木瓜中齐墩果酸的分离提取及含量测定

本文对木瓜中的齐墩果酸进行了分离提取及含量测定研究。以氯仿为溶剂,热回流浸提,采用薄层层析法(TLC)对木瓜中的齐墩果酸进行定性分析,用高效液相色谱法(HPLC)进行含量测定,得到木瓜中的齐墩果酸的平均含量为0.0831%。该法准确度高,结果稳定。     

HPLC测定木瓜果醋中齐墩果酸含量

采用HPLC法进行齐墩果酸的检测，研究了木瓜中齐墩果酸的提取方法，发现以无水酒精等有机溶剂提取效果最好。通过对木瓜果醋研制过程中各个样品的检测发现，齐墩果酸主要分布在木瓜渣中，在木瓜汁中的含量很低，几乎检测不出，只有带渣发酵才能制成含齐墩果酸的功能性果醋。     

响应面法优化木瓜果实中齐墩果酸提取工艺

为优化提取工艺,用超声波法提取木瓜果实中的齐墩果酸,并通过响应面法(RSM)对提取参数进行优化。经高效液相色谱(HPLC)定量分析,齐墩果酸的最佳超声提取条件为溶剂无水乙醇、料液比1∶16、提取温度53℃、提取时间45 min,在该条件下测得木瓜中齐墩果酸含量可达到0.14%。试验提取操作简便、快速,检测方法灵敏、重现性好。     

HPLC测定木瓜果醋中齐墩果酸含量

采用HPLC法进行齐墩果酸的检测,研究了木瓜中齐墩果酸的提取方法,发现以无水酒精等有机溶剂提取效果最好。通过对木瓜果醋研制过程中各个样品的检测发现,齐墩果酸主要分布在木瓜渣中,在木瓜汁中的含量很低,几乎检测不出,只有带渣发酵才能制成含齐墩果酸的功能性果醋。     

响应面法优化云南宣木瓜齐墩果酸和熊果酸的提取工艺研究

探索超声辅助提取宣木瓜齐墩果酸和熊果酸的工艺优化研究。在单因素试验的基础上,选取对提取工艺影响较大的乙醇浓度、超声时间和超声功率3个因素,利用Box-Benhnken中心组合原理进行三因素三水平试验,并通过响应面分析法优化超声波辅助提取宣木瓜中齐墩果酸和熊果酸的工艺参数。结果表明最优工艺条件为:乙醇浓度95%,超声时间3.8 min、超声功率440 W,齐墩果酸和熊果酸的总得率为4.03 mg/g,与理论基本相符。因此,超声辅助提取法能快速有效地提取宣木瓜中的齐墩果酸和熊果酸。     

山楂中齐墩果酸和熊果酸超声提取工艺研究

对山楂齐墩果酸和熊果酸超声波辅助提取工艺进行了优化,以齐墩果酸和熊果酸总含量为响应值,考查了液固比、超声波功率和提取时间对山楂总齐墩果酸和熊果酸含量的影响。结果表明,三个考查因素对山楂齐墩果酸和熊果酸含量影响的顺序为:液固比提取时间超声波功率;方差分析结果表明,液固比和提取时间对齐墩果酸和熊果酸含量有极显著影响(p0.01),超声波功率对齐墩果酸和熊果酸含量有显著影响(p0.05),提取时间的二次项对齐墩果酸和熊果酸含量有极显著影响(p0.01),各因素之间交互作用不显著(p0.05);确定超声波辅助提取山楂齐墩果酸和熊果酸的最佳工艺参数为:乙醇体积分数90%,液固比35∶1m L/g,超声波功率352W,提取时间为4.6min,在优化工艺条件下超声波辅助提取山楂齐墩果酸和熊果酸,其含量为2.87mg/g,与预测值相符。本实验中所用提取方法在显著节约了超声波处理的时间同时也获得了良好的提取效率。     

正交法优选宣木瓜叶齐墩果酸回流提取工艺

试验首次对宣木瓜叶进行TLC定性研究,发现其中含有具有活性的“齐墩果酸”。在此基础上,采用正交法对宣木瓜叶齐墩果酸的回流提取工艺进行优化。研究结果表明,提取最佳工艺条件为:95%乙醇、料液比1∶10、提取时间2h、提取温度60℃。以提取物为基准测得宣木瓜叶中齐墩果酸量为2.86%,而索氏抽提法测得叶中齐墩果酸为3.16%,由此可得,本试验提取效率达90.5%。为宣木瓜叶的综合开发利用提供试验依据。     

木瓜齐墩果酸的研究进展

木瓜齐墩果酸是木瓜果实和叶中重要的活性成分,具有多种医疗功效。本文综述了木瓜齐墩果酸的提取分离、测定方法、生理活性及应用现状等方面的研究进展,并展望其在生物制药、医药保健和经济开发等方面的应用前景。为木瓜齐墩果酸的合理开发和应用提供了科学的依据。     

