Analysis in protein profile,antioxidant activity and structure-activity relationship based on ultrasound-assisted liquid-state fermentation of soybean meal with Bacillus subtilis

This study investigated effects of ultrasound on the contents of peptide and soluble protein, antioxidant activity, functionalities and structural characteristics of fermented soybean meal (FSBM) with Bacillus subtilis systematically. The results showed that there were significant effects of ultrasound treatments (frequency, treatment time and power density) on the contents of peptide and soluble protein (p < 0.05). Under the optimum ultrasound conditions (power density of 0.08 W/mL, frequency of 33 kHz and treatment time of 1 h) by single factor experiment, the contents of peptide and soluble protein increased by 31.27% and 18.79% compared to those of the control, respectively. Additionally, the in vitro antioxidant activity (•OH scavenging rate, Fe²⁺ chelating capacity and DPPH radical scavenging rate) and functional properties (emulsifying activity and emulsifying stability) of FSBM were found to be noticeably improved by ultrasound (p < 0.05). The fourier transform infrared (FTIR) spectroscopy revealed that ultrasound caused protein molecules to unfold with a decrease content of α-helix and β-turn and an increase in the proportion of β-sheet and random coil. Besides, atomic force microscope (AFM) results indicated that ultrasonication generally increased the surface roughness of protein and the protein sonicated with higher frequency (≥33 kHz) exhibited a greater height compared to lower frequency ultrasonication. Structure-activity relationship analysis illustrated that there was a good linear relationship between •OH scavenging rate and β-sheet/β-turn with Pearson’s correlation coefficient r of −0.86/0.90. Collectively, the selection of ultrasonic parameters is essential for the preparation of functional protein and bioactive peptide by enhancing fermentation of agroindustrial by-products.     

Caragisides A – C,New Isoflavone Glucosides from Caragana conferta with Inhibition of Platelet Aggregation

Caragisides A–C ( 1 – 3 , resp.), three new isoflavone glucosides, were isolated from the BuOH sub‐fraction of the EtOH extract of the whole plant of Caragana conferta, along with ononoside ( 4 ), reported for the first time from this species. The structures of the new compounds were elucidated by spectroscopic techniques including MS and 2D‐NMR spectroscopy. Compounds 1 – 3 showed significant inhibition of platelet aggregation.     

Influence of bromoalkyloxy side chain on mesomorphic behavior in heterocyclic 7-(4-bromoalkyloxy)-3-(4′-decyloxyphenyl)-4H- 1-benzopyran-4-ones

A new homologous series of isoflavone-based ethers,7-(4-bromoalkyloxy)-3-(4’-decyloxyprienyl)-4H-1-benzopyran-4-ones were synthesized and characterized.The mesomorphic properties of all homologues were investigated by differential scanning calorimetry(DSC) and polarizing optical microscopy(POM).Enantiotropic smectic A(SmA) phase was observed for all homologues.The structure-property study was carried out by comparing the mesomorphic behavior of the homologues with those previously reported analogues.The bromine atom from the alkyloxy side chain of the benzene ring fused to the heterocyclic moiety was found to be capable of changing the mesomorphic properties.     

Characterization and quantification of secondary metabolite profiles in leaves of red and white clover species by NIR and ATR-IR spectroscopy

Different varieties of two clover species (Trifolium pratense L. and Trifolium repens L.), cultivated in 2008 and 2009 were analysed by near-infrared (NIR) and mid-infrared (MIR) spectroscopy for establishing a fast and reliable quantification protocol for isoflavones and phenolic acids. Based on HPLC–UV/MS reference data, good results were obtained by PLS regression for the prediction of total isoflavone (R² = 0.90) as well as for glycitin content (R² = 0.88). Because of the lower concentration of formononetin and phenolic acids, their prediction quality was generally slightly lower (R² = 0.73 and R² = 0.64, respectively) compared to those of the isoflavones. The applicability of ‘leave one out’ cross validation for such a large data set is proven by comparison to an averaged randomized test-set validation leading to similar results. Additionally, the large sample set (n = 624) was screened by hierarchical cluster analysis allowing a fast evaluation of influences resulting from different cultivation parameters on the isoflavone and phenolic acid content. Climatic changes (cultivation year, date of harvest) seem to have the most impact on the metabolic profile as indicated by higher variability in the referring spectra when both cultivation years were simultaneously regarded. This work offers a new vibrational spectroscopic approach for the qualitative and quantitative determination of isoflavone and phenolic acid profiles, directly performed in the plant material without any laborious sample preparation and time-consuming chromatography. Once validated by HPLC reference, MIR and NIR spectroscopy can be used for the reliable prediction of secondary metabolites in clover as well as for fast screening and pre-evaluation of the diversity of a large sample set, aiming to reduce analytical costs, chemical waste and expenditure of time.     

