Dietary Fiber Polysaccharides Research Articles

Study on the Digestive Behavior of Chlorogenic Acid in Biomimetic Dietary Fiber and the Antioxidative Synergistic Effect of Polysaccharides and Chlorogenic Acid.

Chlorogenic acid (CA) is often combined with dietary fiber polysaccharides in plant foods, which may affect its digestive behavior and antioxidant activity. This study constructed a biomimetic dietary fiber (BDF) model by combining bacterial cellulose (BC) and pectin with CA and investigated the digestive behavior of CA in BDF. Additionally, the study examined the interaction and synergistic effects of polysaccharides and CA against oxidation. Results showed that BDF and natural dietary fiber had similar microstructures, group properties, and crystallization properties, and polysaccharides in BDF were bound to CA. After simulated gastrointestinal digestion, 41.03% of the CA existed in a conjugated form, and it was possibly influenced by the interaction between polysaccharides and CA. And the release of CA during simulated digestion potentially involved four mechanisms, including the disintegration of polysaccharide-CA complex, the dissolution of pectin, escape from BC-pectin (BCP) network structure, and diffusion release. And polysaccharides and CA may be combined through noncovalent interactions such as hydrogen bonding, van der Waals force, or electrostatic interaction force. Meanwhile, polysaccharides-CA combination had a synergistic antioxidant effect by the results of free-radical scavenging experiments, it was probably related to the interaction between polysaccharides and CA. The completion of this work has a positive significance for the development of dietary intervention strategies for oxidative damage.

An approach for evaluating the effects of dietary fiber polysaccharides on the human gut microbiome and plasma proteome

Increases in snack consumption associated with Westernized lifestyles provide an opportunity to introduce nutritious foods into poor diets. We describe two 10-wk-long open label, single group assignment human studies that measured the effects of two snack prototypes containing fiber preparations from two sustainable and scalable sources; the byproducts remaining after isolation of protein from the endosperm of peas and the vesicular pulp remaining after processing oranges for the manufacture of juices. The normal diets of study participants were supplemented with either a pea- or orange fiber-containing snack. We focused our analysis on quantifying the abundances of genes encoding carbohydrate-active enzymes (CAZymes) (glycoside hydrolases and polysaccharide lyases) in the fecal microbiome, mass spectrometric measurements of glycan structures (glycosidic linkages) in feces, plus aptamer-based assessment of levels of 1,300 plasma proteins reflecting a broad range of physiological functions. Computational methods for feature selection identified treatment-discriminatory changes in CAZyme genes that correlated with alterations in levels of fiber-associated glycosidic linkages; these changes in turn correlated with levels of plasma proteins representing diverse biological functions, including transforming growth factor type β/bone morphogenetic protein-mediated fibrosis, vascular endothelial growth factor-related angiogenesis, P38/MAPK-associated immune cell signaling, and obesity-associated hormonal regulators. The approach used represents a way to connect changes in consumer microbiomes produced by specific fiber types with host responses in the context of varying background diets.

Mechanistic insights into consumption of the food additive xanthan gum by the human gut microbiota.

Processed foods often include food additives such as xanthan gum, a complex polysaccharide with unique rheological properties, that has established widespread use as a stabilizer and thickening agent. Xanthan gum's chemical structure is distinct from those of host and dietary polysaccharides that are more commonly expected to transit the gastrointestinal tract, and little is known about its direct interaction with the gut microbiota, which plays a central role in digestion of other dietary fibre polysaccharides. Here we show that the ability to digest xanthan gum is common in human gut microbiomes from industrialized countries and appears contingent on a single uncultured bacterium in the family Ruminococcaceae. Our data reveal that this primary degrader cleaves the xanthan gum backbone before processing the released oligosaccharides using additional enzymes. Some individuals harbour Bacteroides intestinalis that is incapable of consuming polymeric xanthan gum but grows on oligosaccharide products generated by the Ruminococcaceae. Feeding xanthan gum to germfree mice colonized with a human microbiota containing the uncultured Ruminococcaceae supports the idea that the additive xanthan gum can drive expansion of the primary degrader Ruminococcaceae, along with exogenously introduced B. intestinalis. Our work demonstrates the existence of a potential xanthan gum food chain involving at least two members of different phyla of gut bacteria and provides an initial framework for understanding how widespread consumption of a recently introduced food additive influences human microbiomes.

