Multiplex-PCR method application to identify duck blood and its adulterated varieties.

This study applied and validated the Multiplex-PCR method to identify the authenticity of duck blood and four common adulterated animal blood varieties. To this end, the genomic DNAs of duck blood and its counterfeit products were extracted using an efficient high-throughput extraction method. Specific primers were designed using the cytochrome b gene. The reaction system and conditions of a multiplex (namely, Five-plex) PCR were optimized, and the proposed methodology was verified, proving its good specificity, repeatability, and sensitivity. The Five-plex PCR system detected nine duck blood samples sold in the local market, revealing the adulteration of duck blood products. The Multiplex-PCR system can accurately and quickly detect adulterated animal blood in duck blood products, effectively finding counterfeits and identifying the authenticity of genuine duck blood products.

Characterization of a novel aspartic protease from Trichoderma asperellum for the preparation of duck blood peptides.

A novel aspartic protease gene (TaproA1) from Trichoderma asperellum was successfully expressed in Komagataella phaffii (Pichia pastoris). TaproA1 showed 52.8% amino acid sequence identity with the aspartic protease PEP3 from Coccidioides posadasii C735. TaproA1 was efficiently produced in a 5 L fermenter with a protease activity of 4092 U/mL. It exhibited optimal reaction conditions at pH 3.0 and 50 °C and was stable within pH 3.0-6.0 and at temperatures up to 45 °C. The protease exhibited broad substrate specificity with high hydrolysis activity towards myoglobin and hemoglobin. Furthermore, duck blood proteins (hemoglobin and plasma protein) were hydrolyzed by TaproA1 to prepare bioactive peptides with high ACE inhibitory activity. The IC50 values of hemoglobin and plasma protein hydrolysates from duck blood proteins were 0.105 mg/mL and 0.091 mg/mL, respectively. Thus, the high yield and excellent biochemical characterization of TaproA1 presented here make it a potential candidate for the preparation of duck blood peptides. KEY POINTS: • An aspartic protease (TaproA1) from Trichoderma asperellum was expressed in Komagataella phaffii. • TaproA1 exhibited broad substrate specificity and the highest activity towards myoglobin and hemoglobin. • TaproA1 has great potential for the preparation of bioactive peptides from duck blood proteins.

Effects of konjac glucomannan as a freeze-denaturation inhibitor or binder on the physiochemical properties of heat-induced gel of freeze-dried duck blood.

During freeze-drying, the degradation or eutectic melting of duck blood proteins can reduce the quality of duck blood gels. However, the interaction between proteins and polysaccharides during drying can improve protein-based gel quality. Therefore, here, we investigated the physicochemical properties of heat-induced gels of freeze-dried duck blood (FDB) and FDB with different proportions of the polysaccharide konjac glucomannan (KG), which serves as a freeze-denaturation inhibitor agent (FDA) or binder (BG). The pH and water-holding capacity (WHC) of FDB + KG gels were higher than those of FDB gel without KG (control). Especially, the WHC increased from 11.00% for control to 55.65% for FDB gel with 1% KG as a BG. Consequently, cooking loss and texture parameters of FDB + KG gels decreased. The hardness of control was 2.14 kg, which significantly reduced to 0.12-0.87 kg with KG addition. The highest carbonyl content was observed in control gel, and the thiobarbituric acid reactive substance content was reduced by the addition of 1% KG as an FDA (T1) or 0.8% KG as an FDA with 0.2% KG as a BG (T2) (p < 0.05). These changes might be induced by the alteration of tertiary structure and thermodynamic stability of gels. In conclusion, 1% KG can be used as an FDA to improve the quality and physicochemical properties of heat-induced gels of FDB. Optimized FDB gels with KG can be used as an innovative food ingredient to fortify nutrition and develop special dietary purposes.

Effect of Drying Methods on Physicochemical Characteristics and Functional Properties of Duck Blood Gel.

The drying of duck blood provides safety and commercial benefits, but each drying method has its own characteristics. Moreover, information on the effects of diverse drying methods on the quality of duck blood is limited. This study aimed to investigate the effects of various drying methods on the chemical and functional properties of duck blood. The physicochemical characteristics and functional properties of duck blood subjected to spray drying (SD), freeze drying (FD), vacuum drying (VD), and hot air drying (HD) were examined. The carbonyl content of FD duck blood powder was the lowest and the thermal stability was higher than that of the other treatments (p<0.05). The gel obtained from spray-dried blood displayed the lowest malondialdehyde content. The hardness, gumminess, and chewiness were the highest in the heat-induced gel prepared from FD duck blood powder (p<0.05). The gel obtained from FD duck blood displayed a denser structure than the other gel samples. Taken together, the FD duck blood exhibited excellent chemical properties and processing suitability.

