Showing papers by "Saroat Rawdkuen published in 2010"

Chemical compositions and characterisation of skin gelatin from farmed giant catfish (Pangasianodon gigas)

Abstract: Gelatin was extracted from the skin of farmed giant catfish (Pangasianodon gigas) with a yield of 20.1 g/100 g skin sample on the basis of wet weight. The chemical composition and properties of gelatin were characterised. The gelatin had high protein (89.1 g/100 g) but low fat (0.75 g/100 g) content and contained a high number of imino acids (proline and hydroxyproline) (211 residues per 1000 residues). Giant catfish skin gelatin had a slightly different amino acid composition than calf skin gelatin. The bloom strength of the gelatin gel from giant catfish skin gelatin (153 g) was greater than that of calf skin gelatin (135 g) (P

Chemical compositions and characteristics of farm raised giant catfish (Pangasianodon gigas) muscle

Abstract: Proximate composition, chemical and physical properties of dorsal, ventral and lateral line cuts of farm raised giant catfish were determined. Protein, fat and ash content of the different cuts averaged 16.88, 4.45 and 1.24 g/100 g, respectively. Dorsal contains higher protein concentrations (19 g/100 g) than other two parts (p 0.05). The highest content of myoglobin and total pigment in lateral line resulted in the highest redness index (a*/b*) of this part. Three major nitrogenous compositions classified based on solubility in giant catfish muscle were myofibrillar, sarcoplasmic and alkaline soluble proteins.

Properties of gelatin films from giant catfish skin and bovine bone: a comparative study

Abstract: Edible films were prepared from the gelatin of farmed giant catfish skin (GC) (Pangasianodon gigas), bovine bone gelatin (BB) and their combination. The physical, mechanical, thermal and chemical properties of the resulting films were characterized and compared. The molecular weight distributions of the giant catfish skin gelatin-containing samples had high quantities of α-chains, β-components and high molecular weight cross-links. The bovine bone gelatin-containing samples showed low contents of major bands with high degradation band components. The GC films had higher water activity (0.45) and mechanical properties [tensile strength: TS 41 MPa and elongation at break: EAB 34 (%)] but lower thickness (38 μm) and water vapor permeability than those of BB films. The lowest light transmission (200–800 nm) and film transparency (3.34) were found in the GC films. However, the color attribute (L, a and b) of BB films was closer to the low-density polyethylene commercial film (ΔE 1.2). The highest value of film and protein solubility (100%) was found in BB film, while the lowest value (41–56%) was found in GC film. The GC films showed the most compact, smooth and continuous surface without porous structures, which corresponds to the greater properties of films.

Assessment of protein changes in farmed giant catfish (Pangasianodon gigas) muscles during refrigerated storage

Abstract: Summary Farmed giant catfish (Pangasianodon gigas) muscles (dorsal and ventral sites) were stored in a refrigerator (at 4 °C) for 14 days to determine the effect of refrigerated storage on biochemical and physical changes. The analyses were carried out at 0, 2, 4, 7, 10 and 14 days of storage. At day 14, Ca2+ -ATPase activity markedly decreased when compared to its value at day 1 (>90%), while a small decrease was observed for surface hydrophobicity and reactive sulfhydryls content. Total volatile basic nitrogen and trichloroacetic-soluble peptide content gradually increased when the storage period was extended. The myosin heavy chain decreased slightly on SDS-PAGE for both meat cuts with increased storage time. Expressible drip and cooking loss were highest during the first day of storage and slightly decreased with storage time. Instrumental hardness was significantly higher in the ventral compared to the dorsal muscle, while the toughness was the highest at the second day of storage. The muscle bundles with scanning electron microscopy were less attached, resulting in the observed big gaps over increasing storage time. Results indicated that changes of proteins have detrimental effects on the quality attributes of farmed giant catfish muscles during refrigerated storage, particularly physical and biochemical properties.