Seaweeds – a potential source of food, feed and fertiliser

Many communities in the world consume naturally growing and cultivated/ farmed seaweeds as food. Currently, commercial cultivation/farming produces more than 96% of seaweeds in the world and only around 3-4% is obtained from wild harvest (noncultivated). Naturally occurring and cultivated seaweeds are categorized into green, brown and red seaweeds, based on their pigmentation. More than 200 species of seaweeds are of commercial value, but only around 10 species of seaweeds are popularly cultivated. China, Indonesia, the Republic of Korea and the Philippines are the leading producers of cultured/ farmed species (viz. Eucheuma, Japanese kelp, Gracilaria, Unndaria pinnatifid); and Chile, China and Norway for wild species (mainly brown and red) and Chilean kelp. Seaweeds are rich in dietary fiber (polysaccharides), essential amino acids, major and micronutrients (minerals), vitamins etc. It has been reported that some species are a good source of plant growth regulators. Mainly, the people in China, Japan and Korea relish the soups, stews, flakes, coatings, snacks, etc., made from seaweeds. The use of seaweeds as human food in India is not very common. The second major use of seaweeds after food is the extraction of three important hydrocolloids (Agar, Alginate and Carrageenan). These are used as food additives and in many other industrial applications. A small portion of seaweed is used as an ingredient as livestock feed and fish feed. Seaweed meal and liquid extract of seaweed have been tried in conjunction with inorganic fertilizers with beneficial effects on crop yield, quality produce and soil health. Seaweed is an important marine resource and the coastline in India can be utilized to commercially cultivate seaweed species beneficial for human health and plants. Research is required in developing functional foods, health foods and nutraceuticals from seaweeds to improve the health and nutritional status of the human population. This paper briefly describes the status of production and utilization of seaweeds in different parts of the world.

Bacteroides thetaiotaomicron.

This infographic on Bacteroides thetaiotaomicron (Bt) explores the ability of this microbe to digest a broad array of complex carbohydrates, alter its surface features, and its emerging role in gastrointestinal diseases. The infographic of Bacteroides thetaiotaomicron (Bt) illustrates two key facets of its symbiotic lifestyle in the human gut: a broad ability to digest dietary fiber polysaccharides and host glycans, and a dynamic cell-surface architecture that promotes both interactions with and evasion of the host immune system. The starch-utilization system (Sus) is a cell-surface and periplasmic system involved in starch cleavage and transport. Over 80 additional Sus-like systems utilize substrates ranging from host glycans to plant cell wall pectins. Bt has evolved intricate strategies to interact with other microbes or its host, including modification of its surface. Some nutrient utilization pathways select for or directly trigger changes in capsular polysaccharide (CPS) expression. Like other fermentative members of the gut microbiome, Bt produces host absorbable short-chain and organic acids, which can all be absorbed by the host as a source of energy.

Physicochemical attributes and starch functional properties of high β-glucan sorghum inbred line

