A review on Zika vaccine development.

Zika virus (ZIKV), which belongs to the Flavivirus family, is mainly transmitted via the bite of Aedes mosquitoes. In newborns, ZIKV infection can cause severe symptoms such as microcephaly, while in adults, it can lead to Guillain‒Barré syndrome (GBS). Due to the lack of specific therapeutic methods against ZIKV, the development of a safe and effective vaccine is extremely important. Several potential ZIKV vaccines, such as live attenuated, inactivated, nucleic acid, viral vector, and recombinant subunit vaccines, have demonstrated promising outcomes in clinical trials involving human participants. Therefore, in this review, the recent developmental progress, advantages and disadvantages of these five vaccine types are examined, and practical recommendations for future development are provided.

Gel properties and interactions of hydrogels constructed with low acyl gellan gum and puerarin.

To develop composite hydrogels based on low acyl gellan gum (GG), the effect of puerarin (PUE) on the gel properties of GG was investigated. The results showed that the maximum storage modulus (G') of the 1.2 % GG/0.8 % PUE composite hydrogel was 377.4 Pa at 0.1 Hz, which was enhanced by 4.7-fold compared with that of 1.2 % GG. The melting temperature of this composite hydrogel increased from 74.1 °C to >80.0 °C. LF-NMR results showed that a significant amount of free water was present in the hydrogel matrix. The surface structure aggregation and the shrinkage of the honeycomb meshes in the composite hydrogel proved the cross-linking of PUE and GG. XRD, FTIR and molecular simulation results illustrated that hydrogen bonds were the most important factor controlling the interaction between GG and PUE. Thus, the GG/PUE composite hydrogel has good elasticity, thermal stability and water retention, which lays a good foundation for further application in the food industry.

Formation and microstructural characterization of scallop (Patinopecten yessoensis) male gonad hydrolysates/sodium alginate coacervations as a function of pH.

Studying the noncovalent interactions between proteins and polysaccharides is quite important mainly due to the wide number of applications such as developing pH-responsive complexes. Scallop Patinopecten yessoensis male gonad hydrolysates­sodium alginate (SMGHs-SA) was investigated as noncovalent complexes at pH from 1 to 10. The critical pH values pHC (around 6) and pHφ (around 4) were independent of the SMGHs-SA ratio, indicating the formation of soluble and insoluble complexes. The pH response of SMGHs-SA complexes was evaluated by investigating the rheological behavior, moisture distribution, functional group change and microstructure. Compared to the co-soluble and soluble complexes phases, the SMGHs-SA complexes had a higher storage modulus and viscosity as well as a lower relaxation time (T23) in the insoluble complexes phase (pHφ>3). Additionally, the amide I band and COO- stretching vibration peaks were redshifted and the amide A band vibration peaks were blueshifted by acidification. Electrostatic interactions and intermolecular/intramolecular hydrogen bonding led to SMGHs-SA agglomeration at pH 3, forming a uniform and dense gel network structure with strong gel strength and water-retention capacity. This study provides a theoretical and methodological basis for the design of novel pH-responsive complexes by studying SMGHs-SA complex coacervation.

Characteristics of the Intestine Extracts and Their Effect on the Crude Collagen Fibers of the Body Wall from Sea Cucumber Apostichopus japonicus.

Sea cucumbers Apostichopus japonicus will vomit their intestines during certain stimulations, and the collagen of the body wall will then be degraded. To define the effect of the sea cucumber intestine extracts on the body wall, the intestinal extracts and crude collagen fibers (CCF) of sea cucumber A. japonicus were prepared. According to the gelatin zymography, the type of endogenous enzymes in intestinal extracts were mainly serine endopeptidases with optimal activities at pH 9.0 and 40 °C. According to the rheology results, the viscosity of 3% CCF decreased from 32.7 Pa·s to 5.3 Pa·s by adding intestine extracts. The serine protease inhibitor phenylmethanesulfonyl fluoride inhibited the activity of intestinal extracts and increased the viscosity of collagen fibers to 25.7 Pa·s. The results proved that serine protease in the intestinal extracts participated in the process of body wall softening in sea cucumbers.

Sterility of Aedes albopictus by X-ray Irradiation as an Alternative to γ-ray Irradiation for the Sterile Insect Technique.

