Advanced Materials Research Vols. 396-398

Abstract: Abstract. The chromatographic conditions for the separation of glucose, maltose and maltotriose on a ZORBAX Eclipse XDB-C18 column (4 um, 4.6×250mm) by use of a 2414 differential refractometer detector were determined. The square of the correlation coefficient of glucose, sucrose, maltose and maltotriose was 0.9973, 0.9981, 0.9977 and 0.9987, respectively. When the ratio of signal and noise was 3, the detection limit of glucose, sucrose, maltose and maltotriose was 0.3, 0.3, 0.20, 0.20 mg/mL the β-amylase hydrolysates consisted mainly of maltose, and maltotriose next, glucose only in trace amount, and no sucrose. The RSD of glucose, maltose and maltotriose was 2.08%, 2.41% and 2.61%, respectively. And the recovery of glucose, maltose and maltotriose was 101.3%, 98.4% and 93.5%. It was credible to separate sugars from hydrolysates. The method is important for improving the inducible enzymes activity.

Abstract: Apple-roxburgh rose dregs are rich in insoluble dietary fiber. To prepare the granular insoluble dietary fiber from the dregs by chemical method, single-factor experiments were carried out considering such factors as the ratio of solution and dregs,the size of the dregs,NaOH concentration,the extraction temperature and time. The optimal extractions conditions were obtained by L9(34) orthogonal methodology considering such factors as the size of the dregs,NaOH concentration,the extraction temperature and time, and they were as follows:fresh dregs were extracted by 70%(v/v) at 60°C for 15 min, then dregs were dried at 70°C and powdered, dregs were sifted through 60-mesh sieve and the soluble pectin was get rid of by slight acid solution. Dregs were sifted through 40-mesh sieve and mixed with 1.0mol/L NaOH solution at the ratio of 5∶1, the mixture was kept at 60°C for 3.0h. At last, dregs were dried and powdered. The granular insoluble dietary fiber was thus prepared with the yield of 83.7%. The water holding capability and hydration capability of finished granular product are 17.0 gram water and 4.3 ml per gram product, respectively. Preparation of granular insoluble dietary fiber from apple-roxburgh rose dregs is practiced and there is a few literatures concerning this research.

Abstract: Purpose To research out a suitable method for the determination of enzymatic activity for β-glucan synthase. Methods According to the methods for the determination of ΒGS in current reports, taking Grifola frondosa as material, a suitable method for the determination of enzymatic activity for ΒGS was researched out. ΒGS was isolated from the mycelium of Grifola frondosa. Taking glucose as substrate, ΒGS activity was reflected by the consumption of glucose. Consumption of glucose was measured by 3,5-dinitrosalicylic acid (DNS) method, the standard curve for glucose content measurement was plotted by determining absorbance values of different glucose concentrations at 540nm. One unit of ΒGS corresponds to the amount of enzyme which incorporated 1μg glucose into β-glucan in 1 minute. The optimum pH and temperature of the determination of enzymatic activity for ΒGS was determined respectively by carrying out the enzyme assay at different pH levels and temperatures. Results The method for the determination of enzymatic activity for ΒGS was a suitable, correct and usable method which can be popularized widely. The regression equation of the standard curve for glucose content measurement was y=0.0008x-0.0247, R2=0.9996. The optimum pH of the determination of enzymatic activity for ΒGS was pH=5.0 and the optimum temperature was 15°C. The suitable determination process for β-glucan synthase enzymatic activity is as follows: 1.0ml of enzyme was added in a test tube followed by 1.0 ml glucose (1.0mg/ml), and then the pH level was adjusted to 5.0. The test tube was incubated at 15°C for 10 minutes. Later, DNS reagent (1.5ml) was added to the test tube kept in boiling water for 5 minutes and cooled in water. A blank was prepared (2.0ml distilled water and 1.5ml DNS solution). Each solution was fixed the volume to 25ml, the color intensity was estimated at 540 nm using spectrophotometry. Conclusion A method for the determination of enzymatic activity for β-glucan synthase was researched out by taking Grifola frondosa as material, and it can be widely extended and applied by its characteristics of simple, rapid, high sensitivity and low cost.

Abstract: The scum of mixed juice is a by-product in sugarcane factory, which used up-floating method for mixed juice clarification. The scum is of great research and utilization value due to its rich organic non-sugar compounds such as proteins, lipids and polyphenols. Studies on the free radical scavenging capacity and reducing power of water extraction sample (A) and macroporous resin purified sample (B) from mixed juice scum were investigated, comparing with Vc. It was showed that the antioxidant activity of macroporous resin purified sample (B) was much stronger than that of water extraction sample (A) and Vc in , and system. For example, the scavenging capacity of sample B on was 11 times than that of Vc and 1450 times of sample A. In addition, the free radical scavenging activity of sample A and B was dependent on the sample concentration. Results in this study indicated that scum of mixed juice may be a promising natural antioxidant, which can be used as additives in food industry or feed industry.