PurposeSorghum is a vital cereal crop and staple food for many peoples around the globe having good nutritional and health-promoting bioactive compounds and recently received great attention as gluten-free food. However, sorghum grains contain low β-glucans contents, dietary fibre polysaccharides with great technological and disease prevention properties, and improving the concentration of these compounds in sorghum is very important. Thus, the purpose of this paper is to investigate the physicochemical and starch properties of high β-glucan sorghum inbred line (Tabat-NL) in comparison with two commercial cultivars (Wadakar and Tabat-C).Design/methodology/approachGrain samples of sorghum cultivars: white colour and low tannin cultivar (Tabat-C), red colour and high tannin sorghum, and new inbred line of white sorghum cultivar (Tabat-NL) were carefully cleaned, examined for physical properties (colour, hectolitre and 1,000 kernel weights, and endosperm texture), and ground to flour and assessed for chemical composition (moisture, protein, ash, carbohydrate, sugars, fibre and β-glucan contents). The starch was extracted and investigated for morphological characteristics and functional properties.FindingsThe results showed that Tabat-NL grains contain significantly (p=0.05) higher values of 1,000 kernel weight, hectolitre weight, total carbohydrate, amylopectin, dietary fibre and β-glucan compared to Tabat-C and Wadakar. Tabat-NL starch had greater (p=0.05) gelatinization temperature, viscosity, bulk density, and water and oil holding capacities and lower (p=0.05) acidity compared to Tabat-C and Wadakar.Research limitations/implicationsThe outcomes of this study demonstrated that Tabat-NL grains had an excellent marketing and milling properties, health-promoting and disease-preventing potentials, and technological features for uses in functional and speciality foods.Originality/valueTo the best of our understating, this is the first study on the evaluation of sorghum cultivar with high β-glucan content and could thus provide the bases for further development and application of this important food grains.

Mucoadhesive functionality of cell wall structures from fruits and grains: Electrostatic and polymer network interactions mediated by soluble dietary polysaccharides

We demonstrate the enhancement of intestinal mucin (Muc2) binding to plant cell wall structures from fruit (parenchymal apple tissue) and grain (wheat endosperm) mediated by soluble dietary fibers embedded within cellulose networks. Mucin binding occurs through two distinct mechanisms; for pectin polysaccharides characteristic of fruits and vegetables, it is governed by molecular mucoadhesive interactions, while for neutral polysaccharides, arabinoxylan and β-glucan characteristic of cereal grains, the interaction stems from the properties of their polymer network. Based on microrheological and microscopic measurements, we show that neutral dietary fiber polysaccharides do not adhere to intestinal mucin, but are capable of disrupting the mucin network, which facilitates interpenetration of mucin molecules into the polysaccharide mesh. This effect becomes significant in the context of ‘whole foods’, where soluble fibers are incorporated within the gel-like matrix of cellulose-reinforced plant cell wall structures. The result of mucoadhesion assay and analysis of microscopy images points to the critical role of entanglements between mucin and polysaccharides as a lock-in mechanism preventing larger mucin from escaping out of plant cell wall structures. These results provide the first indication that non-pectin soluble dietary fiber may influence mucosal interactions, mucus barrier properties, and transmucosal transport of nutrients.

Aggregation of gluten proteins in model dough after fibre polysaccharide addition

FT-Raman spectroscopy, thermogravimetry and differential scanning calorimetry were used to study changes in structure of gluten proteins and their thermal properties influenced by four dietary fibre polysaccharides (microcrystalline cellulose, inulin, apple pectin and citrus pectin) during development of a model dough. The flour reconstituted from wheat starch and wheat gluten was mixed with the polysaccharides in five concentrations: 3%, 6%, 9%, 12% and 18%. The obtained results showed that all polysaccharides induced similar changes in secondary structure of gluten proteins concerning formation of aggregates (1604cm−1), H-bonded parallel- and antiparallel-β-sheets (1690cm−1) and H-bonded β-turns (1664cm−1). These changes concerned mainly glutenins since β-structures are characteristic for them. The observed structural changes confirmed hypothesis about partial dehydration of gluten network after polysaccharides addition. The gluten aggregation and dehydration processes were also reflected in the DSC results, while the TGA ones showed that gluten network remained thermally stable after polysaccharides addition.

