排序方式: 共有34条查询结果,搜索用时 15 毫秒
1.
2.
Patrick J. Gray Sean D. Conklin Todor I. Todorov Sasha M. Kasko 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2016,33(1):78-85
This paper reports the effects of rinsing rice and cooking it in variable amounts of water on total arsenic, inorganic arsenic, iron, cadmium, manganese, folate, thiamin and niacin in the cooked grain. We prepared multiple rice varietals both rinsed and unrinsed and with varying amounts of cooking water. Rinsing rice before cooking has a minimal effect on the arsenic (As) content of the cooked grain, but washes enriched iron, folate, thiamin and niacin from polished and parboiled rice. Cooking rice in excess water efficiently reduces the amount of As in the cooked grain. Excess water cooking reduces average inorganic As by 40% from long grain polished, 60% from parboiled and 50% from brown rice. Iron, folate, niacin and thiamin are reduced by 50–70% for enriched polished and parboiled rice, but significantly less so for brown rice, which is not enriched. 相似文献
3.
目的: 探讨烟酸姜黄素酯(curcumin nicotinate,CN)对低剪切应力(low shear stress, LSS)诱导人脐静脉内皮细胞(human umbilical vein endothelial cells,HUVECs)凋亡的影响及机制研究。方法: 运用平行平板流动腔建立LSS诱导的HUVECs凋亡模型。采用Hoechst33258荧光染色,流式细胞术检测CN对LSS诱导的HUVECs凋亡的影响。Western blot检测CN对LSS诱导的HUVECs中前蛋白转化酶枯草溶菌素9(proprotein convertase subtilisin/kexin type 9,PCSK9)蛋白表达的影响。结果:Hoechst33258荧光染色结果显示,与静态培养组比较,LSS组(3 dyne/cm2,12 h)内呈现凋亡状态的HUVECs明显增多。与LSS组比较,各CN+LSS组内呈现凋亡状态的HUVECs明显减少,并且呈现浓度依赖性。其中以20 μmol/L CN+LSS组凋亡细胞数最少;流式细胞术结果显示,与静态培养组比较,LSS组HUVECs凋亡率明显增加,差异有显著统计学意义(P<0.01);与LSS组比较,各CN+LSS组HUVECs凋亡率明显减少,并且呈现浓度依赖性,其中以20 μmol/L CN+LSS组HUVECs凋亡率减少最为明显,差异具有显著统计学意义(P<0.01)。Western blot结果显示与静态培养组比较,LSS组内PCSK9蛋白表达显著升高,差异具有统计学意义(P<0.01);与LSS组比较,CN+LSS组内PCSK9蛋白表达下降,并且呈现浓度依赖性,差异具有统计学意义(P<0.05)。其中以20 μmol/L CN+LSS组PCSK9蛋白表达下降最为明显(P<0.01)。结论: CN能够抑制LSS诱导的HUVECs凋亡,其作用机制与CN下调LSS处理的HUVECs中PCSK9蛋白表达相关。 相似文献
4.
5.
C. Vidal-Valverde Marin Prodanov Isabel Sierra 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1997,205(6):464-469
Lentils (Lens culinaris, var. vulgaris cultivar Magda-20) were naturally fermented for 96 h at different lentil flour concentrations (79, 150 and 221 g/l) and temperatures
(28, 35 and 42°C). During fermentation, samples were taken at 24-h intervals and the changes in thiamin (vitamin B1), riboflavin (vitamin B2) and total and available niacin (vitamin B3) were investigated. Preparation of the lentil flour suspension to be fermented (i.e. the process of mixing the flour and
sterilized tap water) caused an increase of the available niacin content in all batches, while changes in thiamin and riboflavin
content were related to the conditions in which the preparation of the suspensions was carried out. The whole natural fermentation
process (from the raw state to after 96 h of fermentation), either did not affect or produced a slight decrease in the thiamin
content of lentils. In contrast, riboflavin, available niacin and total niacin contents increased throughout the 96 h period,
which ended with a 35 – 82% increase of riboflavin, a 24 – 91% increase of available niacin and a 20 – 58% increase of total
niacin. The temperature during the fermentation procedure had significant effect on the levels of thiamin and riboflavin in
fermented lentils. To obtain lentil flours with an improved amount of riboflavin and available niacin with a minimum loss
of thiamin, the natural fermentation of lentils should be carried out for 96 h at 42°C and with a lentil flour concentration
of 221 g/l.
Received: 21 February 1997 相似文献
6.
7.