大豆水分含量的高光谱无损检测及可视化研究

采用近红外高光谱成像技术对大豆水分含量进行快速无损检测,实现大豆水分含量可视化。采集了96个不同品种大豆样本在900～2 500 nm的高光谱图像,采用直接干燥法测量每个大豆样品的水分含量。利用系统自带的HSI Analyzer软件提取图像感兴趣区域（ROI）的平均光谱信息,代表样品的光谱信息。利用SPXY算法划分样品校正集和预测集,并保留938～2 215 nm波段范围内的光谱数据。采用移动平滑（moving average）、S-G平滑、基线校正（baseline）、归一化（normalize）、标准正态变量变换（standard normal variate,SNV）、多元散射校正（multiple scattering correction,MSC）、去趋势（detrending）共7种光谱预处理方法,发现Normalize方法处理后的PLSR模型效果较好。为了去除光谱冗余信息,简化预测模型,采用连续投影算法（SPA）、竞争性自适应加权算法（CARS）、无信息消除变量法（UVE）提取特征波长,其中SPA,CARS和UVE三种算法优选出14,16和29个波长,分别占总波长的6.5%,7.4%和13.4%。分别对938～2 215 nm波段光谱和特征波长建立预测模型,并将效果较优的模型与Normalize方法结合。建立的14种预测模型效果相比较,发现SPA算法筛选的特征波长建模预测效果较好,并优选出Normalize-SPA-PCR模型,模型的R２_C和Ｒ２_P值较高,分别为0.974 6和0.977 8,RMSEP和RMSECV值较低,分别为0.238和0.313,模型的稳定性和预测性较好,可以对大豆水分含量进行准确预测。将Normalize-SPA-PCR模型作为大豆水分含量可视化预测模型,计算高光谱图像每个像素点的水分含量,得到灰度图像,对灰度图像进行伪彩色变换,得到大豆水分含量可视化彩色图像。对预测集的24个大豆品种进行可视化处理,发现不同水分含量大豆的可视化图像颜色不同,水分含量变化对应的颜色变化较为明显。结果表明,高光谱成像技术结合化学计量学可以准确快速无损预测大豆水分含量,实现大豆水分含量可视化,为大豆收获、贮藏加工过程中水分含量检测提供了技术支持。     

基于图像检索的大豆食心虫虫害高光谱检测

为减轻虫害对大豆的影响,首先使用相应的高光谱仪器进行样本采集,样本分为4类：包括带有微小虫卵的,带有幼虫的,有啃食痕迹的和完全正常的大豆各20颗;然后提出了一种基于三维图像检索(3D-R-D,3D Resnet18 DCH)的大豆食心虫的高光谱检测方法。该方法从视频检索的应用中得到启发,考虑到视频不同帧之间和高光谱不同层之间存在类比关系,使用了在大规模视频检索数据集下训练而成的分类模型,将它作为预训练3D卷积模型进行训练。和已知的文献方法相同,使用公开的光谱数据集进行正式训练和微调,从而得到能进行特征提取的3D卷积网络,用图像检索来实现间接分类,通过利用样本之间的特征距离,实现在全新类别上的分类。为能适应任务,将模型最后的分类层变成了图像检索常用的hash层,从而得到了代表特征的二进制码。该方法不但完成了对不同情况下大豆种类的检测,还解决了训练时样本不足的问题。为探寻一种好的相似度匹配损失函数,对比了多种较新的方法,最后发现使用融入柯西分布的损失函数,实验效果最佳,最终模型的分类精度达86%±1.00%,和在大豆食心虫检测上最新的小样本方法对比,3D-R-D方法提高了3.5%左右的精度,表明该方法是有效的,它也为结合高光谱检测相关研究提供了一种全新思路。     

大豆二羟异黄酮及三羟异黄酮的高效液相色谱分析

1mol/L盐酸水解大豆及豆制品,乙腈提取,高效液相色谱分析了二羟、三羟异黄酮的含量。以甲醇－2mmol/L乙酸铵(体积比55:45,乙酸铵溶液用乙酸调pH至4.380)为流动相,Hypersil BDS C18色谱分析柱,柱温25℃,260nm紫外检测波长进行分析。二羟、三羟异黄酮的1－500μmol/L的范围内,与峰面积有很好的线性关系 (r=0.9999)。它们的检出限为5ng(S/N=3),平均回收率94.46%以上,6次进样的相对标准差（RSD）小于4％。该法灵敏、重复性好、结果准确、分析迅速。检测大豆及豆制品中异黄酮的含量,得到满意的结果。     

Availability of Isoflavones (Genistin,Genistein and Daidzein) in Soybean ( Glycine Max ) Curd Treated under High Pressure

The article describes the concentration of isoflavones (genistin, genistein and daidzein) in a Spanish commercial tofu treated under high-pressure. The tofu was subjected to pressure of 400 MPa, in cycles of 10 min each with a total of 4 cycles with the progression of 10, 20, 30 and 40 min, and a temperature of about 10-12 °C. The isoflavones were extracted from tofu with aqueous methanol solution (80:20). The content of isoflavones went up directly proportional to the pressure applied for the first 30 minutes. Afterwards, at 40 min, the values dropped close to the control. Significant differences were found in genistein, genistin and daidzein treated for 20 and 30 min in comparison to control values. Finally, we came to the conclusion that, the isoflavones (genistin, genistein and daidzein) of treated tofu were not destroyed at 400 Mpa for 30 min and a major extraction was observed when compared with the untreated tofu.     

四类大豆根瘤菌形态学研究

用电子和光学显微术对已报道的３类大豆根瘤菌以及快慢过渡型大豆根瘤菌进行形态学研究，发现在这４类大豆根瘤菌形态特征，特别是鞭毛特征上，有显著差异：快生型大豆根瘤菌为极生多鞭毛、快慢过渡型为周生鞭毛、慢生型为极生单鞭毛或亚极生单鞭毛．超慢生型未观察到鞭毛