Skin Of Unicorn Leatherjacket Research Articles

Characterization of gelatin obtained from unicorn leatherjacket (Aluterus monoceros) and reef cod (Epinephelus diacanthus) skins

The properties of gelatin oven dried at three different temperatures from unicorn leatherjacket (L50, L60 and L70) and reef cod skin (R50, R60 and R70) were investigated. The gelatin yield was higher in unicorn leatherjacket skin (12.2%) than reef cod skin (9.8%). Unicorn leatherjacket skin gelatin had a higher protein content of 88.0–88.61%, lower moisture (9.51–9.91%), fat (0.18–0.29%) and ash (0.60–0.71%) compared to reef cod skin gelatin which had 87–87.73% protein, 10.29–11.03% moisture, 0.23–0.31% fat and 0.69–0.73% ash. SDS-PAGE revealed all the gelatin samples had α and β chains. Gelatin samples had a good proportion of imino acid, hydrophobic and essential amino acid. Fourier transform infrared (FTIR) spectra showed the presence of amide regions in all the samples. Differential scanning calorimetry (DSC) showed a higher melting temperature in unicorn leatherjacket skin gelatin (115.54–120.80 °C) than reef cod skin (106.25–118.92 °C). Foaming capacity and stability and emulsion stability were higher in unicorn leatherjacket skin gelatin. Emulsion activity index, fat binding and water holding capacities were higher in reef cod skin gelatin. Different oven drying temperatures has not affect the yield and quality of gelatin. This study could pave the way to utilize oven drying for the extraction of gelatin from fish skin.

Production of Antioxidative Maillard Reaction Products from Gelatin Hydrolysate of Unicorn Leatherjacket Skin

ABSTRACTAntioxidative activities of Maillard reaction products (MRPs) derived from gelatin hydrolysate (GH) of unicorn leatherjacket skin as affected by types of saccharides, GH to saccharide ratio, incubation temperatures, relative humidity (RH), and times were investigated. MRPs prepared using mixture of GH and galactose at 2:1 (w/w) ratio showed the highest antioxidative activity. At different incubation temperatures (50–70°C) and RHs (55–75%), optimal condition for preparing antioxidative MRPs included heating GH and galactose (2:1) powder at 70°C and 55% RH for 36 h. Electrophoresis and Fourier transform infrared spectroscopy revealed the formation of high molecular weight polymers, and the advanced glycation took place in MRPs.

In vitro cellular bioactivities of Maillard reaction products from sugar-gelatin hydrolysate of unicorn leatherjacket skin system

The effects of Maillard reaction products (MRP), produced from galactose and a gelatin hydrolysate which was derived from unicorn leatherjacket skin, on in vitro cellular antioxidant activity, immunomodulatory properties and anti-cancer activity were investigated. MRP (750–1500 µg/mL) protected against H2O2-induced DNA damage in U937 cells. DNA damage was reduced by approximately 50% at the highest MRP concentration (1500 µg/mL). The activities of cellular antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) were decreased in HepG2 cells exposed to H2O2 but were induced in the presence of MRP. MRP reduced the production of pro-inflammatory cytokines (IL-1β and IL-6) and nitric oxide in LPS-induced RAW264.7 cells. The proliferation of colon carcinoma, Caco-2 cells was inhibited in the presence of MRP with an IC50 of 1.7 mg/mL. Therefore, MRP demonstrated bioactive potential through the suppression of oxidative stress and inflammation in vitro in addition to inhibiting the proliferation of human colon cancer cells.

Antioxidant, immunomodulatory and antiproliferative effects of gelatin hydrolysate from unicorn leatherjacket skin

The in vitro cellular bioactivities including, antioxidant, immunomodulatory and antiproliferative effects of a gelatin hydrolysate (GH) prepared from unicorn leatherjacket skin, using partially purified glycyl endopeptidase, were investigated in order to optimize the use of fish skin waste products as functional food ingredients. GH under the tested concentrations (750-1500 µg mL(-1) ) protected against H2 O2 -induced DNA damage in U937 cells. GH also protected against the H2 O2 -induced reduction in cellular antioxidant enzyme activities, superoxide dismutase and catalase, in HepG2 cells. GH demonstrated immunomodulatory potential by reducing pro-inflammatory cytokine (interleukin-6 (IL-6) and IL-1β) production and nitric oxide production in lipopolysaccharide-stimulated RAW 264.7 macrophage cells. Cell proliferation in human colon cancer (Caco-2) cells was significantly reduced in a dose-dependent manner following incubation with GH. These results indicate that GH has several bioactivities which support its potential as a promising functional food ingredient with various health benefits. © 2015 Society of Chemical Industry.

