辣椒素对肠道菌体外发酵的影响

食用辣椒会带来肠道不适反应,对肠道环境存在潜在影响。实验拟通过体外发酵验证辣椒素对肠道发酵环境的影响。向大鼠盲肠内容物发酵液中添加0.05%、0.10%、0.15%三种浓度辣椒素,培养10h后检测发酵液中pH、游离氨、短链脂肪酸(SCFA)及双歧杆菌、乳酸杆菌、大肠杆菌3种微生物的变化趋势,探讨辣椒素对肠道发酵环境的影响。结果表明,与空白组相比,添加辣椒素使盲肠内容物发酵液pH、游离氨浓度升高,短链脂肪酸含量降低,双歧杆菌、乳酸杆菌数量下降,而大肠杆菌数量上升。所有变化均与辣椒素添加剂量存在相关性。研究结果表明,辣椒素对肠道发酵环境有潜在危害。      

辣椒素剂量对大鼠肠道发酵产物的影响

目的：研究不同辣椒素灌喂剂量对大鼠肠道发酵产物的影响。方法：将48只SD大鼠按体质量随机分为4组,每组雌雄各6只。按大鼠体质量,分别灌喂辣椒素剂量为0、2.5、5、7.5mg/(kg·d)的辣椒素大豆油溶液。自由采食基础饲料和饮水,喂养4周后解剖,测定各组体质量、盲肠内容物、盲肠组织质量、盲肠内容物游离氨以及盲肠中短链脂肪酸(SCFAs)等指标。结果：随着灌喂辣椒素剂量的增加,大鼠采食量增加,体质量增加量却降低;雌雄大鼠盲肠内容物中游离氨浓度和pH值逐渐增加,盲肠中乙酸、丙酸、丁酸浓度和总SCFAs浓度降低。结论：辣椒素对大鼠肠道发酵产生明显抑制作用,并且表现剂量效应关系。     

大豆寡糖对体外发酵肠道微生物的影响

旨在通过体外发酵技术研究大豆寡糖（soybean oligosaccharides,SBOS）对香猪肠道微生物的影响。无菌采集环江香猪的空肠、回肠和盲肠内容物作为接种物,分别以0（对照组）、0.5%、1.0%、2.0%、5.0%、8.0%的SBOS和2.0%葡萄糖为底物进行体外发酵。利用末端限制性片段长度多态性技术（terminal restriction fragment lengthpolymorphism,T-RFLP）分析48 h后发酵液微生物区系,荧光定量聚合酶链式反应（polymerase chain reaction,PCR）测定发酵液中双歧杆菌、乳酸杆菌、大肠杆菌和链球菌的16S rDNA变化。结果表明：SBOS提高了发酵液微生物的多样性;随着SBOS添加量的增大,发酵液中有益菌先增加再减少、而有害菌呈先减少后增加的趋势,其中以2.0%的SBOS添加量发酵效果最优,促进了回肠和盲肠发酵液中双歧杆菌的增殖（P＜0.05）、降低了盲肠发酵液中大肠杆菌和链球菌的增殖（P＜0.05）。     

柿子单宁对体外模拟发酵环境中肠道微生物的影响

采用体外厌氧发酵法研究了柿子单宁对肠道微生物的影响。将单宁与大鼠肠道微生物共孵育,分别测定0、6、12、24、48 h五个时间点发酵液中六种微生物、短链脂肪酸和p H的变化。结果显示,与空白组相比,添加2 g/L剂量组的柿单宁能有效地促进肠道有益菌(乳杆菌和双歧杆菌)的增殖,抑制有害菌(肠球菌、大肠杆菌、梭菌和拟杆菌)的增殖,增加短链脂肪酸含量,降低发酵液p H。研究结果表明柿子单宁对肠道微生态具有调节作用,可能是其在体内发挥作用的机制之一。      

