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Carotenoids are potent antioxidants with a wide range of biomedical applications. However, their delivery into human cells is challenging and relatively inefficient. While the use of natural water-soluble carotenoproteins capable to reversibly bind carotenoids and transfer them into membranes is promising, the quantitative estimation of the delivery remains unclear. In the present work, we studied echinenone (ECN) delivery by cyanobacterial carotenoprotein AnaCTDH (C-terminal domain homolog of the Orange Carotenoid Protein from Anabaena), into liposome membranes labelled with BODIPY fluorescent probe. We observed that addition of AnaCTDH-ECN to liposomes led to the significant changes in the fast-kinetic component of the fluorescence decay curve, pointing on the dipole-dipole interactions between the probe and ECN within the membrane. It may serve as an indirect evidence of ECN delivery into membrane. To study the delivery in detail, we carried out molecular dynamics modeling of the localization of ECN within the lipid bilayer and calculate its orientation factor. Next, we exploited FRET to assess concentration of ECN delivered by AnaCTDH. Finally, we used time-resolved fluorescence anisotropy to assess changes in microviscosity of liposomal membranes. Incorporation of liposomes with β-carotene increased membrane microviscosity while the effect of astaxanthin and its mono- and diester forms was less pronounced. At temperatures below 30 °C addition of AnaCTDH-ECN increased membrane microviscosity in a concentration-dependent manner, supporting the protein-mediated carotenoid delivery mechanism. Combining all data, we propose FRET-based analysis and assessment of membrane microviscosity as potent approaches to characterize the efficiency of carotenoids delivery into membranes.

The scallop Mizuhopecten yessoensis accumulates carotenoids in the ovary during the maturation stage. Its conspicuous pink color implies the presence of carotenoprotein. However, the carotenoprotein from the scallop ovary has never been isolated and characterized, probably due to its instability and complexity. Here, we developed an extraction and isolation procedure for the carotenoprotein by employing a basic buffer containing potassium bromide to facilitate its efficient extraction from the ovary, and we succeeded in obtaining the carotenoprotein, termed pectenovarin. The carotenoid composition of the pectenovarin was similar to that of the ovary. The N-terminal and internal amino acid sequences of pectenovarin showed a high similarity to those of vitellogenin, the precursor of egg yolk protein under analysis.

The aim of this study was to prepare chitosan (CS) edible films containing shrimp carotenoproteins (CP) and plasticized with glycerol and polyvinyl alcohol (PVA) using the casting method. The effects of CS (1–3%), glycerol (0–10%) and CP (0–3%) amounts on mechanical properties, antioxidant and antimicrobial activities of CS-CP composite films (CSCPFs) were studied using response surface methodology (RSM). The structural properties of CSCPFs were greatly influenced by CS, then by glycerol and CP amounts. According to the best fit and response surfaces, the optimized conditions were found to be 2.43% of CS, 9.93% of glycerol and 0.005% of CP. These conditions allow obtaining the highest elongation at break (149.11%) and tensile strength (24.07 MPa), as well as good antibacterial, antifungal and antioxidant activities of 20.64 mm, 21.93 mm and 51.08%, respectively. Due to their important antioxidant and antimicrobial properties, CS (1.5%) and CS-CP (1.5%–1%) edible coatings were used for strawberries preservation. Microbiological quality and physicochemical properties (pH, weight loss and titrable acidity) were evaluated during storage at 4 °C for 11 days. Results showed that CS and CS-CP coatings were effective on reducing the fungal decay (45–50%), as compared to the uncoated fruits (75%). In addition, it was observed that the weight loss of CS and CS-CP coated strawberries was significantly lower than that of the uncoated ones. Furthermore, phytopathogenic growth on the surface of cold-stored fruits was significantly inhibited for the coated fruits, which extend the strawberries shelf life during storage. Based on our findings, CS and CS-CP showed potential coatings for controlling food-borne bacteria and natural microorganism growth during the cold storage of strawberries. [ABSTRACT FROM AUTHOR]

The present study investigated the biological properties of carotenoproteins extract (CPE) from blue crab shells as well as the influence of its addition on the quality of turkey meat sausages (TMSs) containing reduced amounts of nitrites. CPE exhibited antioxidant activity in a dose-dependent manner evaluated through different in vitro antioxidant assays, and interesting antimicrobial potential. Moreover, data revealed that CPE incorporated in TMSs in combination of reduced-nitrites levels effectively inhibited thiobarbituric acid substances (TBARS) and conjugated dienes formation, and thereby, the degree of lipid oxidation. The investigation of their antioxidant activity exhibited higher potential of CPE-treated TMSs based on 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay. Further, CPE was able of TMSs myoglobin oxidation inhibition, with a significant improvement in the transformation of the Heme iron and lower free fatty acids (FFAs) contents. A significant stability in the color parameters of the CPE-added TMSs was as well noticed. Interestingly, CPE exhibited distinguishable antimicrobial activities in the TMSs within a shelf life of 10 days, as revealed by the estimation of total mesophilic flora (TMF). These results demonstrate that CPE, endowing with high antioxidant and antimicrobial activities, could be used as natural additive in functional foods. [ABSTRACT FROM AUTHOR]