The mosquito Aedes albopictus can transmit various arboviral diseases, posing a severe threat to human health. As an environmentally friendly method, sterile insect technology (SIT) is considered an alternative to traditional methods such as chemical pesticides to control Ae. albopictus. In SIT, the sterility of male mosquitoes can be achieved by γ-ray or X-ray radiation. Compared with γ-rays, X-rays are easier to obtain, cheaper, and less harmful. However, there is a lack of comparative assessment of these two types of radiation for SIT under the same controlled conditions. Here, we compared the effects of X-ray and γ-ray radiation on the sterility of Ae. albopictus males under laboratory-controlled conditions. Neither type of radiation affected the number of eggs but significantly reduced the survival time and hatch rate. The same dose of γ-rays caused a higher sterility effect on males than X-rays but had a more significant impact on survival. However, X-rays could achieve the same sterility effect as γ-rays by increasing the radiation dose. For example, X-rays of 60 Gy induced 99% sterility, similar to γ-rays of 40 Gy. In the test of male mating competitiveness, the induced sterility and the male mating competitiveness index were also identical at the same release ratio (sterile males/fertile males). At a release ratio of 7:1, nearly 80% of eggs failed to hatch. Sterile males produced by X-ray and γ-ray radiation had similar male competitiveness in competition with field males. In conclusion, a higher dose of X-rays is required to achieve the same sterility effect, compared to γ-rays. When γ-rays are not readily available, high-dose X-rays can be used instead. This study provides data supporting the selection of more suitable radiation for the field release of sterile male mosquitoes.

Formation and characteristics of curcumin-loaded binary gels formed from large yellow croaker (Pseudosciaena crocea) roe protein isolate and gellan gum.

The aim of this study was to investigate the effect of gellan gum (GG) on the cold gelation of large yellow croaker roe protein isolate (pcRPI). The water-holding ability and storage modulus of the pcRPI-GG binary gels increased with the GG concentration, where the storage modulus of the pcRPI-0.2% GG gel was approximately 30.7 times that of the pure pcRPI gel. Compare to the other binary gels, pcRPI-0.2% GG gels exhibited a lower lacunarity and higher junction density, with a denser, more aggregated microstructure. Consequently, curcumin was embedded in pcRPI-0.2% GG gels, and simulated gastrointestinal digestion test results showed that GG addition effectively protected and slowed curcumin release in the gastrointestinal environment. These findings may contribute to elucidating the interaction of pcRPI with GG and demonstrate the potential of binary gels for the embedding and delivery of active substances.

Formation and stability of electrostatic complexes formed between scallop female gonad protein isolates and sodium alginate: Influence of pH, total concentration, blend ratio, and ionic strength.

The complex coacervation between scallop (Patinopecten yessoensis) female gonad protein isolates (SFGPIs) and sodium alginate (SA) was determined by the turbidimetric method. The impact of pH, total biopolymer concentration, biopolymer blend ratio, and various salt ionic on the mechanisms governing the complex coacervation of SFGPIs-SA complexes were also investigated. For the SFGPIs:SA ratio of 2:1 without adding NaCl, insoluble and soluble complexes were observed at pH 5.8 (pHφ1 ) and pH 8.2 (pHc ) with the optimum biopolymer interactions appearing at pH 2.6 (pHopt ). The maximum turbidity value increased with the increment of the total biopolymer concentration from 0.37 to 1.83 until attaining the critical value (0.75%). As the blend ratios rose from 1:3 to 12:1, the critical pH values (pHc , pHφ1 , and pHopt ) moved to higher pH. Furthermore, the addition of NaCl led to a remarkable decrease in turbidity over the whole pH region in SFGPIs-SA complexes. Moreover, monovalent ions (Na+ and K+ ) had the same effect on the formation of the SFGPIs-SA complex, whereas the divalent cations (Mg2+ and Ca2+ ) lessened the complex formation in comparison with the monovalent ions. This study offers a methodological and theoretical basis for the design of complex SFGPIs-SA systems by understanding the complex coacervation under different conditions. PRACTICAL APPLICATION: In recent years, several protein-polysaccharides complexes have been widely applied in food and biological systems. Scallop (Patinopecten yessoensis) female gonads are deemed as good marine sources for developing protein matrices on account of their high protein content and nutrients. In our study, the effects of different conditions on the mechanisms governing the complex coacervation of SFGPI-SA mixtures were investigated, and the instability of the system could be overcome by understanding the conditions for SFGPIs/SA complex formation, which have a feasible role in developing marine source-protein as a functional food base such as kamaboko gels, can, sausage, fat substitutes, and delivery vehicles for bioactive compounds.

