简述酸奶防治肠道疾病的特殊功能

酸奶是鲜牛奶经乳酸菌发酵精制而成的发酵型牛奶,是一种含有大量活性乳酸菌的开胃佳品饮料。当人们饮用时,活性乳酸菌直接进入人体消化道,履行它的“人体肠道健康卫士”职责,因而不仅使酸牛奶营养价值远超过鲜牛奶,而且长期     

UreB酸奶的研制及其抗幽门螺杆菌感染的动物实验研究

目的 利用UreB基因工程乳杆菌(UreB-L6032)研制一种预防幽门螺杆菌(Helicobacter pylori,H.pylori)感染的UreB活性酸奶,并对其抗H.pylori感染的能力进行动物实验研究.方法 采用发酵奶制备技术制成酸奶,并对其pH、活菌含量和质粒稳定性进行检测.小鼠在喂食UreB活性酸奶1个月后再感染H.pylori,并设普通酸奶组,阴性和阳性感染组,2个月后测定IL-10(interleukin-10)、IFN-γ(interferon-γ)、sIgA和特异性IgG的水平,并利用快速脲酶法和细菌培养法对小鼠胃部H.pylori进行检测.结果 成功的研制出了色香味颇佳,含UreB-L6032活菌较高,质粒能稳定存在的UreB活性酸奶.与一般酸奶相比,其能诱导小鼠体内特异性IgG的产生,显著增加IL-10的表达,降低小鼠H.pylori感染率.结论 UreB活性酸奶比一般酸奶能更加有效预防H.pylori感染.     

绿豆中的单宁

在东南亚地区,绿豆是一种大众喜爱的食物,它含有20～25％的蛋白质,可以整食,也可制成豆芽或磨成粉做成粉丝食用。此外,还可以加糖制成各种点心或快餐食品。绿豆芽易于消化,富含维生素C、维生素B_1、维生素B_2和蛋白质,它可以与虾、肉等配在一起,做     

酸奶能够克服“乳糖不耐受”的原因探究

随着人们生活水平的提高和对营养健康的关注,牛奶成了家庭必备的食品。但有些人喝牛奶会腹胀、腹泻,而喝酸奶会避免这个症状。通过上网查阅资料,采访专家,参考文献,开展社会调研,亲自制作酸奶,实地考察酸奶生产线,以及对对酸奶成分进行检测后,发现喝牛奶腹胀、腹泻的现象(乳糖不耐受)较为普遍,其主要原因是体内缺乏乳糖酶的人群不能分解牛奶中的乳糖所致。酸奶与牛奶的加工工艺不同,在发酵过程中20%-30%的乳糖被分解,含量明显下降,易于人体消化吸收。加之酸奶中的活性乳酸菌的代谢物可增加小肠乳糖水平,从而有效缓解和克服了乳糖不耐受的症状。     

关于召开“全国绿豆产业发展研讨会”的预备通知

受农业部科技教育司委托,定于2001年9月,在江苏省南京市召开“全国绿豆产业发展研讨会暨第四届全国绿豆科技应用学术交流会”。会议具体时间和地点将另行通知。会议主要内容:1.总结交流近年来绿豆、小豆等食用豆类品种资源、遗传育种、生产栽培、病虫害防治、营养品质、加工利用等方面的研究成果和经验;2.探讨绿豆、小豆等食用豆类在当前西部开发和种埴业结构调整中的地位及发展方向;3.研究绿豆、小豆等食用豆类产业化发展对策;4.绿豆、小豆等食用豆类新品     

绿豆bHLH转录因子家族的鉴定与生物信息学分析

bHLH是真核生物中重要的一类转录因子,其主要由碱性氨基酸区和螺旋-环-螺旋区组成。本研究利用生物信息学的方法鉴定到122个绿豆bHLH转录因子,并对其理化性质、保守结构域、基因结构、在染色体上的分布、系统进化以及部分典型基因的组织表达差异等进行分析。结果表明,bHLH转录因子理化性质差异较大;含有2个保守结构域,分别位于N端的碱性氨基酸区和C端的螺旋-环-螺旋区,碱性氨基酸区含有His5-Glu9-Arg13保守序列,与靶基因结合有关,HLH区含有Arg23和Arg55,与形成二聚体有关,同时含有5种保守元件;bHLH基因在11条染色体上分布不均匀,5号、7号和8号染色体上分布较多,1号、4号和10号染色体上分布较少,大部分基因含有1~9个不等的内含子,在染色体上成簇状分布;122个bHLH转录因子可分为11个亚家族。多数bHLH基因在绿豆根、茎、叶、花和种子等组织中均有表达,但具有组织表达特异性,且不同基因表达量差异较大。本研究为进一步研究绿豆bHLH转录因子家族的生物学功能奠定基础。     

