Cholesterol-lowering properties of oats: Effects of processing and the role of oat components

The cholesterol-lowering effect of oats has been studied for almost fifty years. The effect has hitherto essentially been associated with its content of β-glucans, the primary soluble dietary fibre in oats. Few studies have been published regarding the extent to which other oat components may contribute to the effect and how processing of oats may influence the cholesterol-lowering properties. The objective with the current thesis was to increase the knowledge in this area, and was intended to provide a basis for the development of new functional foods from oats, with optimised cholesterol-lowering properties. For this purpose, different oat products or fractions of oats were produced, characterised and evaluated in mice. The wild-type mouse strain C57BL/6 fed an atherogenic diet was shown to be an appropriate tool for evaluation of effects on plasma cholesterol, although substrain differences in response to oats were found. When oat bran was processed to different average molecular weight of β-glucans and then evaluated in C57BL/6NCrl mice, all products were found to lower plasma cholesterol to the same degree as untreated oat bran. This was also seen for a second mouse model (LDL-receptor deficient mice), although in this case there was a small but statistically significant decline in effect with reduced average molecular weight of β-glucans. It could, however, not be excluded that other components, apart from the β-glucans, might have contributed to the effects on plasma cholesterol in these studies. Indeed, the cholesterol-lowering effect of oat bran, was found to be attributed to two complementary fractions: an oat bran oil and a β-glucan containing fraction, which supported previously published studies that components other than β-glucan may be of importance. The effect of the oat bran oil was shown not to be caused by the content of unsaturated fatty acids, but by other components. An extraction method was developed in order to purify β-glucans from oat bran for studies in mice. The highest yield was obtained after a combined heat treatment and a starch digestion step followed by treatment with pancreatin. Using this method, about 80% of the β-glucans could be extracted. When purified β-glucans from oats were studied, the difference in purity, viscous properties and average molecular weight, seemed not to be crucial parameters for the cholesterol-lowering effect. Further studies are needed to investigate whether purified β-glucan products, with average molecular weights lower than 285 kDa, are able to lower plasma cholesterol and which components in the oat bran oil fraction that cause the effect on plasma cholesterol. The results should also be confirmed in human intervention studies

Biodegradation of ochratoxin A by Pediococcus parvulus isolated from Douro wines

Lactic acid bacteria (LAB) are a promising solution to reduce exposure to dietary mycotoxins because of the unique mycotoxin decontaminating characteristic of some LAB. Ochratoxin A (OTA) is one of the most prominent mycotoxins found in agricultural commodities. The present work reports on the ability of Pediococcus parvulus strains that were isolated from Douro wines that spontaneously underwent malolactic fermentation to detoxify OTA. These strains were identified and characterised using a polyphasic approach that employed both phenotypic and genotypic methods. When cultivated on OTA-supplemented MRS media, OTA was biodegraded into OTα by certain P. parvulus strains. The presence of OTα was confirmed using LC-MS/MS. The conversion of OTA into OTα indicates that the OTA amide bond was hydrolysed by a putative peptidase. The rate of OTA biodegradation was found to be dependent on the inoculum size and on the incubation temperature. Adsorption assays with dead P. parvulus cells showed that approximately 1.3% ± 1.0 of the OTA was adsorbed onto cells wall, which excludes this mechanism in the elimination of OTA by strains that degrades OTA. Under optimum conditions, 50% and 90% of OTA was degraded in 6 and 19 h, respectively. Other LAB strains that belonged to different species were tested but did not degrade OTA. OTA biodegradation by P. parvulus UTAD 473 was observed in grape must. Because some P. parvulus strains have relevant probiotic properties, the strains that were identified could be particularly relevant to food and feed applications to counteract the toxic effects of OTA.This work was funded by FEDER funds through the "Programa Operacional Factores de Competitividade - COMPETE" and by national funds through "Fundacao para a Ciencia e a Tecnologia - FCT", Ref. FCOMP-01-0124-FEDER-028029 and PTDC/AGR-TEC/3900/2012, respectively. The authors also thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013 and the Project "BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes, REF. NORTE-07-0124-FEDER-000028" co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER. Luis Abrunhosa was supported by the grant SFRH/BPD/43922/2008 from FCT

