膳食纤维与结肠癌关系研究

结肠癌目前呈逐年上升趋势,而膳食纤维能降低患结肠癌风险性;近年随着研究不断深入,出现许多不同观点,有些观点甚至认为膳食纤维能增加患结肠癌风险性。该文介绍膳食纤维与结肠癌之间关系及可能性机理,并进行分析。     

益生素、益生菌与结肠癌

介绍了益生素和益生菌及其作用机理。在动物模型中，有大量的数据证实益生素和益生菌能够预防癌症．而在人体内还没有直接实验证据。它们抑制癌症的确切机理目前尚不清楚，其抑制机理可能是：肠道菌群代谢活动的改变，肠道理化环境的改变，潜在的致癌物质的黏附和降解，肠道菌群的改变、抗癌或抗诱变物质的形成、提高宿主的免疫应答、影响宿主的生理活动以及发酵不能被消化的食物并形成有益代谢产物。     

Effects of fat supplementation to diets high in nonforage fiber on production responses of midlactation dairy cows

The effects of dietary nonforage fiber sources on production responses of lactating dairy cattle have been well described, but interactions with other components of the diet have been less thoroughly explored. We investigated the effects of adding 2 commonly fed fat sources to a ration featuring high levels of nonforage fiber supplied by a corn milling by-product. Midlactation Holstein cows were blocked by parity, stratified by days in milk, and randomly assigned to 1 of 6 pens (12 cows/pen). Pens were randomly assigned to treatment sequences in a 3 × 3 Latin square design, where the treatments consisted of prilled saturated fat (SAT; Energy Booster 100, Milk Specialties Co., Dundee, IL), calcium salts of long-chain fatty acids (UNS; Megalac, Church and Dwight Co. Inc., Princeton, NJ), or no added dietary fat (control), with fat sources included to provide 1.2% added fat (dry matter basis). Treatment periods were 21 d; milk and feed samples were collected and milk yield and feed intake were recorded for the last 4 d of each period. Results were analyzed with mixed models with pen as the experimental unit, and orthogonal contrasts were employed to evaluate the overall effect of added fat and the effect of fat source. Dry matter intake and milk yield tended to increase with added fat. Protein content decreased with fat supplementation, to a greater degree for UNS than for SAT, but protein yield was not affected. Fat content, fat yield, and energy-corrected milk yield were not affected by treatment. Conversion of feed to milk tended to increase for UNS compared with SAT. Fat supplementation to diets high in nonforage fiber had effects that were similar to those reported for more traditional lactation diets, except for the dry matter intake response.     

Synbiotic sheep milk ice cream reduces chemically induced mouse colon carcinogenesis

Sheep dairy products containing prebiotic and probiotic ingredients may have health-promoting properties. Thus, this study evaluated the effects of sheep milk ice cream [conventional full-fat (CONV), full-fat enriched with probiotic (PROB, 100 mg % wt/wt of Lacticaseibacillus casei 01), or nonfat synbiotic (SYNB, Lacticaseibacillus casei 01 and inulin, 10% wt/wt)] on carcinogen-induced colonic crypt cytotoxicity and premalignant lesion development. Male Swiss mice received 2 doses of colon carcinogen azoxymethane (AOM, 15 mg/kg of body weight) at wk 3 and 4. Two weeks before and during AOM administrations (4 wk) mice were treated with CONV, PROB, or SYNB by gavage (10 mL/kg). Mice were euthanized at wk 4 or 25 (n = 5 or 10 mice/group, respectively). At wk 4, a significant reduction in micronucleated colonocytes was observed in PROB and SYNB groups, and a significant decrease in both p53 expression and apoptosis indexes in colonic crypts was observed in SYNB group. At wk 25, both PROB and SYNB interventions reduced the mean number of colonic premalignant lesions. However, only SYNB group showed lower incidence and number of high-grade premalignant lesions in the colonic mucosa. These findings indicate that PROB or SYNB sheep milk ice cream, especially SYNB intervention, can reduce chemically induced mouse colon carcinogenesis.     

不同酸奶脂肪营养价值的评价及其影响因素

酸奶因对人体的多种健康作用成为健康饮食的标志,提高酸奶营养与健康功能成为研发新产品的重要内容.在分析烧酸奶(A组)、益生菌酸奶(B组)、普通酸奶(C组)脂肪酸分布及其营养价值差异基础上,探讨了原料脂肪、前处理工艺、发酵剂、乳酸菌数量对脂肪营养价值的影响.结果显示,三类酸奶具有相同的脂肪酸组成和无统计学差异的饱和脂肪酸(...     