Antioxidative gelatin hydrolysate from unicorn leatherjacket skin as affected by prior autolysis

Gelatin hydrolysates from autolysed non-swollen and swollen unicorn leatherjacket skin prepared using partially purified glycyl endopeptidase (GE) from papaya latex were examined for their antioxidative activities. Autolysed swollen skin was more hydrolysed by GE as indicated by higher α-amino group content, compared with autolysed non-swollen skin. ABTS radical scavenging activity and ferric reducing antioxidant power (FRAP) of hydrolysates were increased with increasing levels of GE used. Antioxidative gelatin hydrolysate from autolysed skin, both non-swollen and swollen skins, using 8 % GE termed ‘NS-8GE’ and ‘SS-8GE’ exhibited different modes of action. When both hydrolysates were tested in lecithin liposome system, the efficiency in retardation of lipid oxidation was in a dose-dependent manner. Antioxidative activity of hydrolysates at 5.0 g/L was comparable to that of 0.1 g/L Trolox, in which the oxidation was almost completely inhibited. NS-8GE and SS-8GE also showed their antioxidative activities in gastrointestinal tract model system (GIMs). ABTS radical scavenging activity of both hydrolysates increased, but FRAP decreased in a duodenal condition. Based on size exclusion chromatography, major antioxidative peptides in NS-8GE and SS-8GE had molecular weight of 1,170 and 750 Da, respectively. Therefore, GE could enhance antioxidative activity of autolysed skin. Additionally, swelling process directly determined the modes of actions of resulting gelatin hydrolysates. NS-8GE had high ABTS radical scavenging activity, whereas SS-8GE showed high FRAP.

Cryoprotective and antioxidative effects of gelatin hydrolysate from unicorn leatherjacket skin

Cryoprotective properties of gelatin hydrolysates from autolysed non-swollen and swollen unicorn leatherjacket skin using partially purified glycyl endopeptidase (GE) from papaya latex were examined. Gelatin hydrolysates from autolysed non-swollen skin showed higher cryoprotective property in salt solution system than that from autolysed swollen skin as indicated by lower enthalpy for melting of eutectic and ice crystal. The cryoprotective effect of gelatin hydrolysate (0.5 and 1.0%) was in dose-dependent manner. Gelatin hydrolysate retarded physicochemical changes of natural actomyosin from washed mince system, as evidenced by lower changes in Ca2+-ATPase activity, surface hydrophobicity and disulfide bond formation, compared with the control. Based on DSC analysis, the enthalpy of myosin and actin was also higher in the presence of gelatin hydrolysate. Gelatin hydrolysate could prevent lipid oxidation in washed mince system as shown by lower TBARS value and less abundance of hexanal, heptanal and 1-pentene-3-ol.

Characteristics and Antioxidative Activity of Gelatin Hydrolysates from Unicorn Leatherjacket Skin as Affected by Autolysis-Assisted Process

ABSTRACT Autolysis-assisted process mediated by indigenous protease in combination withthermal hydrolysis and hydrolysis using papain was used for production of gelatinhydrolysate from skin of unicorn leatherjacket. Prior autolysis could enhance theyield and antioxidative activity of gelatin hydrolysates, especially when subsequenthydrolysis by 2% papain was implemented (AU + HP2.0). Hydrolysates possessedABTS (2,2′-azinobis-[3-ethylbenzothiazoline-6-sulfonic acid]) radical and H 2 Oscavenging activities as well as metal chelating activity. AU + HP2.0 and gelatinhydrolysate prepared using papain without prior autolysis (HP2.0) could retardoxidation in lecithin liposome system, and antioxidative activity of hydrolysatesat 10.0 g/L was comparable to that of 0.1 g/L Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), in which the oxidation was almost com-pletely inhibited. On the basis of size exclusion chromatography, antioxidativepeptideinAU+ HP2.0 had molecular weight of 2200 Da. Therefore, autolysis-assisted process showed the potential for the production of gelatin hydrolysateswith enhanced antioxidative activity.

