不同微藻对卤虫生长性能和营养价值的比较分析

为研究微藻对卤虫的生长性能和营养价值的影响,挖掘卤虫作为原料开发海洋食品的潜力,以中肋骨条藻、三角褐指藻、球等鞭金藻、亚心形扁藻、威氏海链藻、小球藻6 种微藻投喂卤虫14 d,测定其体长、生物量、基本营养成分、氨基酸组成和脂肪酸组成,并进行营养评价。结果表明,投喂不同微藻对卤虫生长性能影响显著,其中小球藻效果最优,体长和生物量分别为3.10 cm 和0.98 g,特定生长率为10.95%,显著高于对照组（P＜0.05）;投喂不同微藻对卤虫营养成分影响显著,不同微藻组卤虫的粗蛋白含量为39.63%～56.45%,粗脂肪含量为7.04%～10.26%,氨基酸总量为22.58%～44.10%,其中小球藻组粗蛋白、粗脂肪和氨基酸含量最高,显著高于对照组（P＜0.05）;不同微藻组氨基酸评分为66.50～99.77,其中小球藻卤虫含有8 种必需氨基酸,以氨基酸分和化学分为标准,第一限制性氨基酸皆为半胱氨酸＋蛋氨酸,必需氨基酸占总氨基酸总量的40.27%,氨基酸组成均衡,氨基酸平均分较高,为99.77,符合粮农组织/世界卫生组织推荐的理想蛋白质模式;不同微藻对卤虫脂肪酸组成的影响显著,其中威氏海链藻组二十碳五烯酸（eicosapentaenoic acid,EPA）含量最高,为15.28%,亚心形扁藻组多不饱和脂肪酸含量最高,为38.77%,小球藻组单多不饱和脂肪酸含量最高,为41.24%;不同微藻组血栓形成指数为0.26～0.56,其中亚心形扁藻组最低,为0.26,脂肪酸不饱和程度高。综上,经小球藻营养强化的卤虫生长性能和营养价值有显著提升,蛋白质含量丰富,氨基酸组成合理,EPA、多不饱和脂肪酸含量较高。     

富硒小球藻食品的开发

硒是一种必需微量元素,具有重要的生理保健功能,利用生物合成方法生产有机硒引起了人们的关注。食用微藻中含有丰富的蛋白质、维生素、脂质、多糖及微量元素等,有显著的营养和保健功能。利用有重要食用和保健功能的小球藻进行硒的富集,进而开发富硒小球藻食品,具有富集效率高,营养丰富、均衡,有多种生理保健功能的特点,因而具有良好的开发潜力和市场前景。     

蜜源花粉的保健医疗效能

蜜源花粉不仅含有大量的糖,蛋白质的含量也很高.花粉蛋白质中氨基酸多达19种,并且是以游离状态存在,因而极易被消化、吸收和利用.此外,还含有维生素14种;矿物质包括重要微量元素计有11种;酶类11种,这些完全天然的而且保存着活力的酶类,具有强大的抗衰老功能及恢复青春的活力.     

味精可以放心食用

中华人民共和国国家标准规定,商品名称为味精或味素,其谷氨酸钠含量在99%以上。采用生物技术以粮食(玉米、大米)、淀粉为原料发酵制取的谷氨酸和广泛存在于人们日常食用的牛奶、鸡蛋、鸡、猪肉等营养食品中所含的谷氨酸,其化学结构和性质完全相同。在一般动物性食物中蛋白质含量高的,其谷氨酸含量也高。在植物蛋白中,谷氨酸含量也不少。游离存在的谷氨酸,在很多食物中也存在,如番茄、豆类、香菇、对虾等;在人乳里也含有游离的谷氨酸。人们都知道,蛋白质是人类生存的物质基础,蛋白质是由很多氨基酸构成。但是构成蛋白质的氨基酸哪一种最多呢?…     

经济补品数豆腐

民间对豆腐的评价极高,“有豆腐是穷人之肉”的美称。在现代社会中人们担心动物肉类脂肪和蛋白质给人带来动脉硬化及冠心病等麻烦,于是,豆制食品成了肉类食品的代用品。我们知道,豆腐中含有人体所需要的重要营养素——蛋白质。据分析,黄豆中含有蛋白质8.4%,不但含量丰富,而且质     

