中性蛋白酶限制性水解对高温菜籽粕蛋白功能性质的影响

研究了中性蛋白酶限制性水解菜籽蛋白的功能性质。结果表明,中性蛋白酶水解能显著改善高温菜籽粕蛋白的各种功能性质,限制性水解菜籽蛋白的溶解性随水解度的增加而增加,DH=10的限制性水解菜籽蛋白在pH7.0时溶解度达57.11%;DH=2的限制性水解菜籽蛋白乳化性最好,其在测定的pH范围内乳化性均较菜籽蛋白提高40%以上;DH=4的限制性水解菜籽蛋白起泡性最佳,可达162.5%;DH=2的限制性水解菜籽蛋白吸油性与吸水性均最好,且分别较原菜籽粕蛋白提高了2.6倍与1.9倍。     

Variation of glucosinolates in vegetable crops of Brassica rapa L. ssp. pekinensis

Glucosinolates of Chinese cabbage (Brassica rapa L. ssp. pekinensis) from Korea were characterised to determine the total glucosinolate content and the diversity amongst glucosinolates; 24 varieties were analysed. The profiles of 14 glucosinolates identified from the leaves were subjected to principal component analysis (PCA) to evaluate the differences among varieties. The Kori, Sandun and e-Norang varieties separated from the others based on glucosinolate concentration. Genetically modified Chinese cabbage containing the bar gene could not be separated from non-genetically modified varieties. Glucobrassicanapin, 4-methoxyglucobrassicin, gluconapin and glucobrassicin in Chinese cabbage were confirmed as the main glucosinolate compounds. The Kori, Sandun and e-Norang varieties appear to be good candidates for future breeding programmes since they have a high glucosinolate content. The presence of indolic glucosinolates in all varieties should be studied more extensively because they are the precursor of indole-3-carbinol, a potent cancer chemopreventive agent.     

Comparisons of flavonoids and anti-oxidative activities in seed coat,embryonic axis and cotyledon of black soybeans

Flavonoids contents, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activities and the ferric-reducing antioxidant power (FRAP) were compared in three black soybean varieties CRWD, Tainan 3 and Tainan 5. Varietal differences in antioxidant contents existed among the tested varieties. Variety CRWD accumulated more total phenolics (7.49 mg g⁻¹) and isoflavones (1.77 mg g⁻¹) than varieties Tainan 3 (7.05 mg g⁻¹ total phenolics and 1.58 mg g⁻¹ isoflavones) and Tainan 5 (4.38 mg g⁻¹ total phenolics and 0.63 mg g⁻¹ isoflavones). CRWD also accumulated more proanthocyanidins in seed coat than Tainan 3 and Tainan 5. CRWD also demonstrated greater DPPH and FRAP activities than the other two cultivars. Stepwise regressions indicated that both DPPH and FRAP activities were correlated well with the total contents of phenolics and flavonoids, with total phenolics being the most important anti-oxidative factor. The present results indicate that CRWD has greater anti-oxidative responses than Tainan 3 or Tainan 5, and is useful in functional food and other applications.     

Anti-oxidative characterisation of NaN3-induced common bean mutants

The contents of total phenolics, total anthocyanins, total proanthocyanidins and antioxidant activities were measured using 2,2-diphenyl-1-picrylhydrazyl radicals scavenging activity, ferric reducing antioxidant power, lipid peroxidation inhibition ability and ABTS⁻ radical-scavenging activity assays. These were compared in the seed coats of common bean (Phaseolus vulgaris L.) cultivar Hwachia and its eighteen NaN₃-induced mutants. NaN₃-induced mutants generally accumulated more total phenolics (19% more), total anthocyanins (65% more) and total proanthocyanidins (4% more) than Hwachia (containing 29.94 mg g⁻¹ total phenolics, 0.31 mg g⁻¹ total anthocyanins and 12.94 mg g⁻¹ total proanthocyanidins, respectively). Anthocyanidins including delphinine, cyanidin and pelargonidin were detectable in seed coat, each with different levels depending on the tested accessions. Significant correlations (average of 0.847 across all comparisons, p < 0.01) were found between the tested antioxidant activities, total phenolics, total anthocyanins and total proanthocyanidins. Mutants SA-11-2, SA-13-2 and SA-34-2 that are enriched with antioxidants may be useful in food and other applications.     

