Stability Of Astaxanthin Research Articles

Physico-Chemical Properties, Stability, and Potential Food Applications of Shrimp Lipid Extract Encapsulated by Complex Coacervation

Lipid extract from shrimp cephalothorax is a potential food coloring owing to its intense red color. However, it presents some drawbacks, such as its characteristic odor, astaxanthin instability, and difficult dosage and manipulation. The present work is an attempt to overcome these problems by means of complex coacervation encapsulation using gelatin and gum arabic as wall materials. Round molecules in which the lipid extract was efficiently encapsulated in the form of multiple droplets were obtained. The resulting microcapsules stabilized by freeze-drying had good properties with a view to their application as food coloring, owing to their intense red color, improved astaxanthin stability, and low water activity, water solubility, and hygroscopicity. The coloring capacity and sensory properties were evaluated when added to yogurt and a gellified fish product. For yogurt, a trained sensory panel determined that encapsulation effectively reduced the characteristic odor, whereas the coloring capacity was improved, as compared to non-encapsulated lipid extract. For the gellified fish product, no sensory improvement was observed, but the encapsulated lipid extract provided an attractive, uniform color.

Gypenosides as natural emulsifiers for oil-in-water nanoemulsions loaded with astaxanthin: Insights of formulation, stability and release properties

The formulation, physicochemical stability and bioaccessibility of astaxanthin (AST) loaded oil-in-water nanoemulsions fabricated using gypenosides (GPs) as natural emulsifiers was investigated and compared with a synthetic emulsifier (Tween 20) that is commonly applied in food industry. GPs were capable of producing nanoemulsions with a small volume mean diameter (d4,3 = 125 ± 2 nm), which was similar to those prepared using Tween 20 (d4,3 = 145 ± 6 nm) under the same high-pressure homogenization conditions. GPs-stabilized nanoemulsions were stable against droplet growth over a range of pH (6–8) and thermal treatments (60–120 °C). Conversely, instability occurred under acidic (pH 3–5) and high ionic strength (25–100 mM CaCl2) conditions. In comparison with Tween 20, GPs were more effective at inhibiting AST from degradation during 30 days of storage at both 5 and 25 °C. However, GPs led to lower lipid digestion and AST bioaccessibility from nanoemulsions than did Tween 20.

Critical review of encapsulation methods for stabilization and delivery of astaxanthin

Astaxanthin is an important carotenoid pigment and potent antioxidant with proven health benefits. It is primarily obtained from algae or bacteria and is the natural colorant in crustaceans and salmonids. However, this pigment readily degrades in the presence of light and oxygen and has low absorption rates in the human digestive system. Different encapsulation strategies have been adopted to improve astaxanthin physical stability and bioavailability for nutritional use. This review summarizes and compares different encapsulation techniques and matrices applied to astaxanthin. Typical methods for encapsulation include high pressure homogenization, nano dispersions, liposomes and nanoparticles. More recently low energy methods like membrane and microchannel emulsification have been used to improve astaxanthin stability and delivery. Despites the use of numerous delivery methods, improved delivery systems for concentrated astaxanthin formulations are still required. In addition, not all methods have undergone comprehensive in vivo studies that are required to assure the bioavailability of encapsulated astaxanthin.

Development of a carboxymethyl chitosan functionalized nanoemulsion formulation for increasing aqueous solubility, stability and skin permeability of astaxanthin using low-energy method

In this research, firstly astaxanthin (ASX)-loaded nanoemulsions (NEs) were produced using a convenient low-energy emulsion phase inversion method. The optimised ASX-NEs were prepared in the presence of Cremophor® EL and Labrafil® M 1944 CS, with a surfactant-to-oil ratio of 4:6. The ASX-NE droplets were spherical with a mean droplet diameter below 100 nm and a small negative surface charge. The system was stable without alteration of mean droplet diameter for three months. Then, the ASX-NE was functionalised with carboxymethyl chitosan (CMCS) through direct CMCS (0.02%) incorporation during the preparation process. The ASX chemical stability and skin permeability increased in the following order: ASX solution control < ASX-NE < CMCS-ASX-NE. Cell viability assays on L929 cells revealed low cytotoxicity of blank NE, ASX-NE and CMCS-ASX-NE in the range from 5 to 500 μg mL−1. In conclusion, the CMCS-ASX-NE might be a promising delivery vehicle in dermal and transdermal products.