Effect of dietary fibre polysaccharides on structure and thermal properties of gluten proteins – A study on gluten dough with application of FT-Raman spectroscopy, TGA and DSC

The effect of four dietary fibre polysaccharides (microcrystalline cellulose (MCC), inulin (IN), apple pectin (AP) and citrus pectin (CP)) on structure and thermal properties of gluten proteins in the gluten dough was studied with application of FT-Raman spectroscopy, thermogravimetry (TGA) and differential scanning calorimetry (DSC). The commercially available wheat gluten was mixed with the polysaccharides in five concentrations: 3%, 6%, 9%, 12% and 18%. The obtained results showed that MCC, IN and small amount of pectin (3% and 6%) induced similar changes in the secondary structure of gluten proteins concerning formation of antiparallel-β-sheets connected by intermolecular hydrogen bonds from α-helices and β-sheets. Higher contents of pectin (9–18%) led to formation of aggregates and β-like aggregates. The observed changes in the secondary structure, conformation of disulphide bridges and environment of tyrosine and tryptophan of gluten proteins indicated partial dehydration of gluten network as a result of a competitive water binding by polysaccharides molecules (especially MCC and IN) during the dough mixing. TGA results also confirmed this statement. However, slightly different results were obtained for pectins. They not only competed for water with gluten proteins but also interacted with them since a thermogravimetric peak characteristic for pectin was observed in the derivative TGA profiles of gluten – pectin mixtures.

Characterization of Dietary Fiber Polysaccharides from Dehulled Common Buckwheat (Fagopyrum esculentum) Seeds

Buckwheat is a pseudocereal that has gained increasing interest of industry and consumers over the past decade. Little, however, is known about its dietary fiber composition and nonstarch polysaccharide structures. Analysis of the monosaccharide composition indicated large amounts of pectic polysaccharides in both insoluble and soluble fiber from buckwheat. Methylation analysis gave further insights into the structures of the polysaccharides. The corresponding partially methylated alditol acetates suggested only low amounts of galactans. Xyloglucans were the main hemicellulosic polysaccharides in the insoluble fiber fraction. Highly branched arabinans, exclusively substituted at position O3, were of higher abundance. These results were confirmed by screening endo‐arabinanase and endo‐galactanase liberated oligosaccharides with high‐performance anion‐exchange chromatography with pulsed amperometric detection and LC‐MS2. Application of this method also demonstrated highly branched arabinan areas within the pectic polysaccharides. Only low amounts of fiber associated hydroxycinnamic acids and diferulic acids were liberated by alkaline treatment, and no evidence was found for their attachment to polysaccharides, suggesting only a minor impact of these structural elements on fiber structures in dehulled buckwheat seeds.

Can dietary fibre help provide safer food products for sufferers of gluten intolerance? A well-established biophysical probe may help towards providing an answer

Gluten intolerance is a condition which affects an increasing percentage of the world’s population and for which the only current treatment is a restrictive gluten free diet. However could the inclusion of a particular polysaccharide, or blends of different types, help with the provision of ‘safer’ foods for those individuals who suffer from this condition? We review the current knowledge on the prevalence, clinical symptoms and treatment of gluten intolerance, and the use and properties of the allergens responsible. We consider the potential for dietary fibre polysaccharides to sequester peptides that are responsible for activation of the disease in susceptible individuals, and consider the potential of co-sedimentation in the analytical ultracentrifuge as a molecular probe for finding interactions strong enough to be considered as useful.

Kinetic analysis of bile salt passage across a dialysis membrane in the presence of cereal soluble dietary fibre polymers

The kinetics of passage of a model bile salt and complete porcine bile across a dialysis membrane, in the presence and absence of two cereal-derived soluble dietary fibre polysaccharides, were studied as a model for passage across the unstirred water layer that lines the small intestine. A first-order kinetic analysis allowed rate coefficients to be derived which quantified the effectiveness of barley mixed linkage β-glucan and wheat arabinoxylan in retarding the transport of bile. For both, a model bile salt and complete porcine bile, rate coefficients decreased with both concentration and viscosity. A combination of viscosity and molecular interaction effects is suggested to control the effect of the two polysaccharides on the transport of bile.

