花生麸水不溶性膳食纤维的提取及其吸附亚硝酸根离子的研究

采用化学法从花生麸中提取了水不溶性膳食纤维,并用它对亚硝酸根离子进行了初步吸附实验,结果显示,花生麸水不溶性膳食纤维对亚硝酸根离子有较强的吸附能力,其最大吸附浓度Cmax高达31．12μmol／g。     

花生麸水不溶性膳食纤维的提取及其吸附亚硝酸根离子的研究

采用化学法从花生麸中提取了水不溶性膳食纤维，并用它对亚硝酸根离子进行了初步吸附实验，结果显示，花生麸水不溶性膳食纤维对亚硝酸根离子有较强的吸附能力，其最大吸附浓度Cmax高达31．12μmol／g。     

四种玉米皮膳食纤维的组分对其吸附等功能性质影响的研究

研究玉米皮膳食纤维的组分不同对其功能性质的影响。采用四种(水不溶性、水溶性、水溶性与水不溶性比例为1∶3和含游离阿魏酸)玉米皮膳食纤维(分别记作A、B、C、D)在中性条件(pH 7,模拟小肠环境)和酸性条件(pH 2,模拟胃环境)下对吸附胆固醇、亚硝酸根离子、清除羟自由基等效果进行试验研究。结果对胆固醇的吸附中性条件优于酸性条件的效果,且C>D>B>A;对亚硝酸根离子的吸附,酸性条件优于中性条件,且A>C>D>B;对清除羟自由基,D>C>B>A。得到结论为,四种玉米皮膳食纤维均可吸附胆固醇、亚硝酸根离子和清除.OH,且受膳食纤维的组分及酸碱环境影响。     

酱油渣不溶性膳食纤维的制备及其功能特性研究

以酱油渣为原料,采用酶法辅助碱法制各不溶性膳食纤维,并测定不溶性膳食纤维的膨胀性、持水力、抗脂质过氧化以及吸附亚硝酸根离子等功能特性.实验结果表明,不溶性膳食纤维制备的最佳工艺参数为:NaOH浓度为4%,碱解温度为50℃,碱解时间为70min,酱油渣不溶性膳食纤维得率达37.89%.酱油渣不溶性膳食纤维具有良好的膨胀性、持水力、抗脂质过氧化和吸附亚硝酸根离子的作用,在胃液pH值条件下,在120min时不溶性膳食纤维吸附性能趋于饱和,吸附率达到72.6%,根据模拟方程求得在48.8min吸附率达到50%.     

蔓越莓中膳食纤维的结构性质和功能性质研究

目的 考察蔓越莓中膳食纤维的结构性质和功能性质。方法 利用酶解法提取蔓越莓总膳食纤维、不溶性膳食纤维和可溶性膳食纤维, 并采用红外光谱和高效液相色谱测定其官能团结构和分子量, 采用质构仪和粘度计测定其凝胶性质和粘度, 同时对膳食纤维吸附亚硝酸根离子、交换阳离子、胆固醇、重金属和葡萄糖的能力进行研究。结果 总膳食纤维和不溶性膳食纤维的提取率较高, 分别为54.67%和38.70%, 膳食纤维具有凝胶和粘度的性质, 同时在功能上有吸附亚硝酸根离子, 交换阳离子, 吸收胆固醇, 重金属离子和葡萄糖的性能。结论 蔓越莓膳食纤维具有特殊的结构性质和很好的功能活性, 可以开发蔓越莓新功能食品。     

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。     

浒苔不溶性膳食纤维理化性质研究

研究了浒苔不溶性膳食纤维的理化性质。研究结果表明：浒苔膳食纤维的持水力为12.22g/g,膨胀力为6.40mL/g,吸附饱和脂肪的能力为11.20g/g,吸附不饱和脂肪的能力为8.65g/g,pH值7条件下基本不吸附亚硝酸根离子,pH值2条件下吸附亚硝酸根离子的能力逐渐增大,90min时为6.44mmol/g。以上研究表明浒苔膳食纤维具有较好的理化性质。     

