共查询到19条相似文献,搜索用时 140 毫秒
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本文对加温萎凋与复式萎凋过程中取不同萎凋样品及成品茶,采用国标方法分析水浸出物、茶多酚、游离氨基酸、可溶性糖、咖啡碱及儿茶素组分等生化成分含量变化,同时采用GC/MS分析两种萎凋方式制成的成品茶香气物质差异,来探究两种萎凋工艺对福鼎白茶品质的影响.结果表明,加温萎凋制成的福鼎白茶可溶性糖、茶多酚、儿茶素总量显著高于复式... 相似文献
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茯砖茶不同萃取物对消化酶活性的影响 总被引:5,自引:0,他引:5
将茯砖茶依次用三氯甲烷、乙酸乙酯及正丁醇萃取后制备样品,测定各部分样品对α-淀粉酶及胰脂肪酶活性的影响。研究发现茯砖茶各部分样品对胰脂肪酶活性的影响程度不同,三氯甲烷层稍有抑制作用,活性只有对照的0.82倍,水提物、乙酸乙酯萃取层及正丁醇萃取层有显著的激活作用,正丁醇萃取层部分激活作用最明显,达2.54倍。茯砖茶各部分样品对α-淀粉酶活性均有激活作用,其中以乙酸乙酯萃取层部位的激活作用最强,激活倍数为4.09,其次是水提物,其激活倍数为2.99,水层的激活作用不显著。三氯甲烷萃取层抑制作用不显著,活性只有对照的0.88倍。乙酸乙酯萃取层及正丁醇萃取层部分经过HP-20树脂再分离后,各部分仍有较高的活性。 相似文献
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苦丁茶提取物多酚含量与抗氧化活性的测定 总被引:5,自引:1,他引:4
首先用不同的有机溶剂分部萃取苦丁茶(Ilex kudincha C.J.Tseng)热水提取物(粗提物),得到氯仿萃取物、乙酸乙酯萃取物、正丁醇萃取物及萃取剩余物,然后采用Folin-Ciocalteu比色法测定粗提物和各萃取物的多酚含量,同时应用DPPH法、TEAC法和FRAP法分别测定粗提物和各萃取物的自由基清除能力和还原Fe3+能力。结果表明,苦丁茶提取物具有较高的多酚含量和较强的抗氧化能力;DPPH法和FRAP法测定各提取物抗氧化能力的结果为乙酸乙酯萃取物>正丁醇萃取物>粗提物>萃取剩余物>氯仿萃取物,TEAC法测定结果为乙酸乙酯萃取物>正丁醇萃取物>粗提物>氯仿萃取物>萃取剩余物;多酚含量与抗氧化能力之间、所用抗氧化测定方法之间均存在较好的相关性。 相似文献
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本文简述了超临界萃取技术的发展及基本原理,对超临界CO2流体的性质、特点作了介绍,同时重点介绍了超临界CO2萃取技术在大豆深加工及在其它食品加工方面的应用,并给出了相应的技术参数和工艺条件. 相似文献
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粮油是人类生存的必需品,提供了人体不可缺少的三大基本营养素。粮油质量安全是国家重视、消费者关心的热点问题,检测是保证粮油产品消费安全的重要抓手。固相萃取是从粮油样品中提取待测物的重要手段,萃取材料是决定提取分离效率的关键因素。本文主要综述了基于固相萃取的粮油产品前处理技术研究进展,讨论了不同材料的优势及不足,并对粮油产品检测中新型萃取材料发展趋势进行了展望。 相似文献
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BuchiB—811与YG—2含油量测定的比较 总被引:2,自引:2,他引:2
采用BuchiB-811脂肪测定仪与YG-2脂肪抽提器比较分析油菜、大豆、花生等油料种子含油量的测试差异,结果表明BuchiB-811与YG-2测定的油料种子含油量一致,符合国家标准方法的要求,测试简便,快速准确。 相似文献
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J. van Staden 《Potato Research》1976,19(3):249-252
Summary Using ethyl acetate extraction in a liquid-liquid extractor three cell division inducing compounds, that coelute with authentic
cytokinins, were extracted from sprouting potato tubers. The major peak of activity coeluted and cochromatographed with zeatin
riboside. In the low resolution mass spectrometer the active substance yieldedm/e peaks characteristic of N-6- substituted adenines. 相似文献
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皂苷具有多种药理作用,对野生大豆中各类皂苷的定量分析是研究野生大豆皂苷药理作用的基础.利用索氏提取器以甲醇热回流提取野生大豆中的皂苷,结合理化反应进行鉴别,以齐墩果酸作为对照品进行薄层层析,通过薄层扫描测定皂苷含量.结果表明:野生大豆皂苷1~5μg范围内线性关系良好,平均回收率为98.98%,RSD为0.41%,薄层层... 相似文献
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Anvar U. BuranovGiuseppe Mazza 《Industrial Crops and Products》2012,35(1):77-87
Fractionation of flax shives into major biopolymer constituents, such as cellulose, hemicelluloses, and lignin, was carried out with pressurized aqueous ethanol in a pressurized low-polarity water extractor. The effect of processing parameters such as temperature, ethanol concentration, flow rate, sample size and solvent/feed ratio on the simultaneous extraction of hemicelluloses and lignin was determined. More than 80% of total hemicelluloses and ∼78% of total lignin were removed simultaneously in a single step under the following conditions: 180 °C, 30% (v/v) ethanol concentration, 3 mL/min flow rate, and 45 mL/g solvent/feed ratio. Under these extraction conditions, cellulose degradation was negligible. Further, the separation of lignin from hemicelluloses was carried out using two simple alternative methodologies based on precipitation. Since no acidic or alkali catalysts were used, the degradation of biopolymers was negligible and the oligomer/monomer ratio of sugars was 825:1. Characterization of fractionated biopolymers was carried out with scanning electron microscopy and a Fourier-transform infrared spectrometer (FT-IR). FT-IR spectra of isolated lignin and hemicelluloses showed that both polymers were comparable to commercially available products. 相似文献
