Tilapia Scale Research Articles

Antioxidant Peptides and Protein Hydrolysates from Tilapia: Cellular and In Vivo Evidences for Human Health Benefits.

Antioxidant peptides derived from aquatic organisms have attracted tremendous research interest due to their potential applications in human health. Tilapia is one of the most widely farmed aquaculture species globally. The current understanding of tilapia-derived antioxidant peptides is gradually expanding. This review discusses the current knowledge of peptides and protein hydrolysates derived from tilapia muscle, skin, and scales, whose antioxidant capacity has been validated in various cellular and in vivo models. To date, at least 16 peptides and several hydrolysates have been identified from tilapia that protect human and non-human cell models against oxidative injury. Tilapia hydrolysates and peptide mixtures have also shown protective effects in animal models of oxidative stress-associated diseases and exercise-induced oxidative injury and fatigue. The key mechanisms of tilapia hydrolysates and peptide mixtures involve enhancing antioxidant enzyme activities and suppressing radical production. Notably, such hydrolysates also exerted additional in vivo functions, such as anti-inflammatory, anti-diabetic, wound healing, and antiaging properties. Taken together, tilapia-derived antioxidant peptides and hydrolysates represent a valuable source of functional ingredients for applications in functional food, dietary supplements, and therapeutic applications. Continued research into their health benefits is warranted in the future.

Effects of the extraction temperatures on the protein contents, gelatin purities, physicochemical properties, and functional properties of tilapia scale gelatins

Herein, the effects of the extraction temperatures (45, 55, 65, 75, and 85 °C) on the protein contents, gelatin purities, physicochemical properties, and functional properties of tilapia scale gelatins were studied. Among these temperatures, 65 °C was the best extraction temperature to obtain good production yield (16.0 % ± 0.3 %), good protein contents (excellent total amino acid composition of 94.20 ± 0.76 g/100 g of gelatin, the highest hydrophobic amino acids percentage of 32.68 ± 0.24 g/100 g of gelatin), appropriate ATR-FTIR spectra peaks (Amides A, B, I, II, and III), high β-sheet percentage (38.2 % ± 1.3 %), the highest purity of the gelatin structures (280, 140, and 125 kDa), the lowest nanoparticle sizes in atomic force microscopy results, the highest water-holding capacity (25.3 % ± 0.9 %), the highest fat-binding capacity (16.9 % ± 0.1 %), high foaming properties (foaming capacity of 151.7 % ± 7.6 % and foaming stability of 145.8 % ± 6.3 %), the lowest interfacial tension (2.1 ± 0.2 mN/m), the lowest emulsifying activity index (16.5 % ± 0.9 %), the highest emulsifying stability index (88.9 % ± 5.1 %), highest emulsion viscosity (1462 ± 17 mPa·s at the rotary speed of 6 rpm), the lowest initial droplet sizes, and lowest emulsion creaming index (6.9 % ± 0.7 %). This work provided a useful guide to choosing extraction temperature for gelatin extraction and a useful theory on the relationship between compositions and properties of a protein sample.

Effects of Acid Pre-Treatment on Removal of Organic and Inorganic Substances from Black Tilapia Bones and Scales

Fish bones and scales are good sources of gelatin. However, high mineral content in bones and scales often lead to low quality gelatin with high percentage of ash. Therefore, pre-treatment with acid prior to gelatin extraction is necessary. Black tilapia (Oreochromis niloticus) bones and scales were subjected to Hydrochloric (HCl) acid of 0.6 M to 1.4 M for 0 to 32 hr. The suitable pre-treatment conditions were determined using percentage of ash removed and loss of protein from the samples. Results obtained indicate, 99.86 % and 99.84 % of ash can be removed from bones and scales, with 1.4 M HCl (32 hr) and 1.0 M HCl (10 hr), respectively. Further analysis with UV-Vis revealed that, excessive protein breakdown starts to occur at 1.0 M (32 hr) and 0.6 M (12 hr), in bones and scales, respectively. The data suggest using pre-treatment conditions lower than the above to avoid protein loss which may lead to low gelatin yield.