超声波辅助浸提小麦膳食纤维及其理化性质研究

采用超声波辅助浸提法制备小麦麸皮可溶性物质和不溶性膳食纤维,并研究了不同干燥方式对不溶性膳食纤维理化性质的影响。在膨胀力方面,经过低温真空干燥的膳食纤维大于经过真空冷冻干燥的;在吸附脂肪方面,经过低温真空干燥的膳食纤维小于经过真空冷冻干燥的,而且小麦膳食纤维吸附饱和脂肪的能力明显强于吸附不饱和脂肪的能力。在吸附亚硝酸根方面,受体系的pH值影响较大,在pH值为7时,小麦膳食纤维基本不吸附亚硝酸根;而在pH值为2时,溶液中残留的亚硝酸根的含量随时间呈现明显减小的趋势,低温真空干燥处理的吸附亚硝酸盐的能力强于冷冻真空干燥所制备的膳食纤维。     

几种市售膳食纤维对脂肪、胆固醇、胆酸盐、亚硝酸根离子吸附作用的研究

目的:研究几种市售膳食纤维对脂肪、胆固醇、胆酸盐、亚硝酸根离子的吸附能力。方法:采用体外实验模拟人体胃和小肠的pH条件,以天然小麦麸为对照,测定四种市售膳食纤维制品对脂肪、胆固醇、胆酸盐、亚硝酸根离子的吸附量。结果:小麦麸和魔芋纤维吸附脂肪的能力最强;魔芋纤维吸附胆固醇的能力最强;大豆纤维吸附胆酸盐的能力最强;小麦麸吸附亚硝酸盐的能力最强。在胃pH环境下几种膳食纤维吸附亚硝酸盐的能力显著高于小肠pH环境。结论:四种膳食纤维制品均具有较强的吸附能力,但其吸附效果与天然小麦麸相差不大。     

葡萄籽水不溶性膳食纤维对胆固醇吸附的特性

以葡萄籽水不溶性膳食纤维为试验材料,以胆固醇的吸附量为指标,通过对胆固醇浓度、水不溶性膳食纤维添加量、时间、温度对胆固醇吸附效果影响的研究,旨在确定葡萄籽水不溶性膳食纤维对胆固醇的吸附特性和吸附作用机理。经测定,葡萄籽水不溶性膳食纤维具有较好的持水性(0.440 g/g)和溶胀性(2.367 mL/g)。正交试验得出,其最佳吸附条件为胆固醇浓度4.0 mg/mL、葡萄籽水不溶性膳食纤维添加量0.05 g、吸附时间90 min、吸附温度40℃,葡萄籽水不溶性膳食纤维对胆固醇的吸附量为44.634 mg/g。经正交优化,其吸附量提高了2.25倍。经研究,葡萄籽水不溶性膳食纤维对胆固醇的吸附主要包括物理吸附和化学吸附。     

Physicochemical characterisation of dietary fibre components and their ability to bind some process-induced mutagenic heterocyclic amines,Trp-P-1, Trp-P-2, AαC and MeAαC

The physicochemical properties of potato fibre, wheat bran and oat samples were investigated, along with their binding capability to heterocyclic amines (HCAs). Potato fibre displayed highest total dietary fibre content (71.8/100 g dry weight basis, dwb), followed by wheat bran (57.2/100 g dwb) and oat sample 2 (53.0/100 g dwb). Oat samples 1, 3 and 4 displayed considerably lower dietary fibre content (20.5–28.8/100 g, dwb). Oat samples 3 and 4 displayed highest soluble fibre content (70–83%), and oat sample 3 also displayed highest swelling and water retention capacity (WRC). Dietary fibre samples, except samples 3 and 4, displayed improved binding to HCAs as sample weight increased. The behaviour of wheat bran and potato fibre was similar to oat samples 1 and 2. Binding of MeAαC was comparatively greater than that of other HCAs. Dietary fibre fractions with high insoluble fibre and functional groups of HCAs may significantly contribute to the binding capacity.     

Influence of solvent extraction on the dietary fibre fractions of alfalfa protein concentrates

“Freezing curd” was prepared from alfalfa juice and extracted with 2-propanol, either untreated or after washing with water. The soluble and insoluble dietary fibre fractions of the two extracted concentrates and the unextracted freezing concentrate were analysed to assess the effect of extraction on fibre content. Compared with unextracted “freezing curd”, direct extraction with 2-propanol without washing increased the insoluble and soluble dietary fibre fractions by approximately 55% and 52% respectively, while washing with water followed by extraction with organic solvent led to an increase of about 79% and 28%, respectively. Thus, the washing with water lowered the soluble fibre by around 16%. Analysis of the ash and proteins in the crude fibre residues showed that while the ash content was similar in the residues for both the soluble and insoluble fibre, the protein content was much higher in the insoluble fibre residue.     

