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J H Muyonga - One of the best experts on this subject based on the ideXlab platform.
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extraction and physico chemical characterisation of nile perch lates niloticus skin and bone gelatin
Food Hydrocolloids, 2004Co-Authors: J H Muyonga, C G B Cole, Kwaku G DuoduAbstract:Type A Gelatins were extracted from skins and bones of young and adult Nile perch and analysed to determine their functional and chemical properties. Total gelatin yield (for sequential extraction at 50, 60, 70 and 95 8C) was in the order adult fish skins . young fish skins . adult fish bones . young fish bones, while percentage gelatin recovery at 50 8C was in the order young fish skins . adult fish skins . young fish bones . adult fish bones. The Gelatins obtained were free of fishy odour. Nile perch skin gelatin had turbidity of 20.5 ‐ 158 NTU and ash content of 0.5 ‐ 1.7% while bone Gelatins had turbidity of 109 ‐517 NTU and ash content of 4.4‐ 11.2%. Bloom gel strength was 81 ‐ 229 and 134‐ 179 g, respectively, for skin and bone Gelatins. Gelatin from adult Nile perch skins exhibited higher viscosity and lower setting time than bone and the young fish skin Gelatins. Skin Gelatins were found to exhibit higher film tensile strength but lower film percent elongation than bone Gelatins. Bone and skin Gelatins had similar amino acid composition, with a total imino acid content of about 21.5%. Nile perch skin Gelatins had a higher content of polypeptides larger than b compared to bone Gelatins. Both bone and skin Gelatins also contained low molecular weight ð, aÞ peptides. The differences in functional properties between the skin and bone Gelatins appeared to be related to differences in molecular weight distribution of the Gelatins. q 2003 Elsevier Ltd. All rights reserved.
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extraction and physico chemical characterisation of nile perch lates niloticus skin and bone gelatin
Food Hydrocolloids, 2004Co-Authors: J H Muyonga, C G B Cole, Kwaku G DuoduAbstract:Abstract Type A Gelatins were extracted from skins and bones of young and adult Nile perch and analysed to determine their functional and chemical properties. Total gelatin yield (for sequential extraction at 50, 60, 70 and 95 °C) was in the order adult fish skins>young fish skins>adult fish bones>young fish bones, while percentage gelatin recovery at 50 °C was in the order young fish skins>adult fish skins>young fish bones>adult fish bones. The Gelatins obtained were free of fishy odour. Nile perch skin gelatin had turbidity of 20.5–158 NTU and ash content of 0.5–1.7% while bone Gelatins had turbidity of 109–517 NTU and ash content of 4.4–11.2%. Bloom gel strength was 81–229 and 134–179 g, respectively, for skin and bone Gelatins. Gelatin from adult Nile perch skins exhibited higher viscosity and lower setting time than bone and the young fish skin Gelatins. Skin Gelatins were found to exhibit higher film tensile strength but lower film percent elongation than bone Gelatins. Bone and skin Gelatins had similar amino acid composition, with a total imino acid content of about 21.5%. Nile perch skin Gelatins had a higher content of polypeptides larger than β compared to bone Gelatins. Both bone and skin Gelatins also contained low molecular weight (
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fourier transform infrared ftir spectroscopic study of acid soluble collagen and gelatin from skins and bones of young and adult nile perch lates niloticus
Food Chemistry, 2004Co-Authors: J H Muyonga, C G B Cole, Kwaku G DuoduAbstract:Abstract Fourier transform infrared (FTIR) spectroscopy was conducted on type A Gelatins derived from skins and bones of young and adult Nile perch (Lates niloticus) by a sequential extraction process. Spectra for Gelatins were compared to each other and to that of acid soluble collagen from young Nile perch skins, in order to elucidate changes in protein secondary structure during collagen to gelatin transformation. The first gelatin extracts showed diminished amide III bands while the last gelatin extracts showed distinct amide III bands and their amide I bands consisted of a higher percent area of a component around 1690 cm−1. The differences suggested that the collagen to gelatin transition leads to loss of molecular order. The later gelatin extracts exhibited higher molecular order than earlier gelatin extracts, probably because the former contained surviving crosslinks or/and because renaturation of the low molecular weight gelatin fractions (later gelatin extracts) led to formation of more protein–protein linkages.