Stability of astaxanthin-loaded nanostructured lipid carriers as affected by pH, ionic strength, heat treatment, simulated gastric juice and freeze-thawing.

Nanostructured lipid carriers (NLCs) offer many potential benefits for incorporating lipophilic molecules into clear/opaque food systems. In this study, the influence of pH, ionic strength, thermal treatment, simulated gastric juice (SGJ), and freeze-thawing on the stability of astaxanthin-loaded NLCs (Ax-NLCs) was examined. Ax-NLCs (containing α-tocopherol and ethylenediaminetetraacetic acid as antioxidants) were stabilized with Tween 80 and lecithin (Z-average size: 94nm), and studied for the above mentioned purpose. The size of Ax-NLCs increased at low pH values (≤5), high NaCl concentrations (≥50mM), and slightly at SGJ, mainly because of decreasing the ζ-potential. Moreover, thermal treatment at 80/90°C led to an increase in Ax-NLCs size. Glycerol was found as an appropriate cryoprotectant for preventing aggregation of Ax-NLCs during freeze-thawing. pH, ionic strength, heat and SGJ had no drastic effects on the chemical stability of astaxanthin in NLCs. These results have valuable implications for the utilization of food-grade NLCs.

Astaxanthin stability and color change of krill during subcritical water treatment.

Pacific krill (Euphausia pacifica) contains high amounts of astaxanthin, a carotenoid pigment with strong antioxidative activities. In this study, the effects of subcritical water temperatures (100-180°C) and times (0-10min) on color changes (L*, a*, and b*) and astaxanthin degradation in Pacific krill were investigated. In addition, an aqueous solution of pure astaxanthin and that of crude astaxanthin from Pacific krill, both at a concentration of 5mg/L, were subjected to treatment under subcritical water conditions using a flow-type reactor to compare the degradation of free astaxanthin and astaxanthin fatty acid esters. To compare the results of the different treatment conditions on the properties of astaxanthin, the severity factor (log R0) was calculated, which ranged from 0.38 to 3.52. The extractability of astaxanthin enhanced when the subcritical water treatment was carried out at log R0 values of 2.00-2.44. In contrast, astaxanthin underwent 50% degradation at log R0>2.44. The changes in the a* values correlated well with the astaxanthin content in the treated krill, while the b* and L* values might relate to the browning components forming owing to Maillard reaction. The results show that free astaxanthin was less stable than crude astaxanthin under subcritical water treatment.

Formulation and characterization of O/W nanoemulsions encapsulating high concentration of astaxanthin

This study evaluates the effect of modified lecithin (ML) and sodium caseinate (SC) on the formulation, stability and bioaccessibility of astaxanthin (AXT) loaded oil-in-water (O/W) nanoemulsions. These nanoemulsions were formulated using high-pressure homogenization in four passes at 100MPa. The volume mean diameter (d4,3) of nanoemulsions produced by ML and SC were 163±5 and 144±12 nm, respectively. The physiochemical stability of nanoemulsions was recorded at 25°C. The nanoemulsions prepared by ML were stable for 30 minutes against a wide range of pH and heating temperatures (60–120 °C). However, ML-stabilized nanoemulsions showed droplet growth when treated at high NaCl concentrations. In comparison, droplet growth was observed in SC-stabilized nanoemulsions at pH4 and at high temperature treatment. However, SC-stabilized nanoemulsions were stable at high NaCl concentration (500 mM). The SC-stabilized nanoemulsions showed good physical and chemical stability (>70%) after 30 days of storage. The bioaccessibility of AXT in nanoemulsions was significantly higher in ML (33%) than in SC-stabilized nanoemulsions (6%), indicating a strong influence of emulsifier on bioaccessibility. These findings provide valuable information in designing nutritional products such as aqueous based AXT fortified beverages.

Chemical stability of astaxanthin integrated into a food matrix: Effects of food processing and methods for preservation.

Astaxanthin is a carotenoid pigment found in numerous organisms ranging from bacteria to algae, yeasts, plants, crustaceans and fish such as salmon. Technological importance of this pigment emerged from various studies demonstrating that it is a powerful antioxidant, even with higher activity than alpha-tocopherol and other carotenoids. It has been included in various pharmaceutical products because of several beneficial properties. By its nature, astaxanthin is susceptible to degradation and can undergo chemical changes during food processing. Therefore, different studies have focused on improving the stability of the carotenoid under conditions such as high temperatures, pressures and mechanical force, among others. In this review, common processes involved in food processing and their effect on the stability of astaxanthin, integrated into a food matrix are discussed. Moreover, preservation techniques such as microencapsulation, inclusion in emulsions, suspensions, liposomes, etc., that are being employed to maintain stability of the product are also reviewed.

