Advanced Materials Research Vols. 1073-1076

Abstract: This study aimed to investigate the influence of pickling conditions and drying methods on the safe quality of a traditional dried-salted hairtail (Trichiurus lepturus),with respect to the contents of major biogenic amines (BAs) and TBA. The results showed that the values of putrescine (PUT), cadaverine (CAD), histamine (HIS), tyramine (TYR), total biogenic amines and TBA were significantly affected by pickling conditions and drying methods. Effect of pickling conditions on PUT value was not significant, but PUT value rised after drying. Values of CAD, TYR, total BAs and TBA dropped as salt addition increased. The contents of CAD, TYR and TBA were higher at ice storage than that at 15°C and 20°C, but the contents of HIS and total BAs were less than others. TBA value rose significantly as pickling time increased. Dried-salted hairtail prepared from cold drying at 20°C, 30°C, 40°C and hot drying at 50°C, 60°C were very safe for consumption compared to sun drying.

Abstract: The composite cryoprotectants was created using trehalose, polydextrose and sodium lactate. Response surface methodology based on the single-factor investigation was applied to explore optimal cryoprotectant solution formulation on salt soluble protein content of crisp grass carp, and compared to the traditional commercial cryoprotectants, then studied the optimal immersion time and effect of freeze-thaw treatment on crisp grass carp. The results indicate that the optimal formula of composite cryoprotectants is 4% trehalose, 6% polydextrose and 5% sodium lactate. Salt soluble protein content of the optimal cryoprotectants is higher than that traditional commercial cryoprotectants (4% sucrose +4% sorbitol) in crisp grass carp, and the optimal immersion time is 30min. The optimal composite cryoprotectants with low sweetness and low heat can prevent effectively protein from frozen denaturation. Thus the composite cryoprotectants of trehalose, polydextrose and sodium lactate can replace sucrose and sorbitol.

Abstract: Papain, pancreatin, pepsin, rypsin, neutral protease were used for the enzymatic hydrolysis of silk fibroin solution. It was found that the silk fibroin peptides after hydrolysis by pancreatin exhibited the strongest antioxidant activity, in comparison of five hydrolysed solutions by the pyrogallol method. The pancreatin hydrolysis process was then optimised. The optimum conditions of pancreatin hydrolysis antioxidant activity silk fibroin peptide was determined by orthogonal experiment: reaction time 160min, enzyme concentration 4%,substrate concentration 20mg/ml, pH 8, temperature 38°C. The best hydrolysis under the hydrolyzate on superoxide radical scavenging rate of 72.73%.

Abstract: Oratosquilla oratoria was the experimental raw materials in the paper. Design expert8.0.6 and Excel2007 was used to analyze the optimal process with the factors which were curing time, curing temperature, curing salt contention and the index which was the total bacteria. The pathogenic bacteria and sensory score under various curing conditions were determined simultaneously. After analyzing the significance of the various factors and interactions, the results showed the optimum curing conditions of oratosquilla oratoria were as follows: curing time 7.14h, curing temperature 14.34°C, curing salt contention 8.3%. Under this condition no pathogenic bacteria was detected and the sensory score was the highest.

Abstract: This study investigates the effectiveness of adding carboxymethyl chitosan during steam cooking as an adsorbent for detoxifying paralytic shellfish poisoning toxins (PSP toxins) in the scallop Chlamys nobilis. Toxin analysis using a mouse bioassay test and hydrophilic interaction liquid chromatography–tandem mass spectrometry method (LC–MS) showed that most of the PSP toxins (>80%) were contained in the visceral compartment of the raw scallops. Overall, 82.2Mu/100g of PSP toxins were released from scallop tissues during steaming. The toxicity of the soup steamed with 0.1%, 0.3%, 0.6%, 1.0% and 1.5% carboxymethyl chitosan decreased the toxin content by 35.6%, 44%, 48.4%, 53.3% and 56.9% (p<0.005), respectively. The relative PSP toxin content in the raw adductor muscle was comparable to those after steaming or steaming with carboxymethyl chitosan (p > 0.05).The PSP toxin concentrations in the adductor muscles, gills + mantle and visceral compartments steamed with 0.1%, 0.3%, 0.6%, 1% and 1.5% carboxymethyl chitosan were not significantly different from those in the corresponding raw samples. The LC–MS analysis showed that the adsorbance of carboxymethyl chitosan for each of the PSP toxins was positive correlation with concentration, although the uptake efficiency of each toxin was different. The reduction in toxin content of all analyzed toxins reached 45.6%, 30.2%, 44.5%, 55.9% and 37.6% under the corresponding carboxymethyl chitosan concentrationsis.