Kwaku G Duodu - One of the best experts on this subject based on the ideXlab platform.
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extraction and physico chemical characterisation of nile perch lates niloticus skin and bone gelatin
Food Hydrocolloids, 2004Co-Authors: J H Muyonga, C G B Cole, Kwaku G DuoduAbstract:Type A Gelatins were extracted from skins and bones of young and adult Nile perch and analysed to determine their functional and chemical properties. Total gelatin yield (for sequential extraction at 50, 60, 70 and 95 8C) was in the order adult fish skins . young fish skins . adult fish bones . young fish bones, while percentage gelatin recovery at 50 8C was in the order young fish skins . adult fish skins . young fish bones . adult fish bones. The Gelatins obtained were free of fishy odour. Nile perch skin gelatin had turbidity of 20.5 ‐ 158 NTU and ash content of 0.5 ‐ 1.7% while bone Gelatins had turbidity of 109 ‐517 NTU and ash content of 4.4‐ 11.2%. Bloom gel strength was 81 ‐ 229 and 134‐ 179 g, respectively, for skin and bone Gelatins. Gelatin from adult Nile perch skins exhibited higher viscosity and lower setting time than bone and the young fish skin Gelatins. Skin Gelatins were found to exhibit higher film tensile strength but lower film percent elongation than bone Gelatins. Bone and skin Gelatins had similar amino acid composition, with a total imino acid content of about 21.5%. Nile perch skin Gelatins had a higher content of polypeptides larger than b compared to bone Gelatins. Both bone and skin Gelatins also contained low molecular weight ð, aÞ peptides. The differences in functional properties between the skin and bone Gelatins appeared to be related to differences in molecular weight distribution of the Gelatins. q 2003 Elsevier Ltd. All rights reserved.
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extraction and physico chemical characterisation of nile perch lates niloticus skin and bone gelatin
Food Hydrocolloids, 2004Co-Authors: J H Muyonga, C G B Cole, Kwaku G DuoduAbstract:Abstract Type A Gelatins were extracted from skins and bones of young and adult Nile perch and analysed to determine their functional and chemical properties. Total gelatin yield (for sequential extraction at 50, 60, 70 and 95 °C) was in the order adult fish skins>young fish skins>adult fish bones>young fish bones, while percentage gelatin recovery at 50 °C was in the order young fish skins>adult fish skins>young fish bones>adult fish bones. The Gelatins obtained were free of fishy odour. Nile perch skin gelatin had turbidity of 20.5–158 NTU and ash content of 0.5–1.7% while bone Gelatins had turbidity of 109–517 NTU and ash content of 4.4–11.2%. Bloom gel strength was 81–229 and 134–179 g, respectively, for skin and bone Gelatins. Gelatin from adult Nile perch skins exhibited higher viscosity and lower setting time than bone and the young fish skin Gelatins. Skin Gelatins were found to exhibit higher film tensile strength but lower film percent elongation than bone Gelatins. Bone and skin Gelatins had similar amino acid composition, with a total imino acid content of about 21.5%. Nile perch skin Gelatins had a higher content of polypeptides larger than β compared to bone Gelatins. Both bone and skin Gelatins also contained low molecular weight (
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fourier transform infrared ftir spectroscopic study of acid soluble collagen and gelatin from skins and bones of young and adult nile perch lates niloticus
Food Chemistry, 2004Co-Authors: J H Muyonga, C G B Cole, Kwaku G DuoduAbstract:Abstract Fourier transform infrared (FTIR) spectroscopy was conducted on type A Gelatins derived from skins and bones of young and adult Nile perch (Lates niloticus) by a sequential extraction process. Spectra for Gelatins were compared to each other and to that of acid soluble collagen from young Nile perch skins, in order to elucidate changes in protein secondary structure during collagen to gelatin transformation. The first gelatin extracts showed diminished amide III bands while the last gelatin extracts showed distinct amide III bands and their amide I bands consisted of a higher percent area of a component around 1690 cm−1. The differences suggested that the collagen to gelatin transition leads to loss of molecular order. The later gelatin extracts exhibited higher molecular order than earlier gelatin extracts, probably because the former contained surviving crosslinks or/and because renaturation of the low molecular weight gelatin fractions (later gelatin extracts) led to formation of more protein–protein linkages.
