作为最具毒性的重金属之一,银在食品和环境中的污染对人体健康会造成严重危害.该研究基于稀土铽离子(Tb3+)能够结合单链DNA发出特征荧光的原理,利用Ag+能与胞嘧啶(C)结合形成C-Ag+-C结构以组成双链DNA的特性,构建了一种特异性识别Ag+的非标记核酸适配体荧光传感器.该传感器通过Tb3+对单双链DNA结构变化灵敏的特征荧光响应,能够实现对Ag+的高灵敏和快速的定量检测.该方法对 Ag+的检测限为 391.50 nmol/L,满足国家对于饮用水中 Ag+限量检测的要求(0.05 mg/L,即463.50 nmol/L).该方法的回收率测定结果在93.02％～102.72％范围内,其相对标准差范围为1.27％～7.14％,证明了它的应用有效性;相较于其他的分子检测方法,该方法具有无需进行化学标记以降低成本,且操作简便,检测响应速度快等优点,为临场快速检测重金属银污染提供了一种可能的途径.

背景:目前单一支架材料难以满足骨组织工程的成骨需要,多种材料组合的微球支架可以扬长避短,具有巨大的应用潜力.目的:探究新型复合材料聚三亚甲基碳酸酯/β-磷酸三钙微球支架在动物体内的生物相容性、降解性及骨诱导性.方法:制备β-磷酸三钙骨水泥与聚三亚甲基碳酸酯/β-磷酸三钙微球支架.将18只雄性SD大鼠按体质量分层随机分为3组,空白对照组双侧股骨缺损处不植入任何材料,对照组双侧股骨缺损处植入β-磷酸三钙骨水泥,实验组双侧股骨缺损处植入聚三亚甲基碳酸酯/β-磷酸三钙微球支架,每组6只.术后4,8,12周,取出双侧股骨进行苏木精-伊红染色、Masson染色及骨钙素免疫组化染色.结果 与结论:①苏木精-伊红染色与Masson染色:术后4周时,空白对照组骨缺损处由纤维组织包绕,大量炎性细胞聚集;对照组材料大部分降解,由纤维组织包绕,材料边缘有少量新生骨基质、骨小梁形成,周围有少量炎性细胞;实验组材料无明显降解,由纤维组织包绕,材料边缘有少量新生骨基质、骨小梁形成,周围有少量炎性细胞.至术后12周时,空白对照组骨小梁形态规则,彼此连接,无炎性细胞;对照组材料完全降解,骨小梁形态规则,形成厚的板层状,无炎性细胞;实验组材料部分降解,骨质增多、致密,无炎性细胞.②免疫组化染色:随着时间的延长,对照组骨缺损处骨钙素表达呈先升高后降低的趋势,空白对照组、实验组骨钙素表达呈逐渐升高趋势,对照组、实验组各时间点的骨钙素表达均高于空白对照组(P<0.05),实验组术后12周的骨钙素表达高于对照组(P<0.05).③结果 表明:聚三亚甲基碳酸酯/β-磷酸三钙微球支架具有较好的生物相容性、骨诱导性和适中的生物降解性.

以赶黄草鲜叶为原料,通过模糊数学模型建立赶黄草代用茶感官评价标准.通过单因素结合响应面试验方法,优化得到赶黄草叶茶最佳工艺条件:烘青水分60％,初烘温度124℃,揉捻时间18 min.采用氨基酸分析仪、高效液相色谱技术、顶空固相微萃取(HS-SPME)和气相色谱-质谱(GC-MS)技术分析赶黄草叶茶茶汤中游离氨基酸组成、没食子酸、总黄酮、槲皮素、乔松素及其挥发性成分变化.优化后的制备工艺降低了游离苦味氨基酸与没食子酸含量,其中没食子酸为主要苦味呈味成分;赶黄草叶以青草味、橙油味、清香、花香为主体特征,叶茶中青草味和橙油味变淡,清香和花香增加.本制备工艺对总黄酮、槲皮素和乔松素等赶黄草主要功效成分的溶出无明显影响.