Production of stable food-grade microencapsulated astaxanthin by vibrating nozzle technology.

Astaxanthin is a carotenoid known for its strong antioxidant and health-promoting characteristics, but it is also highly degradable and thus unsuited for several applications. We developed a sustainable method for the extraction and the production of stable astaxanthin microencapsulates. Nearly 2% astaxanthin was extracted by high-pressure homogenization of dried Haematococcus pluvialis cells in soybean oil. Astaxanthin-enriched oil was encapsulated in alginate and low-methoxyl pectin by Ca2+-mediated vibrating-nozzle extrusion technology. The 3% pectin microbeads resulted the best compromise between sphericity and oil retention upon drying. We monitored the stability of these astaxanthin beads under four different conditions of light, temperature and oxygen exposition. After 52weeks, the microbeads showed a total-astaxanthin retention of 94.1±4.1% (+4°C/-light/+O2), 83.1±3.2% (RT/-light/-O2), 38.3±2.2% (RT/-light/+O2), and 57.0±0.4% (RT/+light/+O2), with different degradation kinetics. Refrigeration, therefore, resulted the optimal storage condition to preserve astaxanthin stability.

Molecular mechanism of the protective effect of monomer polyvinylpyrrolidone on antioxidants – experimental and computational studies

We previously developed a lutein–polyvinylpyrrolidone (PVP) complex with improved aqueous saturation solubility and stability, though the conjugation mechanism is still unclear. In this paper, experiments with astaxanthin–PVP complex and curcumin–PVP complex were carried out, which indicated that PVP could improve the solubility and stability of astaxanthin and curcumin. We aimed to construct a computational model capable of understanding the protective effect in complexes formed between PVP and antioxidants, through which the binding mode of PVP and antioxidants was investigated with molecular modelling in order to obtain the interactions, binding energy, binding site and surface area between PVP and antioxidants. Solubility enhancement was attributed to the H-bonds between PVP and antioxidants, and the saturation solubility was curcumin > lutein > astaxanthin. Binding energy, binding site and surface area were beneficial for the stability of complex, and the stability enhancement was lutein > astaxanthin > curcumin. The experimental results were in agreement with the computational results. Furthermore, we established a method for the exploration of a similar system with other polymer complexes. Additionally, the proposed PVP model could predict the interactions between PVP and various ligands, such as antioxidants and drugs.

Preparation of stable microcapsules from disrupted cell of Haematococcus pluvialis by spray drying

SummaryHaematococcus pluvialis, including astaxanthin, disrupted by high‐pressure homogenisation was microencapsulated with Maillard reaction products as wall materials by spray drying. The microcapsules were characterised by scanning electron microscope, size analysis and also the storage stability. The optimised cell disruption process for H. pluvialis based on response surface optimisation was 70 MPa of pressure, 7.38% of H. pluvialis concentration and homogenisation once with a disruption rate of 98.96 ± 0.12%. The optimised spray drying process consisted of a wall‐to‐core material ratio of 2.4:1, inlet temperature of 180 °C and outlet temperature of 80 °C with a microencapsulation rate and microcapsule production rate of (92.1 ± 0.1)% and (97.7 ± 0.2)%, respectively. Characterisation and stability test showed that this microencapsulation process ensured the stability of astaxanthin.

Encapsulation of an astaxanthin-containing lipid extract from shrimp waste by complex coacervation using a novel gelatin–cashew gum complex

In the present work, the suitability of cashew gum for forming coacervates with gelatin and encapsulating a lipid extract from shrimp waste was studied. Gelatin and cashew gum formed coacervates at pHs ranging from 4 to 4.5. They were spherical in shape and tended to aggregate and form clusters at pH 4–4.2, whereas they were formless at pH 4.3–4.5. The coacervates were able to encapsulate the lipid extract (astaxanthin encapsulation efficiency 59.9 ± 0.01%), forming multinucleated, polymorphic microcapsules with an average size of 32.7 ± 9.7 μm. An accelerated stability study (43 days/36 ± 1 °C/80% relative humidity) revealed an improvement in astaxanthin stability as a result of encapsulation. The microcapsules, which showed a water solubility of 28.6 ± 4.7%, dispersed well in plain yogurt, selected as a food matrix to evaluate their coloring capacity. The color provided to the product by the encapsulated lipid extract was different in hue to that of the non-encapsulated one, showing higher chromaticity at comparable concentrations. A trained sensory panel confirmed the improvement in coloring capacity achieved through encapsulation, although no differences in odor were found.