Hideki Kishimura - One of the best experts on this subject based on the ideXlab platform.
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characteristics of gelatin extracted from the swim bladder of yellowfin tuna thunnus albacores as affected by alkaline pretreatments
Journal of Aquatic Food Product Technology, 2016Co-Authors: Onouma Kaewdang, Soottawat Benjakul, Thummanoon Prodpran, Thammarat Kaewmanee, Hideki KishimuraAbstract:ABSTRACTGelatins extracted from the swim bladder of yellowfin tuna (Thunnus albacores) using various alkaline pretreatments were characterized. Alkaline mixtures (Na2CO3:NaOH) at different ratios (9:1, 8:2, 7:3, and 6:4) with a concentration of 4% (w/v) were used. The corresponding Gelatins termed “G1,” “G2,” “G3,” and “G4” had yields of 9.78, 14.91, 35.96, and 13.60% (dry weight basis), respectively. All Gelatins had α-chains as the major components. Fourier transform infrared spectra of obtained Gelatins revealed the significant loss of molecular order of the triple-helix. G3 having the highest imino acid content and exhibited the highest gel strength (p < 0.05), compared with others. The microstructure of G3 gel was finer with smaller voids, compared with others. With increasing proportion of NaOH, the L*-value of gelatin gel increased with coincidental decrease in ΔE*-value. Gelling and melting temperatures of swim bladder gelatin were 12.3–15.1 and 21.3–22.3°C, respectively.
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characteristics of gelatin from swim bladder of yellowfin tuna thunnus albacores as influenced by extracting temperatures
Italian Journal of Food Science, 2015Co-Authors: Onouma Kaewdang, Soottawat Benjakul, Thummanoon Prodpran, Thammarat Kaewmanee, Hideki KishimuraAbstract:Gelatin was extracted from the swim bladder of yellowfin tuna (Thunnus albacores) at different temperatures (60, 70 and 80°C) with the extraction yields of 35.6%, 41.1% and 47.3% (dry weight basis), respectively. The α-chains of gelatin decreased with increasing extraction temperatures. Similar amino acid compositions were noticeable among all Gelatins, in which glycine constituted the major amino acid. Imino acids ranged from 169 to 172 residues/1,000 residues. The gel strength of gelatin extracted at lower temperature was higher than that of Gelatins extracted at higher temperatures. Gelling and melting temperatures for swim bladder gelatin were 11.07- 15.24 and 20.36-22.33°C, respectively. Higher gelling and melting points were observed for gelatin extracted at lower temperatures. Microstructure of gel of gelatin extracted at 60°C was finer with smaller voids, compared with others. FTIR spectra of obtained Gelatins revealed the significant loss of molecular order of the triple-helix. Thus, extraction temperatures showed the direct impact on characteristics of gelatin from swim bladder.
