不同种类人参及其各部位中皂苷组成和比例的研究

研究了不同种类人参中皂苷含量 ,以及人参不同部位中的皂苷成分及比例。总皂苷含量测定结果为 ,三七参根中含 14 .2 % ,西洋参须中含 10 .1% ,人参根中含 4.4% ,人参头中含 8.6% ,人参皮中含 6.7% ,人参叶中含 7.7% ,人参须中含 9.9%。对西洋参须、三七参根及吉林产的人参头、人参皮、人参叶、人参根、人参须中的总皂苷作TLC检测及薄层扫描表明 ,三七参根中Rg1含量最高 ,西洋参须中Rb1含量最高 ,人参根中Rd的含量可以忽略 ,人参叶中含有特征皂苷F2 ;它们的Rb1/Rg1值分别为 ,西洋参须中 2 2 .2 ,三七参根中 0 .6,人参头中 4.3 ,人参皮中 6.7,人参叶中 0 .2 ,人参根中 2 .4,人参须中 11.9。     

山露菜中营养成分及黄酮种类研究

对山露菜营养及黄酮成分进行分析,以评价营养价值。分别对山露菜的茎、叶中纤维素、脂肪、蛋白、多糖、微量元素、黄酮进行测定。结果表明:山露菜中叶含膳食纤维53.50%,茎含49.70%;叶中含蛋白质20.36%,茎中含16.20%;叶中脂肪含14.71%,茎含9.83%;茎与叶中总多糖含量为1.60%,甘露糖与葡萄糖两种单糖摩尔比1.00∶15.30;茎中K含量为59.43 mg/g、Ca为12.64 mg/g、Na为6.24 mg/g,叶中K含70.13 mg/g,Ca为12.61 mg/g,Na为6.67 mg/g;山露菜中总黄酮含量为4.80%,测出芍药苷、牡荆素、木樨草苷、芦丁以及紫云英苷5种黄酮,茎中黄酮含量为1.67%,仅富含芍药苷、牡荆素、木樨草苷,而叶中富含芦丁、紫云英苷,占叶中总黄酮15.70%。山露菜的营养成分丰富并含有多种黄酮化合物,具有很高的营养价值。     

玄参中硒的赋存形态及分布研究

研究了玄参中硒的赋存形态、分布及含硒大分子的提取分离技术。采用不同的浸提液提取玄参中多糖和蛋白质,用原子吸收法测定它们各组分中含硒量。玄参中的含硒组分主要有蛋白硒、多糖硒,分别占样品总硒的58.65%、25.16%,蛋白硒是玄参中硒的主要赋存形态,在硒蛋白质组分中,又以水溶性蛋白结合硒含量最高,占样品总硒的20.95%。     

高效液相色谱法测定含乳饮料中游离甘氨酸的方法研究

采用透析法将含乳饮料中游离的甘氨酸提取,邻苯二甲醛(OPA)衍生,其衍生产物经高效液相色谱分离,于荧光检测器检测。测得含乳饮料中游离甘氨酸的含量,与样品中蛋白质含量比较,从而对含乳饮料中是否违规添加甘氨酸进行分析。此方法的回收率为93.2%～99.4%,方法精密度(RSD)为0.66%～1.01%。     

影响面粉含砂量测定结果准确性的因素浅析

正面粉的含砂量,是影响面粉品质和食品安全的重要指标之一。当面粉中的含砂量达到0.03%~0.05%时,制成品食用时就会产生牙碜的感觉,不仅降低食用品质,也会危害人体健康。因此,现行国标和新标准讨论稿中都严格规定面粉含砂量不超过0.02%,超过即为不合格品。所谓含砂量,是指面粉中含有细砂的数量。其主要来源是在加工过程中由于工艺不合理、设备性能不良或原粮中含杂过多致使加工过程中清理不净造     

营养元素硒在南瓜中赋存形态及分布研究

本文研究了营养元素硒在南瓜中赋存形态、分布及含硒大分子的提取分离技术;采用蒸馏水、稀盐、乙醇、稀碱分别依次提取不同种类的蛋白质,热水浸提法提取多糖,原子吸收分光光度法测定硒的含量;结果表明：南瓜中的含硒组分主要有蛋白硒和多糖硒,分别占样品含硒量的45.76%和27.47%,在硒蛋白组分中又以碱溶性蛋白结合硒含量最高,占样品含硒量的46.34%.     