微藻脂类组成及脂肪酸分布的分析技术

微藻具有光合效率高、生长周期短、有可能异养生长等特性, 并含有多种生物活性物质,尤其是 EPA、DHA 等多不饱和脂肪酸含量丰富, 可以作为功能食品的优质生物资源。多不饱和脂肪酸在微藻细胞中主要以脂质的形式存在, 脂类组成及脂肪酸分布信息可以为藻种筛选、不饱和脂肪酸的分离纯化等提供依据。本文综述了高产多不饱和脂肪酸的藻种, 脂质及脂肪酸的萃取方法与分离鉴定技术, 特别对全二维气相色谱法、高压液相色谱法在微藻中的应用进行了阐述。     

1种快速检测微藻油脂的新方法

微藻油脂是一种非常重要的生物能源,微藻产油能力及油脂含量变化的快速分析在能源微藻的产业化过程中有着很重要的意义。文中以实验室分离的1株栅藻为研究对象,以有机溶剂提取法作为参照,利用磷酸香草醛反应法监测了在不同的糖浓度、氮浓度和磷浓度下栅藻油脂含量的变化。同时,对其他微藻,如小球藻、小环藻、脆杆藻等应用磷酸香草醛反应法进行总脂量分析。结果表明,磷酸香草醛反应法可以快速准确地检测微藻油脂的含量。     

蘑菇营养丰富 盘点蘑菇不为人知的4大功效

<正>蘑菇营养丰富,味道鲜美,自古以来被列为上等佳肴,是高蛋白、低脂肪,富含人体必需氨基酸、矿物质、维生素和多糖等营养成分的健康食品。而且经常食用蘑菇能很好地促进人体对其他食物营养的吸收。蘑菇富含18种氨基酸,有些蘑菇中蛋白质的氨基酸组成比例比牛肉更好。研究发现,蘑菇的营养价值仅次于牛奶。人们一般认为,肉类和豆类食品中才分别含有较高的动物蛋白和植物蛋白,其实蘑菇中的蛋白质含量也非常高。蘑菇含有多种维生素     

乳粉中的微量元素的分析测定

乳粉现已成为人们日常生活中的一种非常重要的营养食品,含有人体所需的各种蛋白质、脂肪及微量元素。由于近几年频繁出现的三鹿乳粉与"大头娃娃"等事件,让人们在关注乳粉安全。原因是乳粉中的微量元素的含量不符合国家食品安全标准,主要测定乳粉中几种微量元素的含量,并进行对比分析。采用微波消解法处理乳粉样品,利用电感耦合等离子体原子发射光谱法测定乳粉中微量元素的组成及含量。结果表明,乳粉中含有大量的对人体健康、儿童发育有益的钙、镁、铁、锌等微量元素。该方法简单、快速、准确性好,回收率在96.7%~101%之间,结果令人满意。     

微藻营养价值及微藻饵料的开发利用

微藻是水生生态系统食物链中的重要组成部分之一,已用作食物和药物被人类消费。其营养物质可防御多种疾病,促进鱼、虾、蟹、贝类等水产生物的生长和品质,是水产养殖过程中应用最普遍的生物饵料。简要综述了微藻中蛋白质、多糖、不饱和脂肪酸、色素等营养成分的研究进展,以及微藻生物饵料的应用现状。以期为微藻营养价值及其微藻饵料的研究与开发提供参考。     

Retention of mineral constituents in frozen brassicas depending on the method of preliminary processing of the raw material and preparation of frozen products for consumption