Improvement of low-acyl gellan gum on gelation and microstructural properties of protein hydrolysates from male gonad of scallop (Patinopecten yessoensis).

This study aimed to examine the gelation and microstructural properties of scallop male gonad hydrolysates (SMGHs) in the presence of low-acyl gellan gum (GG) at different mass ratios. The rheological results showed that both elastic modulus and thermal stability of SMGHs were significantly improved by the addition of GG. Meanwhile, the relaxation time T23 was significantly reduced in SMGHs/GG by low-field nuclear magnetic resonance, indicating a strong interaction between SMGHs and GG. Fourier transform infrared spectroscopy indicated the blueshift of amide I and II peaks in SMGHs/GG further demonstrated the electrostatic interaction between SMGHs and GG. The network structure of SMGHs/GG binary complexes was more compact and the surface was smoother than that of SMGHs by cryo-scanning electron microscopy. Furthermore, increasing the content of GG in the SMGHs/GG binary complex significantly reinforced the gel strength and promoted the gelation process.

Gelation and microstructural properties of ternary composite gel of scallop (Patinopecten yessoensis) protein hydrolysates/κ-carrageenan/xanthan gum.

The objective of this study was to investigate the properties of ternary composite gel of scallop (Patinopecten yessoensis) protein hydrolysates (SMGHs)/κ-carrageenan (KC)/xanthan gum (XG). The rheological properties, moisture-distribution, molecular structure, and microstructure of SMGNs/KC/XG gels were analyzed. The results showed that the G' value, melting temperature, and water holding capacity of SMGHs/KC/XG were higher than those of SMGHs, SMGHs/KC, and SMGHs/XG. FTIR spectrum showed the generation of hydrogen bonds between SMGHs and KC/XG, and the carboxylic acid group of XG interacts with SMGHs. Moreover, the cryo-SEM results showed that SMGHs/KC/XG exhibited a tighter, smoother, and more aggregated microstructure than those of SMGHs, SMGHs/KC, and SMGHs/XG. These results indicate that the gel and microstructural properties of SMGHs are significantly improved by addition of KC and XG, and SMGHs/KC/XG has potential to be used as functional hydrogels for food, pharmaceutical, and biomedical applications. PRACTICAL APPLICATION: Scallop (Patinopecten yessoensis) male gonads are rich in protein and usually regarded as byproducts during adductor processing. Because of its gelation properties, scallop male gonads have potential to be used as functional hydrogels for food. The SMGHs/KC/XG ternary composite gel showed excellent gel properties, which would be potentially applied in delivery system in food and biological fields. Further study is undergoing to apply SMGHs/KC/XG to embed bioactive compounds, such as curcumin and ß-carotene.

Structural characteristics and improved in vitro hepatoprotective activities of Maillard reaction products of decapeptide IVTNWDDMEK and ribose.

Here, a novel decapeptide IVTNWDDMEK with Maillard reactivity derived from scallop Chlamys farreri mantle was identified. The structural characteristics and in vitro hepatoprotective effects of IVTNWDDMEK conjugated with ribose were further investigated. The changes in decapeptide structures were determined by ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR), and atomic force microscopy (AFM), and the modification sites induced by Maillard reaction of IVTNWDDMEK and ribose were monitored by high performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS). Maillard reaction products (MRPs) of IVTNWDDMEK-ribose demonstrate hepatoprotective benefits through the suppression of DNA damage and apoptosis induced by oxidative stress in human HepG2 cells in addition to enhancing the antioxidant activities. Moreover, after treatment with decapeptide-ribose MRPs, the activities of cellular antioxidative enzymes, such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione reductase (GSH-Rx) were remarkably increased, while the content of malondialdehyde (MDA) was decreased compared with H2 O2 - treated group, thereby enhancing the intracellular antioxidant defenses. These findings demonstrate the potential utilization of decapeptide IVTNWDDMEK-ribose MRPs as food antioxidants to suppress oxidative damage. PRACTICAL APPLICATION: In recent years, several food-derived bioactive peptides and their derivatives are regarded as good dietary antioxidants for reducing oxidative stress and improving liver function. Here, a novel Maillard reactive decapeptide IVTNWDDMEK, identified from scallop mantle hydrolysates by peptidomics in the previous study was synthesized. Then, the correlation between intercellular antioxidant activities and chemical structure changes of IVTNWDDMEK-ribose Maillard reaction conjugates was further studied. The preferable hepatoprotective activities of decapeptide IVTNWDDMEK-ribose MRPs indicated that these MRPs could be potentially utilized as food antioxidants or additives in the production of nutritional foods.

