Tilapia head gelatins to stabilize fish oil emulsions and the effect of extraction methods.

The preparation and use of gelatins from fish by-products have attracted much attention in the field of food science. Herein, four types of tilapia head gelatins were extracted and characterized: hot water-pretreated gelatin (HWG), acetic acid-pretreated gelatin (AAG), sodium hydroxide-pretreated gelatin (SHG), and pepsin enzyme-pretreated gelatin (PEG). The gel strength values followed the order: PEG (74 ± 1 Bloom) > AAG (66 ± 1) > HWG (59 ± 1) > SHG (34 ± 1). The foaming properties, fish oil emulsion viscosity, emulsion activity, and emulsion stabilization ability followed this order: PEG > HWG ≥ AAG > SHG. The effect mechanisms of extraction methods and gelatin concentrations on the emulsion stability involved the interfacial tension, emulsion viscosity, and fat-binding capacity. This work provided important knowledge for analyzing the relations between the structure and function of gelatin. It also provided a high-value application method of fish wastes.

Molecular modification of low-dissolution soy protein isolates by anionic xanthan gum, neutral guar gum, or neutral konjac glucomannan to improve the protein dissolution and stabilize fish oil emulsion.

Herein, the effects of anionic xanthan gum (XG), neutral guar gum (GG), and neutral konjac glucomannan (KGM) on the dissolution, physicochemical properties, and emulsion stabilization ability of soy protein isolate (SPI)-polysaccharide conjugates were studied. The SPI-polysaccharide conjugates had better water dissolution than the insoluble SPI. Compared with SPI, SPI-polysaccharide conjugates had lower ß-sheet (39.6 %-56.4 % vs. 47.3 %) and α-helix (13.0 %-13.2 % vs. 22.6 %) percentages, and higher ß-turn (23.8 %-26.5 % vs. 11.0 %) percentages. The creaming stability of SPI-polysaccharide conjugate-stabilized fish oil-loaded emulsions mainly depended on polysaccharide type: SPI-XG (Creaming index: 0) > SPI-GG (Creaming index: 8.1 %-21.2 %) > SPI-KGM (18.1 %-40.4 %). In addition, it also depended on the SPI preparation concentrations, glycation times, and glycation pH. The modification by anionic XG induced no obvious emulsion creaming even after 14-day storage, which suggested that anionic polysaccharide might be the best polysaccharide to modify SPI for emulsion stabilization. This work provided useful information to modify insoluble proteins by polysaccharides for potential application.

Effects of polyphenol and gelatin types on the physicochemical properties and emulsion stabilization of polyphenol-crosslinked gelatin conjugates.

Herein, six types of polyphenol-crosslinked gelatin conjugates (PGCs) with ≥ two gelatin molecules were prepared using a covalent crosslinking method with two types of polyphenols (tannic acid and caffeic acid) and three types of gelatins (bovine bone gelatin, cold water fish skin gelatin, and porcine skin gelatin) for the emulsion stabilization. The structural and functional properties of the PGCs were dependent on both polyphenol and gelatin types. The storage stability of the conjugate-stabilized emulsions was dependent on the polyphenol crosslinking, NaCl addition, and heating pretreatment. In particular, NaCl addition promoted the liquid-gel transition of the emulsions: 0.2 mol/L > 0.1 mol/L > 0.0 mol/L. Moreover, NaCl addition also increased the creaming stability of the emulsions stabilized by PGCs except tannic acid-crosslinked bovine bone gelatin conjugate. All the results provided useful knowledge on the effects of molecular modification and physical processing on the properties of gelatins.

Impact of Processing Methods on the Distribution of Mineral Elements in Goat Milk Fractions.

