Chemical cleavage of fucoxanthin from Undaria pinnatifida and formation of apo-fucoxanthinones and apo-fucoxanthinals identified using LC-DAD-APCI-MS/MS

Assessing the impact of temperature, pH, light and chemical oxidation on fucoxanthin colour changes, antioxidant activity and the resulting metabolites

BACKGROUND

The present study evaluated the effects of temperature, pH, light and chemical oxidation on fucoxanthin changes in terms of colour, antioxidant activity and metabolomic profile. Additionally, the correlation between antioxidant activity and identified metabolites was analysed.

RESULTS

It was found that colour change was significantly reduced at elevated heat (100 °C, *∆E = 0.81 ± 0.05), reduced pH (pH 3, *∆E = 0.59 ± 0.04) and length of light exposure (*∆E = 3.16 ± 0.04). Antioxidant activity decreased under all treatments. Among the temperatures tested, fucoxanthin exhibited the highest activity at 60 °C, ranging from 0.92 to 3.04 mg Trolox equivalents (TE) g-1. Significant activity reductions (P < 0.05) were observed as a result of pH changes in the 2,2-diphenyl-1-picrylhydrazyl and β-carotene bleaching assays. Exposure to light 2: warm white lamp for 120 h significantly reduced antioxidant activity (0.01 to 1.70 mg TE g-1). Chemical oxidation also led to reduced activity, ranging from 0.18 to 0.29 mg TE g-1. Multivariate data analysis revealed distinct profiles for temperature, pH, light and chemical oxidation treatments. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based metabolomics analysis identified 10 metabolites, and significant correlations (P < 0.05) indicate that these metabolites contributed to the samples' antioxidant activities.

CONCLUSION

In conclusion, fucoxanthin tolerates well at 60 °C, within pH range 3-9, and within 8 h of light exposure, as indicated by its consistent antioxidant activity and minimal colour change. Each treatment resulted in distinct metabolite concentrations, as shown by LC-MS/MS-based metabolomics analysis. Further research into these metabolites could advance the understanding of their roles and aid in optimising processing conditions to favour beneficial metabolites. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Recent Progress in Understanding the Impact of Food Processing and Storage on the Structure-Activity Relationship of Fucoxanthin

Fucoxanthin, a brown algae carotenoid, has attracted great interest because of its numerous biological activities supported by in vitro and in vivo studies. However, its chemical structure is susceptible to alterations when subjected to food processing and storage conditions, such as heat, oxygen, light, and pH changes. Consequently, these conditions lead to the formation of fucoxanthin derivatives, including cis-isomers, apo-fucoxanthinone, apo-fucoxanthinal, fucoxanthinol, epoxides, and hydroxy compounds, collectively known as degradation products. Currently, little information is available regarding the stability and functionality of these fucoxanthin derivatives resulting from food processing and storage. Therefore, enhancing the understanding of the biological effect of fucoxanthin derivatives is crucial for optimizing the utilization of fucoxanthin in various applications and ensuring its efficacy in potential health benefits. To this aim, this review describes the main chemical reactions affecting the stability of fucoxanthin during food processing and storage, facilitating the identification of the major fucoxanthin derivatives. Moreover, recent advancements in the structure-activity relationship of fucoxanthin derivatives will be critically assessed, emphasizing their biological activity. Overall, this review provides a critical updated understanding of the effects of technological processes on fucoxanthin stability and activity that can be helpful for stakeholders when designing processes for food products containing fucoxanthin.

Extraction of Fucoxanthin Isomers from the Edible Brown Seaweed Undaria pinnatifida Using Supercritical CO2: Effects of Extraction Conditions on Isomerization and Recovery of Fucoxanthin

Fucoxanthin, a characteristic carotenoid found in brown seaweeds, has been reported to exert beneficial biological activities, including antiobesity and anticancer activities Moreover, the Z-isomers of this compound potentially have greater bioavailability and biological activities than the naturally predominant all-E-isomer. Therefore, the consumption of Z-isomer-rich fucoxanthin through daily meals and dietary supplements may have beneficial effects. In this study, we aimed to investigate the effects of different extraction conditions on the Z-isomer ratio and recovery of fucoxanthin obtained from Undaria pinnatifida using supercritical CO2 (SC-CO2), particularly focusing on the high-temperature conditions that enhance thermal Z-isomerization. High-temperature SC-CO2 extraction at ≥ 120°C was found to enhance the thermal isomerization of fucoxanthin. For example, when the extraction was performed at 40, 80, 120, and 160°C and 30 MPa for 30 min with a co-solvent (ethanol), the total Z-isomer ratios were 11.7, 11.5, 18.7, and 26.5%, respectively. Furthermore, the high-temperature extraction significantly improved fucoxanthin recovery under high-pressure (≥ 30 MPa) conditions in the presence of the co-solvent. For example, when fucoxanthin was extracted at 40, 80, 120, and 160°C under the same conditions as above, the recoveries were 17.5, 20.6, 30.7, and 29.5%, respectively. Hence, the high-temperature SC-CO2 extraction of fucoxanthin from U. pinnatifida would not only enhance health benefits of fucoxanthin via the Z-isomerization but also improve the productivity. Moreover, the use of non-toxic CO2 and a low-toxicity organic solvent (ethanol) ensures that the final fucoxanthin product is safe for consumption. The Z-isomer-rich fucoxanthin obtained using this method is accordingly considered to have potential for use as a dietary supplement.