The gut microbiota and cardiovascular health benefits: a focus on wholegrain oats

Existing scientific data suggest that a high intake of wholegrain foods contributes to improved gut health and a reduced risk of cardiovascular disease. Wholegrain oats are rich in dietary fibre and an important source of many bioactive components, including minerals, vitamins and phenolic compounds. The oat β‐glucans have been reported to lower low‐density lipoprotein cholesterol through their ability to increase the viscosity of intestinal chime, change the gut microbiota composition and increase the production of short‐chain fatty acids, which may contribute to the inhibition of hepatic cholesterol synthesis. Oats are also a rich source of phenolic acids, which are predominantly bound to cell wall polysaccharides through ester bonds. This bound state within oats means that phenolic acid bioavailability will largely be determined by interactions with the colonic microbiota in the large intestine. However, results from in vitro, animal and human studies have been inconsistent in relation to the impact of oats on the gut microbiota, possibly due to differences in experimental techniques and because compounds in oats, other than β‐glucans, have not been considered. This review focuses on the interaction of oat β‐glucans and phenolic acids with gut microbiota, and the subsequent link to cardiovascular health

Processing of oat: the impact on oat's cholesterol lowering effect

Epidemiological and interventional studies have clearly demonstrated the beneficial impact of consuming oat and oat-based products on serum cholesterol and other markers of cardiovascular disease. The cholesterol-lowering effect of oat is thought to be associated with the β-glucan it contains. However, not all food products containing β-glucan seem to lead to the same health outcome. Overall, highly processed β-glucan sources (where the oat tissue is highly disrupted) appear to be less effective at reducing serum cholesterol, but the reasons are not well understood. Therefore, the mechanisms involved still need further clarification. The purpose of this paper is to review current evidence of the cholesterol-lowering effect of oat in the context of the structure and complexity of the oat matrix. The possibility of a synergistic action and interaction between the oat constituents promoting hypocholesterolaemia is also discussed. A review of the literature suggested that for a similar dose of β-glucan, (1) liquid oat-based foods seem to give more consistent, but moderate reductions in cholesterol than semi-solid or solid foods where the results are more variable; (2) the quantity of β-glucan and the molecular weight at expected consumption levels (∼3 g day−1) play a role in cholesterol reduction; and (3) unrefined β-glucan rich oat-based foods (where some of the plant tissue remains intact) often appear more efficient at lowering cholesterol than purified β-glucan added as an ingredient

SÄLLSKAPSSPELSFÖRENINGARS BETYDELSE FÖR DELTAGARNA.

Denna kvalitativa studies syfte har varit vad deltagandet i sällskapsspelsföreningar har för betydelse för deltagarna, samt de som är verksamma i föreningen. Studiens resultat baseras på semistrukturerade intervjuer med åtta respondenter, fyra medlemmar i olika föreningar och fyra ansvariga inom föreningarna. För att analysera respondenternas svar har dessa jämförts med Collins (2004) teori om interaktionsritualer och Bourdieu (1986) kapitalteori för att undersöka deltagande inom sällskapsspelsföreningar och dess betydelse för deltagarna. Studiens resultat visar på den vikt respondenterna lägger vid den sociala samvaron inom deras respektive föreningar.  Inom föreningen finner deltagarna en trygghet bland andra likasinnade då de får möjlighet att vara sig själva och utöva sina intressen med andra, som delar dessa intressen. Deltagarnas egna åsikter om vilken betydelse sällskapsspelsföreningar har för just dem, har överlagt varit liknande. Majoriteten av respondenterna uppger att de både fått känslor av gemenskap inom sina respektive föreningar och ger intryck av att föreningarna har en stor betydelse för dem själva. Författarna anser själva att sällskapsspelsföreningar kan vara bra mötesplatser för människor som söker en gemenskap och en trygg miljö, då föreningarna jobbar aktivt med att skapa en bra social samvaro där målet är att alla kan vara med och är välkomna.

SÄLLSKAPSSPELSFÖRENINGARS BETYDELSE FÖR DELTAGARNA.