Milk and dairy products are excellent sources of mineral elements, including Ca, P, Mg, Na, K and Zn. The purpose of this study was to determine the effect of non-thermal (homogenization) and thermal (heat treatment) treatments on the distribution of mineral elements in 4 milk fractions: fat, casein, whey protein, and aqueous phase. The study results revealed that the distribution of mineral elements (such as Mg and Fe) in fat fractions is extremely low, while significant mineral elements such as Ca, Zn, Fe, and Cu are mostly dispersed in casein fractions. For non-treated goat milk, Mo is the only element identified in the whey protein fraction, while K and Na are mostly found in the aqueous phase. Mineral element concentrations in fat (K, Zn, etc.) and casein fraction (Fe, Mo, etc.) increased dramatically after homogenization. Homogenization greatly decreased the concentration of mineral elements in the whey protein fraction (Ca, Na, etc.) and aqueous phase (Fe, Cu, etc.). After heat treatment, the element content in the fat fraction and casein fraction increased greatly when compared with raw milk, such as Cu and Mg in the fat fraction, Na and Cu in the whey protein fraction, the concentration of components such as Mg and Na in casein fraction increased considerably. On the other hand, after homogenization, Zn in the aqueous phase decreased substantially, whereas Fe increased significantly. Therefore, both homogenization and heat treatment have an effect on the mineral element distribution in goat milk fractions.

Effects of gelatin type and concentration on the preparation and properties of freeze-dried fish oil powders.

The effects of gelatin type (porcine skin gelatin, PSG; bovine skin gelatin, BSG; fish gelatin, FG; or cold-water fish skin gelatin, CFG) and concentration on the preparation and properties of fish oil powders were investigated in this work. The oil powders were prepared using the combination method of gelatin-sodium hexametaphosphate complex coacervation with starch sodium octenyl succinate (SSOS)-aided freeze-drying. Compared with the other gelatins, CFG-with an unobvious isoelectric point, a lower molecular weight, more hydrogen bonds, and longer gel formation time-could not form complex coacervates, which are necessary to prepare oil powders. For oil powders obtained from the other gelatins, gelatin type and concentration did not have obvious effects on microscale morphologies; they did, however, have significant effects on physicochemical properties. The highest peroxide values of the oil powders were mainly dependent on the gelatins, expressed in the following manner: PSG (153 ± 5 - 168 ± 3 meq/Kg oil) < BSG (176 ± 5 - 188 ± 1 meq/Kg oil) < FG (196 ± 11 - 201 ± 22 meq/Kg oil). Acidic and neutral pH could not dissolve the complex coacervates. However, the oil powders could be quickly dissolved to form emulsion droplets in the gastric phase, and that SSOS increased coacervate stability and promoted oil digestion during the in vitro gastrointestinal process. In sum, this study contributes fundamental information to understanding the development of fish oil solid encapsulation preparations.

Effect of lactation on the distribution of mineral elements in goat milk.

The distribution of mineral elements in milk is crucial for their absorption and utilization, however, there has been limited attention given to the status of mineral elements in goat milk. In this study, goat milk was collected at 4 lactation periods (1-3, 90, 150, 240 d) and separated into 4 fractions (fat, casein, whey, and aqueous phase). The concentrations of Mg, Ca, Na, K, Zn, Fe, Cu, Mn, Co, Ni, Mo, and Cr in 4 fractions were analyzed using an inductively coupled plasma emission spectrometer. Our findings reveal that Ca, Zn, Fe, Cu, Mn, and Cr exhibit the highest levels in casein, while Mo demonstrates the highest content in whey. Additionally, Mg, Na, K, and Ni display the highest concentrations in the aqueous phase. Specifically, the contents of Ca, Cu and Fe in casein decrease from 1-3 to 150 d of lactation but increase from 150 to 240 d of lactation. Furthermore, the content of Mg in the aqueous phase decreases from 1-3 to 90 d of lactation but increases from 90 to 240 d of lactation. The content of Na and K in the aqueous phase decreases from 1-3 to 150 d of lactation. Notably, the content of Mo in whey increases from 1-3 to 150 d of lactation and decreases from 150 to 240 d. Our research contributes to the advancement of understanding the bioavailability of mineral elements in goat milk.

CEGAT: A CNN and enhanced-GAT based on key sample selection strategy for hyperspectral image classification.

