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1.
Fish skin gelatin was extracted from the skin of bigeye snapper (Priacanthus macracanthus) and brownstripe red snapper (Lutjanus vitta) with yields of 6.5% and 9.4% on the basis of wet weight, respectively. Both skin gelatins having high protein but low fat content contained high hydroxyproline content (75.0 and 71.5 mg/g gelatin powder). The bloom strength of gelatin gel from brownstripe red snapper skin gelatin (218.6 g) was greater than that of bigeye snapper skin gelatin (105.7 g) (P<0.05). The addition of microbial transglutaminase (MTGase) at concentrations up to 0.005% and 0.01% (w/v) increased the bloom strength of gelatin gel from bigeye snapper and brownstripe red snapper, respectively (P<0.05). However, the bloom strength of skin gelatin gel from both fish species decreased with further increase in MTGase concentration. SDS-PAGE of gelatin gel added with MTGase showed the decrease in band intensity of protein components, especially, β- and γ- components, suggesting the cross-linking of these components induced by MTGase. Microstructure studies revealed that denser and finer structure was observed with the addition of MTGase.  相似文献   

2.
The effects of fatty acids (FA) [palmitic acid (PA) and stearic acid (SA)] and their sucrose esters (FASE) on the mechanical properties, water vapor permeability (WVP), light transmission, and color of films from bigeye snapper and brownstripe red snapper skin gelatins were investigated. Tensile strength (TS) of films generally decreased with the addition of FA (p<0.05), while gradually increased with increasing FASE amount (p<0.05). WVP of films generally decreased with increasing amount of FA or FASE (p<0.05). However, films containing FASE exhibited the superior WVP barrier property to those added with FA. Marked increase in elongation at break (EAB) was observed when either FA or FASE at a level of 25% substitution was incorporated. Light transmission of films in both UV (200–280 nm) and visible ranges (350–800 nm) decreased with increasing FA amount. Films added with FASE were generally more transparent than those with FA. Chain length of FA or FASE affected the properties of films differently, depending upon gelatin sources. Therefore, the properties of fish skin gelatin-based films, especially water vapor barrier, could be improved by the addition of FA or FASE.  相似文献   

3.
Proteolytic activity of pyloric caeca extract (PCE) from bigeye snapper (Priacanthus macracanthus) was studied. The highest activity was observed at 55 °C and pH 8.0 when casein, Nα-Benzoyl-dl-arginine-p-nitroanilide (BAPNA) and Nα-p-Tosyl-l-arginine methyl ester hydrochloride (TAME) were used as the substrates. The activity was inhibited markedly by 1 mg/ml soybean trypsin inhibitor, whereas E-64, pepstatin A and EDTA exhibited a negligible effect on activity. The results suggested that a trypsin-like enzyme was most likely the major proteinase in PCE. As determined by activity staining, two proteolytic activity bands with apparent molecular weights of 55 and 24 kDa were found. Gelatin hydrolysate from bigeye snapper skin prepared using PCE exhibited the increases in 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities and ferric reducing antioxidative power (FRAP) as degrees of hydrolysis (DHs) increased (P < 0.05). Hydrolysates derived from gelatin using Alcalase combined with PCE showed the highest ABTS radical scavenging activity (P < 0.05). Gelatin hydrolysate prepared using Alcalase in combination with Neutrase or PCE at 500 and 1000 ppm, respectively, retarded the oxidation in both linoleic acid oxidation and lecithin liposome oxidation systems. The antioxidative peptide of gelatin hydrolysate had a molecular weight of 1.7 kDa.  相似文献   

4.
Porcine plasma protein (PPP) showed inhibitory activity towards trypsin, papain, digestive enzymes and modori‐inducing proteinases from bigeye snapper. Among the fractions prepared, fraction IV‐1 exhibited the highest inhibitory activity against all proteinases tested and the autolysis of fish muscle. At a level of 0.5% (w/w), both PPP and fraction IV‐1 effectively prevented the degradation of myosin heavy chain in fish muscle. The inhibitory activity of fraction IV‐1 was stable up to 60 °C. Incorporation of fraction IV‐1 significantly increased the breaking force, deformation and water‐holding capacity of surimi gel from bigeye snapper (P < 0.05). However, no increase in breaking force and deformation was found when fraction IV‐1 was added at a level above 0.3% (w/w) (P > 0.05). No significant change in whiteness of surimi gel was observed with the addition of fraction IV‐1 (P > 0.05). © 2001 Society of Chemical Industry  相似文献   

