Shu Xian Hao

Extraction, Purification and Partial Characterizations of Polysaccharides from Gracilaria lemaneiformis

In the present study, the crude polysaccharides were extracted from the microalgae Gracilaria lemaneiformis with ultrasonic-assisted extraction method and purified by DEAE-52 cellulose chromatography and Sephadex G-100 size-exclusion chromatography in that order. Two main fractions, GPC-1and GPC-2, were obtained through the extraction and purification steps. Then partial characterizations, such as chemical composition, ultraviolet (UV) spectrum and infrared (IR) spectrum of the two fractions were analyzed in this study. The results indicated that the total sugar contents of GPC-1and GPC-2 were 89.32% and 88.79%, and the protein contents of these two fractions were only 0.35% and 0.76%, compared with that of crude polysaccharides of 75.49% and 1.92%, respectively. Moreover, both the UV spectrum and the IR spectrum demonstrated that the two fractions were typical purified polysaccharides. As a consequence, these investigated characterizations could be considered as a favorable evidence for the identification of polysaccharides from Gracilaria lemaneiformis.

Extraction of Fish Oil from the Muscle of Sturgeon Using Supercritical Fluids

This study evaluated the extraction of oil from sturgeon (Acipenser baeri) muscle using supercritical fluids. Response surface methodology (RSM) was used to identify and quantify the variables, namely extraction pressure, extraction time and CO2 flow rate on the yield of oil. Statistical analysis indicated that for all three variables, the quadratic terms and interactions between the variables had significant effects on yield (p < 0.05). Polynomial regression model predictions were in good agreement with the experimental results, with a coefficient of determination of 0.9936 for yield. Maximum yield from sturgeon muscle was 26.83% with a pressure of 315.8 bar, extraction time of 10.8 min and CO2 flow rate of 3.5 l/min, which closely matched the predicted value (26.70%). The characteristics of the fish oil extracted with the supercritical fluids were superior to those of oil obtained by other methods.

Comparison of the Effect of Sterilization Pretreatment Using Four Different Bacteriostatic Agents on the Quality of Penaeus vannamei

Four different bacteriostatic agents H2O2, NaClO, ClO2, and ozone water (O3) were used to the sterilization pretreatment of fresh muscle of penaeus vannamei. The bactericidal effect of these bacteriostatic agents were evaluated by aerobic bacterial count method, sensory evaluation and chromatic aberration analysis. The results showed that the optimum pretreatment concentrations of sterilization pretreatment by H2O2, NaClO, ClO2 and ozone water (O3) were 3.0 g/kg, 50 mg/kg, 150 mg/kg and 1.0 mg/kg respectively. The optimum pretreatment time of sterilization pretreatment by H2O2, NaClO, ClO2 and ozone water (O3) were 60 s, 300 s, 300 s and 300 s respectively. Furthermore, the bactericidal coefficients of sterilization pretreatment by H2O2, NaClO, ClO2 and ozone water (O3) were 91.6%, 95.1%, 92.3% and 99.6% respectively. The effects of color and flavor of fresh muscle treated by these four bacteriostatic agents were compared. The results showed that the color and flavor of fresh muscle was less effected by ozone water (O3) method used for sterilization pretreatment method than other three methods. The total number of bacterial colony of sample treated 600 s by 1.0 mg/kg of ozone water (O3) method was reduced to 3.4 lgCFU/g, and the advantages of this method are significant sterilization effect as well as the low influences of color and sensory quality.

Different Temperatures of Frozen Storage Effects on Proteins of Crisp Grass Carp (Ctenopharyngodon idellus C.et V)

This article focused on the study of frozen storage temperatures effect on protein of crisp grass carp, and then induced changes of texture of crisp grass carp muscle. During frozen storage, lower temperature, better texture of crisp grass carp muscle. The little changes of texture characteristics of crisp grass carp were related to lower changes of drip loss, cooking loss, protein solubility and thermal stability. The results indicated that lower temperature of frozen storage was beneficial to maintain the mastication of crisp grass carp.

Study on Synthesis and Characterization of a Fluorescence Probe and its Application for Determination of Superoxide Anion Radical

A novel Schiff base, 2-(Salicylideneamino)pyridine (2-SAP) synthesized by 2-aminopyridine and salicylaldehyde was used as a fluorescence probe to determine superoxide anion radical (O2•-) in this study. The synthetic product was characterized by IR, 1H-NMR and GC-MS methods. A fluorescence quenching reaction occurs between 2-SAP and O2•-, and the fluorescence intensity decreased significantly. The effect of pyrogallol concentration (2.0×10-5 M to1.0×10-3 M) was discussed in this study. In the range from 2.0×10-5 M to 1.0×10-4 M, relative fluorescence intensity (y) and pyrogallol concentration (x) shown a good linear relationship, y=37.801x+76.854, r=0.993. Based on this phenomenon, the O2•- generated by pyrogallol autoxidation could be determined simply with high sensitivity.

