硒的营养缺乏现状及补充方式

硒是人体必需的微量元素之一,适量地摄入硒,对维持生命活动、保证身体健康具有重要作用,硒的缺乏与过量摄入都会导致身体出现异常状况,缺硒会导致克山病、大骨节病,而硒过量会导致脱发、指甲脱落等,因此科学合理地补充硒至关重要。系统总结和分析了硒缺乏的原因、缺硒的危害、硒的营养价值以及不同年龄阶段和身体状态硒的标准补充剂量。研究了人体缺硒会出现的症状,摄入过量与不足会导致的疾病,并提出了增加食物多样性、补充硒制剂等补硒方式,以期为合理开发利用富硒食物、合理进行硒营养摄入与补充提供科学参考。     

硒的生理功能及其对畜禽动物性能和肉质的影响研究进展

微量元素硒不仅是人体必需营养元素之一,也是动物生长发育必不可少的元素,与动物许多重要的生理学功能密切相关。肉类作为人体摄入硒的主要途径,其硒含量普遍较低。通过向动物饲料中添加硒补充剂,可以有效增加可食组织中硒的沉积,这是改善人类饮食中硒摄入的一种有效方法,同时硒对动物体的影响也引起国内外学者的广泛关注。本文综述硒的生理功能和作用,分析国内外开展硒对畜禽动物性能及肉品质影响的研究现状,包括途径、可能的机理以及存在的问题,以期为硒在动物营养、肉质改善及富硒肉制品的生产开发中的应用提供参考。     

富硒食品生产的新策略——化学修饰法大量制备含硒蛋白质

正硒(selenium,Se)是人体必需的微量元素,具有抗氧化、解毒、防癌、促进生长、提高免疫力等多种作用,机体缺硒将导致克山病、人骨节病等一系列疾病的发生。膳食补硒是人们获取硒的主要途径,我国营养学会推荐正常成人每天摄入硒的安全和合适范围为50μg~250μg。然而仅靠天然食品中的硒还不能满足人体的正常需要,因此国内外普遍利用亚硒酸钠,硒酸钠、硒酸酯多糖(硒化卡拉胶)、硒酵母、硒蛋白、富硒食用菌、硒代甲硫氨酸、硒代半胱氨酸等硒营养强化剂制备     

硒对人体健康的影响

硒是地壳中含量极微的稀有元素,且分布均不均匀。据有关专家调查,我国从东北、西北、华北直到云贵川有一个宽的缺硒带,涉及22个省的751个县市,人口约3亿。同时也发现,在我国湖北恩施市和陕西紫阳县的个别乡镇属高硒区。国内外的科学家经过几十年的科学试验得出结论,硒与人体健康密切相关,人体摄入过多会产生毒害;摄入过少会患疾病。     

人体内硒检测与富硒食品开发的研究进展

硒元素在抗氧化和疾病预防中发挥着不可忽视的作用,近些年来有关硒与人体健康的关系研究越来越多,尤其是硒的生理功能与疾病之间的相关性.因此,通过适当的硒检测技术精准测定人体内硒含量,进而反映人体内硒水平对指导精准化补硒具有重要意义.由于人体所需的硒不能由自身合成,需要通过外界摄入,日常补硒方式中,膳食补硒较硒营养补充剂更为...     

不同种类乳制品对心脑血管疾病防控的影响

综述了近年来国内外有关乳制品对心脑血管疾病防控相关的流行病学研究证据和可能机制.研究表明,总乳制品、低脂乳制品以及牛奶摄入有利于高血压的防控,低脂乳制品以及发酵乳制品有利于脑卒中的防控,而对于冠心痛患者以及超重者,摄入乳制品对于疾病的控制有正面效果,但关于乳脂肪的作用研究证据不一致.     

