended to precipitate at pH 3.5–5.5. Simulated gastroenteric digestion was conducted to study the release of ASX in physiological conditions, and showed a maximum bioaccessibility of 76%, with 75% ASX converted into the more bioavailable free form. The collected data suggest that NPs might have possible future applications as supplements for human and animal diets.

Use of pulsed electric field permeabilization to extract astaxanthin from the Nordic microalga Haematococcus pluvialis

The Nordic microalgal strain Haematococcus pluvialis was exposed to various stress conditions to induce astaxanthin accumulation. Highest carotenoid content (19.1 mg·g^-1_dw) was achieved in nitrogen-free culture medium at a high light intensity. The efficiency of Pulsed Electric Field (PEF) pre-treatment of stressed fresh biomass of H. pluvialis followed by incubation in the growth medium was compared to classical disruption methods (bead-beating, freezing-thawing, thermal treatment or ultrasound) for the subsequent extraction of astaxanthin in ethanol. N-starved cells treated with PEF followed by aqueous incubation for 6 h resulted in extraction of 96% (18.3 mg_car·g_dw^-1) of the total carotenoid content compared to 80% (15.3 mg_car·g_dw^-1) using other physical methods. The proportion of free forms of astaxanthin was higher in PEF-treated samples compared to mechanical disruption, suggesting PEF triggering an esterase activity. PEF pre-treatment of the cells followed by incubation in growth medium improved astaxanthin extraction in the eco-friendly solvent ethanol.

Sublingual Delivery of Astaxanthin through a Novel Ascorbyl Palmitate-Based Nanoemulsion: Preliminary Data

Astaxanthin is a carotenoid extracted from several seaweeds with ascertained therapeutic activity. With specific reference, astaxanthin is widely used in clinical practice to improve ocular tissue health and skin protection from UV ray damages. Despite its well-documented pleiotropic actions and demonstrated clinical efficacy, its bioavailability in humans is low and limited because of its hydrophobicity and poor dissolution in enteric fluids. Furthermore, astaxanthin is very unstable molecule and very sensitive to light exposure and thermal stress. Taken together, these pharmacological and chemical–physical features strongly limit pharmaceutical and nutraceutical development of astaxanthin-based products and as a consequence its full clinical usage. This work describes the preliminary in vitro investigation of sublingual absorption of astaxanthin through a novel ascorbyl palmitate (ASP) based nanoemulsion.

Water-dispersible astaxanthin-rich nanopowder: preparation, oral safety and antioxidant activity in vivo

In this research, astaxanthin-rich nanopowder was prepared by nanoencapsulation and freeze-drying techniques with enhanced bioavailability and antioxidant activities. The nanopowder showed a maximum solubility of 230 mg mL-1 with an astaxanthin content as high as 2.9%. Compared with free astaxanthin, the astaxanthin-loaded nanopowder exhibited a more efficient antioxidant effect: an oral dose of 0.9 mg per kg BW significantly reduced the malondialdehyde and protein carbonyl contents, and increased the glutathione content as well as the superoxide dismutase activities in alcohol-induced acute hepatic injured mice, and maintained these oxidative stress indicators at a normal level for a longer period when treated with nanoencapsulated-astaxanthin than free astaxanthin. Simulated gastrointestinal tract studies demonstrated that the nanopowder with pH and DNase I-dependent dissociation properties delivered astaxanthin efficiently to the small intestine. Astaxanthin-rich nanopowder with a dose as high as 2.4 mg per kg BW (equivalent to astaxanthin) showed no chronic toxicity to mice in terms of hematology and pathological histology, indicating its impressive biocompatibility for biomedical applications. Pharmacokinetics and relative bioavailability (207%) of the nanopowder further proved that DNA/chitosan nanocarriers significantly improved the delivery efficiency of astaxanthin. With enhanced bioavailability and antioxidant activities, this novel type of astaxanthin-loaded nanopowder is expected to find broad application in the food and drug industry.

Effect of Agave Fructans as Carrier on the Encapsulation of Blue Corn Anthocyanins by Spray Drying

Effects of agave fructans as carrier agents on the encapsulation of blue corn anthocyanins using spray-drying were evaluated. Blue corn extract was mixed with 6%, 8%, 10%, and 12% (w/v) of agave fructans in duplicate and dried at 150 °C. The extract showed good contents of anthocyanins, polyphenols, and antioxidant activity. The increase of agave fructans in the encapsulated powders caused a significant increase (p < 0.05) in the humidity, water activity (aw), pH, bulk density, water solubility index (WSI), and color L* values. On the contrary, the agave fructan addition decreased the hygroscopicity, water absorption index (WAI), antioxidant activity, total anthocyanin, total polyphenol, and individual anthocyanin contents. The encapsulation of blue corn extract with 6% agave fructans (w/v) resulted in good physical, thermal, morphological, and high antioxidant properties. The results suggest that the use of agave fructans as wall material represents advantages in the conservation of anthocyanins and other bioactive compounds from blue corn extract during their encapsulation. The application of blue corn anthocyanin encapsulated powders as a food ingredient is promising for food pigmentation, representing additional advantages for their contribution as a soluble fiber that can benefit the health of consumers.