In silico-screened cationic dipeptides from scallop with synergistic gelation effect on ι-carrageenan.

In this paper, some cationic dipeptides from scallop (Patinopecten yessoensis) male gonads (SMGs), which can synergistically gel with ι-carrageenan (ι-C), were screened by the in silico approach. Fourteen protein sequences of SMGs were obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and nano liquid chromatography-mass spectrometry/mass spectrometry (nanoLC-MS/MS) analysis and were then hydrolyzed via in silico simulation. A total of 414 sequences were obtained with 56 duplicates, half of which were positively charged at pH 7. Among the cation sequences, 171 had good water solubility, including two amino acids (Lys and Arg). The molecular weight analysis of the cationic water-soluble sequences showed that 0.2-0.3 kDa accounted for the highest proportion. Based on the obvious synergistic effect of Lys and ι-C, 11 Lys-containing dipeptides, including Ser-Lys (SK), Thr-Lys (TK), Trp-Lys (WK), Ala-Lys (AK), Leu-Lys (LK), Gly-Lys (GK), Val-Lys (VK), Cys-Lys (CK), Asn-Lys (NK), Phe-Lys (FK), and Met-Lys (MK), were finally screened out to study gelation with ι-C. It was found that the dipeptides/ι-C formed firm gels except WK/ι-C. The values of the storage modulus (G') of 11 dipeptides/ι-C were investigated by a rheometer. The G' of 8 dipeptides/ι-C was higher than 1000 Pa. These results indicated that the in silico-screened dipeptides from SMGs can form composite gels with ι-C, which can be used for the design and development of functional hydrogels.

Conjugation of (-)-epigallocatechin-3-gallate and protein isolate from large yellow croaker (Pseudosciaena crocea) roe: improvement of antioxidant activity and structural characteristics.

BACKGROUND: Large yellow croaker (Pseudosciaena crocea) roe is the main by-product in the processing of large yellow croaker. Previous studies have found that its protein isolates are composed of vitellogenin, as well as vitellogenin B and C, having good functional properties. (-)-Epigallocatechin-3-gallate (EGCG) is a natural antioxidant component that can be combined with protein to improve antioxidant activity and structural characteristics of protein. RESULTS: EGCG was bound with the P. crocea roe protein isolate (pcRPI) by the free radical method to prepare the conjugate. The formation of pcRPI-EGCG conjugates was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel permeation chromatography, which showed that the calculated weight-average molar masses of native-pcRPI and pcRPI-EGCG conjugates were 86.9 and 215.3 kDa, respectively. The results of fluorescence, ultraviolet, circular and infrared spectra indicated that the conjugation of EGCG with native-pcRPI changed the secondary and tertiary structure of native-pcRPI. The pcRPI-EGCG conjugates exhibited higher thermal stability than native-pcRPI. The radical scavenging and reducing power of native-pcRPI were increased by 2.0-2.5- and 1.4-fold, respectively, after the EGCG-grafting reaction. CONCLUSION: These results indicate that the binding of pcRPI and EGCG effectively improved the antioxidant properties and structural characteristics of the pcRPI. © 2021 Society of Chemical Industry.

Gel properties and network structure of the hydrogel constructed by iota-carrageenan and Ala-Lys dipeptide.

