白花益母草种子的化学成分分析

对白花益母草种子的化学成分进行分析,结果表明,种子油含有大量人体必需的不饱和脂肪酸,其主要成分为：亚油酸（42．60％）、亚麻酸（30．22％）、油酸（20．28％）等,此外种子还含有18种氨基酸和24种矿质元素和蛋白质等成分。其种子和种子油具有较高的营养价值和药用功效。     

小鱼仙草种子化学成分的研究

对小鱼仙草种子的化学成分进行研究,结果表明：种子脂肪油含量为20.26%,其主要成分为：亚油酸（15.117%）、亚麻酸（67.356%）、油酸（11.349%）、棕榈酸（4.988%）、硬脂酸（11.80%）等,种子油含有大量人体所需的不饱和脂肪酸。此外还测定了种子的17种氨基酸和24种矿质元素。其种子和种子油具有较高的营养价值和医疗保健功效,具有潜在开发利用的价值。     

木兰科四种植物种子油的提取及脂肪酸成分分析

采用超声波辅助提取法和微波辅助提取法同时提取白玉兰、凹叶厚朴、深山含笑和醉香含笑四种木兰科植物的种子油,种子油甲酯化后,运用气相色谱—质谱联用技术测定其脂肪酸成分。结果表明:四种植物种子油的提取率不同,白玉兰平均为27.35%、凹叶厚朴23.34%、深山含笑31.66%,醉香含笑9.27%。不同提取方法所得到的种子油脂肪酸成分和相对含量不同,但四种种子油的主要脂肪酸成分相同,包括油酸、亚油酸、硬脂酸和棕榈酸。     

樟科植物中脂肪酸成分的分布

本文报道了樟科11个属49种种子油和‘种果肉油的脂肪酸成分。其中樟族和木姜子族的各属种(滇新樟除外)种子油脂肪酸成分以 C_(10)、C_(12)和 C_(14)饱和或烯酸为主。而厚壳桂属、润楠和楠属种子油脂肪酸成分主要为棕榈酸、油酸和亚油酸。山苍子、天目木姜子、大果山胡椒、山橙、红脉钓樟、鸭公树和锈叶新木姜子种子油中的 C_(10)、C_(12)和 C_(14)烯酸经分离鉴定均是顺式Δ~4烯酸。     

白苏子和荠Lin子形态特征及其化学成分的研究

对白苏子和荠Lin子两种种子的脂肪油,氨基酸,矿质元素等化学成分进行分析,结果表明,两种种子均含有丰富的脂肪油,含量分别为40．18％和20．62％,其脂肪油的主要成分为：亚麻酸,亚油酸,油酸,棕榈酸,硬脂酸等,其中不饱和脂肪酸的含量分别为92．759％和92．990％,具有较高的营养价值,此外,还含有丰富的氨基酸和种类齐全的矿质元素,其种子形状大小,纹饰特征是两种种子鉴别的重要依据。     

中国沙棘种子油成分分析

对辽宁、河北、山西、陕西、甘肃和内蒙古等六个省（区）八个产地的沙棘种子的含油率、种子油的理化常数和各种营养成分进行了分析比较研究,为中国沙棘种子油的利用和建立统一的沙棘种子油标准提供了依据。中国沙棘种子含油率为７．３２～９．８３％。油中饱和脂肪酸与不饱和脂肪酸之比为１：７．０～８．２。油中ＶＥ含量为１１５～２３９ｍｇ％,其中α－生育酚占２０．２５～５１．７３％。胡萝卜素含量在５．７０～１４．９０ｍｇ％。     

白苏子和荠苧子形态特征及其化学成分的研究

对白苏子和荠苧子两种种子的脂肪油、氨基酸、矿质元素等化学成分进行分析 ,结果表明 :两种种子均含有丰富的脂肪油 ,含量分别为 4 0 .18%和 2 0 .6 2 % ,其脂肪油的主要成分为 :亚麻酸、亚油酸、油酸、棕榈酸、硬脂酸等 ,其中不饱和脂肪酸的含量分别为 92 .759%和 92 .990 % ,具有较高的营养价值。此外 ,还含有丰富的氨基酸和种类齐全的矿质元素。其种子形状大小、纹饰特征是两种种子鉴别的重要依据。     

构树种子化学成分研究

对构树种子的脂肪油、氨基酸、矿质元素进行分析,结果表明:种子含脂肪油40.18%,主要成分为:亚油酸(85.42%)、油酸(4.29%)、棕榈酸(7.35%)、亚麻酸(0.98%)等。此外,还含有17种氨基酸和24种矿质元素。     