野生铁核桃制油工艺及经济效益分析

介绍了野生铁核桃的特性、产地、含油率。着重阐述了野生铁核桃制油的瓶颈——粉碎及仁壳分离,介绍了野生铁核桃常温液压榨油工艺和低温螺旋榨油工艺,按工艺要求选配加工设备,分析了野生铁核桃制油经济效益。采用CSJ-200型粉碎机,壳中含仁率小于1%;常温液压榨饼中含油13.7%;采用低温螺旋二次压榨工艺,饼中含油7.3%,出油率达到11%。野生铁核桃制油大大提高了野生铁核桃的经济效益。     

分散固相萃取-气相色谱法快速测定茶叶中27 种常见含卤素农药残留

采用分散固相萃取-气相色谱法对茶叶中27 种含卤素农药残留量进行测定。经丙酮-正己烷（l∶1,V/V）提取后,直接加入无水硫酸钠、硅镁型吸附剂及活性炭净化,使用DB-17毛细管气相色谱柱、微电子捕获检测器,对茶叶中27 种含卤素农药残留量进行测定。该方法样品平均加标回收率为82.2%～113.4%,相对标准偏差为1.2%～6.0%;茶叶中27 种含卤素农药多残留检出限为0.005～0.075 mg/kg。     

氨基酸分析仪测定含乳饮料中游离甘氨酸的方法研究

本文用氨基酸分析仪测定含乳饮料中游离甘氨酸含量,研究了样品预处理方法和仪器色谱分离条件.测得含乳饮料中游离甘氨酸的含量,从而对含乳饮料中是否添加甘氨酸进行分析,此方法具有较好的重现性,添加标准的回收率为98.8 %～101.7 %,方法精密度为0.53 %.     

粒径分析法研究稳定剂对含乳饮料稳定性的影响

研究水溶性大豆多糖(SSPS)、羧甲基纤维素钠(CMC)和高酯果胶(HMP)在含乳饮料中的粒径分布和离心沉淀率。结果表明：在SSPS、CMC和HMP的质量分数大于0.3%时,酸性含乳饮料的体系开始趋于稳定,当HMP添加量为0.3%、SSPS和CMC的添加量分别为0.5%时,含乳饮料体系稳定性最好,而且粒径分析与离心沉淀率结果相一致。通过分析含乳饮料的粒径分布和离心沉淀率可以快速、准确的判断所添加稳定剂的含量在含乳饮料体系中应用的可行性。     

苏云金芽胞杆菌不同发酵阶段的补糖发酵

通过苏云金芽胞杆菌工程菌BMB005发酵不同阶段补加葡萄糖发酵试验,研究了补糖对苏云金芽胞杆菌发酵的影响.结果表明:对数生长期补加葡萄糖可以提高生物量,进而使发酵液中杀虫晶体蛋白的质量分数提高33 1%,而稳定期补加葡萄糖则是通过提高菌体合成晶体蛋白的能力而使发酵液中晶体蛋白的质量分数提高18 1%. 30 L发酵罐补糖实验结果表明:在起始碳源质量浓度为3 0 g/dL的情况下,对数生长期补加1 0 g/dL葡萄糖可以将发酵液中杀虫晶体蛋白的质量分数和生物效价分别提高37%和51%;稳定期补加 1 0 g/dL葡萄糖可以将发酵液中杀虫晶体蛋白的质量分数和生物效价分别提高33 7%和75 1%;而且稳定期补加比对数生长期补加葡萄糖更有利于增效因子的合成.     

Duodenal glucose increases glucose fluxes and lactose synthesis in grass silage-fed dairy cows

The effect of intestinal glucose supply on whole body rate of glucose appearance (WBGRa) and mammary utilization of glucose was studied in four lactating dairy cows. Glucose (0, 443, 963 and 2398 g/d) was continuously infused in the duodenum over 14-d periods using a Latin square design. A grass silage-based diet was formulated so that treatments were isoenergetic and isonitrogenous and contained 100 and 110% of energy and protein requirements according to INRA (1989). The WBGRa was measured by the [6,6-(2)H2]glucose dilution technique, and mammary glucose balance by arteriovenous differences and blood flow measurements. Duodenal glucose infusion increased arterial glucose concentrations linearly, whereas arterial concentrations of insulin, growth hormone, and glucagon were not changed. The WBGRa increased linearly with increasing glucose loads. The increase represented 42% of the intestinal glucose supplement. Mammary blood flow dramatically increased (up to 45%) and was associated with a significant increase of arterial insulin-like growth factor-1 concentrations. Mammary gland rate of glucose disappearance ([6,6-(2)H2]glucose measurement) increased linearly, whereas net mammary balance of glucose, lactose, and milk yields increased quadratically. Net mammary balance of glucose accounted for 60% of WBGRa, except for the greatest dose (47.6%). The decrease in milk yield with 2398 g/d of glucose may be explained by an imbalance in intracellular intermediate concentrations. The milk ratio of glucose-1-phosphate to glucose-6-phosphate decreased significantly at the greatest infusion of glucose. In conclusion, exogenous glucose supply to a grass silage-based diet increased WBGRa, mammary utilization of glucose and milk synthesis.     