In recent years, the application of convolutional neural networks (CNNs) and graph convolutional networks (GCNs) in hyperspectral image classification (HSIC) has achieved remarkable results. However, the limited label samples are still a major challenge when using CNN and GCN to classify hyperspectral images. In order to alleviate this problem, a double branch fusion network of CNN and enhanced graph attention network (CEGAT) based on key sample selection strategy is proposed. First, a linear discrimination of spectral inter-class slices (LD_SICS) module is designed to eliminate spectral redundancy of HSIs. Then, a spatial spectral correlation attention (SSCA) module is proposed, which can extract and assign attention weight to the spatial and spectral correlation features. On the graph attention (GAT) branch, the HSI is segmented into some super pixels as input to reduce the amount of network parameters. In addition, an enhanced graph attention (EGAT) module is constructed to enhance the relationship between nodes. Finally, a key sample selection (KSS) strategy is proposed to enable the network to achieve better classification performance with few labeled samples. Compared with other state-of-the-art methods, CEGAT has better classification performance under limited label samples.

Tween emulsifiers improved alginate-based dispersions and ionic crosslinked milli-sized capsules.

The blending of surfactants might change the properties of alginate-based oil encapsulation preparations. Herein, the effects of Tween series (Tween 20, 40, 60, and 80) blending on the fish oil-encapsulated sodium alginate dispersions and calcium alginate capsules were studied. The results suggested Tween 80 showed better emulsifying properties than Span 80 for the alginate/surfactant emulsions. All the Tween series induced higher creaming stability than the sodium alginate-stabilized dispersion. Tween series blending did not change the sizes, decreased the water contents, and induced similar particle-like protrusions of calcium alginate capsules. Loading capacity and encapsulation efficiency of fish oil were dependent on the hydrophilic heads and fatty acid moieties of the Tween series. Tween series blending could increase the fish oil oxidative stability of the capsules. In the in vitro digestion process, Tween with saturated fatty acid moieties increased the free fatty acid release percentages. This work provided potential innovative processing technologies for improving the biological potency of fish oil.

Correlation between physicochemical properties and volatile compound profiles in tilapia muscles subjected to four different thermal processing techniques.

This work studied the physicochemical properties and odor profiles of tilapia muscles after exposure to four types of thermal processing methods: microwaving, roasting, boiling, or steaming. The effect of thermal processing on textural properties followed a pH-water state-water content-tissue microstructure-mass loss-textural properties route, expressed in the following manner: microwaving > roasting > steaming ≈ boiling. After processing, muscle pH increased from 6.59 ± 0.10 to 6.73 ± 0.04-7.01 ± 0.06, and hardness changed from 1468.49 ± 180.77 g to 452.76 ± 46.94-10723.66 ± 2898.46 g. Gas chromatography-based E-nose analysis confirmed that these methods had significant odor fingerprint effects on the tilapia muscles. Finally, the combined analysis of headspace solid-phase microextraction-gas chromatography-mass spectrometry, statistical MetaboAnalyst, and odor activity value showed that the microwaved, roasted, steamed, and boiled tilapia muscles had, respectively, three (hexanal, nonanal, and decanal), four (2-methyl-butanal, 3-methyl-butanal, decanal, and trimethylamine), one (2-methyl-butanal), and one (decanal) relatively important volatile compounds.

Development and application of lipidomics for food research.

Lipidomics is an emerging and promising omics derived from metabolomics to comprehensively analyze all of lipid molecules in biological matrices. The purpose of this chapter is to introduce the development and application of lipidomics for food research. First, three aspects of sample preparation are introduced: food sampling, lipid extraction, and transportation and storage. Second, five types of instruments for data acquisition are summarized: direct infusion-mass spectrometry (MS), chromatographic separation-MS, ion mobility-MS, MS imaging, and nuclear magnetic resonance spectroscopy. Third, data acquisition and analysis software are described for the lipidomics software development. Fourth, the application of lipidomics for food research is discussed such as food origin and adulteration analysis, food processing research, food preservation research, and food nutrition and health research. All the contents suggest that lipidomics is a powerful tool for food research based on its ability of lipid component profile analysis.

Gelatin as a bioactive nanodelivery system for functional food applications.

Gelatin has long been used as an encapsulant agent in the pharmaceutical and biomedical industries because of its low cost, wide availability, biocompatibility, and degradability. However, the exploitation of gelatin for nanodelivery application is not fully achieved in the functional food filed. In this review article, we highlight the latest work being performed for gelatin-based nanocarriers, including polyelectrolyte complexes, nanoemulsions, nanoliposomes, nanogels, and nanofibers. Specifically, we discuss the applications and challenges of these nanocarriers for stabilization and controlled release of bioactive compounds. To achieve better efficacy, gelatin is frequently used in combination with other biomaterials such as polysaccharides. The fabrication and synergistic effects of the newly developed gelatin composite nanocarriers are also present.