Antioxidant Activity of Gelatin Hydrolysate Produced from Fish Skin Gelatin Using Extracellular Protease fromBacillus amyloliquefaciens H11

Antioxidant activities of gelatin hydrolysates (GHs) from unicorn leatherjacket skin prepared using extracellular protease from Bacillus amyloliquefaciens H11 (GH-H11) with different degrees of hydrolysis (DHs) were comparatively studied with those of hydrolysate produced using Alcalase (GH-Al). Antioxidative activities of hydrolysates produced by both proteases increased with increasing DH (P 0.05). Both hydrolysates (100 and 1,000 ppm) could inhibit lipid peroxidation in lecithin liposome system in a dose-dependent manner. In vitro simulated gastrointestinal digestion study indicated that the antioxidative activity of GH was not affected by pepsin, while further hydrolysis by pancreatin enhanced the antioxidative activity. The dominant antioxidative peptides in GH-H11 and GH-Al had molecular weights of approximately 750 and 3,600 Da, respectively.

Impact of divalent salts and bovine gelatin on gel properties of phosphorylated gelatin from the skin of unicorn leatherjacket

The impact of zinc chloride (ZnCl2) and calcium chloride (CaCl2) as well as bovine gelatin (BG) on the gel strength of phosphorylated fish gelatin (PFG) from the skin of unicorn leatherjacket was investigated. The gel strength of PFG increased with increasing concentrations of ZnCl2 and CaCl2 (2.5–40 μmol L−1). A higher gel strength was observed with CaCl2, compared with ZnCl2. The gel strength of PFG with 20 μmol L−1 CaCl2 increased by 15.7%, compared to the control gel. Nevertheless, at higher concentration (40 μmol L−1) of both salts, gel strength of PFG decreased. Hardness of gels decreased with increasing PFG content (P < 0.05). Nevertheless, no differences in hardness were found amongst gels with BG/PFG ratios of 4:0 and 3:1 (P ≥ 0.05). Thus, PFG could be used in combination with CaCl2 to substitute for BG at a level of 25%.

Characteristics and gelling property of phosphorylated gelatin from the skin of unicorn leatherjacket

The characteristics and gelling property of gelatin from the skin of unicorn leatherjacket, phosphorylated with sodium tripolyphosphate (STPP) at various concentrations (0.25%, 0.50%, 0.75% and 1.00% w/w), for different times (1 and 3h) at 65°C, were studied. With the increase of STPP concentration and time, no increase in bound phosphate was observed. The highest gel strength was obtained for gelatin phosphorylated using 0.25% STPP for 1h (P<0.05). When the effect of pH (5, 7, 9 and 11) on phosphorylation and gel property of gelatin was investigated, gelatin phosphorylated at pH 9 had the highest gel strength (204.3g) (P<0.05) and exhibited a finer and more compact network structure with smaller pores. Gelatin became negatively charged (−3.89mV) and might undergo an ionic interaction to a higher extent, thereby strengthening the gel network. Thus, the phosphorylation, under the appropriate condition, could improve the gelling property of gelatin from the skin of unicorn leatherjacket.

Effect of phosphorylation on gel properties of gelatin from the skin of unicorn leatherjacket

Phosphorylation of gelatin from the skin of unicorn leatherjacket was carried out by incorporating sodium tripolyphosphate (STPP) at varying concentrations during pretreatment and extraction. Phosphate attached to gelatin during pretreatment and extraction was found at levels of 12.43 and 18.25 μmol/g, respectively. Based on zeta potential analysis, phosphorylated gelatin became negatively charged, reconfirming the charge modification mediated by phosphorylation. For gelatin phosphorylated during pretreatment, that using 0.2% STPP had the highest gel strength (128.3 g). Amongst all gelatins incorporated with STPP during extraction, that added with 0.08% STPP showed the highest gel strength (146.0 g). Slight differences in FTIR spectra were observed when gelatin was phosphorylated, compared with the control gelatin. Gel of gelatin phosphorylated with 0.08% STPP during extraction exhibited a finer and more compact structure with smaller pores and was able to set at 4 °C at the fastest rate, compared with other gelatins. Thus, the phosphorylation under the appropriate condition could improve gelling property of gelatin from skin of unicorn leatherjacket.

