Oxidase-peroxidase method for determination of ethanol in fermented musts and wine products

A new alcohol oxidase-peroxidase method of determination of ethanol content in fermented musts and wine products is described and compared to conventional methods routinely used in winemaking. The sensitivity, accuracy, and reliability of this method were determined. The results of ethanol determination in fermented musts and wines correlated well with the data obtained by refractometry (correlation coefficient R = 0.9595, p < 0.0001) and densitometry (correlation coefficient R = 0.9384, p < 0.0001). This method is less time- and labor-consuming and allows simultaneous testing a series of wine samples.     

Sources of error in the channels ratio method for efficiency determination in liquid scintillation counting

The reliability of the channels ratio method for determining counting efficiency in liquid scintillation counting was investigated. It was found that the efficiency of counting gels, cloudy samples, two-phase samples, samples in which the radioactive material was precipitating, and samples on solid supports could not be reliably determined from a normal quench correction curve. A curve constructed from external standard channels ratios was unreliable when mixing different vial sizes and sample volumes, but one constructed from sample channels ratios was not. It was also found that variation in instrument performance can result in large errors unless samples and standards are counted together. Statistical error changed relatively little within the range of ratios 0.3 to 0.8.     

响应面法优化以豆饼粉为基质发酵猪苓菌

为了提高豆饼粉的附加值,以豆饼粉为液体基质发酵猪苓菌。首先用Plackett-Burman方法筛选出影响菌体产量的主要因素,继而采用中心组合设计及响应面分析确定主要影响因子的最佳浓度。通过实验发现,当豆饼粉质量分数为3.7%,蛋白胨质量分数为0.6%,MgSO4质量分数为0.27%时,菌体产量达到最大值47.44 g/L。     

Optimization of free radical scavenging activity by response surface methodology in the hydrolysis of shrimp processing discards

Response surface methodology (RSM) was used to optimize the hydrolysis conditions (temperature, pH and Alcalase^® 2,4L concentration), in order to obtain the hydrolysate with the strongest antioxidant activity using the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) decolouration assay. The optimum conditions obtained from experiments were pH 9.7, 66.2 °C, enzyme concentration = 68.1 Anson units (AU)/kg crude protein. The analysis of variance in RSM showed that pH and temperature (T) were the most important factors of the process (P < 0.001). The experimental conditions produced both an enzymatic and chemical protein solubilization.     

Determining the optimum model parameters for oligosaccharide production efficiency using response surface integrated particle swarm optimization method: an experimental validation study

Abstract

Glucansucrases (GTFs) catalyzes the synthesis of α-glucans from sucrose and oligosaccharides in the presence of an acceptor sugar by transferring glucosyl units to the acceptor molecule with different linkages. The acceptor reactions can be affected by several parameters and this study aimed to determine the optimal reaction parameters for the production of glucansucrase-based oligosaccharides using sucrose and maltose as the donor and acceptor sugars, respectively via a hybrid technique of Response Surface Method (RSM) and Particle Swarm Optimization (PSO). The experimental design was performed using Central Composite Design and the tested parameters were enzyme concentration, acceptor:donor ratio and the reaction period. The optimization studies showed that enzyme concentration was the most effective parameter for the final oligosaccharides yields. The optimal values of the significant parameters determined for enzyme concentration and acceptor:donor ratio were 3.45?U and 0.62, respectively. Even the response surface plots for input parameters verified the PSO results, an experimental validation study was performed for the reverification. The experimental verification results obtained were also consistent with the PSO results. These findings will help our understanding in the role of different parameters for the production of oligosaccharides in the acceptor reactions of GTFs.     

