酶水解制备山药皮可溶性膳食纤维及性能测定

本研究以山药皮为原料研究纤维素酶法制备可溶性膳食纤维工艺条件,研究考察了料液比、加酶量、提取时间、提取温度、醇沉时间等因素,确定最佳工艺条件为:料液比1∶30、酶添加量4 U/m L、提取时间2 h、提取温度50℃,醇沉时间4 h。通过响应面法对工艺条件进一步优化,确定料液比1∶35,酶添加量5 U/m L,温度48℃时,SDF制备率最高达22.87%,较初始SDF含量7.96%提高近3倍。同时对制备的SDF性能进行测定,其持水性可达到10.74 g/g,溶胀力为6.45 m L/g,具备了一定的工业应用潜力。     

酶法提取分离甘薯渣可溶性膳食纤维的研究

目的:提高甘薯渣中可溶性膳食纤维含量.方法:以干燥、粉碎的甘薯渣为原料,利用纤维素酶将原料中不可溶性膳食纤维转化为可溶性膳食纤维,同时用淀粉酶,糖化酶和碳酸钠去掉杂质,酒精沉淀,从而获得可溶性膳食纤维.结果:在单因素基础上通过正交实验确定最佳酶法提取可溶性膳食纤维条件为淀粉酶100μl,纤维素酶90μl,pH为5.6,酶作用时间为3 h,反应温度为40℃.国标法提取的甘薯渣中可溶性膳食纤维含量为10.06%,正交实验优化提取条件后得到的甘薯渣可溶性膳食纤维含量为25.52%,提高了15.46%.结论:甘薯渣可溶性膳食纤维含量受纤维素酶,淀粉酶,酶提取时间,酶反应pH,反应温度等提取工艺影响.     

菌物膳食纤维研究

菌物已成为膳食纤维开发和利用的新的潜在资源。为了进一步开发和利用菌物中的膳食纤维资源,作者对目前的研究成果进行了综述,包括膳食纤维的概念、生理活性和分析方法、及菌物中膳食纤维的化学组成、开发利用等方面内容。     

甘薯膳食纤维酶法改性及其特性研究

采用纤维素酶和木聚糖酶相结合,对甘薯膳食纤维进行改性研究。通过单因素试验和正交试验优化甘薯膳食纤维酶法改性工艺条件,并对改性前后膳食纤维的理化特性和抗氧化活性进行分析研究。结果表明：甘薯膳食纤维酶法改性中,纤维素酶最适添加量1.2%,木聚糖酶最适添加量1.6%,最佳酶解时间30 min,最适料液比1∶11,获得的可溶性膳食纤维得率为8.84%。与天然膳食纤维相比,改性后的甘薯膳食纤维持油力上升,膨胀力和持水力下降（P<0.05）。同时,酶法改性显著提高了甘薯膳食纤维对DPPH的清除能力,增强了甘薯膳食纤维的功能特性。     

双挤压膨化可提高对麦麸膳食纤维的溶解性

采用双螺杆挤压膨化机处理添加了0%、10%、20%、30%玉米的小麦麸皮及100%玉米的样品,提取各组样品中的水溶性膳食纤维（SDF）、水不溶性膳食纤维（IDF）、总麦麸纤维（TDF）,从而选出SDF含量最高的一组,并测定了100%麦麸与添加20%玉米样品的组分,研究了由该两组样品提取出来的SDF的物理性质。结果表明：水溶性麦麸纤维有了很大的变化,其中添加20%玉米的样品组相对于其他样品组提高了4.33%~7.00%,被改性的物质主要是不溶性纤维中的半纤维素。由添加20%玉米的样品组得到的SDF相对于同条件下未添加玉米的样品组的膨胀力由0.100 4增长到2.291 0mL/g,保水能力由2.098 9增长到4.274 6g/g,水溶解度由79.29%增长到84.02%。     

膳食纤维及其生理保健作用的研究进展

膳食纤维被称为“第七营养素”,是过去30年来的研究热点。本文参考近5-6年来的最新研究成果,综述了膳食纤维的定义、成分及测定方法,膳食纤维的理化特性、生理保健作用、适宜推荐量及其应用现状和发展前景,对人们全面认识膳食纤维与人体健康的关系有较大的参考价值。     