酸奶中乳酸菌含量的检测

目的检测酸奶发酵前后以及贮藏期间的乳酸菌活菌数及酸度变化,以对酸奶的质量进行控制.方法应用高层半固体琼脂试管法. 结果酸奶中乳酸菌含量极高,达2.65×1010个/ml以上,并随贮藏时间的延长而发生变化. 糖对酸奶的含菌量无明显影响.双菌酸奶比单菌酸奶含菌量高,常可达到倍增,pH值随发酵和贮藏进程而下降.结论高层半固体琼脂试管法操作简便、快速、准确、活菌检出率高.     

绿豆Ty1/Copia类反转录转座子逆转录酶序列的克隆和分析

利用Ty1/copia类反转录转座子的保守位点设计简并引物,从绿豆(Vigna radiata(L.)Wilczek)基因组中扩增得到了反转录转座子的逆转录酶序列.对扩增得到的约270bp的片段进行分离和克隆,并随机挑选了40个克隆进行测序,结果得到了36个单独的核酸序列,其中18个含有移码突变或终止子.根据序列比对,这些克隆可分为9组以及单个的9种.这40个克隆中,核酸序列相似性从8%到100%,显示出其核酸序列的高度异质性.将这些克隆的核酸序列与来自其他种植物的相应序列进行谱系分析,发现有些克隆与来自其他种植物的相应序列的亲缘关系比这些克隆之间更为接近.斑点杂交显示Ty1/copia反转录转座子约占绿豆基因组的9.3%.     

斑马鱼功效模型在验证乳制品补钙和促进肠蠕动中的应用

目的基于斑马鱼补钙和肠蠕动模型,验证和对比不同牛奶补钙和酸奶促进肠蠕动的作用效果。方法选择发育健康且阶段一致的3 dpf野生型斑马鱼,加入不同浓度(2. 5、5. 0、10. 0 mg/m L)的纯牛奶稀释液,同时设置空白对照组。处理至7 dpf后,用2 mg/m L钙黄绿素染色,在荧光显微镜下观察拍照,计算斑马鱼的椎骨荧光强度。选取5 dpf的斑马鱼,用尼罗红染料处理16 h,加入不同浓度(2. 5、5. 0、10. 0 mg/m L)的酸奶和乳酸菌饮料稀释液,同时设置空白对照组。处理24 h后,在荧光显微镜下观察拍照,计算斑马鱼肠道内荧光强度。结果纯牛奶、酸奶和乳酸菌饮料作用效果都随浓度的增加而增强。与空白对照组比较,6种纯牛奶中2种纯牛奶处理的斑马鱼骨骼荧光强度有一定增加; 8种酸奶和乳酸菌饮料都显著引起了肠道荧光强度的减弱,酸奶的效果优于乳酸菌饮料。结论纯牛奶、酸奶和乳酸菌饮料对斑马鱼的最大耐受浓度(MTC)为10 mg/m L,且对斑马鱼起到补钙和促进肠蠕动的作用。     

分子标记在绿豆遗传连锁图谱构建和基因定位研究中的应用

绿豆(Vigna radiata(L.)Wilczek)作为一种医食两用作物,不仅是重要的食物资源,在改善土壤环境、提高农民收入等方面也发挥着重要作用。然而,相对于大宗作物而言,绿豆基础研究薄弱,基因组研究更是落后。近年来,分子标记技术迅速发展,在绿豆基因组学研究中发挥了重要的作用。国内外利用分子标记技术已构建了超过20张绿豆遗传连锁图谱。一些优良基因尤其是与抗性相关的基因被鉴定或精细定位,为绿豆分子标记辅助选择打下基础,加快了抗性新品种的培育进程。本研究通过对分子标记技术在绿豆遗传连锁图谱构建、重要功能基因的定位等方面的应用进行综述,以期为绿豆遗传育种研究及功能基因组学分析提供参考。     

Impact of the Coffea canephora gene introgression on beverage quality of <Emphasis Type="Italic">C. arabica</Emphasis>