Biodegradable monolayer film based on the collagen extracted from Oreochromis sp. processing byproducts blended with chitosan and assembled with PCL and PLA monolayers to form bilayers films

AbstractThe objective of the study is to develop and characterize biodegradable monolayer and bilayer films using collagen extracted from tilapia skin and scales (Oreochromis sp.) with chitosan in combination with biodegradable polyester; polylactic acid (PLA) or polycaprolactone (PCL). Collagen extraction was conducted with acetic acid (0.5 M). Monolayer films based on collagen and chitosan were formed by the casting process with a solution of chitosan (2% w/w) in 1.5% acetic acid, followed by the addition of skin collagen at concentrations of 0.5%, 1%, or 2% w/w, and dried at 45–50°C. The PLA and PCL films were made by compression molding. The films were characterized according to their appearance, structure, morphology, interaction with water, thermal stability, and mechanical and barrier properties. The results indicated that collagen from tilapia skin and scales yielded 36.5% and 2.57%, respectively. The results showed that adding chitosan increased the tensile strength but decreased the elongation of the films. An improvement in thermal stability was observed by increasing the proportion of collagen or chitosan, and it also influenced water solubility and water vapor permeability. Microscopy showed a crack‐free interface between collagen and chitosan. The color of the films varied depending on the composition, highlighting the influence of chitosan in yellow and reddish tones. The bilayers with PLA had lower water vapor permeability and higher gloss compared to those with PCL. Finally, the developed films showed promising properties for their application in food packaging and promote the use of fishery waste.Practical applicationsThe study aims to develop and characterize biodegradable monolayer and bilayer films using collagen extracted from tilapia skin and scales (Oreochromis sp.) combined with chitosan and biodegradable polyester such as polylactic acid or polycaprolactone. The practical applications of this research span a wide range of industrial fields. For instance, monolayer films could be used as sustainable food packaging, offering enhanced barrier properties and biodegradability, thus reducing the environmental impact of conventional packaging. Furthermore, bilayer films could find applications in the healthcare industry, such as controlled‐release drug patches or dressings leveraging the antimicrobial properties of chitosan. This research also provides valuable insights into improving the mechanical, thermal, and barrier properties of biodegradable films, potentially leading to the production of more efficient and versatile materials for a variety of industrial applications.

Upcycling waste tilapia (oreochromis niloticus) scales through a decellularization process for extracellular matrix extraction

Tilapia scales, typically regarded as low-value biological waste, possess valuable organic components such as collagen and inorganic components such as hydroxyapatite. Converting these wastes into functional biomaterials like decellularized extracellular matrix (dECM) contributes to long-term fish waste management to achieve sustainable fish consumption and promote a circular economy by creating a product with a high market value. Triton X-100 (TX-100) and Sodium-dodecyl sulfate (SDS) at varying concentrations (0.1%, 0.5%, and 1%) are utilized to extract the extracellular matrix. The study aims to evaluate the effectiveness of these agents in decellularizing the scales and producing a suitable dECM scaffold. Histological analysis using H&E staining revealed a significant decrease in cellular components in the decellularized samples. This was supported by the dsDNA quantification results showing the highest removal rate of 96% in the samples treated with 1% SDS. Attenuated Total Reflectance-Fourier-transform infrared (ATR-FTIR) spectra showed the amide peaks (Amide A, B, I, II, and III) indicating the presence of type I collagen. The confirmation of type I collagen was further supported by the analysis of SDS-PAGE images, which displayed the presence of α1 and α2 chains, β-dimer, and the γ-band. Among the dECM, samples treated with 0.1% TX-100 exhibited the highest protein content, averaging 593.33 ± 17.78 μg mg−1 while 1% SDS showed the lowest protein content averaging 61.33 ± 24.03μg mg−1. All dECM samples demonstrated protein denaturation temperatures ranging from 70–75 °C. This study presents baseline data of the single chemical decellularization treatment method utilized to extract ECM from tilapia scales and its resulting dECM. Further research is recommended to assess the biocompatibility and cytotoxicity of the produced dECM and explore its potential applications.