木姜子属三种植物油的脂肪酸成分

山苍子、天目木姜子、桂北木姜子种子油中脂肪酸成分均主含月桂酸(34.6—75.4%)。桂北木姜子果肉油的脂肪酸成分与其种子油不同,主要成分是亚油酸。生长在不同地区(湖南、福建、杭州等省市)的山苍子种子含油量及其脂肪酸成分是有差异的。采用减压分馏、硝酸银硅胶桂层析和液液分配层析方法,从山苍子种子油脂肪酸中分离出 C_(10)—C_(14)烯酸。通过高碘酸钠、高锰酸钾氧化方法、红外光谱、核磁共振和质谱分析,确定它们是顺式4-十碳烯酸、顺式4-十二碳烯酸和顺式4-十四碳烯酸。     

黄蜀葵种子形态及其化学成分的研究

本文报道了黄蜀葵种子的形态特征和化学成分。研究结果表明 :种子含有脂肪油 ,含量为31 16 % ,其主要成分为 :亚油酸 (82 179% )、油酸 (9 195 % )、棕榈酸 (4 75 6 % )、硬脂酸 (2 6 81% )、亚麻酸 (0 32 8% )等 ,此外 ,还含有 18种氨基酸和 2 4种矿质元素。其种子含有多种氨基酸和矿质元素 ,而且种子油含有大量人体所必需的不饱和脂肪酸 ,含量达 91 815 %。因此 ,其种子和种子油具有较高的营养价值和医疗保健功效 ,具有潜在开发利用的价值。     

Separation and simultaneous determination of nalidixic acid, hydroxynalidixic acid and carboxynalidixic acid in serum and urine by micellar electrokinetic capillary chromatography

Separation in capillary electrophoresis is governed by various factors, including buffer type, buffer concentration, pH, temperature, voltage and micelles. Through proper adjustment of these parameters, nalidixic acid and its two major metabolites, 7-hydroxynalidixic and 7-carboxynalidixic, could be separated by micellar electrokinetic capillary chromatography using an electrophoretic electrolyte consisting of 50 mM borate buffer (pH 9) containing 25 mM sodium dodecyl sulphate and 10% acetonitrile. A linear relationship between concentration and peak area for each compound was obtained in the concentration range 0.15–100 μg ml⁻¹, with a correlation coefficient greater than 0.999 and detection limits in the 0.2–0.7 ng ml⁻¹ range. Intra- and inter-day precision values of about 0.8–1.2% RSD (n=11) and 1.3–2.0% RSD (n=30), respectively, were obtained. The method has been applied to the analysis of nalidixic acid and its two major metabolites in serum and urine with limits of sensitivity lower than 0.8 ng ml⁻¹.     

酚酸类物质对三七幼苗的化感影响

该文研究了不同浓度的阿魏酸、对香豆酸、丁香酸、对羟基苯甲酸、香草酸5种酚酸类物质对三七幼苗生长和生理的影响。结果表明:处理后,三七幼苗的苗高、根长、可溶性蛋白质含量、根系活力、CAT以及POD活性均有所降低。其中,阿魏酸各处理组幼苗的苗高及POD活性均显著降低,50、100 mg·L~(-1)的对香豆酸以及100 mg·L~(-1)的香草酸处理组幼苗苗高也分别比对照显著降低16.19%、16.67%和29.29%;对香豆酸、丁香酸以及对羟基苯甲酸各处理组幼苗根长均显著低于对照;香草酸处理组幼苗的根系活力也显著低于对照,且幼苗的CAT活性在10、50、100 mg·L~(-1)丁香酸、对羟基苯甲酸以及香草酸处理下也达到了显著降低水平。此外,1 mg·L~(-1)阿魏酸以及100 mg·L~(-1)香草酸处理组幼苗的叶绿素含量也均显著降低;中高浓度的阿魏酸、对香豆酸、丁香酸、对羟基苯甲酸增加了三七幼苗的MDA含量,而香草酸在0.1、1、10、100 mg·L~(-1)浓度下显著降低幼苗的MDA含量;丁香酸、香草酸、对羟基苯甲酸以及中高浓度的对香豆酸增加了三七幼苗的SOD活性,且香草酸各处理组均达到了显著性水平。综上结果表明,5种酚酸类物质对三七幼苗均具有一定的化感抑制作用,但各酚酸物质的作用方式及强度并不完全一致,阿魏酸的化感影响较大,这为进一步研究三七的化感自毒作用提供了一定的理论参考。     

氨基酸分析仪测定饲料添加剂——叶酸的方法

用６ｍｏｌ／Ｌ盐酸于１１０℃条件下水解饲料添加剂——叶酸,使之游离出谷氨酸,用氢氧化钠中和调节ｐＨ到２,氨基酸分析仪测定谷氨酸含量,经与标准叶酸水解样品比较,计算出叶酸的纯度。该方法重现性好,变异系数ＣＶ＝０．０８％,平均回收率为９８．３４％,浓度与峰面积呈线性相关,相关系数ｒ＝０．９９８７,可随氨基酸分析同时进行,不需改变任何分析条件。     

Triterpene acids from Salvia and Teucrium species

The pentacyclic triterpene acids ursolic acid, oleanolic acid, micromeric acid, maslinic acid and 3-epi-maslinic acid have been isolated from several Salvia and Teucrium species.     