加拿大研究发现吃盐并非越少越好

加拿大研究人员称,摄入适量食盐,比摄入过多与过少都更健康。该研究很可能引起关于饮食中盐的健康效应的辩论。多年来,医生警告称,大量摄入食盐会增加患高血压及其他心脏疾病的风险,但是最近的     

富硒畜产品研究进展

综述了硒的生物学功能、居民摄入现状、富集载体选择以及富硒肉、蛋、奶等优质畜产品的国内外研究进展等,并结合该领域目前的发展现状及存在问题,提出我国富硒产业未来的工作重点,为推进我国营养型农业生产、保障国民健康提供科学依据。     

富硒堇叶碎米荠蛋白质提取最近研究成果

正硒是人体必须的微量元素,参与多种代谢途径,具有清除自由基、调节免疫力、拮抗重金属等作用,缺硒与克山病等40多种疾病有关。富硒堇叶碎米荠是为数不多的超富硒植物,且生长适应性强,原料充足,具有很好的医用价值和民用价值。人体食用的蛋白质经过体内酶水解成多肽、短肽、氨基酸,进而被人体吸收。蛋白质的吸收利用率比多肽低,摄入硒肽比摄入硒蛋白质的补硒的效果较好。     

富硒啤酒的试验生产

开发加硒啤酒,使人们在饮用啤酒的同时摄入一定量的硒,有助于提高人体免疫功能,预防疾病,增强体质。1我公司酿造用水中的矿物质含量(见表1) 我公司使用的酿造水     

不同形态硒的功效研究进展

硒是人体中必不可少的微量元素之一。现阶段硒以及衍生物的研究已经有一定的基础, 国内外也开始重点研究硒以及硒衍生物的具体作用。硒在有机硒的形态下添加到食品中可以起到预防心血管疾病的作用。有机硒存在人体内也可以起到防止人体器官老化、预防心脏病、预防风湿性关节炎的作用。硒在硒蛋白的形态下也起到维持人体内激素动态平衡, 维持人体生理活动可以正常运转的作用。现如今对硒的诸多深入研究也只是刚刚起步, 本文介绍了硒的2种同形态, 并说明这2种形态下的具体作用机制, 以期让人们更好地理解不同形态硒。硒的更多形态和作用都有很大的研究价值, 今后也应该将硒作为重点研究的对象之一, 更好地将硒利用到各个领域当中。     

食品中叶黄素的研究与应用

为给叶黄素的利用提供借鉴，综述了叶黄素的定义、生理功能、安全性评价、安全摄入量、在国内外的批准和使用情况。     

低钠替代盐在火腿中的研究进展

传统火腿加工过程中食盐含量普遍超标,食盐的过量摄入已被证实会诱发高血压等一系列心脑血管疾病。为保障消费者的健康,降低火腿中钠盐含量是火腿制品所面临的重要任务。通过使用低钠替代盐可以降低钠含量且优化火腿的品质,但低钠替代盐需替代最适比例才能达到理想的替代盐的效果,超过最适替代比则会对火腿的风味、口感、质构和保质期产生不利影响。本文论述了国内外低钠替代盐的研究现状,阐述了近年来有关氯化物替代盐(钾盐、镁盐、钙盐)、非氯化物替代盐以及风味增强剂在火腿中应用的研究进展,以期为低钠火腿的研究与开发提供参考。     

Selenium and vitamin E and incidence of retained placenta in parturient dairy cows.

In a 2 X 2 X 2 factorial experiment, protein intake, selenium supplementation, and intake of phosphorus were related to the incidence of retained placenta in cows fed varying concentrations of these nutrients during the dry period. The population incidence of 38% retained placenta in 26 control cows was independent of phosphorus intake which ranged between 39 and 95 g per day. When a protein supplement was included in the concentrate as soybean meal, the incidence of retained placenta was reduced to 20% for supplemented animals from 50% for the animals that received no soybean meal. This increased protein in the ration was reflective of a mean increase from .02 ppm of selenium to .06 ppm of selenium in the ration. By increasing the mean daily intake of selenium at least 3 wk prepartum from .23 mg to .92 mg daily, overall incidence of retained placenta was reduced from 38% to 0%. A positive prophylactic effect was achieved regardless of whether alpha tocopherol was supplemented as well. These mature dairy cows were deficient in selenium, and supplementation of selenium reduced the incidence of retained placenta.     