In vitro model to correlate viscosity and bile acid-binding capacity of digested water-soluble and insoluble dietary fibres

Binding and excretion of bile acids in the small intestine by water-soluble and insoluble dietary fibres is one of the main mechanisms for their cholesterol-lowering effects. A model for the determination of the bile acid-binding capacity of dietary fibres was developed. The experimental set-up allowed to correlate the bile acid-binding capacities of different fibres with their viscosities after in vitro digestion. For cellulose, native oat fibre and psyllium fibres clear correlations between viscosity and bile acid-binding capacity could be observed, whereas for water-insoluble lupin fibre such a correlation did not exist. Heat-damaged oat fibre also showed bile acid-binding despite of significantly decreased viscosity. The data demonstrated that bile acid-binding of digested dietary fibres may not be solely based on their viscosity but may be influenced by additional binding forces.     

Oat fibre: overview on their main biological properties

Oat is a species of cereal grain grown for its seed and widely accepted to contain many valuable constituents. These include especially fibre that posses important biological properties, particularly with regard to promotion of health, as well as to prevention of diseases. Reducing risk of coronary heart disease and plasma LDL cholesterol has, indeed, been associated with such oat fibre. The most important advances reported to date pertaining to biological properties of oat fibre are reviewed in this communication. The purpose of this review is to focus on available knowledge on the interactions between insoluble or soluble dietary fibre and lipid metabolism in the human body.     

Effect of micronised oat bran by ultrafine grinding on dietary fibre,texture and rheological characteristic of soft cheese

The purpose of this research was to study the effect of micronised oat bran on dietary fibre, textural and rheological of soft cheese. The soft cheese was processed by using the different particle size oat bran as fibre supplement, and its dietary fibre content, rheological and textural properties were determined. The results show that the micronised oat bran with 5–30 μm particle size was prepared by ultrafine grinding and passed through 60–400 mesh sieves. The soluble dietary fibre content in micronised oat bran soft cheeses was higher than that of the control (untreated oat bran soft cheeses; P < 0.05), with a maximum of 2.65 g per 100 g cheeses when oat bran was ultrafine crushed and passed through 300 mesh sieves, while the content of insoluble dietary fibre was lower than that of the control (P < 0.05). The micronised oat bran soft cheese in fermentation is a typical non-newtonian fluid. G′, G″ and apparent viscosity of soft cheeses were increased with the reduction of oat bran particle size. The chewiness and springiness of micronised soft cheeses were increased with the reduction of oat bran particle size, and were higher than that of the control (P < 0.05). The hardness and cohesiveness of micronised soft cheese were decreased with the reduction of oat bran particle size, the hardness was lower, but the cohesiveness of micronised soft cheese was higher than that of the control (P < 0.05). The 1% micronised oat bran can obtain better processing characteristics and overall acceptability for cheese products.     

Treatment with hydrogen peroxide improves the physicochemical properties of dietary fibres from Chinese yam peel

Yam is a common ‘medicine food homology’ vegetable in Asia, and its peel is often considered a food residue during processing or cooking. In this work, the effects of hydrogen peroxide modification on the dietary fibres (DFs) from Chinese yam peel (CYP) were investigated. The structural characteristics of soluble dietary fibre (SDF), insoluble dietary fibre (IDF), modified soluble dietary fibre (MSDF) and modified insoluble dietary fibre (MIDF) were analysed using Fourier-transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, granularity analysis, scanning electron microscopy and GC-MS (monosaccharide composition). As results, after modification with hydrogen peroxide, the sizes of the DFs were reduced and MIDF exposed more cellulose. Experiments on the physicochemical and functional properties of DFs showed that MSDF and MIDF obtained a better water holding capacity, oil absorption capacity, swelling capacity and absorption abilities with altered structures, which is of great importance in food processing and development.     