Effects of lipase,lipoxygenase, peroxidase and free fatty acids on volatile compound found in boiled buckwheat noodles

BACKGROUND: Relationships between buckwheat (Fagopyrum esculentum Moench) flour lipase, lipoxygenase and peroxidase activity, along with levels of individual free fatty acids (FFAs) and levels of headspace volatile compounds of boiled buckwheat noodles, were investigated for 12 different buckwheat varieties. Enzyme activities and FFA levels in flour were correlated with their respective varietal arrays of boiled noodle headspace volatile compounds, measured by gas chromatography–mass spectrometry. RESULTS: The volatiles hexanal, tentative butanal, tentative 3‐methylbutanal and tentative 2‐methylbutanal showed significant positive correlation with one another, indicating that they may be generated through similar mechanisms. These important volatile components of buckwheat flavor were also positively correlated with lipase and/or peroxidase activity, indicating that enzymatic reactions are important in flavor generation in boiled buckwheat noodles. On the other hand, pentanal, which showed no significant correlation with any enzyme activity, showed a significant positive correlation to the levels of C18:2 and C18:3 FFAs, suggesting the existence of a ‘non‐enzymatic’ and/or ‘uncertain enzymatic pathway’ for flavor generation in boiled buckwheat noodles. CONCLUSION: Lipase and peroxidase in buckwheat flour are important for flavor generation of boiled buckwheat noodles. This information is important for increasing desirable flavor of buckwheat products as well as for selecting varieties with improved flavor. Copyright © 2010 Society of Chemical Industry     

Microwave atomic force microscopy imaging for nanometer-scale electrical property characterization

We introduce a new type of microscopy which is capable of investigating surface topography and electrical property of conductive and dielectric materials simultaneously on a nanometer scale. The microwave atomic force microscopy is a combination of the principles of the scanning probe microscope and the microwave-measurement technique. As a result, under the noncontact AFM working conditions, we successfully generated a microwave image of a 200-nm Au film coating on a glass wafer substrate with a spatial resolution of 120 nm and a measured voltage difference of 19.2 mV between the two materials.     

EDGE技术在电力设备远程监控系统中的应用

阐述了EDGE无线路由通信系统的性能优越性,对系统硬件设计和软件设计进行了分析。将EDGE技术应用于电力系统监控中,保证了现场对实时性和可靠性的要求。     

TSD-10kW DAM发射机高压泄放电路的技术改造

通过TSD-10kWDAM中波全固态数字调幅广播发射机高压泄放电路的技术改造,提高了在特殊环境下机器工作的稳定性。特别是短期内买不到可控硅代换时（通常发射台都远离市区）,这是个很好的办法。     

新型Z源光伏并网发电系统

本文提出了一种新型Z源光伏并网发电系统,与传统的Z源光伏并网发电系统相比,具有更高的功率密度,同时光伏电池与逆变桥臂实现了共地,电磁干扰(EMI)也更小。分析了该发电系统的工作原理和调制策略,并提出了一种能够维持直流链峰值电压恒定的并网控制策略,实现了光伏电池的最大功率点跟踪(MPPT)、直流链电压的升压以及网侧电流的单位功率因数运行。仿真和实验结果验证了新型Z源光伏并网发电系统能够适应光伏电池电压的宽范围变化,具有很好的应用前景     

Intelligent wheelchair using head tilt and mouth shape

Proposed is an intelligent wheelchair (IW) for the severely disabled, where the direction of the IW is determined by the inclination of the user's head, while the stopping and starting are determined by the shape of the user's mouth. Since this mechanism requires minimal motion, the proposed IW is more comfortable and adaptable for the severely disabled.