益生菌联合膳食纤维改善便秘

目的 建立标准化的洛哌丁胺诱导的大鼠便秘模型,分别使用益生菌、膳食纤维以及益生菌联合膳食纤维对模型进行干预,用以探讨益生菌联合膳食纤维对便秘的改善作用及其机制。方法 洛哌丁胺腹腔注射（5 mg/kg）,连续5 d,建立大鼠便秘模型,益生菌（2 mL/只）,膳食纤维（1 g/kg）,益生菌联合膳食纤维（2 mL/只）干预7 d。造模5 d后,通过观察各组大鼠的粪便性状以及检测其粪便含水率,用以判断造模是否成功。第12天通过碳粉推进率实验检测各组大鼠小肠推进率。利用PCR-DGGE指纹图谱技术分析各组菌群多样性的改变。ELISA法测定各组大鼠结肠组织样品中VIP、P、Cl-、Ca2+浓度。Western blotting实验方法对各组大鼠结肠组织中AQP3、C-Kit进行含量检测。RT-PCR实验方法测定各组大鼠结肠组织中PKA、NK1的含量变化。应用Na+-K+-ATP酶活性测定试剂盒对各组大鼠结肠组织中Na+-K+-ATP酶活性进行测定。结果 造模后模型组大鼠粪便干结呈颗粒状,粪便含水率显著下降,提示造模成功。经益生菌、膳食纤维以及益生菌联合膳食纤维干预7 d后,与经自然恢复的便秘模型组相比,各组大鼠肠道菌群多样性升高,更接近正常大鼠,小肠推进率、VIP、P、Cl-、Ca2+、AQP3、C-kit、PKA、NK1以及Na+-K+-ATP酶活性均有不同程度的恢复,而其中益生菌联合膳食纤维组效果最为显著。结论 益生菌和膳食纤维均可不同程度的改善便秘,而益生菌联合膳食纤维可显著改善便秘。     

益生菌联合膳食纤维改善便秘

摘要：便秘是由多种病理因素引起的一种慢性肠道紊乱症状,严重影响人们的生活质量。目前改善便秘除了饮食方式的改变,适当的运动,常用的方式是从肛门用润滑通便剂,或口服致泻性药物,但是这些药物会带来一些潜在的副作用。因此寻找作用温和的缓解和治疗便秘的药物具有重要的临床意义。本文主要对益生菌和膳食纤维以及二者联合使用对便秘的改善作用进行探讨。     

膳食纤维与肠道健康

由于食物的精加工和生活习惯改变,运动减少,现代人的肠道健康状况下降,肠道疾病发病率不断增加,这已经影响到人们的身体健康和日常生活。肠道疾病的发生多与有毒有害物质在肠道内过久滞留,引起肠道环境改变恶化,进而损伤肠道细胞并引发各类炎症有关。本研究综述了59篇有关于膳食纤维和肠道相互作用的文献。研究表明摄入膳食纤维有助于促进肠道蠕动,保持大便顺畅,防止便秘,清除肠道内的有毒有害物质,保持肠道清洁和促进肠道内的益生菌生长等功效。而且,膳食纤维对肠易激综合征,炎症性肠病和肠癌等常见肠道疾病也具有一定的预防和治疗作用。综上,膳食纤维的摄人有益于保持肠道正常生理功能,修复和改善受损肠道环境,对于维护肠道健康有重要意义。     

从米糠中提取降血管紧张素转换酶抑制剂

采用盐析法提取米糠蛋白,分别选用胃蛋白酶、胰蛋白酶、木瓜蛋白酶等单独或联合水解米糠蛋白,以从酶解米糠蛋白中分离获得具有血管紧张素转换酶（ACE）抑制活性的短肽组分。经Sephadex G-15凝胶层析和SP—Sephadex C-25离子交换层析分离各酶解组分,并检测各组分的ACE抑制活性。结果表明,米糠蛋白的酶解分离产物中含有较强ACE抑制活性的组分,其中经胃蛋白酶和胰蛋白酶共同水解时得到的小分子量寡肽组分的抑制活性最强,为后续对其进行结构分析奠定了基础。     