Analysis and Evaluation of Nutrient Composition of the Factory Farming Jade Perch

Jade perch (Scortum barcoo) meat nutrition analysis and evaluation was carried out in this paper, results showed that: the protein content, fat content and total amino acid content of Jade perch are 18.4%, 9.0% and 19.99% respectively. As a balanced amino acid combination, it contains a variety of amino acids necessary for the meat, glutamic acid content of up to 3.10%, delicious amino acids in the total amino acid content 7.64%. Jade perch has a lower fat content, but rich in unsaturated fatty acids, DHA content is 3.36%, rich in Ca, Fe, Zn, Se and other trace elements, in the jade perch, the heavy metals and other toxic substances analysis showed that they are in line with national health and safety standards, the Jade Perch is a good quality, high nutritional value of edible fish.

Preparation and Antioxidant Properties of Tilapia (Oreochromis niloticus) Protein Hydrolysates-Copper Complex

Tilapia protein hydrolysates (TPH) were obtained by enzymatic hydrolysis of tilapia meat using papain, and then the TPH binded with copper at various mass ratios of TPH to CuCl2 (5:1, 10:1 and 20:1) to obtain complex I, complex II and complex III, respectively. The copper-binding rate, antioxidant properties, and FTIR spectrum of the complex were investigated. It was found that the copper-binding rate increased with the increase of mass ratios (TPH/CuCl2) from 5:1 to 20:1. The DPPH radical scavenging activity and reducing power activity of TPH were higher than that of the complexes. However, the lipid peroxidation inhibition activity was improved after TPH binded with copper. It was also found that the antioxidant activities of complex III were highest in the complexes. FTIR spectra demonstrated that some sites such as amino nitrogen atoms in TPH could bind with copper to form the complex.

Antioxidant Activities of Tilapia (Oreochromis niloticus) Protein Hydrolysates-Iron Chelate Based on Properties of Biological Materials

Tilapia (Oreochromis niloticus) protein was hydrolysed by papain, and then the tilapia (Oreochromis niloticus) protein hydrolysates (TPH) chelated with ferrous ions at various mass ratios of TPH to FeCl2 (5:1, 10:1 and 20:1) to obtain the biological materials of chelate I, chelate II and chelate III, respectively. The ferrous-binding rate and antioxidant activities of the chelates were investigated. It was found that the ferrous-binding rate increased with the increase of mass ratios (TPH/FeCl2) from 5:1 to 20:1. The DPPH radical scavenging activity and reducing power activity of chelate III were highest in the chelates, and the lipid peroxidation inhibition activity of the chelate III was obviously higher than that of TPH. Compared with TPH, marked changes in microstructure were observed in the biological material of TPH-iron chelate.

High-Purity Isolation of Trans-Resveratrol from Rhizma Polygoni Cuspidati by High-Speed Counter-Current Chromatography

In this paper, high-speed counter-current chromatography (HSCCC) was established and successfully applied for the separation and purification of trans-resveratrol from Rhizma Polygoni Cuspidati. After extracted by microwave assisted extraction (MAE), the dry extract was directly dissolved in HSCCC solvent and introduced to HSCCC separation system. Two-phase solvent system of HSCCC was optimized. Trans-resveratrol was separated from extract of Rhizma Polygoni Cuspidati by high-speed counter-current chromatography in two-step using two different solvent systems composed of chloroform-methanol-water (4:3:2, v/v/v) and n-hexane-ethyl acetate-methanol-water (3:5:4:6, v/v/v/v). From 200 mg of crude extract, 2.5 mg of trans-resveratrol was obtained at over 99% purity by HPLC analyses, and its chemical structure was identified by ESI-MS, 1H NMR.

Antioxidant Activities of Flavonoids from Canavalia maritime

Flavonoids was isolated from canavalia maritime by accelerated solvent extraction (ASE) coupled with high-speed counter-current chromatography (HSCCC). The antioxidant activities of flavonoids were investigated in vitro and evaluated by IC50. The results indicated that flavonoids possessed obvious reducing power and significant inhibitory effects on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical and superoxide radical. These results suggest that canavalia maritime flavonoids could be a suitable natural antioxidant for humans.