目的:探究小茴香对去势雌性大鼠骨密度功能的影响,通过大鼠颅骨成骨细胞(ROB)初探其机制.方法:采用SD大鼠进行含小茴香的保健食品配方的急性经口毒性试验,以去势雌性SD大鼠建立骨质疏松动物模型进行增加骨密度的功能性验证.用新生SD乳鼠颅骨为细胞来源培养ROB,CCK-8法观察小茴香40％甲醇提取物对ROB增殖的影响,并观察小茴香40％甲醇提取物对ROB中碱性磷酸酶(ALP)的活性.结果:体内试验中,小茴香配方食品对SD大鼠急性经口LD50大于10g/kg·bw,为实际无毒级别;与模型对照组比较,小茴香配方食品可显著增加去势模型大鼠骨密度、骨皮质厚度(P＜0.05),改善骨小梁结构.在体外试验中,与阴性对照比较,小茴香甲醇40％提取物对ROB的增殖作用显著,最高增殖率为84.96％(P＜0.05),同时显著增加ROB的ALP活性(P＜0.05).结论:小茴香配方食品急性经口毒性为实际无毒级别,小茴香40％甲醇提取物具有增加骨密度功能的作用,对ROB具有细胞增殖分化作用.

食品新原料赶黄草茎泡饮具有护肝解酒作用,常采用制茶工艺脱苦增香,但其功效及风味成分变化机制不明.文章采用氨基酸分析仪、HS-SPME-GC-MS和HPLC等仪器,分析了赶黄草茎及茎茶中游离氨基酸、没食子酸、挥发性成分、总黄酮、槲皮素、乔松素含量变化,发现赖氨酸和没食子酸为赶黄草茎主要苦味贡献成分,其在茎茶中含量明显降低;茎原料以壬醛、反式-2-壬醛、癸醛、1-辛烯-3-醇、月桂醛为主要挥发性成分,呈现强烈的草青味、药味和橙油味,而茎茶中上述成分显著减少,苯甲醛、6-甲基-3,5-庚二烯-2-酮、 2-戊基呋喃含量增加,故药味、草青味和橙油味变弱,以清香、果香和豆香为主体香气.此外,赶黄草茎茶对槲皮素、乔松素等主要功效成分的溶出无明显影响.

采用响应面法研究了提取温度、pH、提取时间和液料比对豆腐柴果胶得率和酯化度(DE)的影响,并对最佳提取条件下的果胶进行了微观结构和加工特性的研究.最佳提取条件为:提取温度90℃,pH6,提取时间67 min,液料比24∶1 mL/g,果胶得率为17.8％.在最佳条件下获得的果胶为低甲氧基果胶(DE=43.1％),半乳糖醛酸含量为65.8％,具有果胶多糖典型的红外光谱图,扫描电镜显示果胶呈多褶皱的团聚状.其持水力和持油力分别为6.52和6.03 g/g,在2％和4％时的起泡能力分别为52.7％和72.4％,30 min后的泡沫稳定性为18.5％和44.6％.综上所述,豆腐柴叶为低甲氧基酯果胶的良好来源,且具有作为乳化剂、稳定剂、起泡剂用于高脂食品体系感官品质改善的潜在应用价值.

我国茶叶生产长期存在质量安全问题并影响着整个产业高质量发展.贵州湄潭县以建设欧标茶园为突破口,对全县茶产业转型升级进行有益探索,取得了一定成效.文章总结了湄潭茶产业转型升级的实践成效及其主要管理机制,分析了茶产业"四位一体"优化运营与驱动机制,指出了茶产业转型升级与高质量发展面临的挑战及对策,以期对今后湄潭茶产业高质量发展提供参考,也为其它茶叶生产区转型升级提供事实依据和借鉴价值.

秋葵多糖具有多种生理活性,是功能性食品开发的潜在原料.目前,主要采用酸法、碱法、酶法和热水浸提法提取秋葵多糖,提取过程中的化学、物理因素易对秋葵多糖活性产生不利影响.通过单因素、响应面实验优化超声辅助热水浸提秋葵多糖工艺参数,发现提取过程中各因素对提取率的影响大小为:提取时间＞提取温度＞水料比＞提取次数;超声辅助热水浸提最佳提取工艺参数为:水料比32∶1、提取时间59 min、提取温度66℃,实际提取率30.23％,高于现有提取方法.进一步测定该优化工艺下秋葵多糖的抗氧化能力发现:在秋葵粗多糖浓度为8mg/mL时,对DPPH、ABTS、·OH清除率、脂质过氧化抑制率和还原力分别为88.8％、72.1％、68.3％、56.9％、0.724(OD700 nm),且均表现出良好的量效关系.结果 表明,优化后的超声辅助热水浸提秋葵多糖的新工艺,在提高多糖提取率的基础上,有效保护了秋葵多糖的抗氧化活性.