超声辅助提取杨梅渣膳食纤维工艺研究

利用响应面分析法(Response Surface Method)对超声辅助提取杨梅渣水溶性膳食纤维(SDF)工艺进行优化。在单因素实验的基础上，根据中心组合(Box-Benhnken)实验设计原理，采用三因素三水平的响应面分析法，以杨梅渣SDF得率为响应值进行回归分析。结果表明杨梅渣SDF的最佳提取工艺条件为：超声功率为60 W、超声时间为20.5 min、超声温度为71℃时，杨梅渣SDF的提取率为8.4%，与模型预测值基本相符。超声波辅助提取法是一种较好提取杨梅渣膳食纤维的方法。 Ultrasound-assisted extraction (UAE) of water soluble dietary fiber from Bayberry Pomace was studied. The effects of three factors on the yield of water soluble dietary fiber polysaccharides were investigated. Response surface methodology (RSM) was applied to optimize the process of extraction. Box-Benhnken experimental design was used for experimental design and data analysis was conducted to obtain the optimum extraction conditions. Results: The obtained optimum conditions were ultrasonic time 20.5 min, ultrasonic temperature 71˚C and ultrasonic power 60 W. Under the optimized conditions, the extraction yield of water soluble dietary fiber was up to 8.4%, in close agreement with values predicted by the mathematical model. Ultrasound-assisted extraction is a best method for extraction of wa- ter soluble dietary fiber from Bayberry Pomace.

Chapter 3 - Health Benefits of Algal Polysaccharides in Human Nutrition

The interest in functional food, both freshwater and marine algal products with their possible promotional health effects, increases also in regions where algae are considered as rather exotic food. Increased attention about algae as an abundant source of many nutrients and dietary fiber from the nutrition point of view, as well as from the scientific approaches to explore new nutraceuticals and pharmaceuticals, is based on the presence of many bioactive compounds including polysaccharides extracted from algal matter. Diverse chemical composition of dietary fiber polysaccharides is responsible for their different physicochemical properties, such as their ability to be fermented by the human colonic microbiota resulted in health benefit effects. Fundamental seaweed polysaccharides are presented by alginates, agars, carrageenans, ulvanes, and fucoidans, which are widely used in the food and pharmaceutical industry and also in other branches of industry. Moreover, freshwater algae and seaweed polysaccharides have emerged as an important source of bioactive natural compounds which are responsible for their possible physiological effects. Especially, sulfate polysaccharides exhibit immunomodulatory, antitumor, antithrombotic, anticoagulant, anti-mutagenic, anti-inflammatory, antimicrobial, and antiviral activities including anti-HIV infection, herpes, and hepatitis viruses. Generally, biological activity of sulfate polysaccharides is related to their different composition and mainly to the extent of the sulfation of their molecules. Significant attention has been recently focused on the use of both freshwater algae and seaweed for developing functional food by reason of a great variety of nutrients that are essential for human health.

REVIEW: Rye Arabinoxylans: Molecular Structure, Physicochemical Properties and Physiological Effects in the Gastrointestinal Tract