5.
Properties of film from cuttlefish (Sepia pharaonis) ventral skin gelatin with different degree of hydrolysis (DH: 0.40, 0.80 and 1.20%) added with glycerol as plasticizer at various levels (10, 15 and 20%, based on protein) were investigated. Films prepared from gelatin with all DH had the lower tensile strength (TS) and elongation at break (EAB) but higher water vapor permeability (WVP), compared with the control film (without hydrolysis) (p < 0.05). At the same glycerol content, both TS and EAB decreased, while WVP increased (p < 0.05) with increasing %DH. At the same DH, TS generally decreased as glycerol content increased (p < 0.05), however glycerol content had no effect on EAB when gelatins with 0.80 and 1.20% DH were used (p > 0.05). DH and glycerol content had no marked impact on color and the difference in color (ΔE) of resulting films. Electrophoretic study revealed that degradation of gelatin and their corresponding films was more pronounced with increased %DH, resulting in the lower mechanical properties of films. Based on FTIR spectra, with the increasing %DH as well as glycerol content, higher amplitudes for amide-A and amide-B peaks were observed, compared with film from gelatin without hydrolysis (control film) due to the increased –NH2 group caused by hydrolysis and the lower interaction of –NH2 group in the presence of higher glycerol. Thermo-gravimetric analysis indicated that film prepared from gelatin with 1.20% DH exhibited the higher heat susceptibility and weight loss in the temperature range of 50–600 °C, compared with control film. Thus, both chain length of gelatin and glycerol content directly affected the properties of cuttlefish skin gelatin films.  相似文献   

6.
Different kinds of plasticizers were chosen to study the effects of plasticizer composition, size and shape on the mechanical properties and water vapor permeability (WVP) of gelatin films in this paper. Firstly, oligosaccharides – sucrose, and some organic acids such as oleic acid, citric acid, tartaric acid, malic acid (MA) were added to gelatin. It was found that only MA could improve the ductility of gelatin film, and the visual appearance of MA modified gelatin film was better. Secondly, polyethylene glycols (PEG) with different molecular weights (300, 400, 600, 800, 1500, 4000, 10?000, 20?000) were used to plasticize gelatin films. This showed that PEG of lower molecular weights exhibited better plasticizing effect for gelatin films, and such films had better visual properties. This shows that mannitol (Man) and sorbitol (Sor) could make gelatin films flexible, whereas Man could crystallize from gelatin film. Following this, the plasticization of ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG) series and ethanolamine (EA), diethanolamine (DEA), triethanolamine (TEA) series was studied. At last, suitable plasticizers (MA, PEG300, sorbitol, EG, DEG, TEG, EA, DEA, TEA) for gelatin were selected to investigate the WVP and water content of these plasticized gelatin films. The mechanical properties of these films were also compared.  相似文献   

7.
Acid‐solubilized collagen (ASC) and pepsin‐solubilized collagen (PSC) were isolated from the skin of bigeye snapper (Priacanthus macracanthus) with yields of 64 and 11 g kg?1 wet weight, respectively. Both ASC and PSC were characterized as type I collagens with no disulfide bonds. Peptide maps of ASC and PSC digested by V8 protease and lysyl endopeptidase showed some differences in peptide patterns and were totally different from those of calf skin collagen. The maximum solubility was observed at pH 4 and 5 for ASC and PSC, respectively. A sharp decrease in solubility of both collagens in acetic acid was found with NaCl concentration above 30 g l?1. Thermal transitions of ASC and PSC in deionized water were observed with Tmax of 30.37 and 30.87 °C, respectively, and were lowered in the presence of acetic acid (0.05 mol kg?1 solution). Therefore, ASC was a major fraction in bigeye snapper skin and it exhibited some different characteristics to PSC. Copyright © 2005 Society of Chemical Industry  相似文献   

