杜仲胶提取与规模化生产现状及其产业发展面临的问题

杜仲是我国非常宝贵的战略资源,杜仲胶是带动杜仲大产业发展的核心动力.杜仲胶产业的发展不仅能够改善我国天然橡胶不足的现状,还可以为我国提供新的来源充足的后备胶种,形成以我国杜仲胶新兴产业为龙头的国际天然橡胶市场新格局.近年来,杜仲胶产业化和应用开发虽然取得突出进展,但还远不能适应形势发展的需要,究其原因是杜仲产业链的发展...     

Effect of ultrasound treatment on properties of gluten-based film

Gluten films obtained in acid conditions display some protein dispersion difficulties. Ultrasound treatment (UT) could represent an interesting strategy for improving gluten film appearance. Different UT exposure times were applied to film-forming dispersion. The aim of this work was to investigate the effect of ultrasound treatment on gluten-based films at molecular and mesoscopic levels. Distribution in gliadin and glutenins was determined with SE-HPLC. The UT improved protein dispersion and final film appearance. Sonication did not lead to large changes in various gluten fractions, which suggests absence of important protein breakdown at the molecular level. Gluten showed high tolerance to UT. Surface properties of untreated and treated films were investigated by contact angle measurement: sonication promoted hydrophilic surface properties.Industrial relevanceBio-based packaging has been receiving increasing attention in view of its beneficial impact on the environment. Among proteins, gluten resulted as a very interesting film-forming material. Gluten films prepared in acid conditions showed problems in protein dispersion. Sonication represents a physical strategy which allowed us to obtain gluten-based films without the addition of chemical additives, such as sodium sulphite.     

基于高通量测序分析刺梨果渣自然发酵过程中细菌群落结构及多样性

为分析刺梨果渣自然发酵过程中各阶段的细菌群落结构及多样性,利用MiSeq高通量测序技术检测自然发酵刺梨果渣中细菌的16S rDNA基因V3~V4高变区序列,比较发酵6~60 d (每隔6 d取一次样)时细菌群落的差异。结果显示:10个不同发酵时期样本中共检测而出26个门类、40个纲类群、74个目类群、162个科类群、373个属类群。在整个发酵过程中,主要以葡糖杆菌属和醋酸杆菌属为主。发酵结束后,在门相对水平丰度值依次是变形菌门(Proteobacteria,99.85%)、厚壁菌门(Firmicutes,0.03%)、放线菌门(Actinobacteria,0.02%)和拟杆菌门(Bacteroidetes,0.02%),在整个发酵过程中变形菌门占主要地位;在属相对水平丰度值排前面的葡糖杆菌属(Gluconobacter,65.37%)和醋酸杆菌属(Acetobacter,33.66%)为刺梨果渣发酵过程中绝对的优势菌;发酵后期细菌群落趋于稳定,表明刺梨果渣自然发酵过程中微生物群落结构变化是相对稳定的。     

麸曲酱香白酒自动化通风制曲技术的应用及工艺总结

针对目前麸曲酱香白酒麸曲生产过程中存在的问题,对曲房和通风池进行改善,实现自动控温、控湿,对白曲、酵母、细菌的自动化通风制曲工艺进行了总结。改善后,白曲糖化力由500 mg/(g·h)提高到了700 mg/(g·h),酵母曲菌数由107 CFU/g曲提高到了109 CFU/g曲,细菌曲糖化力由120 mg/(g·h)提高到了200 mg/(g·h),液化力由原来的1.7 g/(g·h)提高到了4.5 g/(g·h)。     

蓝莓果渣花色苷大孔树脂纯化工艺研究

以蓝莓果渣为原料,利用大孔树脂分离纯化蓝莓果渣花色苷。对比了D101和AB-8两种不同极性的大孔树脂静态吸附和解吸效果。结果表明,AB-8型大孔树脂吸附率和解吸率分别为88.5%、64.7%;D101型大孔树脂吸附率和解吸率分别为86.7%、61.2%,AB-8型大孔树脂吸附率和解吸率均优于D101型大孔树脂,故选用AB-8型大孔树脂对蓝莓果渣进行纯化试验。AB-8型大孔树脂最佳吸附和解吸条件为吸附平衡时间4 h,解吸平衡时间4 h,花色苷溶液pH 3.0,解吸液pH 3.0,解吸液乙醇体积分数60%,上样质量浓度1 mg/mL,上样流速1 mL/min,洗脱流速1 mL/min。纯化后蓝莓果渣花色苷色价约为纯化前的3倍,糖和蛋白质等杂质大幅降低,纯度有了较大提高。     

