乳酸介质中麦草浆纤维素的降解及其结构的变化

[目的]为利用纤维素制备热塑性高分子材料提供依据。[方法]在一定温度下,将预处理后的原料（干燥麦草浆）浸入一定量的乳酸中,搅拌一定时间后干燥至恒重,研究温度、时间对纤维素聚合度和碘吸附值的影响,并分析麦草浆纤维素在乳酸介质中化学结构的变化。[结果]温度高于30℃时,纤维素开始降解,且温度越高,纤维素降解越剧烈。温度和搅拌时间对纤维素聚合度和碘吸附值的影响较大,而乳酸用量对其影响较小。红外谱图和X-衍射图谱分析结果表明,60℃之前,麦草浆在乳酸介质中主要发生物理溶胀和少量的降解;超过70℃后,麦草浆除发生降解外,还可能伴随着化学反应,但纤维素的晶型未发生改变。[结论]该研究为纤维素在乳酸介质中的改性提供了资料。     

碘对樱桃番茄开花结果和产量的影响

在深液流水培的营养液中添加不同浓度的碘离子(I-)作为处理,研究碘对樱桃番茄开花结果和产量的影响。结果表明:碘处理的植株第3～5花序的着生节位分别比对照低2～3个节位;2.0mg.L-1碘处理和高浓度(5.0～6.0mg.L-1)碘处理的果实比对照提前5～8d成熟;1.0～4.0mg.L-1碘处理的坐果率与对照均无显著差异,而高浓度(5.0～6.0mg.L-1)碘处理的坐果率显著低于对照;低浓度(1.0～2.0mg.L-1)碘处理的花数、果数和产量均显著高于对照,而高浓度(5.0～6.0mg.L-1)碘处理的产量则显著低于对照;单果质量随着碘处理浓度的增高而降低,但是1.0～3.0mg.L-1碘处理与对照差异不显著。综合以上结果,在樱桃番茄栽培上以1.0～2.0mg.L-1的碘离子供给浓度最适宜。     

不同浓度碘处理对绿瓣大豆芽菜生长及营养素的影响

研究了大豆品种高丰1号于25℃在不同浓度的碘化钾溶液(0、0.5、1.0、1.5、2、2.5、3、3.5 mg/L)中浸泡6 h并培养发芽5 d后,吸水率、发芽率、生物产率和营养成分的变化规律及碘在豆芽各部位中的富集规律。结果表明,低浓度碘可促进豆芽生长,增加可食部分维生素C、游离氨基酸和蛋白质含量,并大幅度提高豆芽中碘的含量,碘质量浓度以0.5~1.5 mg/L时效果最好。     

Effect of dietary iodine on growth and iodine status of growing fattening bulls

The aim of the present study was to assess the influence of different levels of iodine supplementation on animal growth and the iodine content of food from beef cattle. In a dose–response experiment with 34 growing fattening bulls of the “German Holstein” breed, in the range from 223 to 550 kg body weight, three iodine dosages were tested. The animals were fed a corn silage/concentrate ration. Iodine concentration in the diet amounted to 0.79 (Group 1), 3.52 (Group 2) and 8.31(Group 3) mg I per kg dry matter (DM). After slaughtering, I was determined in blood, serum, plasma, thyroid, liver, kidneys and meat (M. longissimus dorsi, M. glutaeus medius) by ICP-MS. I-supplementation did not significantly influence DM intake, daily weight gain (1453 (1), 1419 (2) and 1343 (3) g; p > 0.05) or slaughtering performance, but the weight of the thyroid gland increased significantly with the highest I dosage (32 (1), 26 (2) and 42 (3) g animal^− 1, p < 0.05). I-supplementation significantly increased I-concentration in muscle, liver, kidney and thyroid gland (p < 0.05). The contribution of beef food to I-intake of humans is relatively low, therefore there is no need to reduce the EU-upper limit (10 mg kg^− 1 feed) for growing fattening cattle from the view of consumer safety. In view of animal health and performance more dose–response studies seem to be necessary.     