Denna kvalitativa studies syfte har varit vad deltagandet i sällskapsspelsföreningar har för betydelse för deltagarna, samt de som är verksamma i föreningen. Studiens resultat baseras på semistrukturerade intervjuer med åtta respondenter, fyra medlemmar i olika föreningar och fyra ansvariga inom föreningarna. För att analysera respondenternas svar har dessa jämförts med Collins (2004) teori om interaktionsritualer och Bourdieu (1986) kapitalteori för att undersöka deltagande inom sällskapsspelsföreningar och dess betydelse för deltagarna. Studiens resultat visar på den vikt respondenterna lägger vid den sociala samvaron inom deras respektive föreningar.  Inom föreningen finner deltagarna en trygghet bland andra likasinnade då de får möjlighet att vara sig själva och utöva sina intressen med andra, som delar dessa intressen. Deltagarnas egna åsikter om vilken betydelse sällskapsspelsföreningar har för just dem, har överlagt varit liknande. Majoriteten av respondenterna uppger att de både fått känslor av gemenskap inom sina respektive föreningar och ger intryck av att föreningarna har en stor betydelse för dem själva. Författarna anser själva att sällskapsspelsföreningar kan vara bra mötesplatser för människor som söker en gemenskap och en trygg miljö, då föreningarna jobbar aktivt med att skapa en bra social samvaro där målet är att alla kan vara med och är välkomna.

Extraction of beta-Glucan from Oat Bran in Laboratory Scale

Effects of various enzymes and extraction conditions on yield and molecular weight of beta-glucans extracted from two batches of commercial oat bran produced in Sweden are reported. Hot-water extraction with a thermostable alpha-amylase resulted in an extraction yield of approximate to 76% of the beta-glucans, while the high peak molecular weight was maintained (1.6 x 10(6)). A subsequent protein hydrolysis significantly reduced the peak molecular weight of beta-glucans (by pancreatin to 908 x 10(3) and by papain to 56 x 10(3)). These results suggest that the protein hydrolyzing enzymes may not be pure enough for purifying beta-glucans. The isolation scheme consisted of removal of lipids with ethanol extraction, enzymatic digestion of starch with alpha-amylase, enzymatic digestion of protein using protease, centrifugation to remove insoluble material, removal of low molecular weight components using dialysis, precipitation of beta-glucans with ethanol, and air-drying

Gastrointestinal Release of beta-Glucan and Pectin Using an In Vitro Method

The release of soluble dietary fiber is a prerequisite for viscous effects and hence beneficial health properties. A simple in vitro method was adapted to follow the release during gastrointestinal digestion, and the percentage of solubilized fiber was measured over time. beta-Glucan from oat bran was mainly released during gastric digestion while the release of pectin from sugar beet fiber continued in the small intestine. Unmilled fractions of sugar beet fiber released more soluble fiber than oat bran flakes, probably due to the porous structure of sugar beet fiber as a result of manufacturing processes, but also clue to differences in source. Milling to smaller fiber particles significantly improved releasability (from 20 to 55% released beta-glucan and from 50 to 70% released pectin, respectively, after digestion). When milled fibers were included in individual food matrices, the release was reduced by protein and starch matrices (5% beta-glucan and 35% pectin released, respectively) and slowed by fat (45% beta-glucan and 60% pectin released). This may result in a too low or too late release in the upper small intestine to be able to interfere with macronutrient uptake. The method may be suitable for predicting the gastrointestinal release of soluble dietary fibers from food matrices in the development of healthy food products

Biomedical applications of polypyrrole microactuators : from single-cell clinic to microrobots

Microtools that will be useful for the positioning and investigation microstructures must operate relevant environments, such as cell culture media or blood plasma. They must also be comparatively strong, and preferably allow a muscle like mode of movement. This is given by a novel family of actuators based on conjugated polymers (like polypyrrole, PPy). By miniaturising these structures using standard photolithographic techniques, the authors can reduce the size down to 10-micrometer dimensions and build mechanically active microdevices. These can be moved and positioned by applying a potential to dope or undope the PPy. These novel structures are now being developed as a unique microactuator technology, suitable for operation in applications coupled to cell biology and biomedicin