Showing papers by "Saroat Rawdkuen published in 2014"

Extraction and characterization of gelatin from chicken feet by acid and ultrasound assisted extraction

Abstract: The objective of this study was to extract gelatin from chicken feet using 2 different methods (acid extraction and ultrasound assisted extraction). The obtained gelatin was compared with commercial bovine gelatin in terms of gelatin powder and gelatin gel. Various properties such as, yield, pH, color (L*, a* and b*), proximate analysis (moisture, protein, fat and ash), Fourier Transform Infrared (FTIR) spectrum, maximum force and electrophoresis of gelatin were evaluated. The highest yield of chicken feet gelatin was obtained from acid extraction method with 4.05% (wet weight or 12.64% based on dry weight). Proximate analysis of chicken feet gelatin showed the acid extraction has the higher protein content than ultrasound assisted extraction with 90.06 ± 1.43, while ultrasound assisted gelatin has the lowest moisture content with 5.40 ± 2.44. However, there is no significantly different values of protein, fat, ash and moisture content between acid, ultrasound extraction and commercial bovine gelatin (p>0.05). pH of gelatin solution for both methods has range between 6.13-6.49. Amide A peak was shown at the wave numbers 3,322.12 cm -1 for gelatin extracted with acid condition and 3,619.04 cm -1 for commercial bovine gelatin.

Characterization of acid and alkaline proteases from viscera of farmed giant catfish

Abstract: This work aimed to characterize acid and alkaline proteases extracted from farmed giant catfish ( Pangasianodon gigas ) viscera by using the aqueous two-phase system (ATPS). Determinations of optimum pH and pH stability, optimum temperature and thermal stability, salt stability and hydrolysis activities against bovine muscle protein and gelatin were performed. ATPS consisting of 20% polyethylene glycol (PEG1500)–15% MgSO 4 or 15% PEG2000–15% NH 3 C 6 H 5 O 7 was used for acid and alkaline proteases extraction. The optimum pH and temperature for acid protease was 3.0 and 40 °C, while alkaline protease was 9.0 and 60 °C. High pH stability of the enzymes was found in the ranges of 1.0–5.0 and 8.0–12.0 for acid and alkaline proteases, respectively. About 40 and 60% activities reduction of acid and alkaline proteases were observed when incubated at 90 °C for 30 min. In addition, 0.5% NaCl addition decreased >50% of total enzyme activities. Hydrolytic activities of the acid and alkaline proteases against bovine muscle protein and gelatin were in the concentration dependent manner as clearly indicated by SDS-PAGE. The results showed that the acid and alkaline proteases obtained from farmed giant catfish viscera could be useful for food protein hydrolysate production.

Effect of Longan Seed Extract and BHT on Physical and Chemical Properties of Gelatin Based Film

Abstract: Gelatin films developed from fish skin incorporated with longan seeds extract (LS) or butylated hydroxytoluene (BHT) at different concentrations were prepared and characterized. The film thickness was in the range of 35 to 37 μm, and the transparency was 3.24 to 3.36 for the films with and without the addition of LS or BHT (p 0.05). Tensile strength (TS) and elongation at break (EAB) were in the range of 48 to 53 MPa and 16 to 19 %, respectively. The highest (65.7 J/g) and lowest (38.7 J/g) transition enthalpy was found in the control and LS 500 ppm films, respectively. Slight differences in protein pattern were observed under SDS-PAGE between treatments of the film. These differences were also observed in the FTIR spectrum. Films incorporated with LS or BHT showed the preventive effect on lipid oxidation of soybean oil during 30 days of storage. At the level of 500 ppm, LS provided the highest efficacy for lipid oxidation retardation as evidenced by lower peroxide value (PV), and thiobarbituric acid reactive substances (TBARS) values (p > 0.05). The addition of LS or BHT had an impact on the film properties derived from fish skin gelatin, especially when high levels were added.

Mechanical and physico - chemical properties of biodegradable protein-based films: A comparative study

Abstract: Biodegradable protein-based films were prepared using the commercial gelatin (bovine hide) (CG), giant catfish skin gelatin (GG), soy protein isolates (SPI) in comparison with commercial wrap film (polyvinyl chloride; PVC). The physical, chemical and mechanical properties of the resulting films were determined and compared. The molecular weight distributions of the GG had high quantities of α-chains and β-components. The GG film had higher mechanical properties [tensile strength: TS 26.42 MPa and elongation at break: EAB 128.25 (%)] but lower thickness (0.0454 mm) than those protein-based films. The PVC film had higher mechanical properties [TS: 44.93 MPa and EAB: 253.71 (%)] but lower water vapor permeability [3.37x10-6 g·mm·h-1·cm-2·Pa-1], film thickness [0.0103 mm] and film insolubility than protein-based films. The film appearance of protein-based films was similar to commercial wrap film with uniform transparency.

Rice Bran Protein Isolates: Preparation and their Physico-Chemical and Functional Properties

Abstract: Rice bran protein isolates (RBPI) were prepared by two combination extraction techniques; microwaveassisted extraction with homogenization (MAE-H:800 W for 4 sec, 14000 rpm for 10 min) and the ultrasonicassisted extraction with colloid milled (UAE-C:160W for 5 min, 3000 rpm for 30 min) compared with conventional alkaline extraction (AKE) method before subjected to protein recover by using three-phase partitioning (TPP).RBPI were analyzed for physical, chemical and functional properties. Bulk density and whiteness of RBPI ranged 0.24 to 0.46 g/mL and 83.88 to 88.06, respectively. Lysine and histidine are the major amino acids in RBPI (3017-4877 and 1864-3535 mg/100g). The highest total phenolic content was found in RPBI using AKE (15.89 mg/g), while MAE-H gave the highest content antioxidant activities by FRAP (9.81 x 102mM/g) and DPPH assays (8.83%). The lipid peroxidation of RBPI ranged 11.30 to 19.39%. Nitrogen solubility index of RBPI were 57.84 to 73.12%, while in original rice bran was 18.04%. Water-holding and oil absorption capacity ranged 1.72 to 2.69 g/g, and 1.85 to 3.75 g/g, respectively. The highest foaming capacity was found in RBPI using UAE-C (62.50%), while the lowest was observed in RBPI using MAE-H (54.44%).

Thermoseparating Aqueous Two-Phase System for the Separation of Alkaline Proteases from Fish Viscera

Abstract: The objective of this study was to isolate alkaline proteases from farmed giant catfish viscera by using a thermoseparating aqueous two-phase system (T-ATPS). Different phase partitioning parameters—type of salts, NaCl addition, and temperature—were optimized. The optimum system contained 40% EOPO3900-10% MgSO4 with 17%NaCl, induced phase separation at 55°C, and provided the highest recovery (77.98 %) and purity (PF: 21.50-fold) with a partition coefficient (KE) of 11.90 and a volume ratio (VR) of 0.19. In the recycling step, the mixture of the bottom salt-rich phase and bottom EOPO-rich phase in the ratio of 0.5:1.5 (w/w) provided the highest recovery and purity. Hence, the total recovery of 91.62% was obtained from the separation system. Three major clear zones (24, 36, and 130 kDa) can be distinctively observed on casein-substrate gel electrophoresis for protease activity staining. Major protein components of perilla seed hydrolysates were completely hydrolyzed by the alkaline proteases at 70 units whi...