黄皮黄酮的提取工艺及测定

采用乙醇回流提取法提取黄皮中的黄酮,主要研究乙醇回流提取黄皮中黄酮的最佳工艺条件,探讨乙醇浓度、提取时间、料液比及提取温度等因素对黄酮提取率的影响。通过正交实验确定最佳工艺条件为乙醇浓度50%,提取温度90℃,提取时间2.5h,料液比1∶30,在此条件下,总黄酮提取率为30.65mg/g。     

野菠菜叶总黄酮提取工艺

为探索野菠菜黄酮提取工艺,提高总黄酮提取率。利用正交试验考查不同粒度、料液比、乙醇浓度、提取时间、提取温度下总黄酮浓度,得到最佳提取工艺为:粒度40目、料液比1∶30(g/m L)、提取时间1 h、乙醇溶液体积分数75%,在该工艺下,野菠菜总黄酮得率为3.216 mg/m L。     

石仙桃中总黄酮的提取方法的比较研究

探究石仙桃的总黄酮的提取方法的比较。以乙醇-水为提取体系,分别采用回流法、超声法,探究乙醇浓度、料液比、提取时间等对石仙桃中总黄酮提取的影响,确立最佳条件。通过正交试验证明,超声波辅助提取的最佳工艺为:温度40℃,料液比1∶40(g/mL),提取时间50 min,在此条件下提取的黄酮含量为26.12 mg/g;乙醇回流法提取最佳工艺为:温度60℃,料液比1∶50(g/mL),提取时间50 min,在此条件下提取的黄酮含量为22.03 mg/g。超声波辅助提取法提取石仙桃中总黄酮的提取率高于乙醇回流提取法提取。     

响应面分析法优化仙鹤草总黄酮提取工艺

为优化仙鹤草中总黄酮的提取方法,在单因素试验基础上,选取提取时间、提取温度、乙醇浓度和料液比为自变量,仙鹤草总黄酮提取率为响应值,采用响应曲面试验设计方法,研究各自变量及其交互作用对总黄酮提取率的影响。采用Design-Expert软件,建立总黄酮得率与因素间的二次回归模型。结果表明:该回归模型极显著,预测性强。乙醇浓度和提取温度是影响提取率的主要因素;优化得到的最佳提取工艺条件:提取时间100 min、提取温度100℃、乙醇浓度30%、料液比1∶15(g/m L)。在此提取工艺条件下平行3次进行验证,总黄酮得率为9.92%。     

乙醇回流法提取葛根黄酮的工艺优化研究

采用正交试验法优化乙醇回流法提取葛根黄酮的工艺研究。在单因素试验的基础上,选择回流温度、回流时间、料液比、乙醇体积分数四个因素,进行正交试验设计,评估了这些因素对葛根黄酮提取率的影响。试验结果表明最佳工艺参数为回流温度90 ℃,提取时间120 min,料液比1∶40(g∶mL),乙醇体积分数70%。在此条件下,葛根黄酮的提取率为1.62%。     

葛渣总黄酮提取及葛根素含量测定

目的：优化葛渣中总黄酮提取工艺条件,测定葛渣中葛根素含量。方法：以葛渣为原料、总黄酮得率为评价指标,采用L9(34)正交试验设计,考察乙醇体积分数、提取时间、固料比、提取温度对葛渣总黄酮提取效果的影响,同时采用高效液相色谱法(HPLC法)测定葛根素的含量。结果：葛渣中总黄酮的最佳提取工艺条件为以体积分数70%乙醇溶液为溶剂、提取150min、料液比1:40(g/mL)、提取温度80℃,此条件下的总黄酮得率最高,为32.41mg/g。在该提取条件下,葛根、葛渣和葛粉中总黄酮的含量分别为46.11、32.41mg/g和11.23mg/g;葛根、葛渣和葛粉中葛根素的含量分别为40.63、21.24mg/g和4.71mg/g。结论：葛渣中含有丰富的总黄酮和葛根素,该方法可作为从葛渣中提取总黄酮和葛根素的方法。     

响应面法优选大蒜中黄酮提取工艺研究

目的:利用响应面分析法优化大蒜中黄酮提取工艺条件.方法:以黄酮得率为指标,应用Design-Expert对影响黄酮提取效果的提取时间、料液比、乙醇体积分数、提取温度4个因素进行中心组合设计试验,并建立教学模型,研究这些因素对黄酮提取率的影响.结果:各因素对黄酮提取率的影响大小依次为提取温度＞乙醇体积分数＞提取时间＞料液比,最佳的提取工艺条件为提取时间3.98 h,料液比1 ∶ 40.19,乙醇体积分数68.63％,提取温度96.66℃,该条件下大蒜总黄酮的提取率为1.134mg/g.紫外分光光度法测得实际提取率为1.122mg/g,荧光法测得实际提取率为1.127mg/g.结论:响应面分析法优选黄酮提取工艺条件是合理、可行的.     