Contents937I.937II.938III.939IV.943V.947VI.948948References949 Summary: The orange carotenoid protein (OCP) is a water‐soluble, photoactive protein involved in thermal dissipation of excess energy absorbed by the light‐harvesting phycobilisomes (PBS) in cyanobacteria. The OCP is structurally and functionally modular, consisting of a sensor domain, an effector domain and a keto‐carotenoid. On photoactivation, the OCP converts from a stable orange form, OCPO, to a red form, OCPR. Activation is accompanied by a translocation of the carotenoid deeper into the effector domain. The increasing availability of cyanobacterial genomes has enabled the identification of new OCP families (OCP1, OCP2, OCPX). The fluorescence recovery protein (FRP) detaches OCP1 from the PBS core, accelerating its back‐conversion to OCPO; by contrast, other OCP families are not regulated by FRP. N‐terminal domain homologs, the helical carotenoid proteins (HCPs), have been found among diverse cyanobacteria, occurring as multiple paralogous groups, with two representatives exhibiting strong singlet oxygen (1O2) quenching (HCP2, HCP3) and another capable of dissipating PBS excitation (HCP4). Crystal structures are presently available for OCP1 and HCP1, and models of other HCP subtypes can be readily produced as a result of strong sequence conservation, providing new insights into the determinants of carotenoid binding and 1O2 quenching. [ABSTRACT FROM AUTHOR]

In this study, alkaline proteases from the viscera of the Serranus scriba were extracted and characterized. Interestingly, the crude alkaline protease showed optimum activity at pH 11.0. The relative activities at pH 10.0 and 12.0 were about 79% and 80.5% of that at pH 11.0, respectively. In addition, the crude protease was stable over a broad pH range (7.0–12.0) retaining more than 80% of its initial activity after incubation for 1 h at 25 °C. The optimum temperature for the crude enzyme activity was 50 °C. The crude alkaline protease extract showed high stability towards various surfactants and bleach agents. In addition, the crude enzyme showed high stability and compatibility with various solid and liquid commercial detergents. Further, proteases from S. scriba viscera were found to be effective in the extraction of carotenoproteins from shrimp waste. Extracted carotenoproteins were found to exhibit antioxidant activity evaluated through DPPH radical scavenging activity and inhibition of β-carotene bleaching assay. These results suggest that proteases from S. scriba viscera could be used as additive in laundry detergents and in the deproteinisation of shrimp wastes to extract carotenoproteins. [ABSTRACT FROM AUTHOR]

Highlights: [•] The peptidic fraction of carotenoproteins (PFCP) was generated by enzymatic treatment with Alcalase®. [•] PFCP showed a high percentage of essential amino acids. [•] PFCP showed an excellent solubility and possessed interfacial properties. [•] PFCP exhibited excellent antioxidant activities in different in vitro models. [ABSTRACT FROM AUTHOR]

Abstract: Amino acid profiles of carotenoproteins extracted from fermented and non-fermented shrimp waste were analysed. Fermented carotenoproteins were hydrolysed with a protease and a combination of a protease and a lipase. Essential amino acids in fermented and non-fermented carotenoproteins were 49% and 47%, respectively, with respect to total amino acids. The highest carotenoprotein hydrolysis (900 and 66mg/g soluble protein and total carotenoids, respectively) was obtained by a combination of 15 proteolytic units together with 10 lipolytic units. The most efficient treatment using only protease was obtained with 15 proteolytic units (852 and 48mg/g of soluble protein and total carotenoids, respectively). A relatively protein-free form of astaxanthin derived from shrimp waste carotenoproteins may be of interest for applications in salmon culture, and in natural health products and cosmetics. Furthermore, fermented carotenoproteins could be used in human and animal diets due to their high essential amino acids concentration. [Copyright &y& Elsevier]

Crayfish (Procambarus clarkii) were separated by solid filtration into a proteinaceous fraction (PF-1) and a chitinous fraction (CF). The PF-1 and CF were used as starting materials for carotenoprotein-1 and carotenoprotein-2 preparations, respectively. Crawfish carotenoprotein-1 was obtained by controlled enzymatic autodigestion of FP-1 and carotenoprotein-2 by in situ repeated batch lactic acid fermentation. Carotenoprotein-1 has a high content of essential amino acids, ω-3- and ω-6-fatty acids and carotene (mainly astaxanthin), and constitutes an excellent nutritional source for patients with malnutrition. Carotenoprotein-2, of lower nutritional quality but with a substantial carotene content, can be used as a good protein source for animal nutrition where coloration is required, such as for poultry or for salmonid fish bred by aquaculture. [Copyright &y& Elsevier]

The scallop Mizuhopecten yessoensis accumulates carotenoids in the ovary during the maturation stage. Its conspicuous pink color implies the presence of carotenoprotein. However, the carotenoprotein from the scallop ovary has never been isolated and characterized, probably due to its instability and complexity. Here, we developed an extraction and isolation procedure for the carotenoprotein by employing a basic buffer containing potassium bromide to facilitate its efficient extraction from the ovary, and we succeeded in obtaining the carotenoprotein, termed pectenovarin. The carotenoid composition of the pectenovarin was similar to that of the ovary. The N-terminal and internal amino acid sequences of pectenovarin showed a high similarity to those of vitellogenin, the precursor of egg yolk protein under analysis. [ABSTRACT FROM AUTHOR]

A blue carotenoid-protein complex (λ 635 nm) was extracted and purified from the carapace of the crayfish Procambarus clarkii. The complex was further liberated from astaxanthin, its prostetic group, causing dissociation into apoprotein subunits. Reconstitution of the complex from the various sub-units (isolated by chromatofocusing) plus astaxanthin was attempted. Apoprotein-size pigments of rose-purple color (λ 545 nm) were obtained. It was found that both monomers are required in order to a blue complex fairly similar in structure ot the native one. However, the native conformation was not completely recovered, as indicated by some differences in the UV spectrum. [ABSTRACT FROM AUTHOR]