刺梨白粉病拮抗菌的筛选及其抑菌机制初探

为筛选出对刺梨白粉病具有良好抑制作用的拮抗菌,从健康刺梨及其根系土壤进行微生物分离,以刺梨白粉病病原菌(Sphaerotheca pannosa)为靶标菌株,采用叶盘法对拮抗菌进行筛选,通过形态学、生理生化特征以及16S rRNA对筛选的拮抗菌进行鉴定,测定其OD值绘制生长曲线,并探究拮抗菌对病原菌孢子萌发和菌丝的影响及其产酶情况。结果表明:共分离得到48株细菌,其中JK-6和JK-32具有显著抑制作用,经鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)和空气芽孢杆菌(Bacillus aerius),对刺梨白粉病的防治效果达到了60%和57%;拮抗菌作用下致使病原菌的孢子在萌发过程中发生异常膨大现象,菌丝表面变得粗糙、膨大、缠绕和融断;产酶情况表明两株拮抗菌均可产生蛋白酶、纤维素酶以及果胶酶。为刺梨白粉病的生物防治提供了理论基础,具有进一步研究价值。     

五种果汁的酚类组成及其抗氧化、抗肿瘤细胞增殖活性研究

本文对比研究了五种果汁中维生素C与总酚含量,采用高效液相色谱法测定了果汁中的酚类组成,并采用化学法和细胞法评价了果汁的抗氧化和抗肿瘤细胞增殖活性.刺梨汁的维生素C含量最高,为14.13 g/L.刺梨汁和沙棘汁的总酚含量最高,分别为13.06和12.53 g GAE/L,且二者无显著性差异(P>0.05).从5种果汁中共...     

Optically tuneable broadband terahertz metamaterials using photosensitive semiconductor material

We present optically tuneable broadband terahertz metamaterials consisting of photosensitive semiconductor material. The characteristics of semiconductor materials are very important for terahertz functional devices, which is strongly dependent on the photoexcited carriers in semiconductor materials. Based on the model of the generation of the carriers in semiconductor materials, the tuneability of the resonance frequency and resonance strength in terahertz metamaterials under the femtosecond laser pulse has been analysed. The experimental results of the transmissivities of several bare semiconductor materials show that GaAs semiconductor could be a potential candidate for broadband terahertz functional devices design. Moreover, the simulation results of the resonance frequency increase with the increase of the laser fluence, whereas the resonance strength near the resonance frequency is significantly weakened with the increase of the laser fluence. Meanwhile, the modulation depth can be reached approximately 90% at 1.24 THz. Our proposed broadband tuneable terahertz metamaterials have numerous potential applications, including terahertz modulator, absorber and switches.     

Dispersion-free highly accurate color recognition using excitonic 2D materials and machine learning

Dispersion is accepted as a fundamental step required for analyzing broadband light. The recognition of color by the human eye, its digital reproduction by a camera, or detailed analysis by a spectrometer all utilize dispersion; it is also an inherent component of color detection and machine vision. Here, we present a device (called artificial eye or, A-Eye) that accurately recognizes and reproduces tested colors, without any spectral dispersion. Instead, A-Eye uses N = 3–12 transmissive windows each with unique spectral features resulting from the broadband transmittance and excitonic peak-features of 2D transition metal dichalcogenides. Colored light passing through (and modified by) these windows and incident on a single photodetector generated different photocurrents, and these were used to create a reference database (training set) for 1337 “seen” and 0.55 million synthesized “unseen” colors. By “looking” at test colors modified by these windows, A-Eye can accurately recognize and reproduce “seen” colors with zero deviation from their original spectra and “unseen” colors with only ∼1 % median deviation, using the k-NN algorithm. A-Eye can continuously improve color estimation by adding any corrected guesses to its training database. A-Eye’s accurate color recognition dispels the notion that dispersion of colors is a prerequisite for color identification and paves the way for ultra-reliable color-recognition by machines with reduced engineering complexity.