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characteristics and gel properties of gelatin from skin of seabass lates calcarifer as influenced by extraction conditions
Food Chemistry, 2014Co-Authors: Sittichoke Sinthusamran, Soottawat Benjakul, Hideki KishimuraAbstract:Characteristics and gel properties of gelatin from seabass skin, as influenced by extraction conditions, were studied. Yields of gelatin extracted at 45 and 55 °C for various times were 51.6–57.3% and 62.0–66.4% (dry weight basis), respectively. All Gelatins contained β-chain and α-chains as the predominant components and showed a high imino acid content (198–202 residues/1000 residues). Generally, the gel strength of Gelatins decreased as the extraction temperature and time increased. Gelatin extracted at 45 °C for 3 h exhibited the highest gel strength (369 g). Gelling and melting temperatures for seabass skin gelatin were 19.5–20.0 and 26.3–27.0 °C, respectively. All Gelatins could be set at 25 °C within 30 min, however Gelatins extracted at 45 °C had a shorter setting time than those extracted at 55 °C (P < 0.05). Gelatin from seabass skin showed a higher gel strength than bovine gelatin and could be used as a potential replacement for land animal Gelatins.
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characteristics and functional properties of gelatin from splendid squid loligo formosana skin as affected by extraction temperatures
Food Hydrocolloids, 2012Co-Authors: Muralidharan Nagarajan, Thummanoon Prodpran, Soottawat Benjakul, Ponusa Songtipya, Hideki KishimuraAbstract:Gelatin was extracted from the skin of splendid squid (Loligo formosana) at different temperatures (50, 60, 70 and 80 °C) with extraction yield of 8.8%, 21.8%, 28.2%, and 45.3% (dry weight basis) for G50, G60, G70 and G80, respectively. Gelatin from the skin of splendid squid had a high protein content (∼90%) with low moisture (8.63–11.09%), fat (0.22–0.31%) and ash contents (0.17–0.68%). Gelatin extracted at higher temperature (G80) had a relatively higher free amino group content than gelatin extracted at lower temperatures (G50, G60 and G70) (P < 0.05). All Gelatins contained α- and β-chains as the predominant components. Amino acid analysis of gelatin revealed the high proline and hydroxyproline contents for G50 and G60. FTIR spectra of obtained Gelatins revealed the significant loss of molecular order of the triple-helix. The gel strength of gelatin extracted at lower temperature (G50) was higher than that of Gelatins extracted at higher temperatures including G60, G70 and G80, respectively. The net charge of G50, G60, G70 and G80 became zero at pHs of 6.84, 5.94, 5.49, and 4.86, respectively, as determined by zeta potential titration. Gelatin extracted at higher temperature (G80) had the lower L* value but higher a* and b* values, compared with those extracted at lower temperatures (P < 0.05). Emulsion activity index decreased, whilst emulsion stability index, foam expansion and stability increased as the concentration (1–3%) increased (P < 0.05). Those properties were governed by extraction temperatures of gelatin. Thus gelatin can be successfully extracted from splendid squid skin using the appropriate extraction temperature.
Soottawat Benjakul - One of the best experts on this subject based on the ideXlab platform.
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characteristics of gelatin extracted from the swim bladder of yellowfin tuna thunnus albacores as affected by alkaline pretreatments
Journal of Aquatic Food Product Technology, 2016Co-Authors: Onouma Kaewdang, Soottawat Benjakul, Thummanoon Prodpran, Thammarat Kaewmanee, Hideki KishimuraAbstract:ABSTRACTGelatins extracted from the swim bladder of yellowfin tuna (Thunnus albacores) using various alkaline pretreatments were characterized. Alkaline mixtures (Na2CO3:NaOH) at different ratios (9:1, 8:2, 7:3, and 6:4) with a concentration of 4% (w/v) were used. The corresponding Gelatins termed “G1,” “G2,” “G3,” and “G4” had yields of 9.78, 14.91, 35.96, and 13.60% (dry weight basis), respectively. All Gelatins had α-chains as the major components. Fourier transform infrared spectra of obtained Gelatins revealed the significant loss of molecular order of the triple-helix. G3 having the highest imino acid content and exhibited the highest gel strength (p < 0.05), compared with others. The microstructure of G3 gel was finer with smaller voids, compared with others. With increasing proportion of NaOH, the L*-value of gelatin gel increased with coincidental decrease in ΔE*-value. Gelling and melting temperatures of swim bladder gelatin were 12.3–15.1 and 21.3–22.3°C, respectively.