武陵山区一带不同县市木瓜指标成分含量比较与体外抗氧化研究

目的:比较从武陵山区一带资木瓜产区5个不同县市采集的木瓜样品的指标性成分齐墩果酸和熊果酸的含量差异,并初步评价其体外抗氧化活性。方法:用HPLC法测定样品中齐墩果酸和熊果酸的含量,用DPPH清除实验和还原力测定实验评价样品的抗氧化能力。结果:在湖南桑植、武陵源地区和湖北宣恩、鹤峰、长阳地区等5个县级行政区采集所得的木瓜中,长阳木瓜的齐墩果酸含量最高,为0.90%;宣恩木瓜的熊果酸含量最高,为0.45%;齐墩果酸和熊果酸的总含量以长阳木瓜最高,桑植木瓜次之,武陵源木瓜最低。相同浓度下,桑植木瓜的DPPH的清除率和还原力均最强。结论:武陵山区一带不同县市的木瓜齐墩果酸和熊果酸含量差异明显,抗氧化能力也各有不同,并不与齐墩果酸和熊果酸的含量成正比。     

木瓜中齐墩果酸和熊果酸提取工艺的研究

用正交试验法对木瓜中的齐墩果酸和熊果酸的提取工艺进行研究。在单因素实验基础上,采用L9(34)正交实验考察提取时间、提取温度、料液比、原料粒度对提取得率影响,用高效液相色谱法测定齐墩果酸和熊果酸含量,确定最优提取工艺。齐墩果酸最佳提取参数为95%的乙醇、温度为60℃、时间3h、料液比为1∶8、原料粒度40目、提取2次。熊果酸最佳提取参数为95%的乙醇、温度为60℃、时间3h、料液比为1∶6、原料粒度60目、提取2次。该工艺为齐墩果酸和熊果酸的工业化提取提供理论依据。     

超声波萃取技术在烟草成分分离中的应用研究综述

综述了超声波萃取技术在烟草成分分离中的应用研究情况.超声波萃取技术具有的快速、价廉、安全、高效等特点,已广泛应用于烟草成分中烟碱、茄尼醇、绿原酸、酚类物质、类胡萝卜素等有机成分及矿物元素、微量元素、农药残留的分离.烟草样品的浸泡时间、超声波强度、超声波频率、提取时间等,对超声波萃取技术提取烟草成分均有重要影响,但对其影响程度目前还不很清楚,尚有待今后深入研究.     

落葵籽油的提取及其气相色谱质谱联用分析

采用有机溶剂浸提(SE)、微波辅助旋转回流提取(ME)和超声波提取(UE)三种方法提取落葵籽油并进行气相色谱质谱联用(GC-MS)分析。结果表明,ME法和UE法的提取率十分接近,分别为15.06%、15.09%,均高于SE法的提取率9.20%;经GC-MS分离鉴定,SE法、ME法和UE法提取的落葵籽油分别有14、11、21种成分,其中共有成分为11种;脂肪酸相对含量占总含量85%以上,其中饱和脂肪酸相对含量占总含量25%以上,主要成分为棕榈酸(18%),不饱和脂肪酸相对含量占总含量60%以上,主要成分为油酸(31%)和亚油酸(23%)。     

响应面法优化超声波-微波协同提取富硒蛹虫草硒多糖工艺

在单因素试验基础上,采用响应面法对富硒蛹虫草硒多糖超声波-微波协同提取工艺进行优化,并与超声波提取法和水提法提取硒多糖抗氧化活性进行比较分析,探究3 种提取方法对硒多糖提取效果的影响。结果表明：超声波-微波协同提取最佳工艺条件为超声时间26.0 min、微波时间3.20 min、微波功率350 W、液料比32.00∶1（mL/g）,在此条件下,硒多糖提取率为5.05%,比超声提取法和水提法分别提高了19.96%和3.70%;3 种提取方法硒多糖体外抗氧化活性排序依次为：超声波-微波协同提取法＞超声波提取法＞水提法。此外,超声波-微波协同提取法可获得更高的多糖硒含量,为360.37 mg/kg,相比超声提取法和水提法分别提高了4.47%和12.92%。     

野马追类黄酮的超声提取及其抗氧化活性研究

在单因素试验的基础上,采用Box-Behnken 试验设计优化超声提取野马追类黄酮的最佳工艺参数,并研究野马追类黄酮对DPPH 自由基的清除效果,最后与其他提取方法进行比较。结果表明：超声提取野马追类黄酮的最佳工艺参数为液料比11.3:1(mL/g)、超声温度58℃和超声时间29min,此时得率为1.142%;当野马追类黄酮质量浓度在6.556～32.78μg/mL 范围内,其对DPPH 自由基的清除率为46.90%～61.06%,且存在明显的量效关系。与其他提取方法比较,超声提取时间短、得率高。     