8.
Physical and mechanical properties of edible films based on blends of sago starch and fish gelatin plasticized with glycerol or sorbitol (25%, w/w) were investigated. Film forming solutions of different ratios of sago starch to fish gelatin (1:0, 2:1, 3:1, 4:1, and 5:1) were used and cast at room temperature. Amylose content of sago starch was between 32 and 34% and the protein content of the fish gelatin was found to be 81.3%. The findings of this study showed that the addition of fish gelatin in starch solutions has a significant effect (p < 0.05), resulting in films with lower tensile strength (TS) and higher water vapor permeability (WVP). On the other hand, increasing protein content (from 10.9% to 21.6%) in film samples plasticized with sorbitol showed significantly lower (p < 0.05) TS but no trend was observed in % elongation-at-break (EAB) and no differences in WVP. However, TS decreased with higher protein content in the samples when either plasticizers were used in general, but no significance differences was observed among the samples (p < 0.05) with glycerol with exception to film with high protein content (21.6%) only and no trend was observed in % EAB among samples as well. Significant difference (p < 0.05) was observed in TS and viscosity between different formulations with sorbitol. The morphology study of the sago starch/fish gelatin films showed smoother surfaces with decreasing protein in the samples with either plasticizer. DSC scans showed that plasticizers and protein content incorporated with sago starch films reduced the glass transition temperature (Tg) and melting temperature (Tm) and the melting enthalpy (ΔHm). In this study, observation of a single Tg is an indication of the compatibility of the sago starch and fish gelatin polymers to form films at the concentration levels used.  相似文献   

9.
BACKGROUND: Fish collagen has been paid increasing attention as an alternative to the mammalian counterpart owing to the abundance of fish skin as a processing by‐product. Generally, the low yield of collagen extracted using the typical acid solubilisation process has led to the use of mammalian pepsin as an aid for increasing the yield. Alternatively, fish pepsin, especially from tuna stomach, can be used for the extraction of pepsin‐solubilised collagen (PSC). Therefore the objective of this study was to extract and characterise PSC from the skin of bigeye snapper, a fish widely used for surimi production in Thailand. RESULTS: PSCs from the skin of two species of bigeye snapper, Priacanthus tayenus and Priacanthus macracanthus, were extracted with the aid of tongol tuna (Thunnus tonggol) pepsin and porcine pepsin. PSCs from the skin of both species extracted using porcine pepsin had a higher content of β‐chain but a lower content of α‐chains compared with those extracted using tuna pepsin. All PSCs contained glycine as the major amino acid and had an imino acid (proline and hydroxyproline) content of 189–193 residues per 1000 residues. Transition temperatures of PSCs were in the range 30.6–31.3 °C. Fourier transform infrared spectra revealed some differences in molecular order between PSCs extracted using porcine pepsin and tuna pepsin. Nevertheless, the triple‐helical structure of PSCs was not affected by pepsin digestion. Zeta potential analysis indicated that PSCs from P. tayens and P. macracanthus possessed zero net charge at pH 7.15–7.46 and 5.97–6.44 respectively. CONCLUSION: Tongol tuna pepsin could be used as a replacement for mammalian pepsin in PSC extraction. However, a slight difference in PSC properties was found. Copyright © 2009 Society of Chemical Industry  相似文献   