Photochemical (UV-vis/H2O2) degradation of carotenoids: Kinetics and molecular end products

Constraining the formation mechanisms of organic matter that persists in aquatic reservoirs is important for determining the reactivity and fate of carbon and nutrients in these environments. Recent studies have linked dissolved organic matter (DOM) accumulating in the ocean to linear terpenoid structures, and carotenoid degradation products have been proposed as potential precursors. The prevalence of reactive oxygen species in aquatic environments and their potential to be quenched by carotenoids led us to examine radical-assisted photochemical degradation of carotenoids as a potential mechanism for DOM formation and transformation. Experiments were conducted with aggregates of β-carotene, astaxanthin, fucoxanthin and meso-zeaxanthin in THF:H₂O under solar light irradiation assisted by hydrogen peroxide (UV-Vis/H₂O₂). Based on the fine structure of UV-Vis spectra, it was determined that β-carotene and meso-zeaxanthin formed J-type aggregates in experimental solutions, while astaxanthin and fucoxanthin formed H2-type aggregates, consistent with their structural characteristics. All carotenoids degraded under the combined influence of photolysis and OH scavenging, with fucoxanthin exhibiting the fastest degradation kinetics (k_PO = 3.69 10^-3 s^-1) and meso-zeaxanthin the slowest (k_PO = 4.37 10^-4 s^-1). The major degradation products detected by electrospray ionization (ESI) tandem mass spectrometry (MS/MS) were apo-aldehydes and apo-ketones, with the latter tending to accumulate, but epoxidation of the carotenoids also took place, and longer irradiation times resulted in lower molecular weight products. Reaction kinetics and accumulating carotenoid oxidation products identified in this study provide potential formation mechanisms and biomarkers for examining DOM cycling.

Fucoxanthin has potential for therapeutic efficacy in neurodegenerative disorders by acting on multiple targets

Fucoxanthin, one of the most abundant carotenoids from edible brown seaweeds, for years has been used as a bioactive dietary supplement and functional food ingredient. Recently, fucoxanthin was reported to penetrate the blood-brain barrier, and was superior to other carotenoids to exert anti-neurodegenerative disorder effects via acting on multiple targets, including amyloid protein aggregation, oxidative stress, neuroinflammation, neuronal loss, neurotransmission dysregulation and gut microbiota disorder. However, the concentration of fucoxanthin required for in vivo neuroprotective effects is somewhat high, and the poor bioavailability of this molecule might prevent its clinical use. As such, new strategies have been introduced to overcome these obstacles, and may help to develop fucoxanthin as a novel lead for neurodegenerative disorders. Moreover, it has been shown that some metabolites of fucoxanthin may produce potent in vivo neuroprotective effects. Altogether, these studies suggest the possibility for future development of fucoxanthin as a one-compound-multiple-target or pro-drug type pharmaceutical or nutraceutical treatment for neurodegenerative disorders.Trial registration: ClinicalTrials.gov identifier: NCT03625284.Trial registration: ClinicalTrials.gov identifier: NCT02875392.Trial registration: ClinicalTrials.gov identifier: NCT03613740.Trial registration: ClinicalTrials.gov identifier: NCT04761406.

Scientific Approaches on Extraction, Purification and Stability for the Commercialization of Fucoxanthin Recovered from Brown Algae

The scientific community has corroborated the numerous beneficial activities of fucoxanthin, such as its antioxidant, anti-inflammatory, anticancer or neuroprotective effects, among others. These properties have attracted the attention of nutraceutical, cosmetic and pharmacological industries, giving rise to various possible applications. Fucoxanthin may be chemically produced, but the extraction from natural sources is considered more cost-effective, efficient and eco-friendly. Thus, identifying suitable sources of this compound and giving a general overview of efficient extraction, quantification, purification and stabilization studies is of great importance for the future production and commercialization of fucoxanthin. The scientific research showed that most of the studies are performed using conventional techniques, but non-conventional techniques begin to gain popularity in the recovery of this compound. High Performance Liquid Chromatography (HPLC), Nuclear Magnetic Resonance (NMR) and spectroscopy techniques have been employed in the quantification and identification of fucoxanthin. The further purification of extracts has been mainly accomplished using purification columns. Finally, the stability of fucoxanthin has been assessed as a free molecule, in an emulsion, or encapsulated to identify the variables that might affect its further industrial application.

