一种甜菜碱双子表面活性剂的合成及其性能研究

以油酸酰胺丙基叔胺,3-氯-2-羟基丙磺酸钠和1,4-二溴丁烷为原料,通过两步反应合成出了一种甜菜碱双子表面活性剂,通过傅立叶变换红外光谱仪和核磁共振仪对合成产物进行了结构表征,用表面张力仪测定不同浓度下油酸酰胺羟丙基甜菜碱（B18）和甜菜碱双子表面活性剂（B18-4-18）的表面张力,得出表面张力曲线,并用实验室定制的携液量装置分别测定了两种表面活性剂在清水中,矿化水中和凝析油中的携液率。实验证明：合成的化合物与预期合成物质一致,在25℃时,B18临界胶束浓度cmc=3.5914?0-6mol/L,相应的表面张力"γ" _cmc=36.2155mN/m,B18-4-18的临界胶束浓度cmc=3.3986?0-6 mol/L,相应的表面张力"γ" _cmc=34.6464mN/m;B18和B18-4-18在清水中的携液率可以达到87%,92%,在15万矿化水中的最高携液率可以达到82%,84%。在10%凝析油中的最高携液率可以达到64%,67%。     

外源甜菜碱与褪黑素复合处理对龙眼果实贮藏性能的影响

目的 研究不同浓度甜菜碱与褪黑素复合处理对采后龙眼果实冷藏的保鲜效果,以期为龙眼贮藏保鲜新技术提供理论参考。方法 以‘储良’龙眼为实验材料,分别采用0、5、10、15 mmol/L的甜菜碱与300 mmol/L的褪黑素复配制成保鲜剂处理果实。在温度为4 ℃、相对湿度为85%条件下贮藏,研究其冷藏期间质量损失率及可溶性固形物(TSS)、可滴定酸(TA)、抗坏血酸(VC)、丙二醛(MDA)、游离脯氨酸含量和过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性的变化。结果 与300 mmol/L褪黑素对照组相比,复合保鲜剂能有效减少龙眼果实水分、TSS、TA、VC和游离脯氨酸含量的损失,使龙眼果肉保持较高的SOD、CAT活性(P<0.05),而POD活性和MDA含量维持在较低水平。结论 300 mmol/L褪黑素+10 mmol/L甜菜碱处理对龙眼的冷藏保鲜效果最佳。     

Effects of Molecular Crowding and Betaine on HSPB5 Interactions,with Target Proteins Differing in the Quaternary Structure and Aggregation Mechanism

The aggregation of intracellular proteins may be enhanced under stress. The expression of heat-shock proteins (HSPs) and the accumulation of osmolytes are among the cellular protective mechanisms in these conditions. In addition, one should remember that the cell environment is highly crowded. The antiaggregation activity of HSPB5 and the effect on it of either a crowding agent (polyethylene glycol (PEG)) or an osmolyte (betaine), or their mixture, were tested on the aggregation of two target proteins that differ in the order of aggregation with respect to the protein: thermal aggregation of glutamate dehydrogenase and DTT-induced aggregation of lysozyme. The kinetic analysis of the dynamic light-scattering data indicates that crowding can decrease the chaperone-like activity of HSPB5. Nonetheless, the analytical ultracentrifugation shows the protective effect of HSPB5, which retains protein aggregates in a soluble state. Overall, various additives may either improve or impair the antiaggregation activity of HSPB5 against different protein targets. The mixed crowding arising from the presence of PEG and 1 M betaine demonstrates an extraordinary effect on the oligomeric state of protein aggregates. The shift in the equilibrium of HSPB5 dynamic ensembles allows for the regulation of its antiaggregation activity. Crowding can modulate HSPB5 activity by affecting protein–protein interactions.     