10.
Jang Woo Park  Seung Yong Cho 《LWT》2008,41(4):692-700
Gelatin-based edible films were produced by extruding hot melt of gelatin-based resins through a die with slot orifice and followed by heat-pressed method. The resins were plasticized with glycerol, sorbitol and the mixture of glycerol and sorbitol (MGS). The effect of type of plasticizer on extruded and heat-pressed (EHP) film-forming capacity was studied, and the mechanical and water barrier properties of resulting EHP gelatin films were compared with those of gelatin films prepared by solution casting method. Stretchable films were formed when glycerol or MGS were used as plasticizer, whereas resins plasticized with sorbitol were extruded in non-stretchable sheets. Glycerol plasticized gelatin film showed the highest flexibility and transparency among the EHP films tested. Tensile strength (TS), elongation (E) and water vapor permeability (WVP) of glycerol plasticized EHP gelatin films were 17.3 MPa, 215.9% and 2.46 ng m/m2 s Pa, respectively, and EHP gelatin films had higher E values, lower TS values and higher WVP values compared to the glycerol plasticized cast gelatin films.  相似文献   

11.
The functional properties of pH-shifted protein isolates from bigeye snapper head were evaluated. Alkaline isolate showed a superior salt-solubility and gel forming ability to acid counterpart as indicated by a regular gel structure (i.e., imaged by scanning electron microscope) with higher gel strength and lower expressible drip (p < 0.05). Acid isolate exhibited higher surface hydrophobicity (p < 0.05) and thereby improved interfacial properties. Emulsifying activity index of acid isolate was lower than commercial whey protein and egg-white (p < 0.05) but its emulsion stability was better (p < 0.05). Both protein isolates had lower foamability than commercial proteins but their foam stability was not different (p > 0.05).  相似文献   

12.
Gelling characteristics of bigeye snapper (Priacanthus tayenus) surimi functionalised by lecithin at different concentrations were investigated. Lecithin at ≤1 g 100 g−1 had no impact on breaking force and deformation (> 0.05). Expressible drip tended to decrease with increasing lecithin level up to 1 g 100 g−1. Lecithin at 1–3 g 100 g−1 improved the whiteness (P < 0.05). Jointed clusters were formed in the gel microstructure with 1 g 100 g−1 lecithin. Gel without and with 1 g 100 g−1 lecithin had the same texture profile and likeness scores (texture, odour and flavour) (> 0.05). Peroxide value, TBARS content and rancid odour score of gels were changed considerably during refrigerated storage (4 °C/polyethylene bag) for 15 days but lower values of all indices were noticeable in gel with lecithin. Therefore, lecithin at 1 g 100 g−1 was the optimum concentration for stabilising the texture, improving the water holding capacity, whitening the colour and retarding the lipid oxidation of bigeye snapper surimi gel.  相似文献   

13.
Effects of the ratios of fish myofibrillar protein (FMP) from bigeye snapper (Priacanthus tayenus) to polyvinyl alcohol (PVA) (FMP:PVA; 10:0, 8:2, 6:4, 5:5, 4:6, 2:8, 0:10) and pH levels (3 and 11) on the properties of resulting films were investigated. Both tensile strength (TS) and elongation at break (EAB) of films increased with increasing PVA content (p < 0.05). When PVA was incorporated up to 40%, films prepared at pH 11 had the higher TS than did those prepared at pH 3 (p < 0.05). However, as PVA content was greater than 40%, films prepared at pH 3 exhibited the higher TS than did those prepared at pH 11 (p < 0.05). Water vapor permeability (WVP) of the films prepared at pH 3 increased when PVA content increased up to 40% and decreased with further increases in PVA content (p < 0.05). PVA films had the higher TS, EAB and WVP than did FMP films and FMP/PVA blend films prepared at both pHs. Films exhibited the increased L∗ and a∗ values but decreased b∗ value with increasing PVA content at both pHs. Films prepared at pH 11 showed higher b∗ value than did those prepared at pH 3 when PVA content was greater than 40% (p < 0.05). FMP/PVA blend films exhibited the negligible transmission to the UV light. At pH 3, light transmission of the films increased as PVA content increased (p < 0.05). At all FMP/PVA ratios, films prepared at pH 11 were less transparent than those prepared at pH 3 (p < 0.05). Therefore, blend composition and pH level influenced the properties of FMP/PVA blend films.  相似文献   