SIRT5 reduces the inflammatory response and barrier dysfunction in IL-17A-induced epidermal keratinocytes.

Psoriasis is a chronic multisystemic inflammatory disease with inflammatory cell infiltration, hyperproliferation of keratinocytes in skin lesions, and epidermal barrier dysfunction. Normal human epidermal keratinocytes (NHEKs) were stimulated with interleukin 17A (IL-17A). The expression levels of sirtuin-5 (SIRT5) were analyzed by RT-qPCR and western blot assay. The proliferation levels of NHEKs were assessed by EdU staining. The expression of ELOVL1 and ELOVL4 was analyzed by RT-Qpcr, and the expression levels of filaggrin, loricrin, and aquaporin-3 were analyzed by RT-qPCR and western blot. Extracellular signal-regulated kinase 1/2 (ERK1/2) activator t-butylhydroquinone was used to activate ERK1/2. Here, we show that SIRT5 overexpression reduces cell viability and cell proliferation, and improves barrier dysfunction in IL-17A-treated human epidermal keratinocytes, this effect of which is significantly blunted by the ERK1/2 activator. In epidermal keratinocytes, SIRT5 decreases cell proliferation and inflammation and improves barrier dysfunction via ERK/STAT3. This study reveals the role of SIRT5 in the pathogenesis of psoriasis, epidermal hyperplasia, keratinocyte-mediated inflammatory responses, and barrier dysfunction, the role of which is mediated by ERK/STAT3.

SIRT5 reduces the inflammatory response and barrier dysfunction in IL-17A-induced epidermal keratinocytes

Psoriasis is a chronic multisystemic inflammatory disease with inflammatory cell infiltration, hyperproliferation of keratinocytes in skin lesions, and epidermal barrier dysfunction. Normal human epidermal keratinocytes (NHEKs) were stimulated with interleukin 17A (IL-17A). The expression levels of sirtuin-5 (SIRT5) were analyzed by RT-qPCR and western blot assay. The proliferation levels of NHEKs were assessed by EdU staining. The expression of ELOVL1 and ELOVL4 was analyzed by RT-Qpcr, and the expression levels of filaggrin, loricrin, and aquaporin-3 were analyzed by RT-qPCR and western blot. Extracellular signal-regulated kinase 1/2 (ERK1/2) activator t-butylhydroquinone was used to activate ERK1/2. Here, we show that SIRT5 overexpression reduces cell viability and cell proliferation, and improves barrier dysfunction in IL-17A-treated human epidermal keratinocytes, this effect of which is significantly blunted by the ERK1/2 activator. In epidermal keratinocytes, SIRT5 decreases cell proliferation and inflammation and improves barrier dysfunction via ERK/STAT3. This study reveals the role of SIRT5 in the pathogenesis of psoriasis, epidermal hyperplasia, keratinocyte-mediated inflammatory responses, and barrier dysfunction, the role of which is mediated by ERK/STAT3 (AU)

Effect of ß-cyclodextrin deodorization on the volatile chemicals and functional properties of three types of gelatins.

The exploration of deodorization is important for the application of gelatin in food industry. In this work, the effect of ß-cyclodextrin (ß-CD) deodorization on the volatile chemicals and functional properties of three types of gelatins (commercial porcine skin gelatin, cold water fish skin gelatin, and Chinese longsnout catfish skin gelatin) were studied. The results suggested the odors of commercial gelatins were significantly less than home-extracted gelatins. The ß-CD deodorization efficiency was dependent on both ß-CD concentration and volatile chemical. (E)-2-Octenal (C8H14O), 1-octen-3-ol (C8H16O), 2-pentyl-furan (C9H14O), and hentriacontane (C17H36) could be deodorized at low ß-CD concentration (even at 2 mg/mL). The best ß-CD deodorization concentration for 66.7 mg/mL of Chinese longsnout catfish skin gelatin was 30 mg/mL. ß-CD addition could not change the gel forming ability and emulsion activity of gelatins, whereas it had different and concentration-dependent effects on the emulsion stability of gelatins. ß-CD addition had no obvious effects on the droplet sizes, droplet coalescence and liquid-gel transition behaviors, but had different effects on the creaming of the emulsions stabilized by three types of gelatins. The encapsulation of ß-carotene did not significantly change the droplet trimodal size distribution and liquid-gel transition of fish oil-loaded emulsions. However, ß-carotene might delay the droplet coalescence. The creaming stability of ß-carotene/fish oil-loaded gelatin/ß-CD-stabilized emulsions was dependent on the gelatins, ß-CD, and ß-carotene. Finally, the ß-carotene retention in the emulsions was dependent not on ß-CD addition but on the nature of the gelatins. These results provided useful information to understand the molecular deodorization behaviors and explore the deodorization of emulsifiers for food emulsions.