Formulation of an antiseptic topical cream based on chitosan extracted from the scales of the Nile tilapia (Oreochromis niloticus)

The Nile tilapia is a widely consumed fish, its scales dumped in nature as waste have been recovered in the formulation of antiseptic creams because of its high content in chitin, precursor of chitosan. Creams have the advantage of being more comfortable on the skin and allow prolonged administration of the active ingredient. Chitosan is obtained with a yield of 21.2%. FTIR analysis of chitosan showed numerous bands of phase groups present and a successful deacetylation assessed on the intensity of the bands at 1650 cm−1 and 1315 cm−1 and confirm by SEM analysis with an abundance of Carbone followed by EDS analysis. Solubilisation of chitosan in 2% acetic acid at 96% and the antibacterial activity test revealed antibacterial activity on Escherichia coli. The viscosity and the optimum spreading capacity of the cream base has been obtained at 14.65% for sesame oil, 9.08% for lanette and 1.26% for glycerine.

Impacts of pre-treatment methods on the morphology, crystal structure, and defects formation of hydroxyapatite extracted from Nile tilapia scales.

The comprehensive control of hydroxyapatite (HAp), involving morphological and structural variations, particle sizes, and defect formations, has garnered considerable attention for its versatile functionalities, rendering it applicable in diverse contexts. This work examined the shape, structure and optical characteristics, and defect formation in hydroxyapatite (HAp) extracted from Nile tilapia (Oreochromis niloticus) scales with various pre-treatments through experiments and density functional theory (DFT) calculations. Utilizing scanning electron microscopy, our findings revealed that dried fish scales (FS-D) exhibited a layered pattern of collagen fibers, while boiled fish scales (FS-B) had smoother surfaces and significantly reduced collagen content. After calcination, the FS-D sample produced nanorods with an average length of 150 ± 44 nm, whereas the FS-B samples yielded agglomerated spherical particles whose size increased with the rising calcining temperature. In-depth analysis through X-ray diffraction and Fourier-transform infrared spectroscopy confirmed the presence of biphasic calcium phosphates in the FS-B samples, while the FS-D sample presented a pure HAp phase. The boiled fish scale calcined at 800 °C (FS-B800) exhibited an optical band gap (Eg) of 5.50 eV, whereas the dried fish scale calcined at 800 °C (FS-D800) showed two Eg values of 2.87 and 3.97 eV, as determined by UV-visible spectroscopy. DFT calculations revealed that the band gap of 3.97 eV correlated with OH- vacancies, while that of 2.87 eV indicated Mn-substituted HAp, explaining the blue powder. The Eg value for the white powder resembled pure HAp, S- and Cl- substituted OH- vacancies, and various cations substituting Ca sites of HAp. Different pre-treatment procedures influence the characteristics of HAp, offering opportunities for applications in bone replacement and scaffolds for bone tissue engineering.

Effect of seasonal variation and farming systems on the properties of Nile tilapia gelatin extracted from scales

Although fish gelatin has become a research hotspot in recent years, researchers and manufacturers are still looking for high-quality sources of fish galatin to meet the commercial demand for safer gelatin.became This study aimed to evaluate the impact of seasonal variation and farming systems on the properties of gelatin extracted from Nile tilapia scales. Gelatin extracted from farmed tilapia had lowest impurities, higher clarity as well as desirable color characteristics (L* = 65.95 and a* = −0.33). The protein and fat composition of Wild (91.00 ± 0.00c) and 1.94 ± 0.05a respectively were higher than farmed gelatin of protein (91.00 ± 0.00c) and fat (0.84 ± 0.08b) but gelatin from the farmed type were clearer (98.30 ± 0.28a) than wild type (94.60 ± 0.28b). In addition, the XRD analysis confirmed its amorphous structure (2θ = 11°, 21°. 29°, and 31°). The gelatin extracted from wild tilapia showed an average yield of 1.98 % and good physicochemical and functional properties. Furthermore, FTIR indicated a strong bond positioned in the amide I region (1650.88 cm-1) of the wild tilapia gelatin. Partial Least Square (PLS) confirmed that viscosity is positively correlated with melting temperature upon a unit change in gelatin yield. This work highlights the significance of farming systems and seasonal variation in extraction conditions and great parameter to comprehensively navigate the functional, biochemical, and physical properties of Nile tilapia gelatin for broadening both food and non-food industrial appliactions.