ABSTRACTArabinoxylans (AX) are the main dietary fiber (DF) polysaccharides in rye where they represent ≈55% of the total polysaccharides. Rye AX consist of a backbone of (1→4)‐β‐d‐xylopyranosyl residues (X) mainly substituted with α‐l‐arabinofuranosyl residues (A) to varying degrees at the O‐2 position, the O‐3 position, or both. The A/X ratio of total AX is 0.49–0.82 and extractable AX ratio is 0.34–0.85 in different studies. AX also contain small amounts of ferulate residues bound to arabinose as esters at its O‐5 position. The weight average molecular weight varies from 40,000 to 900,000 with an average of ≈200,000. AX influence physiology in different segments of the gastrointestinal tract. The complex molecular structure of rye AX makes them resistant against microbial modification in the small intestine; consequently, rye AX have a much higher influence on the viscosity in the small intestinal digesta than does β‐glucan from oats and barley. In spite of that, it has not been possible in studies with AX‐rich foods such as bread to demonstrate a significant effect on the postprandial glucose response, however, a significantly reduced insulin response has been seen. Nevertheless, addition of 6 g and 12 g of AX‐rich wheat fiber to a breakfast meal has significantly lowered postprandial glucose and insulin response. Studies with hypercholesterolemic pigs fed rye buns rich in AX have resulted in dramatic reductions in plasma total and LDL cholesterol, whereas a gender difference was seen in studies on the effect of AX on plasma lipids in humans. Only certain species of bacteria from the human gut produce the enzymes needed for the degradation of AX. Nevertheless, wheat AX stimulate prebiotic bacteria presumably brought about by cross feeding of lactobacilli and bifidobacteria with degradation products from versatile carbohydrate‐degrading bacteria. Soluble AX are readily fermented in the large intestine, the majority is broken down between the ileum and the cecum. AX, characterized by a low degree of substitution and virtually no doubly substituted xylose, are slowly degraded at more distal locations. The remaining AX, characterized by a high degree of substitution, are not degraded at all. Although the fermentation pattern of AX may vary in different experimental models, in vitro fermentation studies and in vivo intervention studies with animals and humans point to AX as substrates that enhance the formation of butyrate in the large intestine.

Mechanisms underlying the cholesterol-lowering properties of soluble dietary fibre polysaccharides

A number of studies have shown a positive relationship between diets rich in soluble dietary fibres (SDF) such as β-glucan, pectin, guar gum and psyllium, and reduced serum cholesterol and thus a decreased risk of cardiovascular disease (CVD). Three major biological mechanisms have been proposed to explain the cholesterol-reducing effects of SDF: prevention of bile salt (BS) re-absorption from the small intestine leading to an excess faecal BS excretion; reduced glycemic response leading to lower insulin stimulation of hepatic cholesterol synthesis; and physiological effects of fermentation products of SDF, mainly propionate. Evidence for the latter mechanism is inconclusive, whereas in vivo, ex vivo and in vitro experiments suggest that BS micelles "bind" to SDF preventing their re-absorption. Whereas, glycemic responses to SDF have been studied extensively, the nature of interactions between bile salt micelles and SDF that lead to incomplete BS re-absorption are poorly defined. Three potential physicochemical mechanisms are proposed together with suggestions for in vitro experiments to test them.

Enzymatic solubilization of a pectinaceous dietary fiber fraction from potato pulp: Optimization of the fiber extraction process

Upgrading of potato pulp, a byproduct stream from industrial manufacture of potato starch, is important for the continued economic competitiveness of the potato starch industry. The major part of potato pulp consists of the tuber plant cell wall material which is particularly rich in galactan branched rhamnogalacturonan I type pectin. In the work reported here, the release of high-molecular weight pectinaceous dietary fiber polysaccharides from starch free potato pulp was accomplished by use of a multicomponent pectinase preparation from Aspergillus aculeatus (Viscozyme® L). The enzyme reaction conditions for the solubilization were optimized via a surface response design to be addition of 0.27% Viscozyme® L by weight of potato pulp substrate dry matter, 1 h treatment at pH 3.5, 62.5 °C. Analysis of the molecular size and monomer composition of the enzymatically released fibers showed that they were rich in galactose and uronic acid indicating that the solubilized fibers were mainly made up of galactan branched rhamnogalacturonan I type pectin polymers.