Comparative acid stress response of Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella Typhimurium after habituation at different pH conditions

AIMS: The aim of the study was to evaluate the effect of habituation at different pH conditions on the acid resistance of Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enterica serotype Typhimurium, and to identify potential differences between the adaptive responses of the three pathogens. METHODS: Stationary phase cells of L. monocytogenes, E. coli O157:H7 and S. Typhimurium, grown in glucose-free media, were exposed to pH 3.5 broth directly or after habituation for 90 min at various pH conditions from 4.0 to 6.0. Survivors at pH 3.5 were determined by plating on tryptic soy agar and incubating at 30 degrees C for 48 h. The kinetics (death rate) of the pathogens at pH 3.5 was calculated by fitting the data to an exponential model. RESULTS: Habituation to acidic environments provided protection of the pathogens against lethal acid conditions. This acid protection, however, was found to be pH dependent. For example, for E. coli O157:H7 an increased acid resistance was observed after habituation at a pH range from 4.0 to 5.5, while the maximum acid tolerance was induced at pH 5.0. Furthermore, the effect of low pH habituation was different among pathogens. For L. monocytogenes, E. coli O157:H7 and S. Typhimurium, the pH range within which habituation resulted to increased acid resistance was 5.0-6.0, 4.0-5.5 and 4.0-5.0, respectively, while the maximum acid tolerance was induced after habituation at pH 5.5, 5.0 and 4.5, respectively. SIGNIFICANCE: Acid stress conditions are common within current food processing technologies. The information on adaptive responses of L. monocytogenes, E. coli O157:H7 and S. Typhimurium after habituation to different pH environments provided in the present study, could lead to a more realistic evaluation of food safety concerns and to a better selection of processes in order to avoid adaptation phenomena and to minimize the potential for food safety risks.     

Temperature regulates tuber-inducing lipoxygenase-derived metabolites in potato (Solanum tuberosum)

Temperature is one of the major environmental factors affecting potato tuberization. It has been suggested that lipoxygenase (LOX) mediates between temperature and tuber induction. In this study, the contents of the LOX-derived metabolites hydroperoxylinolenic acid (HPOT), jasmonic acid (JA), tuberonic acid (TA) and tuberonic acid glucoside (TAG) were analyzed in leaves of potatoes growing at different temperatures. At low, tuber-inducing temperature, endogenous levels of JA, TA and TAG rise, indicating their crucial role in tuber induction. The concentration of 13(S)-HPOT seems not to be directly affected by temperature. Instead, the molecule has only a short half-life in leaves and is readily metabolized.     

Effects of flaxseed,raw soybeans and calcium salts of fatty acids on apparent total tract digestibility,energy balance and milk fatty acid profile of transition cows

Oilseeds offer some protection to the access of ruminal microorganisms and may be an alternative to calcium salts of fatty acids (FA), which are not fully inert in the ruminal environment. This study aimed to evaluate the effects of different sources of FA supplementation on apparent total tract nutrient digestibility, milk yield and composition, and energy balance (EB) of cows during the transition period and early lactation. We compared diets rich in C18:2 and C18:3 FA. Multiparous Holstein cows were randomly assigned to receive one of the four diets: control (n=11); whole flaxseed (WF, n=10), 60 and 80 g/kg (diet dry matter (DM) basis) of WF during the prepartum and postpartum periods, respectively; whole raw soybeans (WS, n=10), 120 and 160 g/kg (diet DM basis) of WS during the prepartum and postpartum periods, respectively; and calcium salts of unsaturated fatty acids (CSFA, n=11), 24 and 32 g/kg (diet DM basis) of CSFA during the prepartum and postpartum periods, respectively. Dry cows fed WF had higher DM and net energy of lactation (NE_L) intake than those fed WS or CSFA. The FA supplementation did not alter DM and NDF apparent total tract digestibility, dry cows fed WF exhibited greater NDF total tract digestion than cows fed WS or CSFA. Feeding WS instead of CSFA did not alter NE_L intake and total tract digestion of nutrients, but increased milk fat yield and concentration. Calculated efficiency of milk yield was not altered by diets. FA supplementation increased EB during the postpartum period. Experimental diets increased long-chain FA (saturated and unsaturated FA) in milk. In addition, cows fed WS and CSFA had higher C18:1 trans-11 FA and C18:2 cis, and lower C18:3 FA in milk than those fed WF. Furthermore, cows fed CSFA had higher C18:1 trans-11 and cis-9, trans-11 FA than cows fed WS. Although supplemental C18:2 and C18:3 FA did not influence the milk yield of cows, they positively affected EB and increased unsaturated long-chain FA in milk fat.