The Influence of Different Media on The Physiological Response of Nila Fish (Oreochormis nilaticus)

Nila fish (Oreochromis niloticus) is one of the leading commodities in freshwater fish cultivation in Indonesia is a freshwater fish commonly found in Indonesian waters. Media will be the main obstacle in cultivating tilapia on idle land (land that cannot be operated). Different water media influence the physiological responses of tilapia fish. The purpose of this activity is to determine the effect of differences in freshwater, brackish water and sea water media on the physiological response of tilapia fish. The parameters of this research are differences in water media, physical factors of the media, survival of tilapia fish, respiration rate of tilapia fish, mobility of tilapia fish, weight of tilapia fish and flexibility of tilapia scales. This study used quantitative methods with a completely randomized design (RAL). The collection technique makes observations. Data were analyzed using ANOVA with a significance level of 5%. The results of this study show that differences in the aquatic environment significantly affect the physiological response of tilapia. Where in sea water the fish mortality rate is quite high compared to fresh water and brackish water.

Nanoparticles fabricated from the bioactive tilapia scale collagen for wound healing: Experimental approach.

The creation of innovative wound-healing nanomaterials based on natural compounds emerges as a top research goal. This research aimed to create a gel containing collagen nanoparticles and evaluate its therapeutic potential for skin lesions. Collagen nanoparticles were produced from fish scales using desolvation techniques. Using SDS PAGE electrophoresis, Fourier transform infrared spectroscopy (FTIR) as well as the structure of the isolated collagen and its similarities to collagen type 1 were identified. The surface morphology of the isolated collagen and its reformulation into nanoparticles were examined using transmission and scanning electron microscopy. A Zeta sizer was used to examine the size, zeta potential, and distribution of the synthesized collagen nanoparticles. The cytotoxicity of the nanomaterials was investigated and an experimental model was used to evaluate the wound healing capability. The overall collagen output from Tilapia fish scales was 42%. Electrophoretic patterns revealed that the isolated collagen included a unique protein with chain bands of 126-132 kDa and an elevated beta band of 255 kDa. When compared to the isolated collagen, the collagen nanoparticles' FTIR results revealed a significant drop in the amide II (42% decrease) and amide III (32% decrease) band intensities. According to SEM analysis, the generated collagen nanoparticles ranged in size from 100 to 350 nm, with an average diameter of 182 nm determined by the zeta sizer. The produced collagen nanoparticles were polydispersed in nature and had an equivalent average zeta potential of -17.7 mV. Cytotoxicity study showed that, when treating fibroblast cells with collagen nanoparticle concentrations, very mild morphological alterations were detected after human skin fibroblasts were treated with collagen nanoparticles 32 μg/ml for 24 hours, as higher concentrations of collagen nanoparticles caused cell detachment. Macroscopical and histological investigations proved that the fabricated fish scale collagen nanoparticles promoted the healing process in comparison to the saline group.

Collagen Hydrolysate from the Scales of Mozambique Tilapia (Oreochromis mossambicus) Improve Hair and Skin Health by Alleviating Oxidative Stress and Inflammation and Promoting Hair Growth and Extracellular Matrix Factors.

Fish-derived collagen hydrolysate (CH) has shown promise in improving hair and skin health. Therefore, this study sought to comprehensively assess the effects of CH extracted from Mozambique tilapia (Oreochromis mossambicus) scales on hair and skin using in vitro and in vivo models. Human dermal papilla cells (hDPCs) were used for antioxidant and gene expression analyses, while C57BL/6 mice were orally administered CH for six weeks to assess hair growth patterns. The mice were divided into four groups: negative control (NC; distilled water), positive control (PC; 1 mg/kg finasteride), CH500 (500 mg/kg BW CH), and CH1000 (1000 mg/kg BW CH). CH mitigated catalase activity reduction in hDPCs, increased IGF-1 and VEGF levels, and decreased TGF-β1, TNF-α, and IL-1β expression. In vivo, CH treatment improved hair growth index, length, diameter, weight, and density. Scanning electron microscopy revealed reduced hair damage. Moreover, CH up-regulated IGF-1, VEGF, Elastin, and HAS2 mRNA expression while down-regulating TNF-α and IL-1β. CH enhanced hair shine, growth, and skin health while alleviating inflammation. These findings demonstrate the potential of CH in alleviating oxidative stress, promoting hair growth, and enhancing skin health, both in vitro and in vivo. Fish-derived CH offers a cost-effective and bioavailable option for improving hair and skin health.