14.
The influence of iced storage of two species of bigeye snapper, Priacanthus tayenus and P macracanthus, on the gel‐forming ability of the resulting surimi was investigated. Upon iced storage, whole fish underwent deterioration faster than beheaded/eviscerated fish. Total volatile base and trimethylamine contents of whole fish were higher than those of beheaded/eviscerated fish, particularly after 9 days of storage (P < 0.05). P macracanthus muscle was more susceptible to proteolytic degradation than P tayenus muscle. Ca2+‐ATPase activity decreased as the storage time increased (P < 0.05), indicating the denaturation of myosin. A marked decrease in Ca2+‐ATPase activity was found in whole fish kept for more than 6 days in ice (P < 0.05). Breaking force and deformation of surimi gels from both species decreased, with a concomitant decrease in whiteness, as the storage time increased (P < 0.05). Beheading and evisceration of fish retarded the deterioration. However, the gel‐forming ability of surimi produced from both species decreased continuously throughout iced storage (P < 0.05), probably owing to the denaturation and degradation of myofibrillar proteins. © 2002 Society of Chemical Industry  相似文献   

15.
Properties of film from cuttlefish (Sepia pharaonis) ventral skin gelatin without and with partial hydrolysis (1.2% degree of hydrolysis) incorporated with 1% ethanolic extract of cinnamon (CME), clove (CLE) and star anise (SAE) were determined. Films with different herb extracts (without and with oxidation) had higher tensile strength (TS) but lower elongation at break (EAB), compared with the control film (without addition of herb extracts) (p < 0.05). Lower water vapor permeability (WVP) and L-value but higher b- and ΔE-values were observed when the extracts were incorporated (p < 0.05). Electrophoretic study revealed that cross-linking was pronounced in films containing different herb extracts. Oxidized extracts yielded films with higher TS and WVP than those without oxidized herb extracts (p < 0.05). Generally, similar properties were noticeable for films from gelatin with and without partial hydrolysis. Nevertheless, higher mechanical properties were obtained for the latter. FTIR spectra indicated that protein–polyphenol interactions were involved in the film. Thermo-gravimetric analysis revealed that films incorporated with SAE or SAE with oxidation (OSAE) exhibited lower heat susceptibility and weight loss in the temperature range of 50–600 °C, compared with control film. Films with SAE and OSAE had smoother surface for gelatin without hydrolysis; however, coarser surface was observed in film from gelatin with partial hydrolysis. Thus, the incorporation of different herb extracts directly affected the properties of film from cuttlefish skin gelatin with and without hydrolysis.  相似文献   

16.
Gelatins extracted from the skins containing fine scales of two species of bigeye snapper, Priacanthus tayenus (GT) and Priacanthus macracanthus (GM), were characterised. Both gelatins had the protein as the major component with high content of imino acids (proline & hydroxyproline) (186.29–187.42 mg/g). GT and GM contained calcium at levels of 6.53 and 2.92 g/kg, respectively. Both gelatins contained α1 and α2 chains as the predominant components and some degradation peptides. The absorption bands of both gelatins in Fourier transform infrared (FTIR) spectra were mainly situated in the amide band region (amide I and amide II). GT and GM had a relative solubility greater than 90% in the wide pH ranges (1–10). The bloom strength of GM (254.10 g) was higher than that of GT (227.73 g) (P < 0.05), but was slightly lower than that of commercial bovine gelatin (293.22 g) (P < 0.05). Finer gel structure with smaller strands and voids was observed in GM gel, in comparison with that observed in GT counterpart.  相似文献   

17.
Tensile strength (TS), percent elongation (%E), oxygen permeability (OP), and water vapor permeability (WVP) of lactic acid and rennet precipitated casein-based edible films were studied to determine the effect of protein to plasticizer ratio (0.6:1, 1:1, 1.4:1) and plasticizer type (sorbitol, glycerol) on these properties. TS increased (p<0.05) with increase in protein to plasticizer ratio. Sorbitol plasticized films were stronger (p<0.05) than glycerol plasticized films. However, films plasticized with glycerol were more extensible (p<0.05). Film %E decreased with increase in protein/plasticizer ratio for lactic acid casein films, whereas it increased for rennet casein films. Films plasticized with sorbitol were more effective (p<0.05) moisture and oxygen barriers than glycerol plasticized films. Overall, lactic acid casein films plasticized with sorbitol had the most effective mechanical and barrier properties.  相似文献   