麦麸替代玉米对蛋鸡生产性能和蛋品质的影响

本试验旨在研究用部分麦麸替代基础日粮中的玉米对蛋鸡生产性能的影响。选取24周龄的海兰褐蛋鸡600只,随机分为5组,每组6个重复,每个重复20只。对照组饲喂基础日粮,试验组分别饲喂麦麸替代基础日粮中玉米的5%,10%,15%,20%的试验日粮,预饲期7 d,正式试验期35 d。结果表明:麦麸替代玉米提高了平均日采食量、平均蛋重、产蛋率、料蛋比、蛋比重和哈夫单位(P<0.05)。试验表明,麦麸替代玉米,可以提高蛋鸡生产性能,改善蛋品质,且替代10%的玉米效果最佳。     

米糠蛋白抗氧化活性肽的制备

以水解度(DH％)和对DPPH自由基清除率为指标,筛选出制备米糠蛋白抗氧化活性肽的最适蛋白酶.研究最适蛋白酶的酶解条件,探讨底物浓度、蛋白酶的加入量、pH值、酶解时间等因素对水解度(DH％)和DPPH自由基清除率的影响;在单因素基础上采用Box-Behnken响应曲面中心组合设计法,对酶解米糠蛋白的工艺进行优化.试验结果表明,在加酶量13970.82 U/g,时间3.05h,底物浓度4.97％的水解条件下,米糠蛋白的水解度能够达到23.67％,活性肽对DPPH自由基清除率达到64.26％.     

Preventive Effect of Germinated Barley Foodstuff on Diarrhea Induced by Water-soluble Dietary Fiber in Rats

We investigated the preventive effect of germinated barley foodstuff (GBF) added to the diet on diarrhea induced by the dietary water-soluble dietary fibers, polydextrose, hemicellulose, and poly-acrylic acid sodium salt, in Sprague-Dawley rats. The minimum content of GBF necessary for blocking diarrhea was 3% (by weight) of the diet.

Since GBF is mainly derived from the aleurone and scutellum of malted barley, we assessed the physiological effects of the aleurone and scutellum fractions derived from barley grains before and after germination. The addition of fractions containing only germinated barley, and not barley collected before germination, increased the fecal output and jejunal mucosal protein content. The effects of malted barley were very similar to those of GBF.

It was concluded that germination was necessary to bring about the physiological effects of GBF. Since non-lignified hemicellulose and Gin-rich protein were newly synthesized during germination, these might have contributed to the increased fecal output and jejunal mucosal protein content.     

生物酶法提取米糠蛋白的研究进展

米糠蛋白具有低过敏性、营养价值高等突出优势,是一种新型的优质植物蛋白。米糠蛋白一般以米糠为原料,主要提取方法有碱法提取、物理法提取以及生物酶法提取等,其中,生物酶法由于反应条件温和、蛋白产品品质高等优势备受关注。针对此,本文对生物酶法提取米糠蛋白方法进行了综述,包括酶制剂种类以及酶用量、温度、pH值和料液比等因素对酶解反应的影响规律等,并对生物酶法提取米糠蛋白的前景进行了展望。     

Co-production of Schizophyllan and Arabinoxylan from Corn Fiber

Schizophyllum commune strain ATCC 38548 grew well on a medium containing alkaline H₂O₂-pretreated corn fiber as a sole carbon source, and clarified the culture medium within 7 days. The strain preferentially utilized the starch component of corn fiber for growth and production of schizophyllan. Culture supernatants contained approx. 50 mg schizophyllan and 200 mg arabinoxylan per g corn fiber. These polysaccharides were recovered separately by differential precipitation with ethanol. USDA - Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. Revisions requested 29 November 2005; Revisions received 24 January 2006     

Long-term Effects of Water-soluble Corn Bran Hemicellulose on Glucose Tolerance in Obese and Non-obese Patients: Improved Insulin Sensitivity and Glucose Metabolism in Obese Subjects

We examined the effect of soluble corn bran hemicellulose (CBH, 10g/day) on glucose control and serum insulin in three groups: patients with impaired glucose tolerance (IGT) with (20 subjects) or without (8 subjects) obesity and with healthy non-obese controls (10 subjects). Long-term supplementation (6 months) with CBH decreased the post oGTT curve for patients with impaired mild Type II diabetes, but not that for the controls. Hemoglobin A_1c decreased significantly during CBH supplementation in the obese patients, while the fasting glucose level decreased in all three groups, although not significantly. A decreased serum insulin response by oGTT was found in those patients with IGT.