Tyler J. Titcomb Sherry A. Tanumihardjo 《Comprehensive Reviews in Food Science and Food Safety》2019,18(6):1968-1984
The prevalence of undernutrition due to insufficient energy intake has been reduced by nearly 50% since 1990. This reduction is largely attributed to improved yields of staple crops, such as wheat, rice, and maize; however, these improvements did little for micronutrient deficiencies that affect an estimated two billion people worldwide. Starchy staple crops are energy dense but are often lacking in one or more B vitamins, making resource‐constrained people who consume monotonous diets comprised predominantly of these staples at risk for developing deficiency. B vitamin deficiencies occur due to a poor overall nondiversified diet and rarely occur alone. Many B vitamins are essential cofactors involved in the metabolism of other nutrients, including other B vitamins, whereby the deficiency of one B vitamin affects the metabolism and status measurements of another. Food fortification efforts have nearly eradicated diseases of extreme B vitamin deficiency, such as beriberi from thiamin deficiency and pellagra from niacin deficiency. However, subclinical deficiency, sometimes referred to as hidden hunger, is still common especially in low‐income countries. Most dietary B vitamins, due to their water‐soluble nature, are not a concern for excessive intakes, but synthetic forms used for fortification and supplements sometimes can have adverse effects when consumed in high amounts. Biofortified crops offer a long‐term sustainable method to increase the amount of dietary B vitamins for people who rely on staple crops for most of their caloric intake. Efforts have been made to improve B vitamin content of crops, especially for thiamin, vitamin B6, and folate, but none have undergone human feeding trials; therefore, more research is needed to provide sustainable and scalable solutions in many parts of the world. 相似文献
8.
A dose-response evaluation of rumen-protected niacin in thermoneutral or heat-stressed lactating Holstein cows 总被引:1,自引:0,他引:1
S. Rungruang J.L. Collier R.P. Rhoads L.H. Baumgard M.J. de Veth R.J. Collier 《Journal of dairy science》2014
Twenty-four multiparous high-producing dairy cows (40.0 ± 1.4 kg/d) were used in a factorial design to evaluate effects of 2 environments [thermoneutral (TN) and heat stress (HS)] and a dose range of dietary rumen-protected niacin (RPN; 0, 4, 8, or 12 g/d) on body temperature, sweating rate, feed intake, water intake, production parameters, and blood niacin concentrations. Temperature–humidity index values during TN never exceeded 68 (stress threshold), whereas temperature–humidity index values during HS were above 68 for 24 h/d. The HS environment increased hair coat and skin, rectal, and vaginal temperatures; respiration rate; skin and hair coat evaporative heat loss; and water intake and decreased DMI (3.5 kg/d), milk yield (4.1 kg/d), 4% fat-corrected milk (2.7 kg/d), and milk protein yield (181.7 g/d). Sweating rate increased during HS (12.7 g/m2 per h) compared with TN, but this increase was only 10% of that reported in summer-acclimated cattle. Niacin supplementation did not affect sweating rate, dry-matter intake, or milk yield in either environment. Rumen-protected niacin increased plasma and milk niacin concentrations in a linear manner. Heat stress reduced niacin concentration in whole blood (7.86 vs. 6.89 μg/mL) but not in milk. Reduced blood niacin concentration was partially corrected by dietary RPN. An interaction existed between dietary RPN and environment; dietary RPN linearly increased water intake in both environments, but the increase was greater during HS conditions. Increasing dietary RPN did not influence skin temperatures. During TN, supplementing 12 g/d of RPN increased hair coat (unshaved skin; 30.3 vs. 31.3°C at 1600 h) but not shaved skin (32.8 vs. 32.9°C at 1600 h) temperature when compared with 0 g/d at all time points, whereas the maximum temperature (18°C) of the room was lower than skin temperature. These data suggest that dietary RPN increased water intake during both TN and HS and hair coat temperature during TN; however, core body temperature was unaffected. Thus, encapsulated niacin did not improve thermotolerance of winter-acclimated lactating dairy cows exposed to moderate thermal stress in Arizona. 相似文献
9.
在微波辐射下,用邻苯二胺和烟酸合成了2-(3-吡啶基)苯并咪唑,采用L9(34)正交实验法,2-(3-吡啶基)苯并咪唑的最佳合成工艺条件为:微波辐射时间120 min,微波辐射功率为162 W,邻苯二胺与烟酸物质的量比为1∶1.1。产物的收率为68.72%,通过数字熔点仪、红外光谱仪、元素分析仪进行了表征。 相似文献
10.
选用四头装有永久性瘤胃瘘管的黑白花奶牛,进行交叉试验设计。测定了添加8克/头·日烟酸对瘤胃内pH、氨氮、微生物蛋白、总挥发性脂肪酸及其组分的影响。奶牛日粮中精料由豆饼、棉籽饼、玉米、麸皮及矿物质组成,粗料为玉米青贮和干草。日粮配合参照《中国奶牛饲养标准》。 试验结果表明,试验组和对照组的瘤胃内微生物蛋白量分别为84.10±7.33和78.59±8.80mg/dl,统计分析差异显著(P<0.05)。烟酸对瘤胃内pH、氨氮、总挥发性脂肪酸及其组成均无显著影响(P>0.05)。但试验组奶牛瘤胃内丙酸有提高趋势。试验组在饲喂后1~2小时出现的氨氮峰值比对照组高,而以后的吸收利用也比对照组快。试验结果说明添加烟酸可促进瘤胃内氨氮利用,提高微生物蛋白量并有提高丙酸量的趋势。 相似文献