Reduction of Glucose Content in Potatoes with Glucose Oxidase

Two commercial glucose oxidase preparations, DeeO 1500 and Fermcozyme CBB-750, were investigated for their activities and use in decreasing glucose levels in Norland and Shepody potatoes. When DeeO was added at 0.01% by weight of peeled potatoes, glucose of potato extracts of both cultivars was decreased by about 22% when the extracts were first blanched, and about 15% if not blanched, indicating the presence of some inhibitors in raw potatoes. When applied to steam-blanched potato strips, 0.10% (v/v) solution of Fermcozymc reduced glucose by 25–35%. These experiments showed a potential use of glucose oxidase as a processing aid to reduce nonenzymatic browning in potato products.     

外源乙醇对果糖与葡萄糖酒精发酵的影响

研究了不同体积分数外源乙醇对酵母GJ2008利用等量果糖与葡萄糖混合发酵过程的影响,旨在为高浓度甘蔗汁酒精发酵提供参考和依据。用YPDF培养基模拟甘蔗汁,并调节乙醇体积分数为0%、6%、9%和12%,以初始酵母数为1.12×108个/mL进行酒精发酵,高效液相色谱法测定发酵过程中果糖与葡萄糖含量,并采用曲线下面积法对果糖与葡萄糖代谢曲线进行分析。在外源乙醇体积分数为0%~9%时,酵母GJ2008可以快速利用果糖和葡萄糖进行酒精发酵,但对葡萄糖有着明显的偏好;在外源乙醇体积分数为12%时,果糖和葡萄糖消耗缓慢,生物量得不到有效增加。等质量浓度果糖与葡萄糖混合发酵表明:外源乙醇对果糖代谢的影响明显大于对葡萄糖代谢的影响,外源乙醇体积分数达6%以上时,糖转化乙醇的产量减少了19%~27%。     

稀糖分罐发酵对L-色氨酸发酵的影响

为了解决现有L-色氨酸发酵工艺中浓糖补料和中途排料造成的乙酸积累过多和资源浪费等问题,该研究提出一种稀糖分罐 发酵的新工艺。 利用30 L发酵罐考察稀糖分罐发酵对L-色氨酸发酵的影响,在发酵中期（发酵时间为20 h左右）将部分发酵液移至另 一灭好菌的空罐继续进行发酵,并将浓糖替换为稀糖补料。 在稀糖分罐发酵工艺条件下,菌体生物量、L-色氨酸产量、糖酸转化率分 别为44.31 g/L、43.82 g/L、20%,较普通工艺分别提高了5.4%、9.9%和12.36%;乙酸积累量较普通工艺下降65.5%。 避免了料液的浪费, 提高了L-色氨酸产量和糖酸转化率,降低了乙酸积累量,在工业生产方面有一定实用性和推广价值。     

Effects of sugars on post-mortem glycolysis in bovine muscle mince

Sternomandibularis muscles from steers were minced, within 75 min of slaughter, with sugars or amylases. The minces were held anoxically at 25°C for at least 7 h. At times samples were removed and chemically analysed. Glucose (1·5%) retarded the post-mortem pH fall, with kinetics similar to those of NaCl (2·0%). Typically, 1·5% glucose maintained the pH at 6·1, whereas control mince attained 5·5. Lesser amounts of glucose had a reduced effect. Other sugars were inactive. The metabolic effects of 1·5% added-glucose were compared with those of an iso-osmotic control, 1·5% added-fructose. For the glucose mince there was no change in glucose concentration over 7 h suggesting that the endogenous hexokinase was inactive. Further, more glycogen remained in the glucose mince that in the control, indicating that glucose inhibited glycolysis. This was confirmed by electron microscopy and was reflected in pH and lactate levels. Hexose monophosphates were strongly affected by glucose. In the control, their concentrations each fell in the first 2 h then increased steadily, as expected. In the presence of glucose, their concentrations were initially lower and decreased steadily with time. Concentrations of adenosine phosphates were little affected by glucose, but downstream products of purine metabolism showed marked differences, probably due to enhanced nucleotidase activity above pH 6. Glucose plus yeast hexokinase produced a mince with a rigor pH close to normal. The data indicated that phosphorylase activity was inhibited by glucose, and suggested that glucose was not phosphorylated because of muscle hexokinase inhibitors such as glucose-1,6-diphosphate.     