Lines of Coffea arabica derived from the Timor Hybrid (hybrid between C. arabica and C. canephora) are resistant to coffee leaf rust (Hemileia vastatrix) and to the nematode Meloidogyne exigua. The introgression of C. canephora resistance genes is suspected of causing a drop in beverage quality. Coffee samples from pure lines, compared in a Trial 1, and from F1 hybrids and parental lines from a half-diallel trial in a Trial 2, were studied for beverage quality, chemical composition and amount of introgressed genetic material. Chemical analyses (caffeine, chlorogenic acids, fat, trigonelline, sucrose) were carried out with near-infrared spectrometry by reflectance of green coffee. The number of amplified fragment length polymorphic (AFLP) markers introgressed from the Timor Hybrid varied from 1 to 37 for the lines studied. There were significant differences between lines for all of the biochemical compounds analysed and for the acidity and the overall standard of the beverage. Two lines (T17927, T17924) were significantly poorer than the controls for sucrose and beverage acidity. T17924 also had more chlorogenic acids and was poorer for the overall standard. However, two highly introgressed lines, T17934 and T17931 (25 and 30 AFLP markers, respectively), did not differ from the non-introgressed controls. There were no correlations between the number of AFLP markers and the chemical contents or beverage attributes. Significant correlations were found between the performance of the parents and their general combining ability for beverage quality. It was concluded that it should be possible to find lines with both the desired resistance genes and good beverage quality. Selection can avoid accompanying the introgression of resistance genes with a drop in beverage quality.     

Phytosterols in low- and nonfat beverages as part of a controlled diet fail to lower plasma lipid levels

Dietary phytosterols have been shown to reduce plasma cholesterol concentrations when consumed in different food matrices, but their effectiveness in nonfat or low-fat beverages has not been established. The objective of this study was to examine whether phytosterols alter plasma lipid levels when incorporated into nonfat or low-fat beverages. Fifteen moderately hypercholesterolemic men and women consumed three precisely controlled diets for periods of 21 days each in random order. Diets contained either a nonfat placebo beverage (NF), a beverage that is nonfat with added phytosterols (NFPS), or a beverage that is low in fat with added phytosterols (LFPS). Total cholesterol concentrations were not different between groups at endpoint, decreasing (P < 0.05) equally by 8.5%, 11.6%, and 10.1% with NF, NFPS, and LFPS consumption, respectively. There was no effect of dietary treatment on LDL cholesterol concentrations, which decreased over time (P < 0.05) by 5%, 10.4%, and 8.5% with NF, NFPS, and LFPS, respectively. HDL cholesterol and triacylglycerol concentrations were unaffected by the diets. Provision of phytosterols as part of nonfat and low-fat beverages did not exert any greater hypocholesterolemic effect than a nonfat placebo beverage. These results show that intake of phytosterols in a low-fat beverage format is not efficacious for lipid level modification.     

Effects of dietary caffeine on renal handling of minerals in adult women

Thirty-seven women, aged 31-78 years, on two separate mornings consumed a decaffeinated beverage to which 6 mg caffeine/kg lean body mass or no caffeine were added. Total urine output of water, calcium, magnesium, sodium, chloride, potassium and creatinine increased in the two hours following caffeine ingestion when compared to the control beverage. Increased urinary mineral (mg)/urinary creatinine (g) ratios were seen for calcium (120 to 200), magnesium (70 to 110), sodium (3,800 to 6,200) and chloride (9,200 to 14,800), following the caffeinated beverage. Creatinine clearance did not change significantly. The percent reabsorption of calcium (98.6% to 97.5%, p less than .001) and magnesium (97.0% to 94.2%, p less than .0001) decreased significantly during the post-caffeine period. The calcium and magnesium filtered loads did not differ significantly between the caffeine and no caffeine beverages. Therefore, caffeine-induced urinary loss of calcium and magnesium is largely attributable to a reduction in calcium and magnesium renal reabsorption, although the physiological mechanism and tubular segment affected remain to be established.     

Flavour preference acquired via a beverage-induced conditioning and its transposition to solid food: Sucrose but not maltodextrin or saccharin induced significant flavour preferences in pigs