Monitoring the content and intake of trace elements from food in Denmark

The content of cadmium, lead, nickel, mercury and selenium in 83 foods was monitored from 1993 to 1997. In comparison with similar results from 1988 to 1992, a general decrease in lead levels had occurred, whereas the contents of cadmium, nickel, mercury and selenium were stable or declined only slightly. The distribution in dietary intake of the five trace elements was estimated by combining the mean trace element concentrations with food consumption data from 1837 Danes aged 15-80 years. The lead intake for 1993-97 showed a decrease in comparison with similar estimates from the previous monitoring cycles: 1983-87 and 1988-92. The intake of cadmium and mercury decreased to a lesser extent, whereas the intake of selenium and nickel remained unchanged in the same period. The dietary intake of trace elements was compared with the provisional tolerable weekly intake (PTWI). The 95th percentile of the distribution in cadmium intake amounts to 34% of PTWI, which is relatively high, and therefore calls for a more detailed future risk assessment. The intakes of lead and mercury were 11% of PTWI and, like the intake of nickel, did not cause any health concern in the adult population. The Danes ingest close to 100% of the Nordic Nutrition Recommendation for selenium at 50 μg day -1 , and no individuals had an intake less than the lower limit of 20 μg day -1 .     

Enhancing the selenium content of bovine milk through alteration of the form and concentration of selenium in the diet of the dairy cow

Since estimated dietary selenium intake in the UK has declined steadily from around 60 µg day^?1 in 1975 to 34 µg day^?1 in 1997, there is a need to increase selenium intake from staple foods such as milk and milk products. An experiment was therefore done to investigate the relationship between dietary source and concentration of selenium and the selenium content of bovine milk. In a 3 × 3 factorial design, 90 mid‐lactation Holstein dairy cows were supplemented over 8 weeks with either sodium selenite (S), a chelated selenium product (Selenium Metasolate?) (C) or a selenium yeast (Sel‐Plex?) (Y) at three different dietary inclusion levels of 0.38 (L), 0.76 (M) and 1.14 (H) mg kg^?1 dry matter (DM). Significant increases in milk selenium concentration were observed for all three sources with increasing inclusion level in the diet, but Y gave a much greater response (up to +65 µg l^?1) than the other two sources of selenium (S and C up to +4 and +6 µg l^?1 respectively). The Y source also resulted in a substantially higher apparent efficiency of transfer of selenium from diet to milk than S or C. Feeding Y at the lowest dietary concentration, and thus within the maximum level permitted under EU regulations, resulted in milk with a selenium concentration of 28 µg l^?1. If the selenium concentration of milk in the UK was increased to this value, it would, at current consumption rates, provide an extra 8.7 µg selenium day^?1, or 11 and 14% of daily recommended national intake for men and women respectively. Copyright © 2004 Society of Chemical Industry     

Estimation of selenium intake in Switzerland in relation to selected food groups

The selenium concentration in foods was analysed in order to identify principal sources of this trace element in Switzerland. Selenium intake estimations based on three different approaches were carried out. From the relationship between intake and serum/plasma concentration, the selenium intake was estimated to 66 µg day^?1. The second approach based on measured food groups combined with consumption statistics; and the third approach consisted of duplicate meal samples. With the last two methods, over 75% of the serum/plasma based intake was confirmed. Swiss pasta made of North American durum wheat was the food with the highest contribution to the dietary intake, followed by meat. The strong decrease in imports of selenium-rich North American wheat of the last years was not reflected in the present intake estimations. It appears that this intake loss was compensated by a consumption increase of other foods. Compared with former intake estimations, selenium intake seems to be in Switzerland nearly constant for the last 25 years.     

Effect of dietary calcium on selenium absorption by the nonlactating dairy cow

Eleven nonlactating Holstein cows in late gestation were used to study the effect of dietary calcium concentration on apparent selenium absorption. Digestion trials with total collection helped to estimate apparent absorption of specific nutrients. Mean daily selenium intake ranged from 900 to 1700 micrograms per day. Regression analysis indicated apparent selenium absorption was maximum when dietary calcium was .8% of dry matter intake. Amounts of dietary calcium less or greater than .8% of dry matter intake reduced apparent selenium absorption. Dietary calcium quantitatively affected apparent selenium absorption in amounts of nutritional significance when selenium was provided from natural feedstuffs.     

优质牛肉屠宰加工技术进展

阐述了国内外牛肉屠宰加工业的现状,综合概括了国内外优质肉牛屠宰加工技术和贮藏保鲜技术,并结合国内行业发展趋势,提出牛肉屠宰加工业的发展思路。