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Macroalgae are one of potential sources for carotenoids, such as fucoxanthin, which are consumed by humans and animals. This carotenoid has been applied in both the pharmaceutical and food industries. In this study, extraction of fucoxanthin from wet brown seaweed Undaria pinnatifida (water content was 93.2%) was carried out with a simple method using liquefied dimethyl ether (DME) as an extractant in semi-continuous flow-type system. The extraction temperature and absolute pressure were 25 °C and 0.59 MPa, respectively. The liquefied DME was passed through the extractor that filled by U. pinnatifida at different time intervals. The time of experiment was only 43 min. The amount of fucoxanthin could approach to 390 μg/g dry of wet U. pinnatifida when the amount of DME used was 286 g. Compared with ethanol Soxhlet and supercritical CO2 extraction, which includes drying and cell disruption, the result was quite high. Thus, DME extraction process appears to be a good method for fucoxanthin recovery from U. pinnatifida with improved yields. 相似文献
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《Industrial Crops and Products》2007,25(1):8-16
Development of a flax (Linum usitatissimum L.) industry in North America is desired to supply a domestic source of clean, consistent quality textile fiber for blending with cotton. The objective of this work was to evaluate portions of traditional cotton gin equipment (extractor feeder and lint cleaner) and the “50-g cotton-spinning test (CST)” for flax. Dust was collected on an area sampler in an isolated card room to evaluate dust potential during textile pilot plant processing. Fibers retted by diverse means were cleaned on two separate portions of Continental Eagle's pilot plant cotton gin stand, the Super 96 Feeder and the 24D lint cleaner. Fibers separated and removed from flax stalks by these gin sections were compared against the standard ‘unified line’ processing technique of the USDA Flax Pilot Plant. Test yarns were then made in a CST with cotton and flax blends to provide an indirect measurement of fiber properties that can be related to the retting and gin cleaning processes. The yarns were tested for strength and evenness. Flax fibers that displayed the most favorable properties in the CST were then spun in 23 kg lots in the pilot plant at the following cotton/flax blend ratios: 100/0, 75/25, 50/50, 25/75, and 20/80. With modifications, it appears that portions of a cotton gin stand are able to process adequately small samples of properly retted flax stalks. The CST with minor adjustments provides useful data for ranking and further large-scale flax processing. As expected, it appears that flax fiber can be successfully cleaned on a cotton processing line and that increasing the amount of flax generates additional dust. 相似文献
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Most phenolic compounds in cereals are bound to cell wall components and thus they are difficult to extract. Finding techniques to enhance polyphenol extraction is important due to their potential health benefits. The objective of this study was to evaluate extractability of sorghum phenolic compounds using solvents under high pressure and temperature conditions. Polyphenols from black and tannin sorghum bran were extracted using an accelerated solvent extractor (ASE) at 60, 120 and 150 °C. ASE at 120 and 150 °C using 50 and 70% ethanol/water (v/v) was efficient in extracting similar amount of phenols (45 mg GAE/g) and 12% more antioxidants (628 μmol TE/g) from black sorghum compared to traditional methods using aqueous acetone and acidified methanol. High pressure and temperature did not improve the extraction of phenols and antioxidants in tannin sorghum as much as in black sorghum. This could be due to differences in grain structure and phenolic profile (different molecular weights) between the two samples. Another reason is that tannins may be interacting with proteins and carbohydrates under heat, thus they could be extracted but not measured. Therefore, there is a potential of using ASE extracts from black sorghum bran to produce beverages and colorants containing high antioxidant content. 相似文献