Improving the Stability of Astaxanthin by Microencapsulation in Calcium Alginate Beads.

There has been considerable interest in the biological functions of astaxanthin and its potential applications in the nutraceutical, cosmetics, food, and feed industries in recent years. However, the unstable structure of astaxanthin considerably limits its application. Therefore, this study reports the encapsulation of astaxanthin in calcium alginate beads using the extrusion method to improve its stability. This study also evaluates the stability of the encapsulated astaxanthin under different storage conditions. The evaluation of astaxanthin stability under various environmental factors reveals that temperature is the most influential environmental factor in astaxanthin degradation. Stability analysis shows that, regardless of the formulation used, the content of astaxanthin encapsulated in alginate beads remains above 90% of the original amount after 21 days of storage at 25°C. These results suggest that the proposed technique is a promising way to enhance the stability of other sensitive compounds.

Direct Treatment of Isada Krill under Subcritical Water Conditions to Produce Seasoning with Shrimp-Like Flavour.

Characterization, sensory evaluation, and astaxanthin stability of isada krill under various subcritical water conditions were investigated to optimize the quality of krill extract and residue for producing food seasoning. Raw krill (82% wet basis moisture content) without additional water was treated in a pressure-resistant vessel for 10 min at a temperature range of 100-240 °C. The yield of water-soluble protein was maximized by treatment at 200 °C and decreased with treatment at higher temperatures. The degradation of large molecules and the concomitant production of small molecules depended on the treatment temperature. Astaxanthin in the krill was unstable at temperatures higher than 140 °C. The odour intensities of krill extract and residue increased with higher treatment temperature; however, the highest intensity of pleasant shrimp-like flavour was obtained by treatment at 140 °C. Subjective preference scores were the highest for extract and residue obtained at 140 °C. Thus, treatment at 140 °C is the most promising method for production of seasoning with shrimp-like flavour from isada krill.

Fatty acids attached to all-trans-astaxanthin alter its cis–trans equilibrium, and consequently its stability, upon light-accelerated autoxidation

Fatty acid esterification, common in naturally occurring astaxanthin, has been suggested to influence both colour stability and degradation of all-trans-astaxanthin. Therefore, astaxanthin stability was studied as influenced by monoesterification and diesterification with palmitate. Increased esterification decelerated degradation of all-trans-astaxanthin (RP-UHPLC–PDA), whereas, it had no influence on colour loss over time (spectrophotometry). This difference might be explained by the observation that palmitate esterification influenced the cis–trans equilibrium. Free astaxanthin produced larger amounts of 9-cis isomer whereas monopalmitate esterification resulted in increased 13-cis isomerization. The molar ratios of 9-cis:13-cis after 60min were 1:1.7 (free), 1:4.8 (monopalmitate) and 1:2.6 (dipalmitate). The formation of 9-cis astaxanthin, with its higher molar extinction coefficient than that of all-trans-astaxanthin, might compensate for colour loss induced by conjugated double bond cleavage. As such, it was concluded that spectrophotometry is not an accurate measure of the degradation of the all-trans-astaxanthin molecule.

Effect of lipids and carbohydrates extraction on astaxanthin stability in Scenedesmus sp.

Effect of lipids and carbohydrates extraction on astaxanthin stability in Scenedesmus sp.

Microencapsulation of H. pluvialis oleoresins with different fatty acid composition: Kinetic stability of astaxanthin and alpha-tocopherol

Haematococcus pluvialis is a natural source of astaxanthin (AX). However, AX loses its natural protection when extracted from this microalga. In this study, a supercritical fluid extract (SFE) of H. pluvialis was obtained and added to oils with different fatty acid compositions (sunflower oil (SO) or high oleic sunflower oil (HOSO)). The oleoresins of H. pluvialis ((SO+SFE) and (HOSO+SFE)) were encapsulated with Capsul by spray drying. The stability of the oleoresins and powders were studied at 40, 50 and 70°C. AX and alpha-tocopherol (AT) degradation followed a zero-order and first-order kinetic model, respectively, for all systems. The encapsulation of oleoresins improved the stability of AX and AT to a greater extent in oleoresins with a monounsaturated fatty acid profile, as shown by the significantly lowest degradation rate constants and longest half-lives. Therefore, the encapsulation of H. pluvialis oleoresins is an alternative to developing a functional ingredient for healthy food design.