中老年低脂高纤牛奶的研制

巴氏杀菌低脂高纤牛奶是根据中老年人群的生理特点，合理调配多种维生素、矿物质、增加膳食纤维、降低牛奶中的脂肪含量，采用合理的巴氏杀菌生产工艺，最大程度的保证产品的营养物质，该产品具有口感佳、产品稳定性好、营养物质高等特点。     

Whole grains — impact of consuming whole grains on physiological effects of dietary fiber and starch

Much of the present research on the physiological effects of dietary fiber and starch has been done on sources isolated from the parent material, and it is not clear whether they have the same effects if fed in the intact or whole grain. For dietary fiber, physiological effect depends on extent of fermentation in the large intestine, and this is influenced by chemical composition, solubility, physical form, and presence of lignin or other compounds. All of these factors are altered by isolation of a fiber source from the whole grain, and hence effects of eating fiber vary. Similarly, physical form and presence in the whole grain will affect digestibility of starch in the small intestine, which in turn influences the glycemic response and colonic effects determined by the extent of malabsorption and entry into the colon. Starch that enters the colon is fermented and produces short‐chain fatty acids, particularly butyrate, which is necessary to maintain a healthy mucosa. Hence, their presence within the whole grain may have important implications for health for both dietary fiber and starch. Evidence indicates that such effects are beneficial and that whole‐grain consumption should be encouraged.     

下关生沱茶的HT-29人体结肠癌细胞的体外抗癌效果

对2005年,2007年和2009年产下关生沱茶,进行HT-29结肠癌细胞体外抗癌效果评价,通过MTT试验、细胞生长率试验和RT-PCR分析验证其抗癌效果。200μg／mL质量浓度下2005年产下关生沱茶（85％）表现出对HT-29结肠癌细胞最强的生长抑制效果。RT—PCR检查Bax,Bcl-2基因表达情况显示2005年产下关生沱茶对HT-29结肠癌细胞有最强的诱其凋亡的能力。由此得出,储存时间越长的沱茶具有更好的抗癌预防效果。     

藕渣不溶性膳食纤维和菊粉混合添加对广式香肠品质的影响

为探究藕渣不溶性膳食纤维(insoluble dietary fiber,IDF)和菊粉可溶性膳食纤维混合添加对广式香肠品质的影响,在单因素试验的基础上进行混料试验,筛选出两个优化组,对比两个优化组和对照组广式香肠的烘烤时间、L*值、感官品质和风味.结果显示:两个优化组广式香肠(藕渣IDF、菊粉、脂肪的添加量分别为0....     

谷物膳食纤维与结肠健康

膳食纤维(DF)为微生物生长提供均衡的能量和营养,这是维持结肠生态系统平衡所必需的。另外,膳食纤维的发酵,特别是丁酸发酵,有利于结肠健康。目前,结肠癌、炎症性肠炎和其他结肠紊乱疾病已经严重影响身体健康。作者综述了谷物膳食纤维中非淀粉谷物多聚糖、抗性淀粉,通过发酵产物短链脂肪酸和菌群的调节对于结肠健康的影响。     

碱法提取荞麦壳中膳食纤维

以荞麦壳为原料,采用氢氧化钠浸泡方法,对荞麦壳中膳食纤维进行提取,得出提取最佳工艺为:料液比为1:14,碱解时间为60 min,碱解温度为45℃,NaOH质量分数为4%。在此条件下,荞麦壳中水不溶性膳食纤维持水力为332.25%,膨胀力为6.4875 ml/g,膳食纤维含有较低蛋白质、脂肪,且无淀粉检出。     

单糖链和双糖链大豆皂甙对结肠癌细胞增殖和凋亡的影响

反相柱层析法从大豆胚轴提取单糖链大豆皂甙和双糖链大豆皂甙,研究其抗结肠癌细胞增殖的作用。MTT比色法观察大豆皂甙对结肠癌HT-29细胞增殖的影响,TUNEL法检测其对HT-29细胞凋亡的影响。结果表明,不同糖链结构的大豆皂甙均可时间和浓度依赖性地抑制结肠癌细胞增殖和诱导细胞凋亡,其中单糖链大豆皂甙的诱导细胞凋亡作用更明显。大豆皂甙可通过诱导结肠癌细胞凋亡发挥抗结肠癌作用,其抗肿瘤作用机制以及抗肿瘤作用与糖链结构之间关系需进一步的探讨     

膳食纤维抗癌作用及其分子机理的研究进展

综述了膳食纤维流行病学和动物实验方面的抗癌证据,以及膳食纤维的量与不同类型癌症发生率的关系,分析了膳食纤维通过排毒、消炎、肠道菌群和脂代谢的调控参与抗癌的机理;在分子细胞水平,总结了膳食纤维对癌细胞周期阻滞和促使癌细胞凋亡的分子机理,以及其对癌变信号通路的调控。近年来的研究发现,膳食纤维具有抗肥胖、抗心脑血管疾病、消炎和抗糖尿病等生理功能,已成为维系人类身体健康、不能被其它物质所替代的一种营养素,被誉为人体的\"第七营养素\"。本文将为深入研究膳食纤维的抗癌分子机理和进一步开发膳食纤维功能性食品提供参考。     

Germination of Cereal Grains as a Way to Improve the Nutritional Value: A Review

Whole grain cereals have been found to be a good source of nutritionally valuable substances, such as antioxidants, minerals, vitamins, and dietary fiber. A wide range of these compounds is affected by germination. While some compounds, such as beta-glucans are degraded, others, like vitamins can be increased by means of malting. Therefore, germination and malting of cereals is a way not only to produce fermentable extract for the brewing and distilling industries, but can also be a way to produce ingredients enriched with health promoting compounds. Malt extracts have also been shown to be good substrates for the growth and application of probiotic bacteria.     