The content of ash, P, K, Ca, Mg, Na, Fe, Zn, Mn, Cu, Cr and Ni was determined in four species of brassicas: Brussels sprouts, broccoli, and green and white cauliflowers. The investigation covered the raw material, the material blanched or cooked before freezing and frozen products after 12 months of refrigerated storage and prepared for consumption. Frozen products were obtained by the traditional method of freezing the blanched material or by the modified method of freezing the cooked material. The processing of vegetables before freezing (washing, grinding, blanching or cooking) caused statistically significant decreases in most constituents analysed. Blanching did not basically change the content of sodium and calcium; or that of chromium in both types of cauliflower; copper and nickel in white cauliflower; and nickel and phosphorus in Brussels sprouts. Cooking in brine, however, caused increases in the content of ash, sodium and calcium in white cauliflower, decreases in the content of potassium and iron and, in some species, of the remaining constituents. In comparison with the traditional method, a greater content of most analysed elements was found in frozen products obtained by the modified technology and prepared for consumption. However, no significant differences were noted in the level of chromium in all the samples; in the level of calcium in broccoli and green cauliflower; of nickel in broccoli; of nickel, copper and zinc in white cauliflower; and of copper in green cauliflower.     

Amino-acid composition of maturing wheat

Amino-acids were determined in hydrolysates of two wheat varieties harvested at various stages of maturity, and in flours milled from the wheat samples. During maturation, the concentration in protein of lysine, aspartic acid, glycine. alanine and valine decreased; and concentrations of glutamic acid and proline increased. Milling of wheat into flour reduced the concentrations of lysine, arginine, aspartic acid, threonine, glycine and alanine. Concentrations of glutaniic acid and proline were higher in flour than in wheat proteins. Concentrations of cationic side-chains in amino-acids were higher in wheat than in flour, and in both decreased with maturity. Total carboxyl and amide groups were higher in flour than in wheat, and their concentrations increased as the wheat matured. About 84% of the dicarboxylic acids were in amide form. Small changes were observed in concentrations of amino-acid residues with hydroxylic or hydrophobic groups, and in cystine.     

Dioxins,furans, and non-ortho PCBs in Canadian Arctic seabirds

This is the first account of PCDDs, PCDFs, and non-ortho PCBs in Canadian Arctic seabirds. Livers and eggs of thick-billed murres, northern fulmars, and black-legged kittiwakes were collected in 1975 and 1993 from Prince Leopold Island in Lancaster Sound, Canada. Detectable concentrations of PCDDs, PCDFs, and non-ortho PCBs were found in all the Arctic seabird samples analyzed. Of the PCDD congeners assayed, only 2,3,7,8-substituted PCDDs were detected in the samples, whereas non-2,3,7,8-substituted PCDFs were found in addition to 2,3,7,8-substituted PCDFs in some of the samples. The predominant PCDD/F congener found in the livers of all three species was 2,3,4,7,8-PnCDF, both in 1975 and 1993. Concentrations of most dioxins and furans decreased in the fulmars and kittiwakes between 1975 and 1993 but increased in the murres. Of the non-ortho PCBs measured, PCB-126 occurred in the highest concentrations and contributed the majority of the non-ortho PCB-TEQ in all three species in both years. The highest concentrations of dioxins and furans as well as the highest TEQ values were found in the northern fulmar livers in both 1975 and 1993. Concentrations of some of the PCDDs and PCDFs are among the highest reported for Canadian Arctic biota.     

Effects of duration of moderate increases in grain feeding on endotoxins in the digestive tract and acute phase proteins in peripheral blood of yearling calves