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characteristics of gelatin from swim bladder of yellowfin tuna thunnus albacores as influenced by extracting temperatures
Italian Journal of Food Science, 2015Co-Authors: Onouma Kaewdang, Soottawat Benjakul, Thummanoon Prodpran, Thammarat Kaewmanee, Hideki KishimuraAbstract:Gelatin was extracted from the swim bladder of yellowfin tuna (Thunnus albacores) at different temperatures (60, 70 and 80°C) with the extraction yields of 35.6%, 41.1% and 47.3% (dry weight basis), respectively. The α-chains of gelatin decreased with increasing extraction temperatures. Similar amino acid compositions were noticeable among all Gelatins, in which glycine constituted the major amino acid. Imino acids ranged from 169 to 172 residues/1,000 residues. The gel strength of gelatin extracted at lower temperature was higher than that of Gelatins extracted at higher temperatures. Gelling and melting temperatures for swim bladder gelatin were 11.07- 15.24 and 20.36-22.33°C, respectively. Higher gelling and melting points were observed for gelatin extracted at lower temperatures. Microstructure of gel of gelatin extracted at 60°C was finer with smaller voids, compared with others. FTIR spectra of obtained Gelatins revealed the significant loss of molecular order of the triple-helix. Thus, extraction temperatures showed the direct impact on characteristics of gelatin from swim bladder.
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characteristics and gel properties of gelatin from skin of seabass lates calcarifer as influenced by extraction conditions
Food Chemistry, 2014Co-Authors: Sittichoke Sinthusamran, Soottawat Benjakul, Hideki KishimuraAbstract:Characteristics and gel properties of gelatin from seabass skin, as influenced by extraction conditions, were studied. Yields of gelatin extracted at 45 and 55 °C for various times were 51.6–57.3% and 62.0–66.4% (dry weight basis), respectively. All Gelatins contained β-chain and α-chains as the predominant components and showed a high imino acid content (198–202 residues/1000 residues). Generally, the gel strength of Gelatins decreased as the extraction temperature and time increased. Gelatin extracted at 45 °C for 3 h exhibited the highest gel strength (369 g). Gelling and melting temperatures for seabass skin gelatin were 19.5–20.0 and 26.3–27.0 °C, respectively. All Gelatins could be set at 25 °C within 30 min, however Gelatins extracted at 45 °C had a shorter setting time than those extracted at 55 °C (P < 0.05). Gelatin from seabass skin showed a higher gel strength than bovine gelatin and could be used as a potential replacement for land animal Gelatins.
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effects of bleaching on characteristics and gelling property of gelatin from splendid squid loligo formosana skin
Food Hydrocolloids, 2013Co-Authors: Muralidharan Nagarajan, Soottawat Benjakul, Thummanoon Prodpran, Ponusa SongtipyaAbstract:Abstract Gelatins obtained from splendid squid ( Loligo formosana ) skin subjected to bleaching using hydrogen peroxide (H 2 O 2 ) at various concentrations were characterised. Yield of gelatin increased with increasing H 2 O 2 concentration used. Gelatin from skin bleached with higher H 2 O 2 concentrations had the lower free amino group and carbonyl group contents than the control gelatin (without bleaching). Gelatins had α-chains with MW of 123–129 kDa as the major components. FTIR spectra of all Gelatins revealed the significant loss of triple-helix. Gel strength of gelatin generally decreased as H 2 O 2 concentrations increased. Varying pHs rendering net charge of zero (5.18–6.34) were found among samples, as determined by ζ-potential titration. Gelatin prepared from skin bleached with 2% H 2 O 2 showed the highest L *, but lowest ΔE *-values, compared with others. H 2 O 2 at higher concentrations yielded gelatin with increasing b *-value. Thus, the properties of gelatin were governed by bleaching process, particularly H 2 O 2 concentration.