Optimisation of gelatin extraction from Unicorn leatherjacket (Aluterus monoceros) skin waste: response surface approach.

Physical properties of gelatin extracted from Unicorn leatherjacket (Aluterus monoceros) skin, which is generated as a waste from fish processing industries, were optimised using Response Surface Methodology (RSM). A Box-Behnken design was used to study the combined effects of three independent variables, namely phosphoric acid (H3PO4) concentration (0.15-0.25M), extraction temperature (40-50°C) and extraction time (4-12h) on different responses like yield, gel strength and melting point of gelatin. The optimum conditions derived by RSM for the yield (10.58%) were 0.2M H3PO4 for 9.01h of extraction time and hot water extraction of 45.83°C. The maximum achieved gel strength and melting point was 138.54g and 22.61°C respectively. Extraction time was found to be most influencing variable and had a positive coefficient on yield and negative coefficient on gel strength and melting point. The results indicated that Unicorn leatherjacket skins can be a source of gelatin having mild gel strength and melting point.

Physicochemical and functional properties of gelatin from the skin of unicorn leatherjacket (Aluterus monoceros) as affected by extraction conditions

Abstract Physicochemical and functional properties of gelatin from the skin of unicorn leatherjacket extracted at different temperatures for various times were determined. Yield, recovery and free amino group content of gelatin increased, but gel strength generally decreased as the extraction temperature and time increased (P

Molecular and functional properties of gelatin from the skin of unicorn leatherjacket as affected by extracting temperatures

Gelatins extracted from the skin of unicorn leatherjacket at different temperatures (45, 55, 65 and 75°C) in the presence and the absence of soybean trypsin inhibitor (SBTI; 100units/g pretreated skin) for 12h were characterised. In general, the addition of SBTI resulted in the lower yield, regardless of extraction temperature. Higher yield was obtained when higher extraction temperature was used (P<0.05). Gelatin from skin extracted at 75°C in the absence of SBTI showed the highest yield (10.66±0.41%) (based on dry weight). The highest α-amino group content was observed in gelatin extracted at 55°C without SBTI incorporated. The band intensity of β-chain and α-chains increased as the extraction temperature increased, particularly above 55°C. Gelatin extracted at 65°C with and without SBTI incorporation exhibited the highest gel strength (178.00±7.50g and 170.47±1.30g, respectively). FTIR spectra indicated that a greater loss of molecular order of triple helix with a higher degradation was found in gelatin extracted at 55°C in the absence SBTI. Gelatin extracted at 65°C, either with or without SBTI, had the highest EAI and ESI with high foam expansion and stability. Thus, the extraction of gelatin from the skin of unicorn leatherjacket at temperature sufficiently high could render the gelatin with less degradation.

Physico-mechanical and antimicrobial properties of gelatin film from the skin of unicorn leatherjacket incorporated with essential oils

Gelatin films incorporated with bergamot (BO) and lemongrass oil (LO) at various concentrations as glycerol substitute were prepared and characterised. Incorporation of BO and LO at 5–25% (w/w protein) resulted in the decreases in both tensile strength (TS) and elongation at break (EAB) of the films. Water vapour permeability (WVP) were decreased in LO incorporated films, while it was increased in film added with BO at level higher than 5% (P < 0.05). Film solubility and transparency values decreased, and the films had the lowered light transmission in the visible range when BO and LO were incorporated. Films incorporated with LO showed inhibitory effect in a concentration dependent manner against Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Salmonella typhimurium, but BO added film inhibited only L. monocytogenes and S. aureus. Films containing both BO and LO did not inhibit Pseudomonas aeruginosa. Significant change of molecular organisation and higher intermolecular interactions among gelatin molecules were found in the film structure as determined by FTIR. Thermo-gravimetric analysis (TGA) demonstrated that films added with BO and LO exhibited enhanced heat stability with higher degradation temperature, compared with control film. Scanning electron microscopic (SEM) images revealed the presence of micro-pores in the essential oil incorporated films, which contributed to physical properties of the resulting films. Thus, gelatin films incorporated with BO and LO can be used as active packaging, but the properties could be modified, depending on essential oil added.