In this work, we extracted, purified and structurally analysed okra polysaccharides (OPs), which were found to contain mainly rhamnogalacturonan I with long galactan side branches. The results of the line spread test and rheological measurement confirmed that although the high-methoxyl pectin (HMP) solution remained in a liquid state with less than 55% sucrose, HMP and OPs synergistically formed stable gels with only 40% sucrose at ratios from 9: 1 to 2: 8 (total polysaccharide concentration 2.0 wt%) at pH 2.0-3.5. Similar to the HMP gel, the HMP/ OPs blend gels were spreadable, shear thinning and heat-irreversible but exhibited no obvious thermal annealing behaviour and higher strain capacity. The critical strain, fracture strain, storage modulus G' and complex viscosity.* of the HMP/OPs blending (ratio 8: 2, 40% sucrose, 0.1 rad/s, 20 degrees C) were 7.56%, 56.6%, 177.49 Pa and 1846.25 Pa s, respectively, while those of the HMP sample (55% sucrose) were 1.79%, 42.5%, 565.81 Pa and 5982.5 Pa s. The blend gels also showed smoother gel surfaces with lower porosity in the FESEM observations. The CLSM observation revealed that the uniformly distributed OPs molecules and locally aggregated HMP chain blocks formed a ratio-dependent microphase separation network in blend gels. The FT-IR spectra showed the decrease of sucrose free hydroxyl in the blend gel, indicating an enhancement of sucrose hydration. The sucrose hydration enhancement and strong water-binding capacity of galactan side branches in OPs molecules could compensate for the insufficient quantity of sucrose, which could promote HMP chain-chain connection and form microphase separation structures in blend gels.

采用超声水提-醇沉法提取秋葵多糖,研究了不同因素对秋葵多糖黏度的影响、秋葵多糖的动态流变学特性以及秋葵多糖对冷冻面团品质的影响.结果表明,秋葵多糖溶液是剪切稀化的“非牛顿流体”,秋葵多糖的黏度随浓度、蔗糖添加量和金属离子浓度的增加逐渐增大;随着温度升高、热处理时间的增加而逐渐减小.当体系pH逐渐增大时,秋葵多糖的黏度先增大后减小,在pH为5时达到最大值.秋葵多糖的储能模量G’和损耗模量G”均随多糖浓度增加而增大,G’的增长速度低于G",表明随秋葵多糖浓度增加,其弹性下降而黏性增加.秋葵多糖能显著降低冷冻面团的硬度,增强其弹性和内聚性;添加3％秋葵多糖的冷冻面团,与对照相比,其面团硬度降低了39.82％,弹性和内聚性分别增大了35.99％和26.90％(p＜0.05).

Objective: The aim of this study is to investigate the antioxidant activity in vitro of anthocyanins extracted from the fruits of Habenaria ciliolaris Kranzl and the protective effect of the extract on H2O2-induced oxidative stress in V79-4 cells. Methods: The anthocyanin composition was detected by high performance liquid chromatography-mass spectrometry, and the antioxidant activity was evaluated by using 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assays. Moreover, the protective effect of the extract on H2O2-induced oxidative damage in V79-4 cells was measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, thiobarbituric acid reactive substances and 2’,7’-dichlorofluorescein diacetate assays. Results:The anthocyanins in the extract were identified as cyanidin 3-galactoside, cyanidin 3-(6"-coumaroyl) glucoside, peonidin 3-galactoside and peonidin 3-(6"-coumaroyl) glucoside by retention time and mass spectral data. The anthocyanins extract exhibited strong ABTS and DPPH free radical scavenging capacity with half maximal inhibitory concentrations of (1.72 ± 0.26) and (0.74 ± 0.24) μg/mL, respectively, which was superior to that of soluble VE. The pretreatment of V79-4 cells with the extract in the ranges of 50-200 μg/mL significantly reduced H2O2-induced cytotoxictiy, potentially inhibited lipid peroxidation and reduced the level of intracellular reactive oxygen species. Conclusion: These findings confirm the in vitro free radical scavenging activity of anthocyanins extracted from H. ciliolaris Kranzl and their cytoprotective effect on H2O2-induced oxidative stress in V79-4 cells.