Scale Based Age and Growth Analysis of Exotic Fish Tilapia (Oreochromis mossambicus P 1852) in Vallabhsagar Reservoir, Gujarat, India

The current study was conducted during post monsoon season (November, 2021–April, 2022) and 505 tilapia scales were randomly collected from the commercial fish collection centers i.e. Naranpur, Nesu Vadpada and Rumkitalav of Vallabhsagar reservoir, Gujarat, India. Fish scales described the age and growth of tropical conditions that provided detailed facts about their life history, ecology and habitat of fish which help to manage the water body for optimum fish production. The result showed that age of tilapia ranged from 1+ to 5+ year with total length 15.000–33.700±23.598 cm and weight 77.000–662.000±309.951 g. The calculated length (cm) of the back was 8.80, 14.758, 21.612, 26.170 and 28.846 cm while body weight (g) 17.690, 76.171, 223.369, 386.865 and 506.744 g were noted for 5 age classes respectively. The average specific size (5.77) and the index of population weight growth intensity (157.00) were observed whereas specific rate of linear growth (Cl) and specific rate of weight increase (Cw) were decreasing with increase in age. The growth constant average (Clt(Ave)) shows two growth phases, i.e. 0.67 and 0.22. The findings of current study help to conclude that the aquatic environment of Vallabhsagar reservoir was suitable to harbour these fishes and was conducive for satisfactory growth and wellbeing of tilapia. Results of the study provided baseline information which would be helpful for the scientific management of Tilapia fisheries in the Vallabhsagar Reservoir in Gujarat.

Dissolution Performance of Carbon/Hydroxyapatite Nanocomposite Prepared from Fish Scales

The utilization of waste as raw materials in the production of functional materials is a growing area of interest to promote global sustainable growth. This work studied the microstructure, chemical properties, and phosphorus (P) dissolution efficiency of carbon/hydroxyapatite (HAP) nanocomposites derived from fish scale wastes, namely FSBCs. Tilapia scales were pyrolyzed at different temperatures (450–600 °C) and the dissolution performance of the biochars in acidic media was evaluated. The pyrolysis of fish scales yielded biochars which are carbon/HAP nanocomposites of which the characteristics, including the specific surface area, carbon content, degree of crystallinity of HAP, and the degree of CO32− substitution in HAP crystals, were dependent on the pyrolysis temperature and had an influence on the dissolution efficiency. P dissolution experiments suggested that the specific surface area and the presence of carbon in the composite played an important role during the dissolution process. The presence of the organic residues on the carbon could potentially block the calcium sites on HAP from citric acid and lower the dissolution efficiency. The ratio of CO32−/PO43− substitution in HAP also affected the dissolubility of FSBCs. The manipulation of their surface area and the CO32−/PO43− ratio of these materials would allow us to increase its solubility, which could benefit a prospective application such as P fertilizer production.

Evaluation of Surface Properties of Chitosan and Scale Gelatin Coatings on Shrimp Fillets (Litopenaeus vannamei)

ABSTRACT This study aimed to evaluate the wettability of edible coatings based on chitosan or the gelatin of Nile tilapia (Oreochromis niloticus) scales on the surface of shrimp fillets (Litopenaeus vannamei) with glycerol as a plasticizer. Initially, the surface was characterized according to Zisman’s methodology. The surface tension and dispersive and polar components of the shrimp fillet was 59.93 (low-energy surface), 14.14, and 45.79 mN/m, respectively. The mathematical modeling applied to experimental design 32 showed that the minimum concentration of biopolymers favored wettability, among other observations about the interactions between the components of the coatings and the surface of the shrimp fillet. The behavior of the plasticizer was influenced by the biopolymer; as the concentration of the plasticizer increased, the cohesion coefficient of chitosan coatings decreased, while the opposite effect was observed for gelatin coatings. The coating compositions with optimized wettability were 1.0% chitosan and 0% glycerol (W s = −12.934 mN/m), and 1.0% gelatin and 0% glycerol (W s = −5.588 mN/m).

Hair-Growth-Promoting Effects of the Fish Collagen Peptide in Human Dermal Papilla Cells and C57BL/6 Mice Modulating Wnt/β-Catenin and BMP Signaling Pathways.

