响应面设计对牛蒡无糖保健饮料口味的优化

以鲜牛蒡为原料制备牛蒡无糖保健饮料,通过响应面优化了其最佳配方,并测定了可溶性固形物含量、酸度、粘度、总糖、V C含量、菌落数等指标。研究结果表明,最佳配方为:牛蒡汁15.25%,甜蜜素0.32‰,柠檬香精0.32%,柠檬酸0.42%,制得的产品具有牛蒡的特殊香气,味感柔和,酸甜适口,乳白色,均匀一致无沉淀。      

基于改进EMD和LS-SVM的刀具磨损状态识别

针对经验模态分解(empirical mode decomposition, EMD)的端点效应、停止准则和虚假分量作了改进处理, 通过对仿真信号的对比验证证明了改进方法的可行性.采集切削加工中的声发射(acoustic emission, AE)信号并对AE信号运用改进EMD方法分解为若干个固有模态函数(intrinsic mode function, IMF)分量, 利用IMF分量和原始信号的相关系数作为判断依据, 剔除分解中产生的虚假分量, 然后提取IMF分量的归一化能量值并将其作为特征向量.将提取的特征向量分为2组:一组用于对最小二乘支持向量机(least squares support vector machine, LS-SVM)训练;另一组用于识别刀具磨损状态.实验结果表明该方法可有效地表征刀具的磨损状态.     

产乳酸菌素菌株的筛选鉴定及其特性分析

本实验对广西巴马村天然发酵米粉中的乳酸菌进行分离鉴定,筛选出一株具有抑菌活性的植物乳杆菌M44,并研究了其所产乳酸菌素的基本性质。采用微生物形态学和16S r DNA序列分析法鉴定菌株M44为植物乳杆菌,其发酵上清液具有抑菌活性,抑菌物质确定为蛋白类。采用盐析法粗提所产乳酸菌素,确定最佳硫酸铵沉淀浓度为60%。由乳酸菌素产量与菌株生长的关系实验得出乳酸菌素的最佳收获时间为发酵培养12 h。管碟法抑菌实验表明,该乳酸菌素在p H范围2~8时有良好的抑菌活性;121℃处理15 min后仍具有抑菌活性;胃蛋白酶、胰蛋白酶处理后抑菌性消失;对单核增生李斯特细菌、大肠杆菌、沙门氏菌,金黄色葡萄球菌均有抑制作用。该乳酸菌素为天然生物防腐剂的开发与应用提供了研究基础。      

不同干燥方法对酸枣叶中核苷类、氨基酸类及黄酮类成分的影响

为研究不同干燥方法对酸枣叶干燥过程中内在质量的影响,采用UPLC-TQ MS法和HPLC法分别建立酸枣叶中20种核苷类和23种氨基酸类,以及黄酮类成分芦丁的分析方法,并探索不同干燥方法对酸枣叶中上述组分组成及含量的影响。研究结果表明本研究所建立的分析方法简便、准确可靠;所有样品均富含核苷类、游离氨基酸类及黄酮类成分芦丁,其中核苷类成分以磷酸化产物如胞苷-5’-单磷酸、腺苷-5’-单磷酸、鸟苷-5’-单磷酸含量相对较高,游离氨基酸类成分以脯氨酸、酪氨酸、γ-氨基丁酸含量相对较高;且所有干燥加工后样品其上述成分含量均总体高于新鲜样品。依据各样品中所测定成分的含量,采用TOPSIS分析法,对不同干燥方法干燥样品的内在质量进行了综合评价,结果显示以自然晒干样品和40℃热风干燥样品品质较优,而新鲜样品及70℃热风干燥样品品质较差。以上研究结果为酸枣叶产地干燥加工过程适宜干燥工艺的确定提供了数据支撑,也为叶类药材的干燥加工提供了借鉴。      

花生红衣乙醇提取物乙酸乙酯组分抑菌活性的研究

花生红衣乙醇提取物乙酸乙酯部位加入AB-8大孔树脂层析柱中,用20%、40%、60%、80%、100%乙醇水溶液依次洗脱,得到花生红衣乙醇提取物乙酸乙酯组分,采用滤纸片法研究其抑菌活性,确定最小抑菌浓度。结果表明:花生红衣乙醇提取物乙酸乙酯组分对大肠杆菌、金黄色葡萄球菌、枯草芽胞杆菌、青霉、毛霉和黑曲霉的生长具有一定的抑制作用,最低抑菌浓度均为0.5 g/L,且抑菌圈大小随浓度的增加而变大。花生红衣乙醇提取物乙酸乙酯组分均具有广谱抑菌活性。      

羧甲基纤维素钠纳米抗菌复合膜的制备及其性能研究

以羧甲基纤维素钠（CMC-Na）为基质,添加天然抗菌剂肉桂醛和纳米蒙脱土（MMT）,通过溶液流延成膜法制备不同MMT含量的纳米抗菌复合膜,研究纳米MMT含量对复合膜的机械性能、水蒸气透过率、透明度、肉桂醛释放能力及抗菌性的影响。结果表明膜的拉伸强度和断裂伸长率都随着MMT含量的升高而先增加后降低,在MMT含量为4%时,拉伸强度达最大。水蒸气透过率和透明度随MMT含量的增加逐渐降低;并且MMT能有效限制肉桂醛在膜中的扩散和释放,使肉桂醛释放速率变慢,随着存放时间的延长,含MMT的膜保持较高的抗菌性活性,而不含MMT的膜,肉桂醛挥发较多,抗菌性大大降低。结论:纳米蒙脱土能有效控制肉桂醛在羧甲基纤维素钠膜中的释放。      

