Effects of Pediococcus parvulus 2.6 and its exopolysaccharide on plasma cholesterol levels and inflammatory markers in mice

Intake of dietary fibres may reduce the prevalence of physiological risk factors of the metabolic syndrome, such as high plasma lipid levels and low-grade inflammatory state. Dietary fibres are usually of plant origin however microbial exopolysaccharides (EPSs) have analogue structures that could potentially exert similar physiological effects. Pediococcus parvulus 2.6 (Pd 2.6) excretes a ropy EPS and has previously shown probiotic potential. The aim of this work was to evaluate physiological effects of Pd 2.6 and its EPS in vivo. The live Pd 2.6 (both the ropy and non-ropy isogenic variant) and its purified EPS were fed to hypercholesterolemic LDL-receptor deficient mice for 6 weeks to investigate their effects on cholesterol levels and the inflammatory tone of the animals. Both variants of Pd 2.6 survived passage through the mouse gut fulfilling an important criterion of probiotics. The ability to produce EPS was conferring an advantage to survival (faecal recovery of 3.7 (1.9-8.7) vs. 0.21 (0.14-0.34) *108 CFU, P < 0.001, median and 25th and 75th percentiles). The ropy Pd 2.6 decreased the levels of soluble vascular cell adhesion molecule-1 compared to the EPS alone (591 ± 14 vs. 646 ± 13 ng/ml, P < 0.05). An increase in liver weight in mice fed the purified EPS was observed, but with no change in liver lipids. No changes in blood lipids were detected in any group. Further the EPS induced growth of the caecal tissue and increased the amount of caecal content showing bulking properties like that of a dietary fibre

Solid-state characteristics and redispersible properties of powders formed by spray-drying and freeze-drying cereal dispersions of varying (1→3,1→4)--glucan content

Cereal powders containing 33, 18 and 4% (w/w) (1→3,1→4)--glucan, prepared from cereal suspensions, had distinct differences in surface morphology as observed by scanning electron microscopy, depending both on the drying process (spray- or freeze-drying) and the dietary fibre level. Freeze-drying produced powders with a ‘flake-like’ matrix, without particle formation and similar matrix morphology independent of the (1→3,1→4)--glucan content, in contrast to spray-drying, which gave powders with morphologies that were (1→3,1→4)--glucan-dependent and consisted of aggregated particles and microspheres. Choosing the concentration of (1→3,1→4)--glucans permits control of the particle size and particle size distribution of the spray-dried cereal powders. pH-dependent zeta () potential measurements of re-dissolved powders indicated that the isoelectric point was in the pH range of 3.8–4.8 and that it increased at higher pH as the (1→3,1→4)--glucan content of the powders was decreased from 33 to 4% (w/w). The absolute value of the zeta () potential fell with increasing pH and was largest for the powder dispersion with the lower (1→3,1→4)--glucan content, leading to the greatest dispersion stability. The importance of particle size, net surface charge and (1→3,1→4)--glucan and protein content in controlling the surface activity at the air–water interface of cereal powder dispersions is also discussed. Author Keywords: Spray-drying; Freeze-drying; (1→3,1→4)--glucan; Morphology; Particles; Zeta potential; Surface activit

Changes in plasma lipids and faecal Bifidobacterium spp. in humans after consumption of fermented oat-based products for 5 weeks

In order to obtain milk like products from oats, an industrial process to manufacture a palatable, liquefied oat base has been developed (Lindahl et al 1994). This oat base per se has shown to be appreciated as a non-dairy milk alternative in the health market (Anon, 1999). It has also been shown that it is possible to obtain fermented oat milk with texture properties resembling that of traditional yoghurt (Mårtensson et al 2001). In this study we have investigated the effects of fermented oat-based products containing both native and microbial -glucans, on plasma lipids and on faecal total bacterial count and Bifidobacterium ssp. Sixty-two volunteers (free-living subjects) with moderately increased plasma cholesterol levels were recruited. One of the oat products (ropy) was co-fermented with an exopolysaccharide (EPS)-producing strain, Pediococcus damnosus 2.6. A significant (p=0.022) reduction in total cholesterol by 6% was observed in volunteers who had eaten the fermented, ropy oat-based product compared to the control group. A significant increase of total bacterial count (p=0.001) and Bifidobacterium ssp. (p=0.012) was observed in faecal samples from volunteers in the group who had eaten the fermented, ropy oat-based product. This study shows that a fermented, ropy oat-based product, containing both native and microbial glucans can reduce the cholesterol level and also stimulate the bifidobacteria flora in the gastrointestinal tract. Anonymous, 1999, in Daily Mail on Sunday, You-magazine March; Lindahl, L.et al. 1997. US Patent 5,686,123; Mårtensson, O. et al. 2001. Journal of the Science of Food and Agriculture 81, 1314-1321.vokMyynti MTT tietopalvelu

Complex formation in aqueous medium of partially hydrolysed oat cereal proteins with sodium stearoyl-2 lactylate (SSL) lipid surfactant and implications for bile acids activity