The vacuum packaged spiced beef as the material, the effect of irradiation at 3, 6, 12 k Gy using 60 Co-γ ray on the quality of the beef was investigated, during storage at 28 ℃ for 90 days. The results showed that the peroxide value of the irradiation sample was significantly different from that of the control (P＜0.05) , and the peroxide value of the sample was also increased after irradiation. The microbial quantity of the irradiation sample was lower than that of the control within the range permitted by the state. The redness value (a*) of the irradiated sample was lower than that of the control. With the irradiation dose increased, the hardness value of the irradiation sample increased, then decreased, whereas the score of the sensory evaluation decreased. Comparing to the control, the moisture content, the peroxide value, the redness value (a*) , the texture properties, and the score of the sensory evaluation of spiced beef irradiated with 3 k Gy were not significant difference (P＞0.05) . Moreover, the microbial quantity and the peroxide value of the spiced beef irradiated with 3 k Gy were within the range permitted by the state during the storage for 90 days.

In this work, the gelling capacity of okra polysaccharides (OPs) and their interaction with the commonly used additive kappa-carrageenan in aqueous solution were studied. In rheology research, pure OPs solutions were found to always remain in liquid state, showing an elasticity performance during heating-cooling cycles. However, OPs formed stable synergistic gels with kappa-carrageenan in a wide range of pH values (5.0-9.0). OPs remarkably increased the texture parameters of the blend gels and influenced the water holding capacity (WHC) by altering the water distribution. The hardness and WHC of the OPs/kappa-carrageenan blend gels reached to the highest and lowest, respectively, at the ratios of 0.6/1.4 and 1.0/1.0. Dynamic rheology measurements and differential scanning calorimetry (DSC) revealed that the blend gels at ratios of 0.6/1.4 and 1.0/1.0 both exhibited higher sol/gel transition temperatures, gel/sol transition enthalpy (Delta H), critical gel strength (n) and fractal dimension (df) values than pure kappa-carrageenan and displayed similar trends of viscoelastic modulus (G', G") to those of kappa-carrageenan gel. Blend gels at the ratios of 0.6/1.4 or 1.0/1.0 also showed a sole endothermic peak in differential scanning calorimetry (DSC) spectra, representing melting temperatures at 62.3 degrees C and 56.1 degrees C, respectively. AFM observation confirmed that OPs and.-carrageenan formed denser and irregular network structures in mixed solution, which is obviously different from the sparse meshwork formed by OPs self-assembly and could have contribute to the synergistic gelation of OPs with.-carrageenan.

The extraction of crude polysaccharides (YP) from the tubers of Habenaria ciliolaris Kranzl was performed by hot water extraction and alcohol precipitation. DEAE cellulose 52 ion exchange column and Toyopearal HW-65 gel filtration column chromatographies were successively used to separate and purify the crude polysaccharides, yielding four fractions: YP1-1, YP2-1, YP2-2 and YP3-1. The purities and molecular masses of the purified polysaccharides were determined by high performance liquid chromatography (HPLC) with evaporative light-scattering detection and their structures were investigated by Fourier transform infrared (FT-IR) spectroscopy, ultraviolet (UV) spectroscopy, and HPLC. The monosaccharide composition was determined by HPLC with precolumn derivatization. The in vitro bile acid-binding capacity of these polysaccharides was evaluated in a simulated intestinal environment. The results showed that the yield of YP was 2.41% and the total sugar content of YP was 96.35%. YP1-1, YP2-1, YP2-2 and YP3-1 were purified to homogeneity and did not contain nuclear acid or protein. Their molecular masses were 3.52 × 106, 3.08 × 106, 1.93 × 106 and 3.35 × 106Da, respectively. The four polysaccharides mainly contained pyranose rings connected through β-glucoside bonds. Monosaccharide composition analysis demonstrated that YP1-1 and YP3-1 were composed of rhamnose, arabinose, mannose, glucose, and galactose while YP2-1 and YP2-2 were composed of rhamnose, arabinose, mannose, glucose, galactose, and fucose. All four polysaccharides exhibited strong ability to bind bile acid.