When exposed to novel food during food transitions, growing pigs often elicit a neophobic response that is responsible for decreased food consumption. Flavour preference conditioning may represent an interesting way to reduce neophobia and improve food intake in growing pigs. The present series of experiments investigated the pig's conditioned preference for a flavoured beverage added with different carbohydrates and sweeteners and the possible transition of those beverage-induced preferences to flavoured solid food. In Experiment 1A, nine juvenile pigs were given three two-day conditioning sessions: they received a flavoured beverage added with 1.125% sucrose (F + S_1.125) and a second flavoured beverage with no additive (F−). In Experiment 1B, nine juvenile pigs were given six two-day conditioning sessions: they received a flavoured beverage added with 10% sucrose (F + S₁₀) and a second flavoured beverage with no additive (F−). In subsequent two-choice drinking tests, the pigs exhibited no clear-cut preference for F + S_1.125, whereas F + S₁₀ was preferred compared to F− (P < 0.05) but only during the first subsequent two-choice drinking tests, suggesting that pigs developed a short-term preference for the flavour previously paired with 10% but not 1.125% sucrose. The Experiment 2 was conducted to assess the independent effects of visceral (caloric intake) and gustative (sweet taste) reinforcement in flavour preference conditioning. Nine juvenile pigs were subjected to four three-day conditioning sessions: they received flavoured beverages added with 2.25% maltodextrin (F + m, caloric intake), 0.37% saccharin (F + s, sweet taste), or no additive (F−). During further two-choice drinking tests, no clear-cut preference emerged, but the consumption of F + m was 107% and 35% higher than that of F− and F + s, respectively. Despite pigs exhibited some conditioned flavour preferences during two-choice drinking tests in Experiments 1B and 2, no clear-cut preference was observed during two-choice feeding tests with flavoured solid food. Overall, these findings highlight the importance of the combination and/or synergy between gustative and visceral reinforcements for conditioned flavour preference and suggest that a visceral reinforcement via maltodextrin might be sufficient to condition such a preference. Moreover, the absence of clear-cut preference during two-choice feeding test illustrates the difficulty to transpose a flavour preference acquired via a sweet beverage to solid food. Further studies are needed to investigate the failure of saccharin-conditioned preference in pigs.     

Sugar-sweetened and diet beverages in relation to visceral adipose tissue

Frequent sugar-sweetened beverage (SSB) intake has been consistently associated with increased adiposity and cardio-metabolic risk, whereas the association with diet beverages is more mixed. We examined how these beverages associate with regional abdominal adiposity measures, specifically visceral adipose tissue (VAT). In a cross-sectional analysis of 791 non-Hispanic white men and women aged 18-70 we examined how beverage consumption habits obtained from a food frequency questionnaire associate with overall and abdominal adiposity measures from MRI. With increasing frequency of SSB intake, we observed increases in waist circumference (WC) and the proportion of visceral to subcutaneous abdominal adipose tissue (VAT%), with no change in total body fat (TBF%) or BMI. Greater frequency of diet beverage intake was associated with greater WC, BMI, and TBF%, but was not associated with variation in visceral adiposity We conclude that increased frequency of SSB consumption is associated with a more adverse abdominal adipose tissue deposition pattern.     

Beverage vs. solid fruits and vegetables: effects on energy intake and body weight

Beverage consumption has been implicated in weight gain, but questions remain about the veracity of the association, whether the relationship is causal and what property of beverages is responsible. It was hypothesized that food form is the most salient attribute. Thus, a randomized controlled trial of food form was conducted. Energy-matched beverage or solid forms of fruits and vegetables were provided to 34, lean or overweight/obese adults for two 8-week periods with a 3-week washout interspersed. Dietary compensation was incomplete (beverage 53%; solid 78%) and body weight increased after the beverage (1.95 ± 0.33 kg) (77% fat mass) and solid (1.36 ± 0.30 kg) (85% fat mass) treatments (both P < 0.0005). Differences between food forms were not significant. The lean group had the highest dietary compensation (119%) and no significant weight change (0.84 ± 0.53 kg) after consuming the solid fruits and vegetables whereas the overweight/obese group had lower compensation and significant weight gain during the solid arm (46%, 1.77 ± 0.32 kg, P < 0.0001). In contrast, incomplete dietary compensation and weight gain occurred in both the lean (43%, 1.61 ± 0.44 kg, P = 0.003) and overweight/obese (61%, 2.22 ± 0.47 kg, P < 0.0005) groups during the beverage arm. Secondary analyses revealed the obese group gained more weight than the lean and overweight groups during the beverage intervention (P = 0.024). These data demonstrate energy consumed as beverages may be especially problematic for weight gain. They also indicate that advice to increase fruit and vegetable consumption should emphasize total energy intake because the additional energy contributed may promote weight gain, especially among overweight and obese individuals.     

褐色乳酸菌饮料稳定体系的优化

为探究褐色乳酸菌饮料的体系稳定性,通过单因素和正交试验证明了葡萄糖添加量、褐变时间和发酵时间对乳酸菌饮料稳定性的影响较小;而基料添加量(蛋白质含量)、饮料pH和均质压力对稳定性的影响较大。获得褐色乳酸菌饮料最优稳定体系参数为：葡萄糖添加量80 g,褐变时间2 h,发酵时间72 h,基料添加量200 g,饮料pH 3.7,均质压力200 MPa。研究结果不仅优化了褐色乳酸菌饮料的制作工艺,而且降低了稳定剂的添加量,降低了生产成本。     

Gastrointestinal permeability during exercise: effects of aspirin and energy-containing beverages.