Aggregation of Fucoxanthin and Its Effects on Binding and Delivery Properties of Whey Proteins

In this study, aggregation of fucoxanthin (FX) and its effects on binding and delivery properties of whey proteins were explored. Initially, the H- and J-aggregates of FX were successfully prepared by adjusting the water/ethanol ratio and water-dripping rate. The transition from J- to H-aggregates was observed over the standing time. Then, the molecular arrangement of FX H-aggregates was analyzed using the point-dipole approximation model and molecular dynamics, showing that their intermolecular distance and angle were about 5.0-6.7 Å and -35° to 35°, respectively. The transformation of J- to H-aggregates was also observed during molecular dynamics, with a shortened intermolecular distance, a reduced solvent accessible surface area, an enhanced interaction force, and a narrowed dihedral angle. Further, the interactions of whey proteins with different forms of FX were investigated, indicating that both β-lactoglobulin and whey protein isolates could form complexes with the monomers, H-aggregates, and J-aggregates of FX. In terms of affinity, whey proteins bound FX monomers more strongly than aggregates. Furthermore, the complexes comprising whey proteins and monomeric FX had better delivery capabilities than aggregated FX, manifested in encapsulation efficiency, physical stability, and bioaccessibility.

Construction of Fucoxanthin Vector Based on Binding of Whey Protein Isolate and Its Subsequent Complex Coacervation with Lysozyme

In this study, a novel vector for fucoxanthin (FX) was constructed using the ligand-binding property of whey protein isolate and its subsequent heteroprotein complex coacervation with lysozyme. The results showed that FX could quench the intrinsic fluorescence of the whey protein isolate by a static mechanism, indicating that they could spontaneously form a nanocomplex through non-covalent interactions. Moreover, the structural and electrostatic properties of the resulting whey protein were different from those before the binding of FX, and this could be well explained by molecular dynamics simulation. The size and ζ-potential tests showed that when the whey protein isolate was combined with FX and then coacervated with lysozyme, the heteroprotein ratio and pH, which affect the coacervation process, also changed compared to those of the free whey protein isolate. FT-IR spectroscopy results showed that FX was successfully encapsulated into complex coacervates. In addition, the heteroprotein system exhibited a higher loading efficiency and also provided a better protection for FX in heating, storage, and simulated gastrointestinal environments.

The stability and bioaccessibility of fucoxanthin in spray-dried microcapsules based on various biopolymers

Fucoxanthin is a major marine carotenoid with many biological activities. It is well known that fucoxanthin is unstable to heat and acid due to its polyunsaturated structure. Another defect of fucoxanthin is the low bioavailability and all these drawbacks make it limited in the food industry. In order to improve its stability and intestinal absorption, fucoxanthin was encapsulated with biopolymers by spray drying in this study. All the microspheres we prepared had a spherical shape with encapsulation efficiencies (EE) ranging from 86.48% to 97.06%. A heat stability test showed that maltodextrin (MD), gum arabic (GA) and whey protein isolate (WPI) improved the thermal stability of fucoxanthin. The degradation kinetics of the loaded fucoxanthin encapsulated with biopolymers also indicated that GA and MD had a better protective effect on fucoxanthin. The encapsulated fucoxanthin degradation rate within MD, GA, WPI and gelatin (GEL) followed second-order kinetics and their half-life (t 1/2) was 92.6 d, 99.8 d, 50.9 d and 69.3 d, respectively. The simulated digestion test in vitro suggested that MD, GA and WPI effectively protected fucoxanthin in the gastric acid environment, meanwhile increasing the release rate of fucoxanthin in the intestinal tract.

Effective Biodegradation of Mycotoxin Patulin by Porcine Pancreatic Lipase

Patulin is a common contaminant in fruits and vegetables, which is difficult to remove. In this study, the biodegradation of patulin using porcine pancreatic lipase (PPL) was investigated. The method of HPLC was used to analyze the concentration of patulin. Batch degradation experiments were performed to illustrate the effect of PPL amount, pH, temperature, contact time, and initial concentration. Besides, the degradation product of patulin was characterized by full wavelength scanning and MS technologies. The results showed that the optimum degradation conditions of PPL for patulin was observed at pH 7.5, 40°C for 48 h. The percentage of degradation could reach above 90%. The structure of degradable product of patulin was inferred by the molecular weight 159.0594, named C7H11O4+. It indicated that PPL was effective for the degradation of patulin in fruits and vegetables juice.