一株产高浓度酒精酵母的流加发酵策略初步研究

对一株产高浓度酒精的酿酒酵母的流加发酵策略进行了初步研究，采用均匀试验设计方法考察了流加速率、流加葡萄糖浓度以及流加初始葡萄糖浓度对高浓度酒精发酵的影响，以得率为评价指标，用SPSS进行回归分析，得到最优流加条件为流加速率114．3mL/H，流加葡萄糖浓度44．8％，初始葡萄糖浓度9．7％。     

Coordination of mammary metabolism and blood flow after refeeding in rats

The production of milk is closely linked to nutritional state in many mammalian species, but the mechanisms by which changes in nutritional state are signaled to the mammary glands are poorly understood. Simultaneous measurements of mammary blood flow and glucose arterio-venous difference were made across the inguinal mammary glands of anesthetized, lactating rats. Blood flow to the mammary glands of previously fed rats was 0.48 mL/min per gram of mammary tissue. Glucose supply was 1.7 μmol/min per gram and 28% was extracted by the mammary glands. After food deprivation for 18 h, mammary blood flow decreased 48%, glucose arterio-venous difference decreased 72%, and hematocrit increased 7%, resulting in a 60% decrease in glucose supply and an 88% decrease in glucose uptake. After 1 h of refeeding, glucose supply had returned to a similar level to that of normally fed animals, but glucose uptake was 60% higher than in the normally fed state. Mammary glucose uptake was not closely linked to either blood flow or glucose supply, suggesting that substrate supply was not the primary determinant of mammary metabolism. Denervation experiments showed that the mammary metabolic response to altered nutritional state was also unlikely to be closely controlled by neural pathways. Severance of the cutaneous branch of the posterior division of the femoral nerve innervating the inguinal mammary glands did not reduce the high glucose uptake by mammary glands of either fed or refed rats, nor did denervation change the low glucose uptake by mammary glands of food-deprived rats. Denervation reduced blood flow in the associated mammary gland, however, indicating that neural pathways may play a role in supporting mammary blood flow when food is available. In in vitro experiments, the rate of glucose uptake was 35% lower in mammary acini from food-deprived rats than in fed rats 2.5 h after tissue removal, indicating some persistence of the food deprivation-induced suppression of mammary metabolism. Administration of insulin increased glucose uptake in acini from both fed and food-deprived rats, indicating that insulin may be involved in signaling the mammary gland of the restoration of nutrient supply when food-deprived rats are refed. The effects of administration of a gut extract in vivo and in vitro are discussed.     

谷氨酸棒状杆菌葡萄糖代谢阻断工程菌的构建

采用反向代谢工程的策略,以谷氨酸棒杆菌ATCC 13032野生型为出发菌株,利用无抗性标记的同源重组方法,敲除了编码葡萄糖pts系统关键转运蛋白基因ptsG、ptsH-ptsI和葡萄糖转运系统关键转运蛋白基因abc、abc2和iolt1,得到了5株逐次敲除了相应基因的突变株。结果表明:当以葡萄糖为唯一碳源培养时,CGΔptsG菌株的葡萄糖的消耗是野生型的50%,菌体OD值为1.473;CGΔptsH-ptsI菌株的葡萄糖的消耗是野生型的39.5%,菌体OD值为1.226;CGΔabc菌株的葡萄糖的消耗是野生型的36%,菌体OD值为1.092;CGΔabc2菌株的葡萄糖的消耗是野生型的26.2%,菌体OD值为0.486;CGΔiolt1葡萄糖的消耗和菌体生长OD值为0,实现了谷氨酸棒状杆菌葡萄糖代谢的阻断,说明ptsG、ptsH-ptsI、abc、abc2和iolt1所编码的转运蛋白具有葡萄糖转运功能。     

葡萄糖对快速发酵虾头酱中组胺抑制的作用

为探讨葡萄糖对快速发酵虾头酱中组胺的抑制作用,提高其安全性,本论文以新鲜虾头为原料,采用外接微生物快速发酵工艺,分别向虾头酱中添加2%、4%和6%葡萄糖,检测了虾头酱发酵过程中组胺含量的变化。对虾头酱发酵期间的TVB-N含量、氨基酸态氮及pH的变化进行了探讨,通过比较理化指标、菌落总数以及感官评价分析虾头酱的品质。结果表明,葡萄糖的添加能显著降低组胺的生成,添加2%、4%和6%的葡萄糖分别能降低54.6%、57.2%和43.2%的组胺;葡萄糖的添加一定程度上促进了TVB-N的生成,增加了产品总糖含量以及降低了氨基酸态氮的含量和pH,但并不影响蛋白质、脂肪、水分及菌落总数的含量;感官评价表明,产品风味相似度较高,葡萄糖的添加能明显抑制产品的氨气味。因此,虾头酱中添加2%、4%和6%的葡萄糖能降低组胺含量以及减少氨气味,同时产品也保持较高的品质特性。