Alterations in juvenile diploid and triploid African catfish skin gelatin yield and amino acid composition: effects of chlorpyrifos and butachlor exposures

Skin is a major by-product of the fisheries and aquaculture industries and is a valuable source of gelatin. This study examined the effect of triploidization on gelatin yield and proximate composition of the skin of African catfish (Clarias gariepinus). We further investigated the effects of two commonly used pesticides , chlorpyrifos (CPF) and butachlor (BUC), on the skin gelatin yield and amino acid composition in juvenile full-sibling diploid and triploid African catfish. In two separate experiments, diploid and triploid C. gariepinus were exposed for 21 days to graded CPF [mean measured: 10, 16, or 31 mg/L] or BUC concentrations [Mean measured: 22, 44, or 60 mg/L]. No differences in skin gelatin yield, amino acid or proximate compositions were observed between diploid and triploid control groups. None of the pesticide treatments affected the measured parameters in diploid fish. In triploids, however, gelatin yield was affected by CPF treatments while amino acid composition remained unchanged. Butachlor treatments did not alter any of the measured variables in triploid fish. To our knowledge, this study is the first to investigate changes in the skin gelatin yield and amino acid composition in any animal as a response to polyploidization and/or contaminant exposure

Molecular characteristics and properties of gelatin from skin of seabass with different sizes

Gelatin was extracted from the skin of seabass (Lutes calcarifer) with different average sizes (2, 4 and 6 kg/fish), termed G2, G4 and G6, respectively and their characteristics and functional properties were determined. Yields of G2, G4 and G6 were 38.22, 40.50 and 43.48% (based on dry weight), respectively. G2 contained cc-chains as dominant component, whilst G4 and G6 comprised alpha-, beta- and gamma-chains with a larger content of high MW cross-links. All gelatins had the similar imino acid (hydroxyproline and proline) content. Net charge of G2, G4 and G6 became zero at pH of 6.73, 6.41 and 7.12, respectively. Amongst all gelatin samples, G6 exhibited the highest gel strength (321.5g) (p < 0.05), but had the lowest turbidity (p < 0.05). Gels of G6 sample had the lower L*-value but higher a*-, b*- and Delta E*-value, compared with others. Gelling and melting temperatures of all gelatins were 17.09-19.01 and 26.92-28.85 degrees C, respectively. Furthermore, all gelatins were able to set at room temperature, regardless of size of seabass used. G6 had the shorter setting time at room temperature than others. Therefore, size of seabass, in which skin was used for gelatin extraction, had the impact on yield, composition and properties of resulting gelatin. (C) 2014 Elsevier B.V. All rights reserved

ผลของสภาวะการสกัดและไฮโดรคอลลอยด์ต่อสมบัติของเจลาตินจากหนังและถุงลมปลากะพงขาว (Lates calcarifer)

Thesis (Ph.D., (Food Science and Technology))--Prince of Songkla University, 201

Characteristics and Properties of Gelatin from Seabass (Lates calcarifer) Swim Bladder : Impact of Extraction Temperatures

Purpose This study aimed to investigate the impact of various extracting temperatures on yield and properties of gelatin from swim bladder of seabass (Lates calcarifer), a byproduct from processing. Methods Gelatin from seabass swim bladder was extracted at different temperatures (45, 55, 65 and 75 degrees C). The gelatins obtained using various extraction temperatures were characterized. Results The yield and recovery of gelatin from swim bladder (44.83-71.95% and 49.08-74.83%, based on dry weight) increased with increasing extraction temperatures. All gelatins contained a-chains as the predominant components, followed by alpha-chain. Gelatin from seabass swim bladder showed a high imino acid content (195 residues/1000 residues). FTIR and CD spectra revealed the loss of triple helix during heating via breaking down hydrogen bonds between a-chains. Gel strength generally increased as the extraction temperature increased up to 65 degrees C (P < 0.05). Gelatin extracted at 65 degrees C for 6 h showed a higher gel strength, compared to bovine gelatin (P < 0.05). Gelling and melting temperatures were 10.419.7 and 19.3-28.4 degrees C, respectively, depending on extraction temperature. Conclusion Properties of gelatin from swim bladder were affected by extraction temperature. Therefore, sea-bass swim bladder could serve as an alternative collagenous material for gelatin production, when the appropriate extraction condition was implemented

Characteristics of collagen from the skin of clown featherback (Chitala ornata)

Acid soluble collagen (ASC) and pepsin soluble collagen (PSC) from the skin of clown featherback (Chitala ornata) were isolated and characterised. Yields of ASC and PSC were 27.64 and 44.63% (dry weight basis) with total collagen recovery of 82.08%. Both collagens contained glycine as the major amino acid with relatively high content of proline, hydroxyproline and glutamic acid/glutamine. Nevertheless, they had the low content of cysteine, histidine and tryrosine. The collagen was characterised as type I, comprising (1)(2)2-heterotrimer. Pepsin-aided process did not affect triple-helical structure of PSC as determined by FTIR spectra. Thermal transition temperature of ASC (36.28 degrees C) was slightly higher than that of PSC (35.23 degrees C). However, no differences in isoelectric point (5.54-5.68) between ASC and PSC were observed. Therefore, collagen from the skin of clown featherback could be successfully extracted for further applications