Adsorption capacities and related characteristics of wood charcoals carbonized using a one-step or two-step process

Sugi (Cryptomeria japonlca D. Don) wood powder was carbonized at varying temperatures by a onestep process up to 1000C and a two-step process using wood charcoal as the raw material up to 1600C. This study was conducted to evaluate the adsorptive properties of wood charcoal and discuss the mechanism of its adsorptive function in relation to the physical and anatomical characteristics of wood after carbonization. Anatomical characteristics of carbonized wood materials were directly observed under heating using an environmental scanning electron microscope (ESEM); the cell wall structures were analyzed by high-resolution transmission electron microscope (HRTEM). The largest weight losses were observed at the highest temperatures, in both the one-step and twostep processes but leveled off above 800C. Shrinkages in the tangential, radial, and longitudinal directions increased with carbonization temperature, peaking at 1000C. Direct observations by ESEM showed distinct shrinkage at around 400C. The first trial observations by HRTEM on the changes in the ultrastructure of cell walls of wood charcoals were done, and it was assumed to affect the formation of micropores. Adsorption was found to follow the Langmuir isotherm model. With the one-step carbonization process, the iodine adsorption capacities of the carbonized wood powders increased with increasing carbonization temperature, peaking at 800C, but decreased at higher temperatures. The wood powder carbonized at 1000C with the two-step process showed the highest capacity, but further heating up to 1400C drastically decreased the adsorption. The shrinkage of cells was related to the increases and decreases in its specific surface area. Specific surface area and total pore volume were evidently related to the adsorptive properties.Part of this paper was presented at the Second International Wood Science Seminar, Indonesia, November 6–7, 1998     

蔬菜对外源碘的吸收和积累特性及其机理研究进展

碘是人体不可缺少的营养元素,植物性食品是人体摄取碘的重要途径之一。主要对前人在碘的农业效应、蔬菜对外源碘的吸收和积累特性及其机理方面的研究进展状况作了简要综述,并对今后开发功能性蔬菜食品的研究方向进行了展望。     

基于分光光度法的模拟炒菜时食盐中碘含量测定

采用紫外分光光度法测定模拟炒菜时食盐中碘的含量。结果表明,在最大吸收波长350nm处,碘含量在0～1．6μg/ml时呈线性关系,回归方程为A=0．3837C=0．0015。模拟炒菜样品在经过不同高温和加入佐料处理后,食盐中的碘含量均或多或少地流失。     

啤酒辅料抗氧化性研究简

[目的]根据辅料的抗氧化性大小来选择生产啤酒的最优辅料。[方法]研究5种啤酒辅料小麦、大麦、小碎米。大碎米、玉米粉抗氧化性大小,用超临界c0：法萃取辅料的油脂,然后测其碘值,通过其碘值与粗脂肪含量的比值来判断辅料抗氧化性大小,从而选择最优辅料。[结果]试验证明,啤酒辅料抗氧化性强弱顺序为：小碎米〉玉米粉〉大碎米〉大麦芽〉小麦芽,超临界萃取法和索氏提取法所测粗脂肪含量接近。[结论]以玉米粉和小碎米做啤酒的辅料,能提高啤酒的抗氧化能力和啤酒风味稳定性。     

畜禽微量元素营养与疾病的研究——Ⅲ. 湖南省部分地区猪肝碘含量

在从湖南省6个地区取样点采集的215份猪肝样品中,随机从每个取样点猪肝样品中选择5～7个样品,用比色法作碘含量的分析,结果表明,各地猪肝碘含量的平均值为4.02±1.21ppm。各地猪肝碘含量存在极显蓍的地区差异性,以武冈猪肝碘含量为最高(6.68±2.18ppm)。益阳猪肝碘含量最低(3.10±0.59ppm),其它各地猪肝碘含最差异不显著(p>0.05)。     

碘在猪饲粮中的应用

碘是人类发现的第二个必需微量元素。猪体内的碘大部分存在于甲状腺中,碘主要以甲状腺激素的形式发挥其生理作用。甲状腺激素具有细胞氧化、生长和分化、繁殖以及中枢神经系统的活性等方面的生理功能。本文对碘的营养作用、碘的应用和碘的需要量等作一综述。