Gel properties of hydrogel-forming by Ala-Lys dipeptide (AK) and iota-carrageenan (ι-C) were investigated by rheological behavior, fourier transform infrared analysis, cryo-scanning electron microscopy, low field-NMR relaxometry and magnetic resonance imaging. Iota-carrageenan was changed from a liquid to a gel with the addition of AK, and the existence of AK significantly increased the storage modulus (G') of ι-C from 590.4 to 1077.8 Pa. In the ι-C/AK gel, the blue-shift of OH stretching and water deformation were observed, meanwhile, the presence of amide I band at 1682 cm-1 was observed. The network of ι-C/AK gel showed a dense honeycomb structure with flocculating continuous phase and rough entanglement morphology. After adding AK, the water free in the pores of ι-C entered the ι-C/AK gel matrix, and the binding capacity of bound water was enhanced. These scenarios proved that the AK as the cationic dipeptide could control the conversion of negatively charged ι-C from an original random structure to a helical structure due to electrostatic interactions and hydrogen bonds. This study provides a new opportunity for the peptides into carbohydrate-based gel matrices, which could provide insights for the further application of ι-C/AK gels in the fields of food industry, tissue engineering and drug delivery.

Synergistic gelation in the hybrid gel of scallop (Patinopecten yessoensis) male gonad hydrolysates and xanthan gum.

This study evaluated the gel and microstructure properties of scallop (Patinopecten yessoensis) male gonads hydrolysates (SMGHs) combined with xanthan gum (XG). SMGHs/XG hydrogel matrix properties and structures were elucidated via different analysis tools such as rheometry, LF-NMR, FTIR, AFM, and Cryo-SEM. The addition of XG significantly improved the rheological properties of SMGHs, as indicated by 3.1-fold G' and 1.3-fold melting temperature with increasing the XG dose to 5.6 mg/ml. The corresponding decrease in the T23 relaxation time from 450.3 to 365.6 ms also signified the strong binding between SMGHs and XG. SMGHs/XG also had a higher proton density (T1 and T2 weighted images) due to the higher bound and free water content of the hybrid gel systems, respectively. Additionally, the blueshift in the amide I and II bands in SMGHs/XG further indicated stronger electrostatic interactions between SMGHs and XG. Such scenarios resulted in a well-distributed and compact network with a rougher surface of SMGHs/XG in comparison to pure SMGHs and XG, as assessed by AFM and SEM. These results suggest that SMGHs/XG gel could be a potential hybrid gel applied in the food industry. PRACTICAL APPLICATION: Scallop (Patinopecten yessoensis) male gonads are edible, but are usually discarded during processing of scallop adductor. Because of its rich nutrition and gelation properties, scallop male gonads have a potential role in developing marine source-protein as a functional food base. The SMGHs/XG binary gel would be potentially applied in delivery system in food and biological fields. Further study is undergoing to apply SMGHs/XG binary gel to embed bioactive compounds, such as curcumin and ß-carotene.

Intermolecular interaction in the hybrid gel of scallop (Patinopecten yessoensis) male gonad hydrolysates and κ-carrageenan.

Various bond disrupting agents including NaCl, GuHCl, urea, and SDS were introduced to investigate the intermolecular interactions between scallop (Patinopecten yessoensis) male gonad hydrolysates (SMGHs) and κ-carrageenan (κ-C), which were monitored by changes in rheological property, water distribution, conformation characterization and microstructure by using rheometer, low field-NMR relaxometry, Fourier transform infrared (FTIR) spectroscopy, cryo-scanning electron microscopy (cryo-SEM), and confocal laser scanning microscopy. The results showed that the bond disrupting agents deteriorated the rheological property of SMGHs/κ-C in a dose-dependent manner. Indeed, at the same concentration of 2 M, NaCl deteriorated the SMGHs/κ-C more obviously than GuHCl and urea. In addition, SMGHs/κ-C with bond disrupting agents possessed higher relaxation times including T21 and T23 , indicating the migration to free water direction of bound and free water. Moreover, the FITR results showed the red-shift in water regions (amide A and B bands), amide I and II bands, and indicated the breakdown of hydrogen bonds and electrostatic interactions, indicating a disordered structure in SMGHs/κ-C by various bond disrupting agents. Furthermore, cryo-SEM results showed the change of SMGHs/κ-C from a homogeneous network to a looser and ruptured one with larger void spaces, and indicated the disrupted and tattered microstructure of SMGHs/κ-C by various bond disrupting agents. Additionally, SMGHs/κ-C as well showed less aggregates stained by RITC by bond disrupting agents. These results suggest that electrostatic interactions would be mainly involved in the maintenance of SMGHs/κ-C gel network. This study could provide theoretical and methodological basis for hydrogel products with modified gel strength and microstructure by understanding the intermolecular interactions in gel system. PRACTICAL APPLICATION: Scallop (Patinopecten yessoensis) male gonads as a high-protein part of scallop, is usually discarded during processing despite its edibility. In recent years, scallop male gonads are regarded as good sources to develop protein matrices due to their high protein content and numerous nutrients. In this study, scallop male gonad hydrolysates (SMGHs) were obtained by trypsin-treated process. The considerable gelation behavior of SMGHs indicated that the SMGHs could be potentially utilized as a novel thickener and additive in production of kamaboko gels, can, sausage and spread with marine flavor.