Abstract: The study is focused on the extracting polysaccharide from Dendrocalamus latiflorus with assisted enzyme and cool water to maintain its biological activity. The optimized conditions for the cellulase process are listed as follows The enzymatic hydrolysis temperature stays 50°C. The mass fraction of cellulase (MFC) is 0.4% on the basis of the mass of dry leaves. The volume of water added in is 20mL on the basis of the mass of dry leaves and the pH value of buffer solution remains 4.6. Under these conditions, the ratio of polysaccharides (RP) can be 0.92% after two extractions for 180min in total and its RP is 12.05% higher than the traditional process.

Abstract: The present study was carried out to evaluate the anti-diabetic activity of polysaccharides from Agaricus bisporus mycelia (PABM) in alloxan-induced diabetes mellitus (DM) mice. After administration with 100, 200 and 400 mg/kg body weight of PABM to DM mice for 28 days, the effects of PABM on the body weight, blood glucose, serum insulin, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) levels were monitored. The results showed that the PABM could increase body weight, serum insulin and HDL-C levels, as well as decrease TC, TG and LDL-C levels in DM mice. PABM possess anti-diabetic activity.

Abstract: In this study, three kinds of component proteins of tilapia were hydrolyzed with papain for 4h. The effect of hydrolysis and the antioxidant activities of the resulting hydrolysates were characterized. The results showed sarcoplasmic protein hydrolysate had significantly (p < 0.05) highest scavenging ability against hydroxyl, superoxide, DPPH radicals and the total reducing power. Stroma protein hydrolysate had the highest nitrogen recovery (NR) while myofibrillar protein hydrolysate had the highest degree of hydrolysis (DH). Sarcoplasmic protein hydrolysate with high radical scavenging ability was separated by membrane ultrafiltration into four molecular size fractions (<5, 5–10, 10–100, >100kDa). It was found that the antioxidant activities of the <5kDa fraction were higher than that of other fractions. Overall, sarcoplasmic protein is more efficient to obtain antioxidant properties when compared to other component proteins of tilapia.

Abstract: Six kinds of thawing methods, including running water thawing, water/seawater soak thawing, refrigeration thawing, room temperature thawing and microwave thawing had been studied to investigate the influence of different thawing methods on the formaldehyde generation of aquatic product.. Formaldehyde content, water content, thawing loss and thawing time consumption of the frozen squids fillets had been determined. Results showed that the process of thawing could reduce the formaldehyde levels in the squid fillets. Moreover, samples thawed by water soaking had the lowest formaldehyde content and the highest water content. Characterized by a moderate thawing time, the water soak thawing methods was considered to be the best way to thaw frozen squids fillets. Microwave thawing and running water thawing were both highlighted to have the shortest time of thawing, however, they seemed to have slight effect on the formaldehyde reducing.

Abstract: Two reversible trypsin inhibitors, Kunitz trypsin inhibitor (KTI) and Bowman-Birk trypsin inhibitor (BBI) were compared to find the more optimal one as the inhibit factor during trypsin immobilization. Fluorescence spectroscopy, UV–visible absorption spectroscopy and circular dichroism (CD) spectroscopy were used to explore the effects of the two inhibitors on trypsin in activity and structure. The results showed that both inhibitors combined with trypsin in 1:1. CD circular dichroism spectroscopy showed that KTI and BBI led to different changes in trypsin second structure. The results can help us find out the mechanism between the two inhibitors and trypsin and select the more optimal inhibitor in trypsin immobilization.