Effects of duration of grain feeding on the concentration of endotoxic lipopolysaccharide (LPS) in digesta throughout the digestive tract and on acute phase proteins and LPS in peripheral blood were determined in Holstein yearling calves. Twenty-five Holstein yearling steer calves received either a forage-based diet containing 92% hay and 8% of a mineral and vitamin pellet on a dry matter basis (CON) or a moderate-grain diet, obtained by replacing 41.5% of the hay in the forage-based diet with barley grain, for 3 (MG3), 7 (MG7), 14 (MG14), or 21 d (MG21) before slaughter. Immediately before slaughter, blood samples were collected from the jugular vein. Immediately after slaughter, digesta samples were collected from the rumen, jejunum, ileum, cecum, colon, and rectum. Rumen liquid digesta, digesta from the intestines, and peripheral blood plasma were analyzed for LPS. Peripheral blood plasma and serum were analyzed for the acute phase proteins amyloid A, haptoglobin, and LPS-binding protein. Feeding the grain diet increased the LPS concentration in rumen fluid linearly from 15,488 endotoxin units (EU)/mL for CON to 70,146 EU/mL for MG7. Concentrations of LPS in rumen fluid in MG14 and MG21 were 61,944 and 56,234 EU/mL, respectively, and did not differ. The LPS concentrations in jejunal digesta were much lower than that in digesta elsewhere in the digestive tract, which suggests that ruminal LPS is broken down in the abomasum or proximal jejunum. The concentration of digesta LPS in the ileum was higher than that of digesta elsewhere in the intestines and similar to that in rumen fluid. The duration of grain feeding increased the LPS concentration in digesta in the ileum and cecum and tended to increase that in the colon cubically. Concentrations of LPS in this part of the digestive tract were highest in the MG3 and MG21 groups. The highest concentrations of LPS in digesta in the cecum, colon, and rectum were 3.7, 3.8, and 5.6 times higher than that in CON, respectively. Grain feeding and the increase in LPS in digesta were not accompanied by an acute phase response or a detectable concentration of LPS in peripheral blood. The absence of LPS in peripheral blood and the lack of increase in acute phase proteins indicated that the grain feeding protocol used in the current study and the accompanying changes in LPS concentrations of the digesta did not result in systemic inflammation.     

Changes in the concentration of carbohydrates during the soaking of soybeans for tempe production

Soybeans were soaked for 24h in tap water at 30°C in preparation for tempe fermentation. Soaking was conducted under conditions that give a microbial fermentation, and in the presence of antibiotics where microbial growth was inhibited. Sucrose, stachyose and raffinose were the main di- and oligosaccharides in the beans, and their concentrations decreased by 84, 65 and 50%, respectively, during soaking. Glucose, fructose and galactose were found in the soak-water along with lesser amounts of sucrose, melibiose, raffinose and stachyose. Glucose was the main substrate for microbial growth in the soak-water. The concentrations of mono-, di-and oligosaccharides in the beans and in the soak-water were determined by the activity of invertases and α-galactosidases endogenous to the beans, diffusion of the sugars into and out of the bean, and the species of micro-organism growing in the soak-water.     

萝卜丝入坛发酵对安岳坛子肉特征风味形成的影响

为了解萝卜丝入坛发酵对安岳坛子肉特征风味的影响,利用顶空固相微萃取-气相色谱-质谱联用法对发酵 过程中坛子肉和萝卜丝中的挥发性风味物质进行鉴定及分析。结果表明：萝卜丝和坛子肉中共检出11 类301 种挥发 性物质,萝卜丝与坛子肉中挥发性物质的种类及相对含量差异较大;萝卜丝中共检出醇类物质31 种,坛子肉中共 检出27 种;萝卜丝中共检出酯类物质57 种,坛子肉中共检出14 种;萝卜丝中共检出醛类物质17 种,坛子肉中共 检出5 种;萝卜丝中共检出酸类物质7 种,坛子肉中共检出4 种;萝卜丝中共检出酮类物质13 种,坛子肉中共检出 7 种;萝卜丝中共检出碳氢化合物94 种,坛子肉中共检出20 种;发酵坛子肉中相对含量最高的为醇类,其次为酯 类和碳氢化合物,发酵萝卜丝中相对含量最高的为酯类,其次为醇类和碳氢化合物;发酵坛子肉的特征风味物质主 要包括正己醛、乙醇、1-辛烯-3-醇、3-羟基-2-丁酮、乙酸、乙酸乙酯、丙酸乙酯、正己酸乙酯和2,2,4,6,6-五甲基庚 烷;萝卜丝入坛发酵有助于坛子肉特征风味的形成。     

我国不同生态区云烟97烟叶主要品质性状差异分析

为掌握云烟97在我国不同生态区烟叶的主要品质性状差异,系统分析了云南曲靖（清香型烟区）、贵州毕节（中偏清香型烟区）和重庆武隆（中间香型烟区）3个烤烟种植生态区云烟97烟叶的外观质量、化学成分、风格特征和烟气品质。结果表明,贵州毕节烟叶烟气品质综合得分最高,中部叶干草香香韵、香气质、香气量和透发性得分显著高于云南和重庆,还原糖含量和烟气浓度显著高于重庆;云南曲靖烟叶外观质量最好,中部叶总氮含量、氮碱比值以及烟气飘逸感得分均显著高于贵州和重庆,烟气浓度和劲头得分居中,清香型特点显著;重庆武隆烟叶外观质量居中,中部叶总植物碱含量、烟气刺激性、干燥感和悬浮感得分均显著高于云南和贵州,而糖碱比和余味得分则显著低于云南和贵州,中间香型特点显著。由云南经贵州向重庆方向,云烟97烟叶清甜香韵和烟气飘逸感逐渐减弱,木香香韵和烟气悬浮感逐渐加强。     