Effect of drying, storage temperature and air exposure on astaxanthin stability from Haematococcus pluvialis

Astaxanthin is a powerful antioxidant with various health benefits such as prevention of age-related macular degeneration and improvement of the immune system, liver and heart function. To improve the post-harvesting stability of astaxanthin used in food, feed and nutraceutical industries, the biomass of the high astaxanthin producing alga Haematococcus pluvialis was dried by spray- or freeze-drying and under vacuum or air at −20°C to 37°C for 20weeks. Freeze-drying led to 41% higher astaxanthin recovery compared to commonly-used spray-drying. Low storage temperature (−20°C, 4°C) and vacuum-packing also showed higher astaxanthin stability with as little as 12.3±3.1% degradation during 20weeks of storage. Cost-benefit analysis showed that freeze-drying followed by vacuum-packed storage at −20°C can generate AUD$600 higher profit compared to spray-drying from 100kgH. pluvialis powder. Therefore, freeze-drying can be suggested as a mild and more profitable method for ensuring longer shelf life of astaxanthin from H. pluvialis.

Stability of astaxanthin in yogurt used to simulate apricot color, under refrigeration

The aim of this study was to incorporate astaxanthin to yogurts with different fat content to match apricot (Prunus armeniaca L.) color. The samples containing astaxanthin were stored at 5 ± 3 °C, and color stability and astaxanthin content were determined by colorimetry and high performance liquid chromatography (HPLC), respectively. Yogurt samples were analyzed in triplicate every 24 hours for one week and subsequently every week for 3 more weeks There were no significant differences (p < 0.05) between astaxanthin concentration values at 0 and 28 days for both samples; therefore, it can be said that the fat content in the yogurt had not effect on the stability of pigment. The low dispersion of the data showed uniformity in the three chromaticity coordinates L*, a*, b* throughout the storage period for both types of yogurt. Values of ∆E ≥ 5.0 were not obtained at any time during storage, indicating high stability of the pigment.

EDTA and α‐tocopherol improve the chemical stability of astaxanthin loaded into nanostructured lipid carriers

Nanostructured lipid carriers (NLC) as a promising delivery system have specific advantages over other nanocarriers for food applications. This study was aimed to evaluate the effect of different antioxidants on physical and chemical stability of NLC containing astaxanthin, a hydrophobic nutraceutical. Antioxidants (EDTA, ascorbic acid, α‐tocopherol, coenzyme Q10) were added to aqueous and/or lipid phases. Tween 80 and lecithin were utilized as stabilizers; NLC formulations were produced by melt emulsification‐sonication technique, and then stored at 35°C for 15 days. Except formulations with high levels of EDTA or ascorbic acid, others yielded small nanoparticles (Z‐average ≈ 94 nm) which were stable to growth during storage. Of these antioxidants, only EDTA and α‐tocopherol increased the stability of astaxanthin without causing physical instability, and EDTA was more efficient. The utilization of α‐tocopherol and EDTA in combination was more effective than using them individually. Storage temperature and artificial light had significant effects on the stability of astaxanthin in NLC. These results provide useful information for choosing antioxidants and storage conditions to further protection of nutraceuticals within NLC.Practical applications: Fortification of aqueous‐based foods with carotenoids is greatly restricted owing to their poor water‐solubility, chemical instability, and low bioavailability. NLC immobilize the encapsulated compounds effectively, and can improve their stability and bioavailability in aqueous‐based foods. However, pro‐oxidants can still decrease the chemical stability of NLC. Different antioxidants were employed to further increase the chemical stability of astaxanthin‐loaded NLC. It was found that degradation of astaxanthin in NLC could be significantly reduced by utilizing proper chelators and free radical scavengers. But, higher temperatures and light could still decrease the stability of astaxanthin. These results provide strong evidences for utilizing metal chelators and free radical scavengers in carotenoids‐loaded NLC, and for storing commercial foods and beverages fortified with these nanoparticles at low temperature and darkness.Degradation profiles of astaxanthin in astaxanthin‐NLC containing 100 ppm EDTA in aqueous phase and/or different concentrations of α‐tocopherol (in lipid phase) after production (on 0th day) and during storage at 35°C (n = 3).