Study on infrared-assisted extraction coupled with high performance liquid chromatography (HPLC) for determination of catechin,epicatechin, and procyanidin B2 in grape seeds

In this study, infrared-assisted extraction (IRAE) was developed and combined with HPLC for the determination of catechin, epicatechin, and procyanidin B2 in grape seeds. Three factors, extraction solvent, solid/liquid ratio, and illumination time, were investigated to optimise the extraction method of catechin, epicatechin, and procyanidin B2 from grape seeds. The chosen infrared-assisted extraction conditions were as follows: a 50% methanol solution as extraction solvent, solid/liquid ratio of 1:150 g/mL and illumination time of 30 min. The extraction efficiency of IRAE was compared with conventional microwave-assisted extraction (MAE), ultrasonic extraction (UE), and classical electrical heating (CEH) methods. An initial HPLC method was established to identify and quantitate catechin, epicatechin, and procyanidin B2 from grape seeds, simultaneously. The HPLC method was validated for parameters including linearity, analytic limit, reproducibility, accuracy and recovery. The results indicted that IRAE has a great potential for offering an alternative technique for extraction of active components from plants.     

Short communication: Associations of udder edema with health,milk yield,and reproduction in dairy cows in early lactation

Udder edema (UE) is a common condition of cows around calving, but its effects are not well characterized. The objectives of this study were to determine the associations of UE with the incidence of health disorders and with milk yield and reproduction in dairy cows in early lactation. On 3 commercial farms, UE was scored weekly on 1,346 cows, on a scale of 0 to 3, from 1 wk before calving to 3 wk after calving. Among cows with complete UE scores, 30% never had edema, 12% had edema only prepartum, 11% had it only postpartum, and 48% had edema prepartum and in at least 1 wk postpartum. Udder edema was associated with a greater incidence of clinical mastitis before 30 d in milk (5 vs. 2%). Subclinical ketosis (blood β-hydroxybutyrate ≥1.2 mmol/L) was more prevalent at wk 2 (11 vs. 6%) postpartum among cows with UE. No association was observed of UE with other diseases or culling in early lactation. In a subset of 912 cows with complete UE and 3 test-days of milk yield data, differences were observed in yield at test d 1 among UE categories. Cows with UE only prepartum produced less milk (39.9 kg/d) than cows with UE postpartum only (42.4 kg/d) and cows with UE both prepartum and postpartum (41.6 kg/d), none of which differed from cows without UE (40.9 kg/d). Udder edema was not associated with the prevalence of anovulation, or the time to or probability of pregnancy at first insemination, yet to 300 d in milk, cows that had UE postpartum had a shorter time from calving to pregnancy than cows without UE. The associations of UE with health and productivity are mixed, and the mechanisms underlying UE and its effects merit further investigation.     

水产品中多环芳烃分析方法研究进展

随着水环境污染的加剧,水产品的质量安全问题日益成为社会关注的焦点。文中从提取、净化和测定3个方面回顾总结了近年来国内外报道的水产品中多环芳烃的分析方法,重点介绍了索氏提取法、超声波提取法、微波辅助提取法、加速溶剂提取法、基质固相分散萃取法、超临界流体提取法等样品前处理方法和气相色谱法、气相色谱-质谱法、高效液相色谱法等仪器测定方法,并对这些方法的优缺点和局限性进行了比较,以便研究者能在此基础上进一步改进和发展。最后,对水产品中多环芳烃分析方法的未来发展趋势进行了展望。     

Relationship between urinary energy and urinary nitrogen or carbon excretion in lactating Jersey cows