辣椒素对糖尿病大鼠肠道健康的影响

目的：研究辣椒素对链脲佐菌素（streptozotocin,STZ）诱导的糖尿病大鼠肠道环境的影响。方法：将40 只Sprague-Dawley（SD）雄性大鼠按体质量随机分为5 组,每组8 只。其中一组为正常对照组（CON组）,其余4 组采用STZ诱导大鼠建立糖尿病模型,分别为模型空白组,辣椒素低（3.0 mg/（kg•d））、中（6.0 mg/（kg•d））、高（9.0 mg/（kg•d））剂量组。实验期间给大鼠喂食基础饲料,自由采食和饮水。饲养28 d后将大鼠处死解剖,测定各组大鼠体质量、盲肠壁表面积、盲肠内容物的水分含量、pH值、游离氨含量以及微生物数量、短链脂肪酸（short-chain fatty acid,SCFA）含量和肠道组织形态等指标。结果：辣椒素使糖尿病大鼠的总游离氨含量、pH值、水分含量均升高,SCFA含量降低,盲肠内容物中有益菌数量降低,有害菌数量显著增加（P＜0.05）。结论：灌胃低、中、高剂量的辣椒素对糖尿病大鼠肠道环境均有一定的损害作用。     

辣椒素对辣椒发酵中乳酸菌的影响

针对辣椒乳酸发酵中的技术问题,采用植物乳杆菌、短乳杆菌、罗伊氏乳杆菌、瑞士乳杆菌、鼠李糖乳杆菌这5种乳酸菌为研究对象,探讨辣椒中主要成分辣椒素和发酵过程中食盐质量浓度对乳酸菌纯培养物生长的影响,同时结合电镜实验讨论辣椒素对乳酸菌的作用效果。结果表明：辣椒素对乳酸菌的生长均有一定的延迟作用,辣椒素对乳酸菌抑制的最低质量浓度为0.133mg/mL,使其对数生长期延后2h,并且随着其质量浓度的增大,这种延迟效果更加明显。同时还降低了培养液中达到稳定期的OD600nm值,降低了0.2左右。通过电镜实验发现,一定质量浓度的辣椒素对乳酸菌细胞具有一定的伤害作用,会破坏其细胞形态及结构,但不会严重影响发酵效果。     

辣椒素和辣椒水提物的抗氧化特性及对人粪便微生物体外培养特性的影响

为了探究辣椒素和辣椒水提物的抗氧化特性及其对肠道微生物的影响,本研究测定了辣椒水提物的主要营养成分,以辣椒素标品为阳性对照,测定了辣椒水提物的抗氧化活性,并以健康大学生粪便为菌源,采用24 h体外厌氧发酵模式探究其对肠道微生物的影响。结果显示,在微辣（0.028 g/L）到特辣（0.112 g/L）范围内,辣椒水提物对DPPH自由基、超氧阴离子自由基、羟自由基的清除率分别为75.25%、12.87%、19.45%,均低于标准辣椒素。在特辣（0.0924～0.2918 g/L）范围内,辣椒水提物与辣椒素能增加培养体系的短链脂肪酸含量,在培养6 h时,其对乳酸菌、双歧杆菌、梭状芽孢杆菌、肠杆菌和总厌氧菌的生长具有抑制作用,对拟杆菌无明显抑菌效果;培养12 h时,其对肠杆菌的生长具有抑制作用,对其余菌均为促进作用;培养24 h时,其对总厌氧菌、梭状芽孢杆菌、肠杆菌的生长具有抑制作用,对双歧杆菌、乳酸菌、拟杆菌的生长具有促进作用。在培养24 h的发酵体系中益生元指数PI值最大,分别为0.11、0.04;B/E值在培养12 h时最大,分别为1.60、1.61。本研究为辣椒营养价值与保健功能研究提...     

肠道微生物体外发酵模型研究进展及其在食品中的应用

随着分子微生态学,特别是高通量测序技术的快速发展,人们对肠道微生物的作用有了进一步认识。肠道不仅是消化吸收的场所,其微生物菌群现更被认为是一个高度特异化的\     

辣椒素发酵产物对小鼠营养性肥胖的预防作用

目的:研究辣椒素发酵产物对小鼠营养性肥胖的预防效果。方法:小鼠始终饲喂高脂饲料,并以灌胃方式给药,观测体重、Lee’s指数、脂肪组织湿重、脂肪细胞数目和大小及血清总胆固醇和甘油三酯等指标。结果:除血糖外给药组小鼠各项指标与对照组相比均有统计学差异。结论:辣椒素发酵产物对小鼠营养性肥胖有预防作用。      

枸杞多糖体外调节人体肠道菌群的功能研究

为研究枸杞多糖(LBP)对人体肠道菌群结构和代谢产物的影响,对6名健康人的粪便提取物进行单独样本与混合样本的体外模拟厌氧发酵,利用16S rRNA基因高通量测序技术对发酵后肠道菌群进行结构和功能分析,并利用超高效液相色谱(UPLC)检测发酵液中的短链脂肪酸(SCFAs)浓度。结果表明,LBP能够明显改变人体肠道菌群结构与功能,提高肠道菌群中益生菌乳酸杆菌属与双歧杆菌属的丰度,并促进了SCFAs的产生。因此,LBP能够显著影响人体肠道菌群结构与功能。     