Abstract: Tea (Camellia sinensis L.) has became one of the most consumed beverages in the world in the past five thousand years, and tea polyphenols (TPs) are important organic acids widely used in chemical, pharmaceutical, food and other industries, which have been shown to exhibit various biological and pharmacological properties. In order to look for new technology of downstream process for TPs separation from green tea waste, selective extraction of TPs with 12 varieties of solvents were carried out, the distribution coefficient and equilibrium experiments at various temperatures were described by extraction isotherms model. The results indicated that the optimum solvent conditions were as follow: extractent was glyceryl triacetate, extraction temperature range was 20~30°C, pH value of crude TPs and reextractant were 3.17 and 9, respectively. Equilibrium data of TPs were successfully fitted to Henry isotherm, the distribution coefficient decreases with the increasing of the temperature, which showing an exothermic adsorption process. The data obtained is useful in the designing of solvent extraction process for the recovery of TPs from green tea waste.

Abstract: In this paper, B-type microcrystalline starch made a combination with ethanol, butanol, hexanol and octanol respectively under certain conditions, a series of V-type amylose-alcohol complexes were prepared. Infrared absorption spectra of obtained Vethanol, Vbutanol, Vhexanol, Voctanol were measured qualitatively to determine the certain alcohol in V-type complexes; Further application of principal component analysis (PCA) with SPSS13.0, DPS7.05 statistical software for analysis calculation of infrared absorption spectra. The result showed that the content of alcohol in Vethanol, Vbutanol, Vhexanol, Voctanol were 19.8%, 14.1%, 9.79% and 8.3%.

Abstract: In the present work, a hyperthermostable superoxide dismutase (SOD) was isolated from Thermus thermophilus HB27 using a membrane-based process after being expressed in E. coli. It was found that a two-stage ultrafiltration process using a 100 kDa MWCO regenerated cellulose (RC) membrane and a 50 kDa MWCO polyethersulfone (PES) membrane could successfully employed to isolate SOD from the crude feedstock. The effects of solution pH, ionic strength and permeate flux on the transmission of proteins were quantified using parameter scanning ultrafiltration. Under optimized conditions, the purity of SOD obtained was 96% with a sepcific activity of 1412 U/mg protein and the recovery of SOD from the feedback was close to 87%. The enzyme was highly stable at 90°C and retained 63% activity after heat treatment at 100°C for 1 h.

Abstract: The ethanol/moisture contents in fermented grains were measured and systematic experiments were carried out to investigate the optimal operation condition for distillation of Chinese Luzhou-flavor liquor. The results show that from the top surface (0 m depth) of fermentation tank to the bottom (2 m depth), the moisture content in the grains increases linearly from 60.67 wt.% to 70.44 wt.%, while the ethanol content presents a parabolic distribution with maximal content of 6.29 wt.% at 1.5 m depth. It is found that for efficient distillation of fermented grains, there exists an optimal steam flowrate at which the maximum yield of distilled liquor will be achieved. For the grains with given moisture content, the optimal steam flowrate keeps nearly constant with different ethanol contents, while for the grains with given ethanol content, the optimal steam flowrate increases as the moisture content become increased. Combined with the gas chromatography analysis, it is also presented that the distilled liquor obtained from the grains with higher ethanol content and/or lower moisture content will contain higher concentration of alcohol-soluble flavor compounds, so that the distilled liquor has better quality. The findings in this study provide important reference for the optimization of distillation process of Chinese Luzhou-flavor liquor.

Abstract: To improve the production of dextran, fermentation conditions for cultivation of an Leuconostoc mesenteroides CICC-21725 were investigated. The fermentation conditions were optimized preliminarily by using the method of univariate experiment in the shake-flask culture, and the yield rate of dextran was used as the investigation index. The result shows that when the fermentation temperature, initial pH value, rotation speed and inoculum concentration were 25 °C, 7.5 , 0 r/min and 10%, respectively, the yield rate of dextran was the highest. Under the optimal fermentation conditions, the yield rate is approximately 98%, which is about 12% higher than the unoptimized.

Abstract: The effects of germination on the bio-functional components in the germ-remaining polished rice have been investigated. The bio-functional components in the raw GRPR, brown rice and germinated brown rice were also characterized as the comparison. The results showed that a decrease in amylose content and an increase in reducing sugar were observed after germination. The germinated GRPR contains much more bio-functional components (GABA and dietary fiber) than GRPR and brown rice, and slightly less than germinated brown rice. The results also demonstrated that germinated GRPR contained less phytic acid than other three kinds of rice. Consequently, the nutritional value of GRPR had been improved by germination. Germination of GRPR would be a promising processing method to enhance the germinated rice consumption.