玉米皮膳食纤维性质的研究

以玉米皮为原料,分别制备A(玉米皮水不溶性膳食纤维)和B(混合玉米皮膳食纤维)。通过对比A和B的持水力、膨胀力、吸油力以及对胆固醇、亚硝酸根离子的吸附能力这些指标来研究玉米皮膳食纤维的性质。试验结果表明:B的性能优于A。B的持水力和吸油力比A分别高出20.21%和9.87%;A的膨胀力比B高出4.14%;随着pH值的不断增大,膳食纤维对胆固醇的吸附能力增强,在pH7时B对胆固醇的吸附能力比A提高了约33.33%;溶液中残余亚硝酸根离子的浓度随着时间延长而呈下降趋势,并且pH值对样品吸附亚硝酸根离子的能力有较大的影响,在60 min时A和B在pH2时吸附亚硝酸根离子的浓度均比在pH7时高出46.72μmol/L。     

改性燕麦麸的保健营养功效初探

介绍了以燕麦麸为原料,经现代食品加工技术精制而成的新型保健食品－高纤麦维素。总膳食纤维含量高达30％,可溶性膳食纤维9．56％,其中主要成分为β－葡聚糖。在高脂饲料中添加本品10％,饲喂高脂模型大鼠4周,结果：大鼠血脂TC、TG、LDL－C值显著低于对照组,HDL－C值略有提高。利用核素^67Ga直结肠通过显像观察,可显著改善肠蠕动功能,迅速通便。     

纯天然功能性橘子纤维在食品品质提升,成本节约和营养强化方面的应用

橘子纤维作为纯天然功能性食品原料源白美国佛罗里达橘子原浆,目前行销世界各国并已经开始进入中国市场.独创的纯天然加工工艺赋予橘子纤维独特的功能性包括持水性,乳化性,脂肪替代,黏度控制等.其强大的功能性和纯天然绿色食品的本质使其在各个食品行业尤其是烘培业,肉制品,乳产品,方便食品,酱料和饮料方面得到广泛的应用.本文旨在用科学的数据从生产科技,产品组分和具体应用来阐明橘子纤维的特点和优势,从而帮助广大中国食品生产商了解产品如何帮助提升产品品质,节约成本和强化营养.     

The effect of dietary fiber level on milk fat concentration and fatty acid profile of cows fed diets containing low levels of polyunsaturated fatty acids

The objective of this study was to investigate the effect of dietary fiber level on milk fat concentration, yield, and fatty acid (FA) profile of cows fed diets low in polyunsaturated fatty acid (PUFA). Six rumen-fistulated Holstein dairy cows (639 ± 51 kg of body weight) were used in the study. Cows were randomly assigned to 1 of 2 dietary treatments, a high fiber (HF; % of dry matter, 40% corn silage, 27% alfalfa silage, 7% alfalfa hay, 18% protein supplement, 4% ground corn, and 4% wheat bran) or a low fiber (LF; % of dry matter, 31% corn silage, 20% alfalfa silage, 5% alfalfa hay, 15% protein supplement, 19% ground wheat, and 10% ground barley) total mixed ration. The diets contained similar levels of PUFA. The experiment was conducted over a period of 4 wk. Ruminal pH was continuously recorded and milk samples were collected 3 times a week. Milk yield and dry matter intake were recorded daily. The rumen fluid in cows receiving the LF diet was below pH 5.6 for a longer duration than in cows receiving the HF diet (357 vs. 103 min/d). Neither diet nor diet by week interaction had an effect on milk yield (kg/d), milk fat concentration and yield, or milk protein concentration and yield. During wk 4, milk fat concentration and milk fat yield were high and not different between treatments (4.30% and 1.36 kg/d for the HF treatment and 4.31% and 1.33 kg/d for the LF treatment, respectively). Cows receiving the LF diet had greater milk concentrations (g/100 g of FA) of 7:0; 9:0; 10:0; 11:0; 12:0; 12:1; 13:0; 15:0; linoleic acid; FA <C16; and PUFA; and lower concentrations of iso 15:0; 18:0; trans-9 18:1; cis-9, trans-11 conjugated linoleic acid (CLA); trans-9, cis-12 18:2; 20:0; and cis-9 20:1 compared with cows receiving the HF diet. Milk concentrations (g/100 g of FA) of total trans 18:1; trans-10 18:1; trans-11 18:1; trans-10, cis-12 CLA, and trans-9, cis-11 CLA were not different between treatments. The study demonstrated that cows fed a diet low in fiber and low in PUFA may exhibit subacute ruminal acidosis and moderate changes to milk fatty acid profile but without concomitant milk fat depression. The changes in FA profile may be useful for the diagnosis of SARA even in the absence of milk fat depression.