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characteristics and functional properties of gelatin from splendid squid loligo formosana skin as affected by extraction temperatures
Food Hydrocolloids, 2012Co-Authors: Muralidharan Nagarajan, Thummanoon Prodpran, Soottawat Benjakul, Ponusa Songtipya, Hideki KishimuraAbstract:Gelatin was extracted from the skin of splendid squid (Loligo formosana) at different temperatures (50, 60, 70 and 80 °C) with extraction yield of 8.8%, 21.8%, 28.2%, and 45.3% (dry weight basis) for G50, G60, G70 and G80, respectively. Gelatin from the skin of splendid squid had a high protein content (∼90%) with low moisture (8.63–11.09%), fat (0.22–0.31%) and ash contents (0.17–0.68%). Gelatin extracted at higher temperature (G80) had a relatively higher free amino group content than gelatin extracted at lower temperatures (G50, G60 and G70) (P < 0.05). All Gelatins contained α- and β-chains as the predominant components. Amino acid analysis of gelatin revealed the high proline and hydroxyproline contents for G50 and G60. FTIR spectra of obtained Gelatins revealed the significant loss of molecular order of the triple-helix. The gel strength of gelatin extracted at lower temperature (G50) was higher than that of Gelatins extracted at higher temperatures including G60, G70 and G80, respectively. The net charge of G50, G60, G70 and G80 became zero at pHs of 6.84, 5.94, 5.49, and 4.86, respectively, as determined by zeta potential titration. Gelatin extracted at higher temperature (G80) had the lower L* value but higher a* and b* values, compared with those extracted at lower temperatures (P < 0.05). Emulsion activity index decreased, whilst emulsion stability index, foam expansion and stability increased as the concentration (1–3%) increased (P < 0.05). Those properties were governed by extraction temperatures of gelatin. Thus gelatin can be successfully extracted from splendid squid skin using the appropriate extraction temperature.
Joe M Regenstein - One of the best experts on this subject based on the ideXlab platform.
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Yield and Gel Strength of Gelatin Extracted from Smoked Salmon (Salmo salar) Skins
2017Co-Authors: Yue Zhang, Joe M RegensteinAbstract:The gelatin yield and gel strength of gelatin extracted from the skins of smoked salmon were determined. The skins had a crude protein content of 43.5 ± 1.2% and an estimated collagen content of 23.6 ± 1.0%. Following an alkali extraction process under varying extraction conditions, the protein content varied from 2.78% to 32.1%, and the gelatin yield ranged from 2.23% to 22.4% of the initial skin weight. The gelatin purity (gelatin/protein) ranged from 55.4% to 100%, with the highest Hyp/protein sample arbitrarily designated as being 100% pure, i.e., an assumption of pure gelatin. Statistical analysis showed that HCl concentration, pretreatment temperature, and extraction temperature significantly affected the protein yield and gelatin yield. The wide range of gel strengths indicates that the gelatin might have been hydrolyzed to different extents during the different extraction and cooling processes. Statistical analysis did not show that any of the factors studied affected the gel strength. However, the data indicated that low NaOH concentrations and HCl concentrations might not prevent hydrolysis during the extraction process. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS–PAGE) showed that the Gelatins contained α- and β-chains and that the Gelatins composed of higher concentrations of larger molecular weight polypeptide chains had higher gel strengths.
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rheological properties of gelatin from silver carp skin compared to commercially available Gelatins from different sources
Journal of Food Science, 2010Co-Authors: Gokhan Boran, Steven J. Mulvaney, Joe M RegensteinAbstract:ABSTRACT: Gelatin is used as a functional ingredient in many foods, pharmaceuticals, and cosmetics as a stabilizing, thickening, and gelling agent. The rheological properties of Gelatins are important in the potential functionality of gelatin. This study is designed to determine the rheological properties of gelatin extracted from the skins of silver carp (Hypophthalmichthys molitrix Valenciennes 1844). The extracted gelatin is compared with commercially available Gelatins from different sources. The results indicate that the stress–strain relationship of gelatin gels remained in the linear region over a broad range of strains and stresses and gave similar elastic moduli at varying frequency, stress, and strain levels. One exception was a commercial high molecular weight fish skin gelatin that gave a lower elastic modulus indicating that its gel strength was low compared to the other gelatin samples studied. Gel strength varied between 220 and 1230 g while viscosity varied between 4.53 and 6.91 cP among the samples. Melting and gelling temperatures varied between 14.2 and 32.3 °C and 3.2 and 25.4 °C, respectively. Texture profile analysis was done at 2 deformation levels, 25% and 75%, and the results correlated well with gel strength. The correlations between hardness, cohesiveness, and gumminess and gel strength were 0.98, 0.82, and 0.99, respectively, at 25% deformation but lower at 75% deformation. The results suggest that rheological measurements might be used to quickly estimate gel strength using less material. In addition, the silver carp skin gelatin seemed to be of equal quality to some of the commercial Gelatins.