Effects of added cereal fibers on the quality characteristics of black pudding prepared with duck blood.

We investigated the physicochemical and rheological properties of black pudding prepared with duck blood using various combinations of cereal fiber sources: oat, buckwheat, quinoa, amaranth, and sorghum. The processing yield of black pudding made with duck blood and the cereals was higher than that of the control (without cereals) in all cases (P < 0.05). The moisture content of the black pudding was the highest in the buckwheat and amaranth groups (P < 0.05). The water activity, pH, and yellowness of the black pudding combined with duck blood and cereals were lower than that of the control (P < 0.05). The hardness of the black pudding with duck blood and cereals was higher than that of the control (P < 0.05), except for the amaranth group. The cohesiveness, gumminess, and chewiness of the black pudding with duck blood and cereals were higher than that of the control (P < 0.05). Differential scanning colorimetry showed distinct peak points according to treatment at the same temperature, and all treatments exhibited 2 peak temperatures, except for sorghum. The viscosities of all samples, including the control, decreased as the shear rate increased, and the viscosity of the black pudding with oat was slightly lower than that of the other samples. Thus, black pudding prepared with duck blood and cereal fibers showed excellent physicochemical and rheological properties, suggesting an improved processing method. These findings can further the development of products using duck blood as a valuable nutritional source rather than being lost as a by-product during slaughter.

Investigation of optimal conditions for production of antioxidant peptides from duck blood plasma: response surface methodology.

Duck blood is rich in protein. It is one of the main by-products in the slaughter industry. The objective of this research was to optimize and establish a method for producing duck plasma antioxidant peptides. The composition of duck plasma powder was analyzed. Protease selection experiment (Alcalase, Protamex, and Flavourzyme) and single-factor experiment were performed, and response surface methodology was used to determine the optimal hydrolysis conditions for duck plasma. Among the proteases, Alcalase hydrolysate exhibited the strongest 1,1-diphenyl-2-picrylhydrazyl scavenging rate. The optimum enzymatic hydrolysis conditions were hydrolysis time of 6 h, temperature of 65.5°C, pH 10.0, and enzyme-to-substrate ratio of 0.3%. The 1,1-diphenyl-2-picrylhydrazyl scavenging rate reached 64.84%, and the ratio of essential amino acids was 38.76%. Briefly, the duck plasma hydrolysate exhibited strong antioxidant properties and reasonable composition of amino acids. Thus, it may be used as a nutritional or functional ingredient in foods or medicines. This research provides a theoretical basis for comprehensive processing and high value utilization of duck plasma.

Preparation of heme from duck blood by a new acidified acetone extraction method / 中国药学杂志

OBJECTIVE: To prepare heme from cherry valley duck blood. METHODS: Single factor experiments and orthogonal experiment were carried out to establish the optimal process of preparing heme from cherry valley duck blood by a new microwave-assisted acid acetone extraction method. RESULTS: Single factor experiments proved that the microwave-assisted extraction process significantly improved the extraction efficiency of heme. In addition, orthogonal experiment indicated the power of microwave and microwave extraction time had significant effects on the extraction results, and the optimum conditions of microwave-assisted extraction in laboratory were as follows: the power was 800 W, extraction time was 60 min, and the temperature was 50°C. CONCLUSION: The new microwave-assisted method, combining cell disruption and heme extraction process, can simplify the traditional acid acetone extraction process, and it is proved to be feasible.

Experimental Study on In-vivo Effect of Compound Phyllanthus urinaria Ⅱ on Duck Hepatitis B Virus / 广州中医药大学学报

Objective To evaluate the in-vivo effect of Compound Phyllanthus urinaria Ⅱ(CPU Ⅱ) on duck hepatitis B virus(DHBV).Methods Thirty ducks with congenital infection of DHBV,which were DHBV-DNA positive confirmed by polymerase chain reaction(PCR),were randomly divided into 5 groups: DHBV control group,high-,middle-,and low-dosage CPU Ⅱgroups(in the dose of 33.6,18.6 and 8.4 g-1?d-1,respectively),and Lamivudine group(20 mg?kg-1?d-1).The serum DHBV-DNA level of all ducks was detected by quantity real-time fluorescence PCR before and after medication.Results On the 7th,14th,21st,and 28th day of medication and on the 5th day of suspension of medication,the serum DHBV-DNA level in both of the high-and middle-dosage CPU Ⅱ groups was obviously lower than that before medication and than that in the DHBV control group(P