Impact of legume seed extracts on degradation and functional properties of gelatin from unicorn leatherjacket skin

Trypsin inhibitor was extracted from the seed flour of soybean (SB; Glycine max), mung bean (MB; Vigna radiata), cowpea bean (CP; Vigna unguiculata) and adzuki bean (AB; Vigna angularis) using 0.15M NaCl, followed by heat precipitation at 70°C. The extract from SB showed the highest specific trypsin inhibitory activity, followed by those from MB, CP and AB, respectively. Based on inhibitory activity staining, molecular weights (MWs) of trypsin inhibitor from SB, MB, CP and AB were 20.1, 14, 10 and 13kDa, respectively. The SB extract powder (SBEP) containing trypsin inhibitor in the range of 10–100TIU/g effectively prevented the degradation of γ-, β- and α-chains of collagenolytic proteins of leatherjacket skin subjected to incubation at 50°C for 30min. The impact of SBEP on the extraction yield, physical and functional properties of gelatin from leatherjacket skin was investigated. The gelatin extracted in the presence of SBEP contained α1 and α2 chains as the predominant components with some degradation peptides. FTIR spectra indicated the significant loss of molecular order of triple helix and higher degradation was found in gelatin extracted in the absence of SBEP. Gelatin extracted in the presence of SBEP had the higher gel strength (232.8–268.5g) than that extracted in the absence of SBEP (90.4g). Higher foam stability (FS) but lower emulsion stability index (ESI) was observed in the former. Therefore, the addition of SBEP effectively prevented the degradation of gelatin from the skin of unicorn leatherjacket, thereby yielding the gelatin with improved gel strength and foam stability.

Indigenous proteases in the skin of unicorn leatherjacket (Alutherus monoceros) and their influence on characteristic and functional properties of gelatin

Indigenous proteases in the skin of unicorn leatherjacket (Alutherus monoceros) were characterised using autolytic study. Maximised autolysis was found at pH 7 and 50°C. Autolysis was markedly inhibited by 0.04mM soybean trypsin inhibitor (SBTI), suggesting that heat activated serine protease was predominant in the skin. The impact of indigenous proteases on the properties of gelatin extracted from unicorn leatherjacket skin was investigated. Gelatin was extracted from unicorn leatherjacket skin using distilled water at 50°C for 12h in the presence and absence of 0.04mM SBTI. In the presence of SBTI, the degradation was markedly inhibited, but a lower gelatin extraction yield was obtained (P<0.05). Extracted gelatins contained α1 and α2 chains as the predominant components with some degradation peptides. FTIR spectra indicated a greater loss of molecular order of the triple helix and a higher degradation was found in gelatin extracted in the absence of 0.04mM SBTI. The net charge of gelatin samples extracted with and without 0.04mM SBTI became zero at pHs of 8.45 and 7.31, respectively, as determined by ζ-potential titration. Higher gel strength (320.68±3.02g) was obtained in gelatin extracted with SBTI, compared with that of gelatin extracted without SBTI (288.63±1.44g). High emulsifying activity index but lower emulsifying stability index was observed in the former. Therefore, heat-activated serine protease was involved in the degradation of gelatin molecules, thereby affecting the yield, proteinaceous components and properties of gelatin from unicorn leatherjacket skin.

Characteristics of gelatin from the skin of unicorn leatherjacket ( Aluterus monoceros) as influenced by acid pretreatment and extraction time