Sodium stearoyl-2 lactylate (SSL) lipid surfactant molecules specifically bind partially hydrolysed oat proteins in aqueous medium and significantly enhance the dispersion stability of oat cereal preparations. The proposed complexation is composition dependent and a greater understanding of the role of both oat proteins and lipid surfactant in the effect was gained with data from high performance liquid chromatography (HPLC-UV), viscometry and differential scanning micro calorimetry. The effect of the lipid surfactant on the degree of association is primarily governed by the conformational activity of oat protein molecules related to the extent of protein hydrolysed state, as well as protein unfolded and subsequent aggregated structures. SSL does not dissociate oat proteins into subunits or destroy important hydrophobic contacts already stabilising the protein molecules. Although the exact mode of association is unknown, the present study demonstrates that such interactions occur in a specific manner and suggest selectivity of oat proteins for individual fatty acids. The effect of various amounts of bile acids on SSL-oat protein interaction was also investigated, as a first attempt to investigate the role of lipid surfactant molecules in the known cholesterol-lowering action of oat cereal ingredients and to elucidate favourable conditions by which oat cereal can elicit hypocholesterolemic effects. (C) 2004 Elsevier B.V. All rights reserved

The effect of yoghurt culture on the survival of probiotic bacteria in oat-based, non-dairy products

The survival of the probiotic strains Lactobacillus reuteri ATCC 55730, Lactobacillus acidophilus DSM 20079 and Bifidobacterium bifidum DSM 20456, all of human origin, were investigated in three different oat-based, non-dairy products (Adavena M40, MG20 and G40). The products were fermented by the three strains with and without the presence of a commercial yoghurt culture (V2). Samples were stored at 6 degreesC up to 30 days. In general, the oat-based products were shown to be a suitable support for these intestinal bacteria. L. reuteri ATCC 55730 had the highest viability in all of the products investigated. After 30 days the cell viability of L. reuteri ATCC 55730 was 10(8) CFU ml(-1) in all three oat-based products. Lower viability was seen when the strains were grown in the presence of the yoghurt culture compared to when they were grown as pure cultures. These products also exhibited a lower pH value in comparison to products fermented with the pure cultures. The milisation of the main fermentable carbohydrates in the products varied across the bacterial strains. A decrease in beta-glucan content was seen for the products fermented by the B. bifidum DSM 20456 strain. This work shows that these oat-bases with different mono- and disaccharide composition can be used to support the growth of human intestinal bacteria and also maintain high cell viability during cold storage

Texture promoting capacity and EPS formation by lactic acid bacteria in three different oat-based non-dairy media

Four strains of lactic acid bacteria were used as pure or mixed cultures to investigate the texture-promoting capacity and exopolysaccharides (EPS) formation in three different oat-based, non-dairy milk products, Adavena G40, Adavena M40 (both with a dry matter content of 20%) and Mill Milk (with a dry matter content of 10%). Viscosity was measured at two different shear rates during 2 min of shear thinning. The highest viscosity was measured at a shear rate of 129 s(-1) when a mixed culture consisting of Lactobacillus delbrueckii subsp. bulgaricus NCFB 2772 and Lactobacillus brevis DSM 1269 was grown at 30degreesC in the medium containing mostly glucose as the carbohydrate source (Adavena G40). The mixed culture consisting of Lactobacillus delbrueckii subsp. bulgaricus NCFB 2772 and Streptococcus thermophilus DSM 20259 gave the highest viscosity when using the medium with a dry matter content of 20% and maltose as the main carbohydrate source (Adavena M40). The EPS formation in the Adavena G40 medium was confirmed by isolating the soluble polymer fraction after fermentation. A higher yield of polymer dry mass was obtained from the samples with higher viscosity. The study shows that the eo-operative growth that occurs when using mixed cultures also influences the EPS formation and final viscosity in the different oat-based media. This knowledge is of importance when strains are selected for the development of new kinds of fermented, oat-based, non-dairy products

Short-chain fatty acid formation in the hindgut of rats fed native and fermented oat fibre concentrates

The formation of SCFA in rats fed fermented oat fibre concentrates was compared with that of rats fed native oat fibre concentrate. The cultures used were lactic acid bacteria consisting of Lactobacillus bulgaricus and Streptococcus thermophilus (V2), the exopolysaccharide-producing strain Pediococcus damnosus 2.6 (Pd) and L. reuteri (Lr). The materials were incorporated into test diets yielding a concentration of indigestible carbohydrates of 80 g/kg (dry weight). Rats fed the V2-fermented fibre-concentrate diet yielded higher caecal and distal concentrations of acetic acid (P < 0 center dot 01) than rats fed the native fibre concentrate. All the fermented fibre concentrates resulted in a higher propionic acid concentration in the distal colon (P < 0 center dot 05), while rats fed Pd-fermented fibre concentrate resulted in lower concentration of butyric acid (P < 0 center dot 05, P < 0 center dot 01) in all parts of the hindgut as compared with rats fed the native fibre concentrates. Butyrate concentrations ranged between 5-11 mu mol/g (distal colon) and 6-8 mu mol/g (13 d faeces). Higher proportions of acetic acid (P < 0 center dot 05; P < 0 center dot 01) were observed in the caecum of rats fed the fermented fibre concentrates. Rats fed Pd- and Lr-fermented fibre concentrates produced higher proportions of propionic acid (P < 0 center dot 05; P < 0 center dot 01) in the caecum. Changes in SCFA formation in the caecum, distal colon and faeces of rats fed the fermented samples compared with the native sample indicate that these microbes probably survive in the hindgut and that modification of the microflora composition with fermented foods is possible. This may be important for the gastrointestinal flora balance in relation to colonic diseases

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

The ability of different lactic acid bacteria to influence the physicochemical characteristics (content, viscosity and molecular weight) of dietary fibre in beta-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 Streptocoecus 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. (C) 2004 Elsevier Ltd. All rights reserved