Effect of pH and mixing ratio on interpolymer complexation of scallop (Patinopecten yessoensis) male gonad hydrolysates and κ-carrageenan.

The electrostatic complex coacervation between scallop Patinopecten. yessoensis male gonad hydrolysates (SMGHs) and κ-carrageenan (κ-C) were monitored by using turbidimetry at various pH (1-12) and biopolymer mixing ratio (9:1-1:9). The pHc exhibited ratio-independent behavior, and pHφ1, pHmax exhibited ratio-dependent behavior, respectively. The decreasing ratio enhanced the gel strength of SMGHs/κ-C at higher pH while inversely at lower pH, ascribing to more SMGHs aggregates and stronger neutralization between positively charged patches in SMGHs and κ-C at lower pH and higher ratio. Moreover, SMGHs/κ-C gel at acid condition exhibited lower relaxation times (T21 and T23). Furthermore, the rheological and relaxation time T2 data were well associated with microscopy images which indicated that SMGHs/κ-C gel showed a well-distributed network structure at more acidic domains, supporting stronger gel rigidity and water-holding capacity.

Complex coacervation of scallop (Patinopecten yessoensis) male gonad hydrolysates and κ-carrageenan: Effect of NaCl and KCl.

The complex coacervation between scallop Patinopecten yessoensis male gonad hydrolysates (SMGHs) and κ-carrageenan (κ-C) as influenced by ionic strength (NaCl and KCl) were monitored by using turbidimetric analysis at pH 1-12. The optical density of SMGHs/κ-C complexes initially increased at lower ionic strength (0-0.5 M) whereas decreased at higher ionic strength (0.5-1.5 M) as a result of the salt-enhanced and salt-reduced effect, respectively. Both of pHc and pHφ1 exhibited ionic strength-dependent behavior that firstly shifted to acidic pH followed by an increase as salt increasing. Moreover, salt addition strongly promoted the gelation of SMGHs/κ-C which was mainly driven by electrostatic forces, as reflected by increasing storage modulus G' from 3621 to 6559 Pa, 2681-25631 Pa at 0.1 Hz and decreasing T23 relaxation time from 349.10 to 296.89 ms, 241.07-186.89 ms by 0-0.5 M NaCl/KCl, respectively. Furthermore, the rheological and relaxation time T2 data were well associated with microscopy images that SMGHs/κ-C gels with NaCl/KCl showed a denser network with more flocculation formation and larger pore sizes with thicker network wall, especially in KCl group, which indeed supported the gel elasticity. Taken together, this study could provide theoretical and methodological basis for new functional hydrogel products with modified gel strength and microstructure by understanding the complex coacervation in gel system.

Functional properties of gonad protein isolates from three species of sea urchin: a comparative study.