Fish-derived collagen has recently emerged as an alternative collagen source with bioactive properties, including the enhancement of hair and skin health. It is also cost-effective and has high bioavailability, in addition to having fewer side-effects compared to collagen from porcine skin or bovine skin. Collagen peptides (CPs) extracted from the scales of Mozambique tilapia (Oreochromis mossambicus) reportedly promote hair and skin health. This study sought to evaluate the effects of CPs on hair growth using in vitro and in vivo models. CP significantly enhanced hair regrowth and the proliferation of human dermal papilla cells (hDPCs) in vitro. CP was orally administered to C57BL/6 mice for 6 weeks to confirm the hair-growth-promoting effects. The mice were divided into four groups: negative control (distilled water), positive control (1 mg/kg of finasteride), CP500 (500 mg/kg of CP), and CP1000 (1000 mg/kg of CP). CP treatment significantly enhanced the proliferation of hDPCs compared to 0.2 μM finasteride, in addition to enhancing hair regrowth. Particularly, CP1000 treatment achieved a hair-growth index similar to that of the PC. In H&E staining, the CP groups exhibited a high A/T ratio. Furthermore, CP increased the expression of hair growth factors (IGF-1, VEGF, krt27, Gprc5d, and Ki67) and decreased the growth inhibitory factor (TGF-β1). Furthermore, CP significantly upregulated the Wnt/β-catenin pathways and downregulated the BMP pathways. Therefore, these results indicate that CP could be used as food supplements and nutraceuticals for hair loss prevention as well as hair regrowth during alopecia.

Self-curling 3D oriented scaffolds from fish scales for skeletal muscle regeneration

BackgroundVolumetric muscle loss (VML) due to various reasons may cause motor dysfunction and tissue engineering has been proposed for muscle regeneration. However, developing three-dimensional (3D) tissue-engineered scaffolds that can mimic oriented cell growth of muscle tissues are challenging for regeneration medicine. Herein, we propose a novel self-curling 3D oriented scaffold (SCOS) composed of fish derived gelatin methacrylate (GelMA) and fish scales for repairing skeletal muscles.MethodsFish scales of tilapia were decellularized and decalcified. Then, SCOSs were constructed by ultraviolet-coating methylated fish gelatin on the back of fish scales. C2C12 myoblasts were cultured on SCOSs, and after induction of myogenic differentiation, SCOS/C2C12 transplants were prepared for in vivo experiments.ResultsDecellularized and decalcified fish scales (DDFSs) became soft and retained the original oriented microgroove surface structure that could induce oriented cell growth. SCOSs could self-curl into 3D structures when immersing in culture medium due to different swelling properties of fish GelMA and DDFSs. Cell experiments demonstrated that SCOSs enhanced the oriented growth and myogenic differentiation of C2C12 myoblasts. By integrating SCOSs and myogenic differentiated C2C12 myoblasts, the resultant SCOS/C2C12 transplants promoted de novo muscle regeneration and functional restoration of muscle activity in the mouse model of VML.ConclusionsOur results suggest that SCOSs loaded with myogenic differentiated C2C12 myoblasts can promote muscle regeneration in mice with skeletal muscle injuries, indicating application prospects of such scaffolds in muscle tissue engineering and other related fields.

Identification and functional analysis of three novel osteogenic peptides isolated from tilapia scale collagen hydrolysate

On the basis of our previous study that 133 peptides were identified from the tilapia scale peptide-calcium chelate, the potential osteogenic peptide monomers through the calcium-binding properties of peptides and molecular docking were screened, and the osteogenic activity and active mechanism of the peptides were further researched in this study. Three highly osteogenic peptides GPAGPHGPVG (844.4191 Da), APDPFRMY (995.4534 Da), and TPERYY (827.3813 Da) were screened. Molecular docking showed that the three osteogenic peptides had the same interaction sites in the epidermal growth factor receptor (EGFR), namely ARG 285, GLN 8, GLY 317, THR 406, and HIS 409. Compared to the blank control group, within 50 μg/mL of GPAGPHGPVG, APDPFRMY, and TPERYY increased the proliferation of MC3T3-E1 cells by changing the cell proportion in the S and G2/M phases, and the alkaline phosphatase (ALP) activity of MC3T3-E1 cells treated with 50 μg/mL of the three active peptides increased by 25%, 37%, and 56%, respectively. The three active peptides at 10 μg/mL concentration significantly promoted the mineralization of osteoblasts, and the mineralized calcium nodules increased by 166%, 161%, and 111%, respectively. TPERYY significantly increased the expression of osteogenic genes (osteocalcin (OCN), type I collagen (Col I α) and transcription factor (OSX)). Moreover, TPERYY significantly increased the mRNA and protein expression of β-catenin to 1.39 and 2.6 times of the blank control group, respectively, while decreased the mRNA and protein expression of glycogen synthesis kinase (GSK3β) to 1.6 and 2.3 times of the blank control group, respectively. This study provides a theoretical basis for using GPAGPHGPVG, APDPFRMY, and TPERYY peptides as functional foods to prevent osteoporosis.