The purpose of this study was to investigate the bacterial diversity and its influencing factors in bottom pit mud from artificial cellars used for the production of Maotai-flavor liquor.A high-throughput sequencing technique was used to analyze the bacterial diversity of four pit mud samples from different liquor producing regions and its correlations with physicochemical factors.The results showed that there was a significant difference in physicochemical characteristics and bacterial community among bottom pit muds from different regions and the longer the geographic distance was,the greater the difference in bacterial community structure was,the greater in differences was.Cluster analysis showed that the bacterial community structure of bottom pit muds from Erlang,Xijiu and Maotai,which were closer to each other,was similar,with Aminicenantes,Chloroflexi,and Proteobacteria being predominant.However,the bacterial flora of bottom pit mud from a liquor producer in Luzhou was dominated by Firmicutes,which was significantly different from that of bottom pit mud from the above three regions.Correlation analysis showed that available K,pH,and moisture content were the main factors that had significant effects on the structure and diversity of bacterial community in bottom pit muds,especially for Aminicenantes,Firmicutes,Actinobacteria,and Armatimonadetes.

研究南瓜(Cucurbita moschata)皮果胶的最佳提取工艺条件,在预试验的基础上采用Box-Behnken Design设计方法,研究了纤维素酶浓度、pH、液固比、提取温度及其交互作用对南瓜皮果胶提取率的影响.结果表明,最佳工艺条件为酶浓度0.5％、pH 4.34、温度40℃、液固比24.63:1 (mL:g),在此条件下进行验证试验得到果胶提取率为16.3％.

To optimize the extraction technology of melanoidins from Jiangxiang Daqu, L9(34) orthogonal design was adopted with Jiangxiang Daqu as the extracting material and ethanol solution as the extracting solvent. The effects of extraction temperature, ethanol solution concentra-tion, extraction time and liquid-solid ratio on melanoidins concentration were investigated through single factor experiment. The results showed that, the effects of extraction temperature, ethanol solution concentration, extraction time and liquid-solid ratio on melanoidins concentration were significant, and their influencing degree ranked in decreasing sequence as liquid solid ratio>ethanol solution concentration>extraction time>extraction temperature. The optimium extracting parameters of malanoidins from Jiangxiang Daqu were summed up as follows:extrac-tion temperature was at 70℃, ethanol solution concentration was 40%, extraction time was 3 h, and liquid-solid ratio was 17.5∶1.

Four kinds of man-made pit mud cultured by different formulas were selected as the research objects in this experiment. Quantitative analysis of 14 organic acids was performed by using GC. Then correlation analysis and principal components analysis (PCA) among organic ac-ids were made. The results showed that, there were significant correlations among organic acids in man-made pit mud, the first 2 principal or-ganic acids contained 98.526%information of total organic acids, the comprehensive score about organic acids of No.2 pit mud sample was the highest (suggesting it was the best pit mud among the four pit mud samples) and it was consistent with the results of sensory evaluation. This study proved that PCA with organic acid content as the indicators could rapidly identify the quality of pit mud.

采用研磨法从汉源产红花椒果实中分离筛选出了6株内生菌,包括4株内生细菌和2株内生真菌.本文以其中一株内生细菌Z2为研究对象,对其进行了形态特征、生理生化特征及分子生物学特征鉴定.实验结果发现,Z2菌体短杆状,大小约为0.6～0.7μm×1.5～2.5 μm,革兰氏阳性菌,无芽孢,无鞭毛.生理生化特征、16S rDNA基因序列及进化树的结果均表明,Z2为耐寒短杆菌(Brevibacterium frigoritolerans).经过摇瓶液体发酵后,利用高效液相色谱法对其发酵液及未发酵培养基进行了对比分析,发现其中有新物质产生.通过Sephadex LH-20层析柱初步分离发酵液后,利用半制备型高效液相色谱仪对该物质所在组分进行进一步分离纯化,采用电喷雾电离质谱和核磁共振等方法对该物质进行结构解析,结果表明该物质为L-酪氨酸,得率为12.90 mg/L发酵液.

In this study, pure-species bacteria was isolated from distiller’s grains after the stacking in Langjiu Distillery. Then pure-species fer-mentation was done with bran as the culture mediums, and heat-tolerant, acid-tolerant and ester-aroma-producing strains (ZP-3 and ZP-28) were screened out through the change of bran acidity and culture temperature with sensory evaluation score and esterifying power as the judg-ing indexes. The addition of the intensified starter of ZP-3 and ZP-28 in distiller’s grains could evidently improve the accumulation time and the accumulation effects of distiller’s grains.