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effects of alkaline and acid pretreatment on the physical properties and nanostructures of the gelatin from channel catfish skins
Food Hydrocolloids, 2008Co-Authors: Hongshun Yang, Peng Zhou, Yifen Wang, Joe M RegensteinAbstract:Abstract The objective of this study was to illustrate the correlation between the physical properties and nanostructure of Gelatins made of channel catfish ( Ictalurus punctatus ) skins. The gelatin samples were first pretreated with sodium hydroxide, acetic acid, or water, and then extracted with hot water before the measurement. Physical properties including the yield of protein, viscosity and textural properties were determined on Gelatins obtained with different pretreatment conditions. The acid pretreatment group showed the highest gel strength and protein yield, and a reasonable viscosity. The water pretreatment group showed the lowest values for all of the physical properties. Four samples including water, 0.1 M acid and 0.25 and 1.0 M alkaline-pretreated groups’ nanostructures were then studied using atomic force microscopy (AFM). The AFM images showed that the acid-pretreated gelatin was composed of sponge-like aggregates, while the others showed separated individual aggregates. Annular pores were only found in the alkaline pretreatment group. There was no significant correlation between the diameters of the spherical aggregates and the physical properties; however, the different AFM patterns may relate to the gelatin's physical properties.
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comparison of water gel desserts from fish skin and pork Gelatins using instrumental measurements
Journal of Food Science, 2007Co-Authors: Peng Zhou, Joe M RegensteinAbstract:The objective of this study was to compare water gel desserts from various Gelatins using instrumental measurements. The puncture test and texture profile analysis (TPA) with compression were determined at 25% and 75% deformation; the melting properties were determined rheologically by monitoring the change of storage modulus (G') with increasing temperature. The measurements with 25% deformation were always nondestructive, while measurements with 75% deformation were mostly destructive. Desserts made from Alaska pollock gelatin (AG) or gelatin mixtures containing AG were more resistant to the destruction caused by the large deformation than tilapia gelatin and pork Gelatins. In addition, the gel dessert made from AG melted at a lower temperature than those from tilapia skin gelatin and pork Gelatins, while desserts made from gelatin mixtures reflected the melting properties of the separate Gelatins.
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determination of total protein content in gelatin solutions with the lowry or biuret assay
Journal of Food Science, 2006Co-Authors: Peng Zhou, Joe M RegensteinAbstract:ABSTRACT: Gelatins can be obtained from different sources and prepared using different processes, and the end product gelatin may vary in amino acid composition and molecular weight distribution. In the present study, the variation in “protein color” development among Gelatins in colorimetric total protein content measurements was investigated at 540 nm using the Biuret assay and at 650 nm using the Lowry assay, with bovine serum albumin as the reference protein. In both the Biuret and Lowry assays, the color response varied significantly among Gelatins. The difference in imino acid content was the major factor responsible for this variation, which probably influenced the gelatin helix → coil phase transition and resulted in the difference in gelatin associate state. Based on their “protein color” development abilities in both Biuret and Lowry, Gelatins were classified into 2 major groups with the hierarchical cluster analysis: 1 group included all cold water fish Gelatins, while the other included Gelatins from warm water fish, avian, and mammalian species.