Characteristics of Collagen from Rohu (Labeo rohita) Skin

Acid soluble collagen (ASC) and pepsin soluble collagen (PSC) were isolated from rohu skin with the yield of 64.2 and 6.8% (dry weight basis), respectively. Both collagens had glycine as the major amino acid with imino acid content of 196-202 residues/1,000 residues and were characterized as type I collagen with molecular composition of (1)(2)2-heterotrimer. Fourier transform infrared spectra of both collagens were similar, with no shift in wavenumber of all amide bands. The T-max value of ASC and PSC was 36.40 and 35.48 degrees C, respectively. The zero surface net charge of ASC and PSC was found at pH 5.9 and 5.3, respectively

Protein Hydrolysates from Pacific White Shrimp Cephalothorax Manufactured with Different Processes: Compositions, Characteristics and Antioxidative Activity

Hydrolysates from Pacific white shrimp (Litopenaeus vannamei) cephalothorax were prepared using various hydrolysis processes, and their chemical composition, characteristics as well as antioxidative activity were studied. Those processes consisted of autolysis (AU), hydrolysis using Alcalase at 0.5% (0.5A) or 1.0% (1.0A) and autolysis, followed by Alcalase hydrolysis at 0.5 and 1.0% (AU+0.5A and AU+1.0A). All the hydrolysate samples had higher protein contents (86.04-89.24%) and lower amounts of ash (7.46-11.26%) and lipids (0.43-0.64%), compared to those of cephalothorax (P<0.05). The highest yield (54.04%) and protein recovery (84.15%) were observed in the AU+1.0A sample, which had the maximum degree of hydrolysis (DH) (44.93%) (P<0.05). All the hydrolysates had glutamic acid/glutamine (115.80-121.69 mg/g dry sample), aspartic acid/asparagine (84.04-90.28 mg/g dry sample), arginine (63.27-68.62 mg/g dry sample) and leucine (58.67-68.07 mg/g dry sample) as the dominant amino acids. Based on gel filtration chromatography, the hydrolysates with higher DH showed higher proportions of smaller peptides (<1355 Da). When the antioxidant activities of the hydrolysates were determined, the AU+1.0A sample had the highest ferrous ion chelating activity, ABTS radical scavenging activity and ORAC value, compared to the others (P<0.05). However, the highest ferric reducing antioxidant activity and DPPH radical scavenging activity were obtained for the 1.0A and AU samples, respectively (P<0.05). Furthermore, the AU+1.0A sample showed higher inhibitory activity against DNA damage induced by peroxyl radicals than the 1.0A and AU samples. Therefore, different hydrolysis processes directly affected the protein recovery, chemical composition and antioxidant activities of the hydrolysates from shrimp cephalothorax

Characteristics and Gel Properties of Gelatin from Skin of Asian Bullfrog (Rana tigerina)

Characteristics and gel properties of gelatin from frog skin as influenced by extraction temperatures (45-75 A degrees C) were investigated. Yield of gelatin increased as the extraction temperature increased (P 0.05). Gelling and melting temperatures of frog skin gelatin were 23.47-24.87 and 33.22-34.66 A degrees C, respectively. Gels became more yellowish with increasing extraction temperatures (P < 0.05). All gelatin gels were sponge or coral-like in structure but varied in patterns as visualized by scanning electron microscopy (SEM). Gelatin from frog skin could be used as a replacement for land animal counterpart

Effect of proteases and alcohols used for debittering on characteristics and antioxidative activity of protein hydrolysate from salmon frames

Protein hydrolysates were obtained from salmon frame using Alcalase or Flavourzyme at 3% (w/w protein) for 180 min. Protein hydrolysates prepared using Alcalase (HA) and Flavourzyme (HF) had DH and yield of 25.1-26.9% and 28.5-32.3 g/100 g sample, respectively. HF showed lower bitterness score (5.78) than that of HA (8.68) (P < 0.05). When HA and HF were further subjected to debittering with 2-butanol or isopropanol, the recovery of 77.88-81.60% was obtained (P < 0.05). HF and HA debittered with 2-butanol possessed less bitterness score, 3.60 and 3.77, respectively (P < 0.05). Surface hydrophobicity of 81.4 and 124.8 was attained when HF and HA were debittered with 2-butanol (P < 0.05). Selected debittered hydrolysates, produced using Flavourzyme, followed by fractionation using 2-butanol (HF-B) contained glutamic acid/glutamine (15.14 g/100 g), aspartic acid/asparagine (10.07 g/100 g) and glycine (9.30 g/100 g) as the predominant amino acids. HF-B had the decreased ABTS radical scavenging activity and metal chelating activity. A(280) of peptides separated by gel filtration was lowered to some extent and coincided with the lower bitterness score and surface hydrophobicity. Thus, debittered protein hydrolysate from salmon frame could serve as a nutritive ingredient at high levels in health promoting foods