Measurement of urinary energy (UE) excretion is essential to determine metabolizable energy (ME) supply. Our objectives were to evaluate the accuracy of using urinary N (UN) or C (UC) to estimate UE and ultimately improve the accuracy of estimating ME. Individual animal data (n = 433) were used from 11 studies with Jersey cows at the University of Nebraska–Lincoln, where samples were analyzed after drying (n = 299) or on an as-is basis (n = 134). Dried samples resulted in greater estimated error variance compared with as-is samples, and thus only as-is samples were used for final models. The as-is data set included a range (min to max) in dry matter intake (11.6–24.6 kg/d), N intake (282–642 g/d), UE excretion (1,390–3,160 kcal/d), UN excretion (85–220 g/d or 20.6–59.5% of N intake), and UC excretion (130–273 g/d). As indicated by a bias in residuals between observed and predicted ME as dietary crude protein (CP; range of 14.9–19.1%) increased, the National Research Council dairy model did not accurately predict ME of diets, as dietary CP varied. The relationship between UE (kcal/d) and UN (g/d) excretion was linear and had an intercept of 880 ± 140 kcal. Because an intercept of 880 is biologically unlikely, the intercept was forced through 0, resulting in linear and quadratic relationships. The regressions of UE (kcal/d) on UN (g/d) excretion were UE = 14.6 ± 0.32 × UN, and UE = 20.9 ± 1.0 × UN ? 0.0357 ± 0.0056 × UN². In the quadratic regression, UE increased, but at a diminishing rate as UN excretion increased. As UC increased, UE linearly and quadratically increased. However, error variance was greater for regression with UC compared with UN as explanatory variables (8.42 vs. 7.42% of mean UE). The use of the quadratic regression between UN and UE excretion to predict ME resulted in a slope bias in ME predictions as dietary CP increased. The linear regression between UE and UN excretion removed slope bias between predicted ME and CP, and thus may be more appropriate for predicting UE across a wider range of dietary CP. Using equations to predict UE from UN should improve our ability to predict diet ME in Jersey cows compared with calculating ME directly from digestible energy.     

Reproductive tract disease in Irish grazing dairy cows: Retrospective observational study examining its association with reproductive performance and accuracy of 2 diagnostic tests

The detection of reproductive tract disease (RTD) 3 wk postpartum is important because of its effect on subsequent reproductive outcomes. Numerous methods for the diagnosis of RTD are described, some of which are more practical and instantaneous in terms of diagnosis. Two of these methods involve identification of purulent vaginal discharge (PVD) and evidence of ultrasonographic uterine changes indicative of endometritis (UE). The objectives of our retrospective observational study were (1) to assess the association of PVD or UE score at the prebreeding examination (PBE) with the hazard of pregnancy within the subsequent breeding season; (2) to determine the test sensitivity (Se) and specificity (Sp) at the point of sampling of both tests using a Bayesian latent class model; and (3) to determine the effect of varying positivity thresholds on test accuracy. To achieve these objectives, we analyzed an initial data set of 5,049 PBE from 2,460 spring-calved cows in 8 herds between 2014 and 2018. Each PBE was conducted once between 25 and 86 d in milk. At each PBE, vaginal discharge was obtained with a Metricheck device (Simcro) whereas uterine contents were assessed using transrectal ultrasonography. Purulent vaginal discharge was scored on a scale of 0 to 3 depending on discharge character, and UE was scored on a scale of 0 to 4 depending on the presence and consistency of intraluminal fluid. Cows with scores of ≥2 in either test had received treatment. Fertility data were available from 4,756 PBE after data exclusion. The association between PVD or UE score at the PBE and subsequent hazard of pregnancy was analyzed using a Cox proportional hazards model. Cows with a PVD score of 2 or 3 were less likely to conceive than cows with a PVD score 0 [score 2 hazard ratio (HR) = 0.74; 95% confidence interval (CI): 0.59–0.94; score 3 HR = 0.65; 95% CI: 0.51–0.84]. Cows with a UE score of 1, 2, 3, or 4 were less likely to conceive than cows with a UE score of 0 (score 1 HR = 0.82; 95% CI: 0.73–0.93; score 2 HR = 0.79; 95% CI: 0.62–1.00; score 3 HR = 0.43; 95% CI: 0.43–0.90; score 4 HR = 0.39; 95% CI: 0.26–0.58). To determine the Se and Sp of PVD or UE score for diagnosis of RTD at the time of PBE, a Bayesian latent class model was fitted on 2,460 individual cow PBE. Flat priors were used for the Se and Sp of UE, whereas informative priors were used for PVD Se (mode = 65%, 5th percentile = 45%) and Sp (mode = 90%, 5th percentile = 80%) and RTD prevalence (mode = 20%, 5th percentile = 10%). Posterior estimates (median and 95% Bayesian probability intervals; BPI) were obtained using ‘rjags' (R Studio). The optimal test thresholds (PVD and UE score ≥1) were selected by assessing the effect of different thresholds on test estimates and using a misclassification cost analysis. Based on these, median (95% BPI) Se for PVD and UE score ≥1 were 44% (29–60%) and 67% (33–100%), respectively. Median Sp for PVD and UE score ≥1 were 90% (86–93%) and 91% (86–93%), respectively. Higher scores in both tests were associated with impaired fertility, and UE scoring with a threshold of ≥1 had the highest test Se and Sp estimates although test Se was conditional on days in milk when the PBE occurred.     

UE336-2米曲霉应用于酱油生产的研究

该文叙述了UE336-2米曲霉的特性，论述了成曲中性蛋白酶活力比对照菌沪酿3．042米曲霉提高了l倍，酱油生产原料全氮利用率提高7．1％，同时还介绍了新菌种的技术要求。