Gelatins from the skin of unicorn leatherjacket ( Aluterus monoceros) pretreated with different acids (0.2 M acetic acid or 0.2 M phosphoric acid) and extracted with distilled water at 45 °C for various times (4 and 8 h) were characterized. Yields of 5.23–9.18 or 6.12–11.54% (wet weight basis) were obtained for gelatins extracted from the skin pretreated with 0.2 M acetic acid or 0.2 M phosphoric acid, respectively. Extracted gelatins contained α 1 and α 2 chains as the predominant components and some degradation peptides. The absorption bands of gelatins in FTIR spectra were mainly situated in the amide band region (amide I, amide II and amide ІІІ) and showed the significant loss of molecular order of triple helix. Gelatin samples had a relative solubility greater than 90% in the wide pH ranges (1–10). The gel strength of gelatin from skin pretreated with phosphoric acid (GPA) was higher than that of gelatin from skin pretreated with acetic acid (GAA). Both GPA and GAA had the lower gel strength than that of commercial bovine gelatin ( P < 0.05). Net charge of GAA and GPA became zero at pHs of 6.64–7.15 and 6.78–7.26, respectively, as determined by zeta potential titration. Emulsifying and foaming properties of GAA and GPA increased with increasing concentrations (1–3%, w/v). Those properties were governed by pretreatments and extraction time. Thus gelatin can be successfully extracted from unicorn leatherjacket skin using the appropriate acid pretreatment and extraction time.

Compositional and physicochemical characteristics of acid solubilized collagen extracted from the skin of unicorn leatherjacket (Aluterus monoceros)

Abstract Acid solubilized collagen (ASC) was extracted from the skin of unicorn leatherjacket ( Aluterus monoceros ) using 0.5 M acetic acid, followed by precipitation with 2.6 M NaCl. ASC with the yield of 4.19% (wet weight basis) was identified as type I collagen, which was composed of two α 1 chains and one α 2 chain. Different peptide maps were observed between ASC hydrolyzed by V8 protease and lysyl endopeptidase. The maps were also different from those of type I collagen from calf skin, suggesting the differences in amino acid sequences between both collagens. Glycine was the most predominant amino acid. ASC contained the relatively higher content of alanine, but lower contents of proline and hydroxyproline, compared with calf skin collagen. FTIR analysis showed that ASC was in triple helix structure. T max of ASC dispersed in 0.05 M acetic acid and deionized water were 27.7 and 35.8 °C, respectively. Relative viscosity of 0.03% (w/v) ASC dissolved in 0.1 M acetic acid decreased continuously as the temperature increased from 4 to 52 °C, indicating thermal destabilization or denaturation of ASC molecules. ASC had the solubility greater than 90% in very acidic pH range (pH 1–4) and the solubility decreased continuously with increasing NaCl concentrations (0–6%). Net charge of ASC and calf skin collagen became zero at pHs of 5.58 and 5.68, respectively as determined by zeta potential titration. Therefore, skin of unicorn leatherjacket can be used as an alternative collagenous source.

Extraction and characterisation of pepsin-solubilised collagen from the skin of unicorn leatherjacket ( Aluterus monocerous)

Pepsin-solubilised collagen (PSC) was extracted from the skin of unicorn leatherjacket ( Aluterus monocerous), using 0.5 M acetic acid in the presence of pepsin from albacore tuna, yellowfin tuna or porcine pepsin at a level of 20 units/g of defatted skin. Yields of 8.48 ± 0.3%, 8.40 ± 0.3% and 7.56 ± 0.4% (wet weight basis) were obtained for PSC extracted with the aid of albacore tuna pepsin (APSC), yellowfin tuna pepsin (YPSC) and porcine pepsin (PPSC), respectively. All PSCs were classified as Type I collagen containing two α 1-chains and one α 2-chain with no disulphide bond. The peptide maps of different PSCs hydrolysed by V8 protease and lysyl endopeptidase were different. ATR-FTIR spectra analysis revealed that PSC molecules had the compact triple helical structure stabilised mainly by the hydrogen bond. T max of all PSCs (31.68–31.98 °C) shifted to lower values (29.33–29.40 °C) when dispersed in 0.05 M acetic acid, indicating the conformational changes in the collagen structure induced by acid. Relative viscosity of 0.03% PSC in 0.1 M acetic acid solution decreased progressively as the temperature increased from 4 to 52 °C, indicating thermal destabilisation or denaturation of PSC molecules. All PSCs were soluble in the pH range of 1–6 and sharply decreased at neutral pH. Decreases in solubility were observed in the presence of NaCl, especially at concentrations above 2% (w/v). Therefore, the skin of unicorn leatherjacket could serve as a potential source of collagen.