The purpose of this study was to determine whether aspirin (A) ingestion combined with prolonged exercise increases gastrointestinal permeability and whether consumption of a carbohydrate-containing (CHO) or a CHO + glutamine-containing (CHO+G) beverage would reduce this effect. Seventeen subjects completed six experiments. They ingested A (1,300 mg) or placebo (P) pills the evening before and before running 60 min at 70% maximal oxygen uptake. Also, before running they ingested a solution containing 5 g lactulose (L), 5 g sucrose (S), and 2 g rhamnose (R). During each trial, either a 6% CHO beverage, a 6% CHO+G (0.6%; 41 mM) beverage, or a water placebo (WP) was consumed. For 4 h after a run, all urine was collected to measure urinary excretion of L, R, and S. S excretion (percentage of dose ingested; measure of gastroduodenal permeability) was significantly greater (P < 0.05) during the A trial while the subjects drank the WP compared with all other trials. Administration of A also significantly increased L/R (measure of intestinal permeability) for the CHO and WP trials compared with all P trials. Ingestion the CHO or CHO+G beverages significantly reduced S excretion and L excretion when A was administered, but it did not reduce L/R. These results indicate that gastroduodenal and intestinal permeability increase after A ingestion during prolonged running and that ingestion of a CHO beverage attenuates the gastroduodenal effect but not the intestinal effect. Furthermore, addition of G to the CHO beverage provided no additional benefit in reducing gastroduodenal or intestinal permeability.     

Physiological responses to glycerol ingestion during exercise

To study selected cardiovascular, thermoregulatory, and hormonal responses to the consumption of glycerol solutions during exercise, nine subjects cycled for 90 min at 50% peak O2 uptake in a 30 degree C, 45% relative humidity environment. Beverages tested included a 10% glycerol solution (G), a 6% carbohydrate-electrolyte beverage (CE), the 6% carbohydrate-electrolyte beverage plus 4% glycerol (CEG), and a water placebo (WP) ingested at regular intervals during the first 60 min of exercise. The beverages were administered in counterbalanced order with subjects serving as their own controls. Ingestion of the glycerol solutions resulted in an increase in plasma osmolality and attenuation of the decrease in plasma volume associated with the WP treatment (P less than 0.05). Plasma renin activity was highest with WP (P less than 0.05), and G was associated with increased antidiuretic hormone levels (P less than 0.05). Ratings of perceived thirst were lowest for CEG and G, and the frequency of gastrointestinal distress was greatest for G (P less than 0.05). However, no differences among beverage treatments were observed for heart rate, esophageal temperature, sweat rate, ratings of perceived exertion, or changes in cortisol and aldosterone levels. These data indicate that there are no substantial metabolic, hormonal, cardiovascular, or thermoregulatory advantages to the consumption of solutions containing 4 or 10% glycerol during exercise.     

Catechin safely improved higher levels of fatness, blood pressure, and cholesterol in children

Objective: The purpose of this study was to evaluate the effects of a catechin‐rich beverage on body fat and cardiovascular disease risk factors in obese children and to verify the safety of its use. Methods and Procedures: Obese or near‐obese Japanese children were recruited for this study. A double‐blind, randomized, controlled study was performed with a 4‐week lead‐in, a 24‐week beverage ingestion period and a 12‐week follow‐up. Subjects ingested green tea containing 576 mg catechins (catechin group) or 75 mg catechins (control group) once per day for 24 weeks. Randomization was stratified by gender, age, and BMI. Subjects were instructed to maintain their usual lifestyles during the study period. Results: Data were analyzed using samples from 40 subjects (catechin group; n = 21, control group; n = 19). There were no significant differences in major outcome variables, such as body fat mass, between the catechin and the control groups. When, however, the analysis was stratified using the median of the week‐0 values, the decrease at week 24 in waist circumference, systolic blood pressure, and low‐density lipoprotein cholesterol in the catechin group was significantly greater than that in the control group for the above‐median category. Ingestion of the catechin‐rich beverage was not associated with any adverse effects. Discussion: These findings suggest that ingestion of a catechin‐rich beverage ameliorates serious obesity and cardiovascular disease risk factors without raising any safety concerns in Japanese children.