18.
Properties of protein-based film from fish skin gelatin incorporated with different citrus essential oils, including bergamot, kaffir lime, lemon and lime (50% based on protein) in the presence of 20% and 30% glycerol were investigated. Films containing 20% glycerol had higher tensile strength (TS) but lower elongation at break (EAB), compared with those prepared with 30% glycerol, regardless of essential oils incorporated (< 0.05). Films incorporated with essential oils, especially from lime, at both glycerol levels showed the lower TS but higher EAB than the control films (without incorporated essential oil) (< 0.05). Water vapour permeability (WVP) of films containing essential oils was lower than that of control films for both glycerol levels (< 0.05). Films with essential oils had varying ΔE* (total colour difference), where the highest value was observed in that added with bergamot essential oil (< 0.05). Higher glycerol content increased EAB and WVP but decreased TS of films. Fourier transforms infrared (FTIR) spectra indicated that films added with essential oils exhibited higher hydrophobicity with higher amplitude at wavenumber of 2874–2926 cm−1 and 1731–1742 cm−1 than control film. Film incorporated with essential oils exhibited slightly lower thermal degradation resistance, compared to the control film. Varying effect of essential oil on thermal degradation temperature and weight loss was noticeable, but all films prepared using 20% glycerol had higher thermal degradation temperature with lower weight loss, compared with those containing 30% glycerol. Films added with all types of essential oils had rough cross-section, compared with control films, irrespective of glycerol levels. However, smooth surface was observed in all film samples. Film incorporated with lemon essential oil showed the highest ABTS radical scavenging activity and ferric reducing antioxidant power (FRAP) (p < 0.05), while the other films had lower activity. Thus, the incorporation of different essential oils and glycerol levels directly affected the properties of gelatin-based film from fish skin.  相似文献   

19.
Addition of sarcoplasmic fraction from bigeye snapper (Priacanthus tayenus) into natural actomyosin in combination with setting at 40°C resulted in the cross-linking of myosin heavy chain (MHC). Higher amount of sarcoplasmic fraction and extended setting time resulted in a higher cross-linking, indicating the presence of endogenous transglutaminase (TGase) in bigeye snapper muscle. TGase activity was activated by calcium ion and reducing agents (β-mercaptoethanol and dithiotreitol), but was inhibited by N-ethylmaleimide (NEM), NH4Cl and EDTA. TGase in the sarcoplasmic fraction was not stable when heated at temperature above 40°C, particularly with an increasing heating time. TGase was stable at pH ranging from 5.0 to 7.0, in which more than 70% activity was retained. Therefore, sarcoplasmic fraction possessed a cross-linking activity caused by TGase and its recovery for further uses should be considered.  相似文献   

20.
The effect of the ratios of myofibrillar protein (MP) to sarcoplasmic protein (SP) from round scad (Decapterus maruadsi) muscle on the properties of the resulting films was investigated. Tensile strength (TS) of films decreased with increasing SP content (p < 0.05). Films prepared from MP/SP ratio of 10:0 (w/w) exhibited the highest TS (p < 0.05). Elongation at break (EAB) of films prepared with SP content greater than 30% had the decreased EAB (p < 0.05). Water vapor permeability (WVP) of films increased when SP content increased up to 20% and decreased with increasing SP content up to 30% (p < 0.05). Solubility of films decreased but protein solubility increased with increasing SP contents (p < 0.05). The a*-value and ΔE* of film increased with increasing SP content. Films with all MP/SP ratios exhibited the negligible transmission to the light in UV range. Therefore, it is suggested that the type and ratio of proteins in fish muscle, both SP and MP, influenced the properties of film from round scad muscle. Results suggested that the removal of sarcoplasmic protein from fish muscle by thorough washing was an effective means to improve the mechanical properties as well as color of the fish muscle protein-based film.  相似文献   

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