正交试验法优化草莓中总黄酮的提取工艺研究

对草莓中黄酮类物质的提取工艺进行了优化,在单因素的基础上,采用L9(34)正交试验设计,研究乙醇浓度、料液比、提取时间和提取温度对草莓总黄酮得率的影响.结果表明,水浴回流提取草莓总黄酮的影响因素顺序依次为乙醇浓度＞料液比＞提取时间＞提取温度,草莓总黄酮的最佳提取工艺条件为固液比1∶35 (g/mL)、乙醇浓度55％、提取时间130min、提取温度60℃,此条件下总黄酮得率为5.13mg/g.     

超声波辅助法和乙醇回流法提取葛根素

用乙醇做溶剂,分别采用超声辅助法和回流法从葛根中提取有效成分葛根素,考察了反应时间、反应温度、固液比、乙醇浓度等因素对提取率的影响,并采用正交设计进行了优化。研究结果表明,乙醇回流法提取葛根素的最佳工艺条件为:乙醇浓度75%,提取温度90℃,提取时间90 min,固液比为1∶20(g/m L),葛根素的提取率为86.20%;超声波辅助法提取葛根素的最佳工艺条件为:乙醇浓度60%,提取温度80℃,固液比为1∶20(g/m L),提取时间50 min,葛根素的提取率为95.85%。超声波辅助提取的提取率明显高于乙醇回流法。     

苘麻总黄酮提取工艺的研究

采用分光光度法,以芦丁为标准品测定苘麻茎中的总黄酮含量.在提取过程中通过单因素试验分析了乙醇浓度、料液比、回流时间及回流温度四个主要因素对提取率的影响.在单因素试验的基础上通过正交设计法优化苘麻黄酮提取工艺条件.结果表明:苘麻总黄酮的最佳提取工艺条件为乙醇体积浓度为75%,料液比为1:40,回流温度为60℃,提取时间为1.5h.此条件下苘麻茎的总黄酮得率为6.72%.     

Differences in content and composition of free lipids and carotenoids in flour of spring and winter wheat cultivated in Poland

The work presents the content and composition of free lipids and carotenoids in spring and winter classes of wheat flour. It discusses genetical and physiological aspects of their synthesis and accumulation in wheat kernels and also indicates how methodological differences explain differences in results presented in the literature. It has been reported that spring wheat flours are richer in free lipids, especially in the non-polar fraction. The content of glycolipids ranged from 134 to 215 mg/100 g flour and was more stable within the winter wheat class. The percentages of the two main fractions, namely DGDG and MGDG, were similar in both wheat classes and reached ca. 77%. Phospholipids constituted the smallest fraction of the flour free lipids in both wheat classes; however, spring wheat flours were richer in these compounds, which is likely associated with a greater content of spherosomes in the endosperm of this wheat class. The free lipids of spring wheat flour contained more oleic and slightly less linoleic and linolenic acids. Spring wheat flour was also richer in carotenoids, although there were varieties in both classes that deviated from this. The main carotenoid was lutein, whose total percentage in the form of different isomers ranged from 71.3% to 83.3% and was slightly lower for spring wheat flour. Lutein, in the form of a trans-isomer, constituted about 62% and 70% of all carotenoids in spring and winter wheat flours, respectively.     

生物技术在制浆造纸中的应用与研究进展

介绍了生物技术在制浆造纸工业的应用与研究进展，包括生物制浆、生物漂白、生物脱墨及造纸过程中的生物技术等。     

2018年深圳市售蔬菜和鸡蛋中氟虫腈及其代谢物的检测分析

目的 建立超高效液相色谱-串联质谱法同时测定蔬菜和鸡蛋中氟虫腈及其代谢物(氟甲腈、氟虫腈砜和氟虫腈亚砜), 并对深圳市售的蔬菜和鸡蛋中氟虫腈及其代谢物残留状况进行抽样检测。方法 采用QuEChERS前处理方法, 以C18色谱柱为分离柱, 以乙腈和10 mmol甲酸+6 mmol甲酸铵水溶液为流动相进行梯度洗脱, 用超高效液相色谱-串联质谱(ultra performance liquid chromatography-mass spectrometry/mass spectrometry, UPLC-MS/MS), 电喷雾电离(electrospray ionization, ESI), 多反应监测(multiple reaction monitoring, MRM)模式检测, 外标法同时定量测定氟虫腈及其代谢物。结果 方法的线性范围为0.1~2.0 μg/L, 线性相关系数均大于0.9994, 检出限0.0005 mg/kg, 定量限0.001 mg/kg; 蔬菜中3个水平的平均加标回收率88.0%~101.2%, 相对标准偏差(relative standard deviation, RSD)均小于8.5%; 鸡蛋中3个水平的平均加标回收率86.1%~104.8%, 相对标准偏差(RSD)均小于9.2%。结论 该方法具有操作简单、干扰少、快速、准确可靠等特点, 可适用于蔬菜鸡蛋中氟虫腈及其代谢物的检测。     