The improved oGTT result was associated with improved insulin release and perhaps with peripheral insulin sensitivity. These findings suggest that CBH at a low dose might contribute to glycemic control and would play a useful role in treating Type II diabetes patients.     

Comparative Effects of Dietary Fat Types on Hepatic Enzyme Activities Related to the Synthesis and Oxidation of Fatty Acid and to Lipogenesis in Rats

The effects of different types of dietary fat on the activities of hepatic enzymes related to fatty acid synthesis {glucose-6-phosphate dehydrogenase (G6PDH) and acetyl-CoA carboxylase ACC)}, oxidation {acyl-CoA synthetase (AST), carnitine palmitoyl transferase (CPT), and peroxisomal β-oxidation (P βOX)}, and lipogenesis {phosphatidate phosphohydrolase (PAP), diacylglycerol acyltransferase (DGAT), and phosphocholine diacylglycerol transferase (PCDGT)}, and plasma and liver lipid levels were investigated in male Wistar rats. The animals were 6 weeks old and about 120 g of body weight, and were fed on test diets containing 20% of a mixture of tripalmitin, tristearin and corn oil (SFA), olive oil (OLI), sunflower oil (SUN), linseed oil (LIS), and sardine oil (SAR) for 2 weeks. The concentrations of plasma total cholesterol (T-CHOL), high-density lipoprotein-cholesterol (HDL-CHOL), triacylglycerol (TG) and phospholipid (PL) were generally higher in the rats fed on SEA and OLI than in those given SUN, LIS and SAR. The rats fed on OLI had a higher level of liver T-CHOL than those fed on the other fats. The liver TG content was nearly higher from the intake of SFA and OLI than from SUN, LIS and SAR, although the liver PL level was not affected by the type of dietary fat. The SFA and OLI groups had the highest activities of hepatic G6PDH and ACC, and the SAR group, the lowest activities. The activities of AST and CPT, and peroxisomal P βOX in the liver were higher in the rats fed on the LIS and SAR diets than in those given the other diets. The hepatic PAP activity was higher from the intake of OLI and SUN, and tended to be higher from SFA than from LIS and SAR. The activity of liver DGAT was higher from SFA and inclined to be higher from OLI, SUN, and LIS than from SAR, while the PCDGT activity in the liver was not effected by the type of dietary fat. The concentrations of plasma and liver TG were generally positively correlated with the activities of liver enzymes related to the synthesis of fatty acids and lipids, and negatively with those involved in fatty acid oxidation. Based on these results, it is suggested that the levels of plasma and liver TG were controlled by different types of dietary fat through changes in the hepatic enzyme activities related to fatty acid synthesis, lipogenesis, and fatty acid oxidation.     

响应面法优化米糠淀粉酶法水解工艺

以米糠为原料,对米糠淀粉酶法水解生产葡萄糖的液化工艺进行研究和优化,来提高葡萄糖收率。在单因素试验的基础上,用响应面法对液化工艺进行优化。结果表明,液化工艺的最佳条件为酶用量0.11%、醪浓度25%、pH=6.0、温度88℃,在此条件下得到的液化葡萄糖值(即DX值)平均值为6.54%。然后对此液化液进行糖化,最终得到的糖化液DX值为97.07%。     

车前草可溶性膳食纤维的提取及其对自由基清除能力的研究

本文采用超声技术提取车前草中可溶性膳食纤维;通过单因素及L9(34)正交实验获得提取最佳工艺,即用固液比1:30,pH为4的0.2 M乙酸-乙酸钠缓冲液提取,提取时间为20 min。车前草水溶性膳食纤维对.OH-自由基有较强的清除能力,其IC50为0.323 mg/mL;对.O2-和DPPH的最高清除率分别为19.2%和13.7%。