Effects of feeding betaine-containing liquid supplement to transition dairy cows

Betaine is a natural compound found in sugar beets that serves as a methyl donor and organic osmolyte when fed to animals. The objective was to evaluate the effect of feeding betaine-containing molasses on performance of transition dairy cows during late summer in 2 trials. In early September, cows were randomly assigned to betaine (BET) or control (CON) groups either shortly after dry off (trial 1; n = 10 per treatment) or 24 d before calving (trial 2; n = 8 per treatment) based on parity and previous mature equivalent milk yield. Cows were fed common diets supplemented either with a liquid supplement made of molasses from sugar cane and condensed beet solubles containing betaine [BET, 89.1 g/kg of dry matter (DM)] or a sugar cane molasses-based liquid supplement without betaine (CON) until 8 wk postpartum. The liquid supplements had similar nutrient contents and were fed at a rate of 1.1 and 1.4 kg DM/d for pre- and postpartum cows, respectively. Starting at their entry in the studies, cows were housed in the same freestall barn without a cooling system. After calving, all cows were housed in the same barn cooled by misters and fans and milked thrice daily. Intake was recorded daily and body weight and body condition score were assessed every 2 wk. Milk yield was recorded at each milking and composition was analyzed weekly. Blood samples were collected weekly from a subset of cows to assess concentrations of metabolites and AA. No treatment effects were apparent for DM intake and body weight in the prepartum and postpartum periods. For cows enrolled at dry off, BET supported higher milk yield (45.1 vs. 41.9 kg/d) and fat content (4.78 vs. 4.34%) and elevated plasma concentrations of nonesterified fatty acids and β-hydroxybutyrate in early lactation compared to CON. However, no differences were observed for milk yield, most milk component contents and yields, and blood metabolites between treatments for cows enrolled during the close-up period. Compared to cows in the CON group, BET cows enrolled during the far-off period tended to have lower plasma concentrations of Met, Thr, and Trp during the pre- and postpartum periods. They also had lower plasma concentrations of Lys and Phe before calving but higher plasma Gly concentration after parturition. In conclusion, feeding a betaine-containing liquid supplement from far-off through early lactation improves lactation performance but increases adipose tissue mobilization and production of ketone bodies in early lactation.     

甜菜碱对人体健康作用的研究进展

甜菜碱对人类的营养和健康起到重要的作用,本文综述了甜菜碱对人体健康作用的研究进展,展望了甜菜碱应用前景。     

固相萃取-高效液相色谱法测定枸杞中甜菜碱

建立固相萃取液相色谱法净化和测定枸杞中甜菜碱的分析方法。方法采用混合型阳离子交换小柱(WatersOasis MCX)净化枸杞样品提取液,使用Atlantis HILIC 色谱柱,以乙腈- 水为流动相进行梯度洗脱,在195nm 波长处检测。结果表明,线性范围为0.2～5.0mg/mL,方法检出限为0.0066mg/mL,平均回收率为88.3%～104%。本方法能简便、快速、准确地检测枸杞中甜菜碱。     

益生菌乳酸发酵提高低聚果糖含量生产的新方法

研究报告了一种新的提高低聚果糖(FOS)含量的生产方法。以市售低聚果糖为原料,通过添加甜菜碱进行益生菌乳酸发酵,将原料中可发酵性糖葡萄糖、果糖转化为乳酸,蔗糖部分转化为乳酸,使原料中低聚果糖的含量由51%提高到84%,而发酵液无需进行菌体分离即可用于食品加工,为低聚果糖的生产提供了一种低成本、高效率的纯化方法。     

驯化活性污泥处理高含盐量有机废水的研究

在有菌种存在的好氧系统中,采用驯化活性污泥的方法处理高含盐量有机废水。结果表明,驯化活性污泥可以有效地处理高含盐量有机废水,在Na2SO4含量小于20000mg/L范围内,驯化污泥可以正常降解废水中的有机物,指示剂苯酚的去除率稳定在90%以上,通过驯化可以大大增强微生物抵御盐抑制的能力;在好氧系统中甜菜碱的抗钠毒性作用不明显。