Use of the bioluminescent method for the determination of bacterial adenosinetriphosphate (ATP-metry) in microbiology

The attention of a wide circle of specialists has recently been attracted by different methods for rapid determination of pathogenic microorganisms in biological specimens, environmental objects and foodstuffs, as well as in cases of possible acts of bioterrorism. In this respect the bioluminescent method for determination of adenosine triphosphate (ATP) contained in microbial cells is of interest. The method is based on the interaction ATP, luciferase and luciferin, accompanied by giving off energy in the form of light emission. When compared with routine methods, the use of this method considerably reduces the duration of the analysis, and its high sensitivity is comparable with that of the polymerase chain reaction. In this review the data on the prospects of the practical use of the bioluminescent method of ATP-metry are presented.     

Comparison of antiviral efficiency of immune responses in shrimp

The antiviral effectiveness of three major immune responses including phagocytosis, apoptosis and proPO system in the shrimp Marsupenaeus japonicus was characterized. It was found that the suppression of apoptosis and phagocytosis in vivo by their corresponding inhibitors resulted in the increase of white spot syndrome virus (WSSV) copies and shrimp mortality, whereas the inhibition of phenol oxidase generated the least influence on WSSV infection and shrimp mortality. These results suggest that apoptosis and phagocytosis were the essential immune responses to protect shrimp from virus infection, while the phenol-oxidase-dependent proPO system plays a comparatively minor role in antiviral defense of shrimp.     

A new easy method for determination of surface adhesion of phototrophic biofilms

Terrestrial cyanobacteria grow as phototrophic biofilms and offer a wide spectrum of interesting products. For cultivation of phototrophic biofilms different reactor concepts have been developed in the last years. One of the main influencing factors is the surface material and the adhesion strength of the chosen production strain. In this work a flow chamber was developed, in which, in combination with optical coherence tomography and computational fluid dynamics simulation, an easy analysis of adhesion forces between different biofilms and varied surface materials is possible. Hereby, differences between two cyanobacteria strains and two surface materials were shown. With longer cultivation time of biofilms adhesion increased in all experiments. Additionally, the content of extracellular polymeric substances was analyzed and its role in surface adhesion was evaluated. To test the comparability of obtained results from the flow chamber with other methods, analogous experiments were conducted with a rotational rheometer, which proved to be successful. Thus, with the presented flow chamber an easy to implement method for analysis of biofilm adhesion was developed, which can be used in future research for determination of suitable combinations of microorganisms with cultivation surfaces on lab scale in advance of larger processes.     

Use of molecule imprinting-chemiluminescence method for the determination of tamoxifen in breast cancer sufferers' urine.

The reaction between soluble Mn(IV) and tamoxifen can produce chemiluminescence and formaldehyde can enhance this chemiluminescence reaction. A tamoxifen molecular imprinted polymer (MIP) was synthesized and its adsorption selectivity to tamoxifen in aqueous solution was evaluated. Using a synthesized tamoxifen MIP as the recognition material and a soluble Mn(IV)-formaldehyde-tamoxifen chemiluminesence system as the detection system, a new molecule imprinting-chemiluminesence method of determination of tamoxifen was established. The response range of this method was 1.0 x 10(-7)-6.0 x 10(-6) g/mL, with a linear correlation coefficient of 0.997. The detection limit was 4 x 10(-8) g/mL. The relative standard deviation for 5.0 x 10(-7) g/mL tamoxifen solution was 4.1% (n = 9).     

响应面法优化微波辅助提取发酵虫草菌丝体多糖工艺

为优化发酵虫草菌粉多糖的微波辅助提取工艺,在单因素实验基础上,以液固比、微波功率以及提取时间为自变量,多糖提取率为响应值,采用中心组合设计的方法,研究各自变量及其交互作用对多糖提取率的影响。利用SAS软件和响应面分析相结合的方法对发酵虫草菌粉多糖的微波辅助提取工艺进行优化,确定了微波辅助提取多糖的最佳条件：液固比值12．2,微波功率650．5W,提取时间11．8min,在此条件下,多糖提取率达到6．41％。采用此法提取的虫草菌丝体多糖,当质量浓度为1mg／mL时,对二苯代苦味肼基自由基（DPPH）清除率达到76％。