Sea urchin Mesocentrotus nudus, Glyptocidaris crenularis, and Strongylocentrotus intermedius gonad protein isolates (mnGPIs, gcGPIs, and siGPIs) were extracted by isoelectric solubilization/precipitation (ISP) from the defatted gonads, and their functional properties were compared. Sodium dodecyl sulfate polyacrylamide gel electrophoresis results showed the similar protein pattern between each protein isolate and defatted gonad, indicating the high efficiency of ISP processing for protein recovery. Amino acid profileconfirmed that the mnGPIs and siGPIs could be potential sources of essential amino acid in nature. As regard to functional properties, mnGPIs showed higher water- and oil- holding capacities followed bysiGPIs and gcGPIs and all protein isolates presented great foaming property. As for emulsifying activity index (EAI), mnGPIs, gcGPIs, and siGPIs showed the minimum solubility and EAI at pH 5, 3, and 4, respectively, and behaved a pH-dependent manner. The gcGPIs revealed the highest EAI from pH 6 to 8 among the samples. In addition, circular dichroism showed increased content of ß-sheet at the expense of α-helix and ß-turn, suggesting the structure denaturation of the protein isolates. Indeed, no statistical difference was observed between secondary structure of mnGPIs and siGPIs. Moreover, ISP processing increased free sulfhydryl content of sea urchin protein isolates, but no difference was observed among the samples. Furthermore, siGPIs revealed the highest amount of total sulfhydryl and disulfide bonds, whereas both defatted gonads and protein isolates from G. crenularis presented the maximum surface hydrophobicity. These results suggest that gonad protein isolates from three species of sea urchin possess various functionalities and therefore can be potentially applied in food system. PRACTICAL APPLICATION: Sea urchin M. nudus, G. crenularis, and S. intermedius gonads are edible, whereas the functional properties of protein isolates from sea urchin gonad remain unknown. In this case, the extraction and comparison of three species of sea urchin gonad protein isolates will not only confirm functional properties but also screen food ingredients with suitable functions. In this study, functionalities of protein isolates derived from M. nudus, G. crenularis, and S. intermedius gonads would provide potential application in bakery food and meat products or as emulsifier candidates in food system.

Simultaneous extraction by acidic and saline solutions and characteristics of the lipids and proteins from large yellow croaker (Pseudosciaena crocea) roes.

The objective of this study was to simultaneously obtain protein isolates and lipids from the dried powder of large yellow croaker (Pseudosciaena crocea) roes (pcRs) to achieve high-value utilization. Protein isolates and lipids were extracted simultaneously from pcRs by saline and acidic solutions. The purity of the protein isolates from the pcRs (pcRPIs) was greater than 70%, with vitellogenin, vitellogenin B and vitellogenin C as the main proteins. The lipids from pcRs (pcRLs) were mainly composed of triglycerides with high levels of EPA and DHA. The pcRPIs exhibited a higher surface hydrophobicity, water/oil holding capacity and emulsifying ability than those of the pcRs. Moreover, pcRPIs had a better oil holding capacity and emulsifying ability than soy protein isolate. These results suggest that protein isolates and lipids can be simultaneously extracted by saline and acidic solutions, and pcRPIs and pcRLs can be used as functional materials in the food industry.

Quantitative Proteome Reveals Variation in the Condition Factor of Sea Urchin Strongylocentrotus nudus during the Fishing Season Using an iTRAQ-based Approach.

To investigate the variation in the condition factor of the sea urchin Strongylocentrotus nudus (S. nudus), gonads were collected in May (MAY), June (JUN), and July (JUL), at the beginning (AUG-b) and end of August (AUG-e). Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) detection of the gonads revealed an obvious enhancement of the band at about 37 kDa from July, which was identified as transforming growth factor-beta-induced protein ig-h3 (TGFBI) by nanoLC-ESI-MS/MS. Gonadal proteins were identified by isobaric tagging for relative and absolute quantitation (iTRAQ), and regulation of the identified proteins in pairs of the collected groups was observed. A total of 174 differentially expressed proteins (DEPs) were identified. Seven of the DEPs showed significant correlations with both the gonad index (GI) and protein content. These correlations included 6-phosphogluconate dehydrogenase, decarboxylating isoform X2 (6PGD), CAD protein, myoferlin isoform X8, ribosomal protein L36 (RL36), isocitrate dehydrogenase [NADP], mitochondrial isoform X2 (IDH), multifunctional protein ADE2 isoform X3, sperm-activating peptides (SAPs) and aldehyde dehydrogenase, and mitochondrial (ALDH). However, TGFBI had no correlation with gonad index (GI) or protein content. 6PGD, IDH, multifunctional protein ADE2 isoform X3, and ALDH were shown to interact with each other and might play key roles in changing the condition factor of S. nudus gonads.