60Co辐照对卵清蛋白结构和抗氧化性的影响

采用6种钴60辐照剂量(0、2、4、6、8、10 k Gy)处理鸡蛋卵清蛋白(OVA),并探明辐照技术对卵清蛋白结构和抗氧化性的影响。以新鲜鸡蛋为原料,经0、2、4、6、8、10 k Gy 6种钴60辐照剂量处理;硫酸铵沉淀法提取卵清蛋白;并测定不同辐照条件下卵清蛋白溶解度、自由巯基含量、内源性荧光、还原力、DPPH自由基清除率的变化。实验结果表明:辐照对于卵清蛋白的结构和理化性质影响较大,随着辐照剂量的增加,OVA的可溶性蛋白含量、自由巯基含量、DPPH清除能力和还原力,均有不同程度的提高;内源荧光呈现先上升后下降趋势,当辐照剂量为10 k Gy时,内源荧光值显著低于对照组(p<0.05)。此研究为辐照卵清蛋白产品的工业应用提供了理论依据。      

干燥方法对沙芥叶片品质的影响

研究自然干燥、真空干燥、鼓风干燥(40、60、80℃)3种干燥方法对沙芥干燥产品及复水后产品物理性质及营养成分的影响。结果表明:不同干燥方法处理的沙芥叶的物理性质及营养成分与鲜叶有较大差异,在物理性质方面,真空干燥叶片复水率显著高于其它处理(p<0.05);在营养成分方面,真空干燥条件下沙芥叶片与其复水后叶片的游离氨基酸、VC、可溶性蛋白含量均高于其它干燥方法。综上所述,真空干燥对沙芥叶片营养成分的破坏最小,复水性好而且干燥时间较短,是一种较好的沙芥叶片干制品的制备方法。      

Circ_0011129 Encapsulated by the Small Extracellular Vesicles Derived from Human Stem Cells Ameliorate Skin Photoaging

Photoaging is not only the main cause of skin aging caused by exogenous factors, it is also related to a variety of skin diseases and even malignant tumors. Excessive and repeated exposure to ultraviolet radiation, especially UVA induces oxidative stress, DNA damage, inflammation, and collagen and elastin degeneration, ultimately leads to skin photoaging, manifested by skin redness, coarse wrinkles, and pigmentation even skin cancer. There has been a large demand of effective prevention and medications but approaches in the current management of photoaging are very limited. In the previous study, we found that a non-coding circular RNA circ_0011129 acts as a miR-6732-5p adsorption sponge to inhibit the reduction of type I collagen and the denaturation and accumulation of elastin in UVA-induced HDF cells photoaging model. However, in vivo instability and efficient delivery to the target cell of circRNA is a major challenge for its clinical application. Therefore, improving its stability and delivery efficiency are desired. In this study, we proposed a strategy of delivering circ_0011129 with small extracellular vesicles (sEVs) from human adipose-derived stem cells (hADSCs) to intervene in the photoaging process. The results showed that sEVs from hADSCs in 3D bioreactor culture (3D-sEVs) can prevent photoaging. Consequently, by overexpressing circ_0011129 in hADSCs, we successfully loaded it into 3D-sEVs (3D-circ-sEVs) and its protective effect was better. Our studies provide a novel approach to preventing skin photoaging, which has important clinical significance and application value for the development of non-coding RNA drugs to treat skin photoaging. We first screened out hADSCs-derived sEVs with excellent anti-oxidant effects. We then compared the sEVs collected from traditional 2D culture with 3D bioreactor culture. By miRNA-seq and GEO data analysis, we found that miRNAs in 3D-sEVs were enriched in cell activities related to apoptosis, cellular senescence, and inflammation. Subsequently, we prepared circ_0011129-loaded 3D-sEVs (3D-circ-sEVs) by overexpressing it in hADSCs for the treatment of photoaging in vitro. We proved that 3D-circ-sEVs can interfere with the process of cell photoaging and protect cells from UVA radiation damage, as well as in a H2O2-induced oxidative stress model.     

Studies of Mercaptosuccinic Acid-Crosslinked Chitosan Hydrogel with Grafted Cinnamaldehyde and Silver Nanoparticles for Antibacterial Biomedical Application

For the effective clinical antibacterial application of biomaterials, such as for wound management and tissue repair, the biomaterials need to show proper antibacterial capability as well as non-cytotoxicity. Furthermore, the material needs to have suitable mechanical characteristics for further medical use. Chitosan hydrogel is a potential candidate for various antibacterial biomedical applications due to its amine functionalities that lead to antimicrobial characteristics. Nevertheless, its antimicrobial capability is dependent upon the degree of protonation of amine groups caused by the pH value. Moreover, its mechanical compressive strength may not be high enough for clinical use if not chemically or physically crosslinked. This study utilized a novel chemical crosslinker, mercaptosuccinic acid, to improve its mechanical characteristics. The natural antibacterial agent, cinnamaldehyde, was grafted onto the crosslinked chitosan to improve its antimicrobial capability. Meanwhile, to take advantage of the thiol functionality in the mercaptosuccinic acid, the bactericidal silver nanoparticles were incorporated through silver-thiol covalent bounding. NMR analyses indicated the chitosan was successfully mercaptosuccinic acid-crosslinked and grafted with cinnamaldehyde at different ratios. Combined the results from the mechanical assessment, swelling experiments, antimicrobial assessment, and cytotoxicity assay, the chitosan hydrogel with the highest crosslinked degree and grafted with cinnamaldehyde and silver nanoparticles is of great promise for further clinical uses.