Transmission electron microscopy studies of the zona reaction in pig oocytes fertilized in vivo and in vitro

The aim of this study was to determine the ultrastructure of cross-sectioned zonae pellucidae of in vitro-matured and ovulated pig oocytes before or after sperm penetration in vitro and in vivo, respectively. The in vitro and in vivo (ovulated) oocytes and zygotes (fertilized in vitro and in vivo) were fixed with glutaraldehyde either directly or after pretreatment with ruthenium red and saponin, processed and then examined using transmission electron microscopy. The thickness of the zona pellucida, as measured on the section of the specimens with largest diameter fixed with glutaraldehyde, differed between the in vivo (9.19 +/- 0.47 microm) and in vitro (5.95 +/- 0.51 microm) oocytes. The in vivo oocytes had a rather thick external mesh-like structure, whereas it was much thinner in the in vitro oocytes. This mesh-like external rim was less apparent in both in vivo and in vitro zygotes. Obvious differences in the density of the lattice formed by the fixed zonae pellucidae were visible between the outer and inner (ad-oolemmal) zonae. The outer area always formed a concentrically arrayed fibrillar network, whereas the inner area showed a much more compact, trabecule-like mesh. However, both areas, but particularly the outer network, were much more compacted after the zona reaction. Clear differences in the degree of fibrillar aggregation of the inner zona area were also observed between in vitro and in vivo zygotes, being much higher in the latter. This fibrillar network was more clearly visible in the zygotes pretreated with ruthenium red and saponin; the in vitro zygotes had a fibrillar, radially oriented set of parallel fibrils, whereas it was much more aggregated and trabecule-like in the in vivo zygotes. These results demonstrate that the fine structure of the zona pellucida and the zona reaction at sperm penetration differ between pig oocytes fertilized in vivo and in vitro. Moreover, the ultrastructure of the outer and inner pig zonae pellucidae has a different network organization.     

红车轴草不同部位中异黄酮含量的测定

采用反相高效液相色谱法对红车轴草不同部位(花、茎和叶)中四种主要异黄酮(鸡豆黄素A、芒柄花黄素、染料木素和大豆黄素)的含量进行了测定,结果表明:以占干物质计,4种异黄酮总量,叶中含量最高(0.856%),茎次之(0.403%),花中含量较低(0.258%)。鸡豆黄素A和芒柄花黄素是红车轴草中两种最主要的异黄酮,主要分布在叶中,其次是茎,花中含量较低。染料木素和大豆黄素,无论是花、茎还是叶,含量均较低。     

小草坝新鲜天麻中多种金属元素评价分析

目的 分析评价云南小草坝新鲜天麻中9种金属元素含量水平。方法 采用电感耦合等离子体质谱法检测云南小草坝新鲜天麻中铁Fe、铜Cu、钴Co、锰Mn、镍Ni、硒Se、砷As、铅Pb、汞Hg的含量, 并使用食品安全指数IFS法进行重金属污染评价。结果 云南小草坝新鲜天麻中各元素均检出, 参照《现行药用植物及制剂进出口绿色行业标准》及《中国药典》2015年版中重金属限量值判定, 54份天麻中Cu、Pb、As、Hg的含量均没有样品超过限量指标。按照GB 2762-2012食品标准进行判定, Pb有40.7%的超标率, As、Hg均未出现超标样品。小草坝产区新鲜天麻中As、Pb、Hg的IFS值均小于1。结论 云南小草坝新鲜天麻中微量元素丰富, 食品安全风险整体上在可接受范围, 但仍需关注可能存在的铅污染水平。