Downregulation of sperm-associated antigen 5 inhibits melanoma progression by regulating forkhead box protein M1/A disintegrin and metalloproteinase 17/NOTCH1 signaling.

Sperm-associated antigen 5 (SPAG5) has been identified as a driver in several type of cancers. In this study, we aimed to reveal the role of SPAG5 in melanoma and clarify whether FOXM1 (forkhead box protein M1) /ADAM17 (A disintegrin and metalloproteinase 17) /NOTCH1 signaling was involved. The expression of SPAG5 in malignant melanoma (MM) tissues and matched normal tissues was detected using qRT-PCR, immunohistochemistry and Western blotting. Cell viability was tested using CCK-8 (Cell Count Kit-8), colony formation and EdU staining. Cell migration and epithelial to mesenchymal transition (EMT) were measured using transwell chambers and immunofluorescent staining. Cell cycle distribution and tumorigenesis were assessed by flow cytometry and in vivo tumor-bearing experiments, respectively. The results demonstrated that the expression of SPAG5 was increased in MM tissues and cells. Downregulation of SPAG5 inhibited cell viability, migration, invasion and EMT, and induced a G1-phase arrest. In addition, downregulation of SPAG5 decreased the expression of FOXM1, thereafter inhibiting the expression of ADAM17, NOTCH1 and HES1. Furthermore, deletion of SPAG5 expression decreased the tumorigenesis of MM A375 cells. In conclusion, this study demonstrated that SPAG5 was overexpressed in MM. Downregulation of SPAG5 repressed MM cell growth and EMT, which might be induced by inactivation of the FOXM1/ADAM17/NOTCH1 signaling.

Genome-Wide Identification, Characterization, and Expression Analysis of GRAS Gene Family in Ginger (Zingiber officinale Roscoe).

GRAS family proteins are one of the most abundant transcription factors in plants; they play crucial roles in plant development, metabolism, and biotic- and abiotic-stress responses. The GRAS family has been identified and functionally characterized in some plant species. However, this family in ginger (Zingiber officinale Roscoe), a medicinal crop and non-prescription drug, remains unknown to date. In the present study, 66 GRAS genes were identified by searching the complete genome sequence of ginger. The GRAS family is divided into nine subfamilies based on the phylogenetic analyses. The GRAS genes are distributed unevenly across 11 chromosomes. By analyzing the gene structure and motif distribution of GRAS members in ginger, we found that the GRAS genes have more than one cis-acting element. Chromosomal location and duplication analysis indicated that whole-genome duplication, tandem duplication, and segmental duplication may be responsible for the expansion of the GRAS family in ginger. The expression levels of GRAS family genes are different in ginger roots and stems, indicating that these genes may have an impact on ginger development. In addition, the GRAS genes in ginger showed extensive expression patterns under different abiotic stresses, suggesting that they may play important roles in the stress response. Our study provides a comprehensive analysis of GRAS members in ginger for the first time, which will help to better explore the function of GRAS genes in the regulation of tissue development and response to stress in ginger.

Occurrence, Antimicrobial Resistance Patterns, and Genetic Characterization of Staphylococcus aureus Isolated from Raw Milk in the Dairy Farms over Two Seasons in China.