直肠菌群对两种抗性淀粉的体外发酵研究

分别以两种抗性淀粉为唯一碳源,对直肠菌群进行体外发酵。通过研究发现,发酵过程中两种培养基的pH呈逐渐下降的趋势;双歧杆菌属、乳杆菌属的数量呈上升趋势;肠球菌属和肠杆菌属的数量也能保持比较稳定的数量,而拟杆菌的数量在发酵中后期开始减少,但总厌氧菌数比较稳定,因此发酵过程中肯定有不同菌属的生长演替;两种碳源均能被肠道菌群利用产生短链脂肪酸,其中以丙酸的量最大。乳酸在发酵过程中被积累并能快速被一些直肠菌群利用而消耗。     

Effect of lactobacillus fermented beetroot juice on composition and activity of cecal microflora of rats

This study aimed at determination of the effect caused by ingestion of beetroot juice fermented by Lactobacillus casei 0920 and Lactobacillus brevis 0944 strains on the state of cecal ecosystem of experimental rats. The intake of fermented beetroot juice containing 3.5–4.0 × 10⁹ CFU/mL live Lactobacillus sp. cells positively modulated the cecal microflora of the rats and its metabolic activity. The counts of Lactobacillus sp., Bifidobacterium sp., Bacteriodes sp., and Enterococcus sp. were maintained at the level of 8.2–8.6, 6.2–7.5, 8.0–8.3, and 7.3–7.7 log units, respectively, while the number of Clostridium sp. cells was increased by 1.1–1.6 log units and Enterobacteriaceae bacteria were reduced by 0.8–2.1 log units. In this study, the selected cecal enzymes such as β-glucosidase, β-glucuronidase, and β-galactosidase as well as the profile and concentration of short chain fatty acids (SCFA) were the biochemical markers of metabolic activity of the intestinal ecosystem. The considerable decrease in activities of β-glucosidase and β-glucuronidase was observed in all three experimental groups fed with the fermented beetroot juice. Total concentration of SCFA was the highest (78.1 μmol/100 g BW vs. 59.2 μmol/100 g BW in control group) in intestines of rats fed with 6 mL of fermented beetroot juice daily. These results prove that the fermented beetroot juice benefits cecal microbial activity.     

Effect of the combination of monensin and isoacids on rumen fermentation in vitro

Effects of isoacids, monensin, or a combination of them on fermentation by mixed rumen bacteria were investigated using a continuous culture technique. The culture was allowed to stabilize for 4 d before treatments were imposed. Comparisons between treatments were made on d 11 and 12 of the culture. Isoacids (equal proportions of isobutyric, 2-M-butyric, isovaleric, and valeric acids) at 15 mg/dl of culture media increased acetate (6.17 vs. 5.48 meq/dl) and total VFA production (8.93 vs. 7.87 meq/dl) compared with that of controls. Monensin at 150 micrograms/dl reduced acetate (3.74 vs. 6.02 meq/dl) and VFA (6.84 vs. 8.54 meq/dl) but increased propionate (2.28 vs. 1.74 meq/dl) relative to control. The combination of isoacids and monensin increased acetate relative to monensin alone (5.24 vs. 3.74 meq/dl) but did not alter the effect of monensin on propionate concentration (2.32 vs. 2.28 meq/dl). It is concluded that monensin decreases acetate production by 35% and when isoacids are added to the cultures containing monensin, acetate production is restored.     

Study on the microflora and biochemistry of cocoa fermentation in the Dominican Republic