Influence of different fibre sources on digestibility and nitrogen and energy balances in growing pigs

The present study was undertaken to investigate how three different fibre sources, sugar beet pulp, soya bean hulls and pectin residue, constituting 15% of diets for growing pigs, influenced daily body gain, feed conversion, apparent faecal digestibility and nitrogen and energy balances. Eight castrated crossbreed pigs (30 – 80 kg live weight) were used in a replicated 4 × 4 Latin-square design with one control diet and three fibre containing diets. Daily body weight gain and feed conversion were not affected by the dietary treatments. The apparent faecal digestibility of organic matter (OM) and energy were significantly lower for the fibre diets (OM: 0.81 – 0.85; energy: 0.78 – 0.83) compared to the control diet (OM: 0.88; energy: 0.86). The apparent faecal digestibility of crude protein (CP) was lower for the fibre diets (0.71 – 0.78) compared to the control diet (0.83), although it was only significantly lower for the sugar beet pulp and pectin residue diets. The pectin residue diet, which contained the highest amount of dietary fibre, lignin and insoluble non-starch polysaccharides, had the lowest digestibility of OM, CP and energy. There was a tendency (p = 0.07) for a diet effect on retained nitrogen in proportion to digested nitrogen, where the sugar beet pulp and pectin residue diets had numerically the highest values. Heat production and retained energy in proportion to metabolizable energy intake were not affected by fibre inclusion. It was concluded that the inclusion of sugar beet pulp, soya bean hulls and pectin residue in diets for growing pigs decreased the apparent faecal digestibility and in the diets with sugar beet pulp and pectin residue higher utilization of digested nitrogen for retention compensated for the lower amount of digested nitrogen.

Effects of dietary fiber on inflammatory bowel disease

The chronic idiopathic inflammatory bowel diseases (IBDs), namely Crohn's disease and ulcerative colitis, appear to be derived from an inappropriate reaction towards a luminal agent, most probably driven by the intestinal microflora, which upregulates the synthesis and release of different pro-inflammatory mediators, thus contributing to tissue damage that characterizes these intestinal conditions. Several studies have reported that IBD is associated with impairment in short-chain fatty acid (SCFA) production, mainly acetate, propionate, and butyrate. They are produced in the large bowel by anaerobic bacterial fermentation of undigested dietary carbohydrates and fiber polysaccharides, with butyrate being considered as the major fuel source for colonocytes. These SCFAs have been proposed to play a key role in the maintenance of colonic homeostasis. Therefore, it is reasonable to consider therapeutic approaches that increase colonic SCFA production, as it can be achieved by administration of dietary fiber to IBD patients. Unfortunately, there is quite limited documentation of efficacy of dietary fiber in properly designed trials. This review discusses the rationale, available evidence for the use of dietary fiber and its mechanisms of action in the treatment and prevention of IBDs.

On the possibility of using high pressure treatment to modify physico-chemical properties of dietary fibre in white cabbage ( Brassica oleracea var. capitata)

The possibility of using high hydrostatic pressure (HHP) to modify the physico-chemical properties of dietary fibre polysaccharides in white cabbage ( Brassica oleracea var. capitata) was studied. Two cultivars (Heckla and Predikant) were subjected to high pressure treatment (400 and 500 MPa) at different temperatures (20, 50 and 80 °C). The total dietary fibre (TDF) content was only slightly affected by HHP. However, considerable effects were generally seen in the distribution between soluble and insoluble fibre at increased pressure. When the pressure applied was 400 MPa, the proportion of soluble fibre in the cultivar Heckla was reduced at all temperatures. No additional effects were seen when the pressure was increased to 500 MPa. For the cultivar Predikant the pressure generally had to be increased to 500 MPa to attain the same effects. An exception was pressure treatment at 80 °C, where a pressure of 400 MPa was sufficient. The total dietary fibre content in unprocessed cabbage (0.1 MPa and 20 °C) was lower in the cultivar Heckla than in Predikant due to lower contents of insoluble polymers containing glucose and uronic acids. This was the case for most temperatures and pressures. It is concluded that the solubility of the dietary fibre in white cabbage can be affected by high pressure temperature treatment, which may be of importance when producing foods with specific health effects.