Influence of ouabain of electrolyte and water transport in the rabbit ileum and colon in vitro and in vivo

We studied the influence of the Na⁺-K⁺ pump inhibitor ouabain on water and electrolyte transport in the rabbit distal ileum and proximal colon in vitro and in vivo. Under in vitro conditions, ouabain markedly reduced the absorption of water, sodium, chloride and bicarbonate, and reduced potassium secretion in both the ileum and the colon. In vivo results were similar but less marked than those obtained in vitro, with significant differences only at the level of the distal ileum.     

Advantages and limitations of in vitro and in vivo methods of iron and zinc bioavailability evaluation in the assessment of biofortification program effectiveness

ABSTRACT

Biofortification aims to improve the micronutrient concentration of staple food crops through the best practices of breeding and modern biotechnology. However, increased zinc and iron concentrations in food crops may not always translate into proportional increases in absorbed zinc (Zn) and iron (Fe). Therefore, assessing iron and zinc bioavailability in biofortified crops is imperative to evaluate the efficacy of breeding programs. This review aimed to investigate the advantages and limitations of in vitro and in vivo methods of iron and zinc bioavailability evaluation in the assessment of biofortification program effectiveness. In vitro, animal and isotopic human studies have shown high iron and zinc bioavailability in biofortified staple food crops. Human studies provide direct knowledge regarding the effectiveness of biofortification, however, human studies are time consuming and are more expensive than in vitro and animal studies. Moreover, in vitro studies may be a useful preliminary screening method to identify promising plant cultivars, however, these studies cannot provide data that are directly applicable to humans. None of these methods provides complete information regarding mineral bioavailability, thus, a combination of these methods should be the most appropriate strategy to investigate the effectiveness of zinc and iron biofortification programs.     

Distribution and characteristics of Aeromonas in food and drinking water in Denmark

A total of 970 Danish commercial foods and drinking water samples were examined for the presence of motile Aeromonas spp. With a detection limit of 10²/g the frequent prevalence in raw foods was confirmed. Aeromonas occurred in 7% of 779 samples of prepared foods; most frequently in whipped cream from ice cream parlors (28%) and mayonnaise salads (10%) with numbers occasionally exceeding 10⁵/g. The prevalence in drinking water was 28% with a detection limit of 1/100 ml. A. hydrophila was the dominating species in both food and water. Hemolysin production was demonstrated in 37% of the 51 isolates tested with 10% having high titers.     

果蔬制品中链格孢霉毒素检测与控制研究进展

链格孢霉属(Alternaria species)是链格孢霉毒素这种次级代谢产物的已知生产者。链格孢霉毒素具有明显的毒理学潜力,食用被其污染的果蔬和粮食产品会对消费者的健康造成威胁。果蔬营养丰富、含水量高,更易于被链格孢霉毒素感染,因此建立高效、简单、快速的检测技术和实现该毒素的高效控制一直是当今果蔬领域研究的热点。本文总结和分析了链格孢霉毒素常见的检测技术和控制方法,以期为链格孢霉毒素的快速检测和果蔬类食品安全控制与风险评估等提供参考。     

蔬果中氯吡脲残留样品前处理及分析方法研究进展

氯吡脲是一种新的高效植物生长促进剂, 在蔬菜水果生产中广泛应用, 长期接触可引起人体内蛋白质代谢紊乱。因此, 发展简单、快速、高灵敏度的氯吡脲残留分析方法具有重要意义。本文综述了蔬果中氯吡脲残留分析的研究进展, 包括固相萃取等样品前处理方法及液相色谱-质谱、酶联免疫法等分析方法, 并对其发展趋势进行了展望。     

葡萄酒及软木塞中TCA的检测分析方法研究现状及应用前景

软木塞污染已经成为葡萄酒行业最为严重的问题之一,而导致软木塞和葡萄酒污染的最主要物质之一就是TCA。本文主要介绍葡萄酒和软木塞中TCA 的检测方法和萃取浓缩方法,同时也对TCA 检测的应用前景和发展趋势进行了展望。