Cocoa fermentation was monitored at the IDIAF (Instituto Dominicano de Investigaciones Agropecuarias y Forestales) "Mata Larga" experimental station, in San Francisco de Macoris, Dominican Republic. The maximum average fermentation temperature reached 51 degrees C after 48 h and the pH reached 4.5 after 144 h of fermentation. A significant decrease in glucose, fructose and citric acid was seen in the pulp over the first 48 h. There was a delay of 24 h between maximum microbial growth and maximum concentrations of the respective metabolites, which occurred after 48 h for ethanol and after 72 h for acetic acid. A maximum concentration in lactic acid was found after around 120 h of fermentation. The aerobic mesophilic flora increased from 6.1x10(6) to a maximum of 4.2x10(7) CFU g(-1) of dry matter after 48 h of fermentation. Yeasts displayed maximum development after 24 h (6.1x10(7) CFU g(-1) of dry matter), whilst for lactic and acetic acid bacteria it occurred after 48 h (7.3x10(7) and 1.5x10(8) CFU g(-1) of dry matter respectively). The yeasts isolated belonged to the genera Hanseniaspora and Candida, the lactic acid bacteria to the genus Lactobacillus, and the acetic acid bacteria to the genus Acetobacter. The differences compared to other fermentation trials concerned the micropopulation from a qualitative point of view.     

Effect of rabadi fermentation on phytic acid and in vitro digestibility of barley

Rabadi, an indigenous fermented food, was prepared by mixing cereal flour with buttermilk, allowing it to ferment at 30, 35 and 40 °C for 6, 12, 18, 24 and 48 h and cooking the fermented mixture for 0.5 h with continuous stirring. Two types of rabadi were prepared i.e. autoclaved and unautoclaved. In autoclaved type of rabadi cereal flour was mixed with water, autoclaved (0.103 MPa = 15 psi for 15 min), cooled, mixed with buttermilk and fermented. As this type of rabadi was precooked prior to fermentation, hence, the fermented product did not require cooking afterwards, while in unautoclaved rabadi, barley flour and buttermilk were mixed, fermented and then cooked prior to consumption. Phytic acid was reduced drastically at all the temperatures and periods of fermentation in both autoclaved and unautoclaved type of rabadi; greater reduction occurred at higher temperature and duration of fermentation. A significant improvement in the in vitro digestibility of starch and protein was observed; maximum improvement was noticed when fermentation was carried out at 40 °C for 48 h in both the types of rabadi. Phytic acid had a significant (P < 0.05) negative correlation with digestibility (in vitro) of proteins and starch of barley flour rabadi.     

Effect of natural fermentation on in vitro zinc bioavailability in cereal–legume mixtures

There is increasing concern about zinc availability from cereal-based vegetarian diets and the need to improve its native bioavailability. Effects of natural fermentation on zinc availability were assessed by in vitro assay with a ⁶⁵Zn extrinsic tag on four cereals (rice, wheat, sorghum and pearl millet), four decorticated legumes (red gram, bengal gram, green gram and black gram) and their 16 binary combinations. Fermentation significantly increased zinc solubility (2–28%) and zinc uptake by intestinal segment (1–16%). Two-way ANOVA indicated significant effects of combinations on zinc solubility but not on zinc uptake in both fermented and unfermented states. Levels of phytate-P were reduced while titratable acid and ascorbic acid levels were increased by fermentation. However, tannins were unchanged.     

Effect of fructo-oligosaccharides on intestinal microflora

Fructo-oligosaccharides are widely distributed in plants such as onions, asparagus, wheat etc., and obtained from sucrose by the action of fructosyltransferase. They are not hydrolyzed by human digestive enzymes, but are utilized by intestinal bacteria such as bifidobacteria. Bacteroides fragilis group, peptostreptococci and klebsiellae. In the experiment with 23 patients (73 +/- 9 years old), improvement of fecal microflora was observed by oral administration of fructo-oligosaccharides 8 g per day for two weeks: the population of bifidobacteria in feces increased about 10 times compared before the administration; average pH of stool showed 0.3 lower than that before administration.     

The effects of okara on rat growth, cecal fermentation, and serum lipids

Okara, a soymilk residue, was characterized and used as a supplement to enrich dietary fiber in rats. Okara comprised 49% total dietary fiber, of which only 0.55% was soluble, protein (33.4%), fat (19.8%), and ash (3.5%). Okara as a diet supplement had no influence on food intake, but the growth rate and feeding efficiency were lower in the okara-fed group than in the control group. Okara increased fecal weight and moisture. In okara-fed rats, in vivo colonic fermentation of okara resulted in a lower pH, but a higher cecal weight and higher total short chain fatty acid production, compared to controls. There were no significant differences (P≤0.05) between groups in albumin, protein, uric acid, bilirubin, or glucose content in rat serum. The okara-supplemented diet produced a nonsignificant reduction in HDL-lipids and triglycerides. Okara, a rich source of low-cost dietary fiber and protein, might be effective as a dietary weight-loss supplement with potential prebiotic effect.