In vitro approach (solubility and Caco-2 uptake) to compare Cu availability from model cookies

Six model cookies were prepared in order to investigate the possibility of using whole grain raw materials other than wheat (inulin in combination with soy, amaranth, carob, apple dietary fibre or oat dietary fibre) for creating novel cookies with improved copper content and bioavailability. For assessment of copper solubility and intestinal uptake, in vitro enzymolysis approach was combined with Caco-2 cell culture technique and copper concentrations were determined using ICP-AES technique. Results indicate significant increase of the content of total and soluble Cu fractions in all modified cookies (with exception of cookies enriched with oat fibre). Average Cu solubility from investigated samples ranged from 51.6 to 68.9%. The highest Caco-2 cell uptake was determined in soy- and amaranth-enriched cookies. Total Cu content and proteins were determined as promoters of Cu absorption and transport, while addition of pure dietary fibre negatively influenced Cu uptake on the Caco-2 cell monolayer.     

Dietary fibre in fermented oat and barley β-glucan rich concentrates

The ability of different lactic acid bacteria to influence the physicochemical characteristics (content, viscosity and molecular weight) of dietary fibre in β-glucan-rich barley and oat concentrates was investigated. The cultures used were Lactobacillus acidophilus and the exopolysaccharide producing strain Pediococcus damnosus 2.6, together with the yoghurt culture, V2 (a mixture (1:1) of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus). Two methodologies, one including filtration and another centrifugation-dialysis, to quantify the dietary fibre, were compared. The centrifugation-dialysis method generally gave significantly (P<0.05) higher values than the filtration method (for example, 79.8 g/100 g DW versus 59.6 g/100 g DW for the total fibre in the native barley fibre concentrate) with the exception of soluble barley fibres. The insoluble fibre content was found to decrease after fermentation (58.8 g/100 g DW to 39.0/37.0 g/100 g DW in barley and 26.0 g/100 g DW to 4.5/3.0 g/100 g DW in oats as analysed by the centrifugation-dialysis method). The soluble fibre in the barley fibre concentrate was apparently not affected by fermentation, while contents and maximum viscosities of the soluble fibre in oat fibre concentrates decreased after fermentation. However, the molecular weight was apparently not affected.     

不同种类燕麦和苦荞中的膳食纤维测定

采用酶- 重量法分析不同产地的15 种燕麦和苦荞中总膳食纤维(TDF)、可溶性膳食纤维 (SDF)及不溶性膳食纤维(IDF)的含量。对于燕麦,TDF 含量平均为12%,其中黑龙江的米燕麦、山西的73014-336、河北的小莜麦样品含量较多,而青海的玉麦-2、宁夏的固原燕麦和云南的德钦燕麦含量较低;黑龙江的米燕麦的SDF 含量明显高于其他燕麦;河北的小莜麦和山西的73014-336 中IDF 含量较高;国外的Bup-1809 燕麦的TDF、SDF、IDF含量都低于平均值。对于苦荞,TDF 含量平均为7%,四川的额洛木尔惹苦荞的含量最高,为9.64%;贵州的90-3 苦荞的SDF 含量最高,为3.45%;四川的额洛木尔惹苦荞和山西的蔓荞子苦荞中的IDF 含量较高。酶- 重量法测定植物中膳食纤维其重现性较好,不同产地、不同种类燕麦和苦荞中膳食纤维含量与组成差异较大。     

Enrichment of ice cream with dietary fibre: Effects on rheological properties,ice crystallisation and glass transition phenomena

In the present study, the effects of four dietary fibre sources (oat, wheat, apple and inulin) on the rheological and thermal properties of model sucrose–polysaccharides solutions and ice cream mixes were investigated. The content of fibre in insoluble compounds increased significantly the viscosity and the shear thinning behaviour of the model solutions and ice creams, due to the increase of total solids and the formation of networks comprised of hydrated cellulose and hemicellulose. The increase of soluble material did not alter significantly the rheology of the samples but limited the freezing point depression and elevated the glass transition temperatures, indicating a potential cryoprotective action. The use of oat and wheat fibre favoured viscosity development due to water-binding, whereas inulin caused a remarkable increase of glass transition temperature (T_g) in model solutions and ice cream mixes, indicating the reduction of water molecule mobility from the bulk aqueous phase to the ice crystals’ surface. Apple fibre addition greatly increased viscosity and elevated the T_g values, particularly in the presence of proteins. Thus, our results suggest the potential use of dietary fibres as crystallisation and recrystallisation phenomena controllers in frozen dairy products.