Effect of extraction methods on the properties of tilapia scale gelatins

Three types of tilapia scale gelatins (hot water-pretreated gelatin, HWG; acetic acid-pretreated gelatin, AAG; and pepsin enzyme-pretreated gelatin, PEG) were extracted and their gel strength, foaming properties, and emulsifying properties were analyzed. They had different gel strength values: AAG (370 ± 10 g Bloom) > HWG (320 ± 10 g Bloom) > PEG (280 ± 10 g Bloom). The creaming index values of tilapia scale gelatin-stabilized fish oil-loaded emulsions were dependent on gelatin type (HWG ≈ AAG > PEG) at low gelatin concentration (2 mg/mL), whereas they were similar and low (8–10 %) at high gelatin concentration (10 mg/mL). Extraction methods had no consistently significant effects on the gelatin foaming properties. In summary, tilapia scale gelatins had better gel strength and foaming properties and similar or even better emulsifying properties than mammalian gelatins. Therefore, tilapia scales could be a potential source of gelatins to replace mammalian gelatins.

Comparison of Maillard-Type Glycated Collagen with Alginate Oligosaccharide and Glucose: Its Characterization, Antioxidant Activity, and Cytoprotective Activity on H2O2-Induced Cell Oxidative Damage.

To improve the antioxidant activity of collagen molecules using Maillard-type glycation, the relation between antioxidant activity and progress indexes for the Maillard reaction must be understood. In this study, lyophilized tilapia scale collagen was mixed with a half weight of alginate oligosaccharide (AO) or glucose and incubated at 60 °C and 35% relative humidity for up to 18 h to produce the Maillard-type glycated collagen (C-AO and C-Glu, respectively). As glycation progressed, the amount of conjugated sugar coupled with UV-vis absorbance at 294 nm and 420 nm increased more rapidly in C-Glu than in C-AO, and the available lysine decreased rapidly in C-Glu compared with C-AO. The early-to-middle- and late-stage products of the Maillard reaction were involved in enhanced antioxidant activity of digested C-AO and digested C-Glu, respectively. Additionally, C-AO acquired the antioxidant activity without marked available lysine loss. The cytoprotective effect of collagen in H2O2-induced damage was enhanced by glycation, achieved by reducing malondialdehyde content and increasing superoxide dismutase and catalase activities. These results indicate that AO is an excellent reducing sugar that enhances the health benefits of collagen without excessive loss of lysine, which is a nutritional problem of the Maillard-type glycation.

Tyrosinase inhibitory effects of the peptides from fish scale with the metal copper ions chelating ability

Tyrosinase inhibitors have important applications in the cosmetics, medical and food industries due to they can effectively inhibit the synthesis of melanin. In this study, tilapia scale polypeptides were used as raw materials, and high-purity polypeptides with metal copper ions chelating ability were obtained by enzymatic hydrolysis, column chromatography, and EDTA elution. In vitro cell model analysis showed that the fish squamous peptides could strongly inhibit the activity of tyrosinase. When the sample concentration was 5 mg·mL−1, its inhibition rate of tyrosinase reached to 59.73%, which had a better inhibition of enzyme activity compared with the positive control of the same concentration. The comprehensive results showed that the fish scale polypeptide with metal copper ions chelating ability could be a strong tyrosinase inhibitor, and might be used to prevent food browning in food-related fields, and could also be used for skin whitening in the fields of medicine and cosmetics.