This study investigated the occurrence and resistance rates of Staphylococcus aureus strains isolated from raw milk in the dairy farms over two seasons (spring and autumn) and across four regions that included 11 provinces in China. In total, 750 raw milk samples from the 405 dairy farms were collected. Fifteen antimicrobial agents were tested for antimicrobial resistance via disk diffusion tests, and PCR tests were performed to identify drug resistance genes of S. aureus isolates. Out of 750 samples, 276 (36.8%) were positive for S. aureus, with 150 (41.1%) being positive in spring and 126 (32.7%) being positive in autumn. The occurrence rate of S. aureus in northeastern China (45%) was higher than that in western China (33%) and southern China (31.9%), respectively, and the rate significantly (p < 0.05) differed from those of western China and southern China. Of 276 isolates, 261 (94.6%) strains were resistant to more than 1 antimicrobial drug, and 193 (69.9%) strains were multidrug resistant. The blaZ (46.3%), dfrG (35.5%), and tetM (27.2%) genes were detected at a high frequency in the S. aureus strains. Our data revealed a variation (p < 0.05) in the resistance patterns in the different regions and across the two seasons. The occurrence and drug resistance rates of S. aureus isolated from raw milk obtained from dairy farms may still cause severe problems in China.

A Potential Tumor Suppressor Gene Named miR-508-5p Inhibited the Proliferation and Invasion of Human Melanoma Cells by Targeting KIT.

Melanoma is the main death cause of human skin cancer. Increasing evidences demonstrate that microRNAs act as key roles in mediating tumor occurrence and progression. MiR-508-5p has proved to participate in the development of various types of human malignancies. However, the role of miR-508-5p in melanoma remained unclear. In in vitro study, miR-508-5p level in peripheral blood samples of patients with melanoma and human melanoma A375 cells was downregulated compared to that in normal peripheral blood samples or normal human epidermal melanocytes (MHEM). MiR-508-5p overexpression significantly inhibited the cell proliferation, migration and invasion in A375 cells, and thus inhibiting KIT expression at both gene and protein levels. Furthermore, western blot analysis showed miR-508-5p reduced cell proliferation by targeting KIT to modulate RAS/RAF/MEK/ERK pathway. Taken together, we speculated that miR-508-5p functioned as an important suppressor in human melanoma by targeting KIT, suggesting miR-508-5p might be a promising tumor suppressor gene for further target therapies from bench to clinic.

Effect of three types of thermal processing methods on the lipidomics profile of tilapia fillets by UPLC-Q-Extractive Orbitrap mass spectrometry.

Thermal processing methods have important effects on food lipids. In this work, ultra-high-performance liquid chromatography-Q-Extractive Orbitrap mass spectrometry and lipidsearch software were applied to analyze effect of three types of thermal processing methods on the lipidomics profile of tilapia fillets. A total 15 classes of compound lipids (Cer, DG, LPC, LPE, LPG, LPI, LPS, PC, PE, PG, PI, PS, SM, So, TG) were analyzed. In addition, free DHA, EPA, and ARA were also identified. Furthermore, statistical analyses of these lipids were performed based on MetaboAnalyst software. The results demonstrated three types of thermal processing methods had different effects on lipidomics profile differences of tilapia fillets. A total of eight lipid species variables (LPS, LPG, LPI, DG, LPC, TG, LPE, and Cer) and 137 individual lipids variables showed significant differences among raw, steamed, boiled, and roasted tilapia fillets. This work could provide useful information for aquatic product processing and lipidomics.

Effect of extraction methods on the preparation of electrospun/electrosprayed microstructures of tilapia skin collagen.

Collagen plays a pivotal role in human physiological functions and extracted collagen has multiple potential applications. Tilapia skin can be applied to extract collagen for maximizing the profit of tilapia processing. Electrospinning/electrospraying is novel micro- and nano-techniques to fabricate microfibers and microspheres in a simple and easy way. In this work, we extract collagens from tilapia skin by three types of extraction methods: acetic acid method, hot water method, and sodium hydroxide method. Then, these extracted collagens are characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Fourier transform infrared spectrometry. These extracted collagens have different molecular weights and different protein secondary structures. Finally, these extracted collagens are applied to fabricate electrosprayed microspheres, electrospun microfibers, and mixed microspheres/microfibers with multiple potential applications by adjusting the collagen concentrations. Higher polymer molecular weight only needs lower concentration to produce microfibers. The microfiber diameter increases with the increase of collagen concentration. This work proves that extraction methods have obvious effect on the preparation of electrospun/electrosprayed microstructures of tilapia skin collagen and provide a way to maximize resource utilization of tilapia processing waste.