Soluble Fiber Fractions Research Articles

Development and Shelf Stability of Natural Fibre Rich Retort Pouch Ready to Eat Products

The new frontier in the food research is the role of non nutritive components in human health. In the recent past, the importance of dietary fibre in the diet has been increased as a functional ingredient which has opened up a potential market for fibre rich products. The by products available during processing of plant foods are considered as promising source of functional fibres. The aim of the present study was to develop fibre rich products using the natural fibre such as ashgourd (Benincasa hispida) fibre, with high soluble fibre fraction. Ready-to-eat fibre rich Bisi bele bath and vegetable pulav were developed with the optimization of fibre using statistical design software. Fibre, fat and spice mixtures were independent variables with the other components as fixed factors. Since the product acceptance is more dependent on volatile compound form intern the flavour, as well as depends on the test, appearance, colour, texture which are the sensory attributes, total volatiles and sensory attributes were selected as responses. While in the fibre rich vegetable pulav water, fibre and spice mixtures were the independent variables. Both the products were showing good acceptability i.e. in the case of bisi bele bhath 7.1 and in the case of vegetable pulav 6.5 on a 9 point hedonic scale after 6 months of storage at room temperature. The dietary fibre profile of bisi bele bhath was 1.1% soluble fibre and 4.4% insoluble fibre while vegetable pulav had 6.2% insoluble and 1.54% soluble fibre fraction. The products were safe and had an established shelf life of 6 months.

The active role of leguminous plant components in type 2 diabetes.

Diabetes appears to be one of the most frequent noncommunicable diseases in the world. A permanent growth in the incidence of diabetes can be observed and according to the International Diabetes Federation (IDF) the year 2030 will mark the increase in the number of diabetics to 439 mln worldwide. Type 2 diabetes accounts for about 90% of all diabetes incidence. Nutrition model modification not only features the basic element in type 2 diabetes treatment but also constitutes the fundamental factor influencing a morbidity rate decrease. Leguminous plants are a key factor in the diabetic diet; plants such as pulses or soybeans are nutritious products valued highly in nutrition. These legumes are high in the content of wholesome protein and contain large amounts of soluble alimentary fiber fractions, polyunsaturated fatty acids, vitamins and minerals, and bioactive substances with antioxidant, anti-inflammatory, and anticancer activity. They are distinguished by the high amount of bioactive compounds that may interfere with the metabolism of glucose. The most significant bioactive compounds displaying antidiabetic activity in leguminous plants are as follows: genistein and daidzein, alpha-amylase inhibitors, and alpha-glucosidase inhibitors. In vitro research using leguminous plant extracts has confirmed their antidiabetic properties. Leguminous plants should be employed in the promotion of healthy lifestyles in terms of functional food.

Abstract 3674: Chemoprevention of endometrial cancer with urolithin A, a metabolite of berry ellagitannins.

Abstract Berries have been reported to elicit chemopreventive effects in cell culture, in animal model systems and in humans. Bio-fractionation studies indicate that the chemopreventive effects of berries can be ascribed to their component anthocyanins, ellagitannins and compounds in the non-alcohol soluble (fiber) fraction. In the present study, 17 berry-related compounds were evaluated at concentrations ranging from 1- 50 μM for their anti-proliferative effects on cultured human endometrial cancer cell lines (ECC-1, Ishikawa and HEC1A). These compounds include the anthocyanins; cyandin-3-glucoside and cyanidin-3-rutinoside and their metabolite, protocatechuic acid; ellagic acid and its metabolites, urolithins A and B; and three oligosaccharides, four short-chain carboxylic acids and four lignans present in the fiber fraction. Cell proliferation assays indicated that urolithin A was the most effective inhibitor of the growth of all three endometrial cancer cell lines. Cell cycle analysis by flow cytometry revealed that urolithin A induced cell cycle arrest at the G2/M phase. This was associated with up-regulation of the protein expression of cyclins B1 and E2, p21, phospho-cdc2 and myt1 as determined by western blot analysis. Endometrial cells depend on progesterone to limit cellular growth because it is antagonistic to estrogen-mediated cell proliferation. It is of importance therefore, that urolithin A was found to reduce estrogen receptor alpha and induce progesterone receptor expression in all three cell lines. In summary, our findings suggest that urolithin A may be chemopreventive for endometrial cancer through modulating genes that control the G2/M phase of the cell cycle and that regulate steroid receptor expression. This research was supported, in part, by MCW Startup Funds to Y-W Huang. Citation Format: Yi-Wen Huang, Chieh-Ti Kuo, Jibran Siddiqui, Jo-Hsin Chen, Chung-Wai Shiau, Gary D. Stoner. Chemoprevention of endometrial cancer with urolithin A, a metabolite of berry ellagitannins. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3674. doi:10.1158/1538-7445.AM2013-3674

A meta-analysis on the role of soluble fibre in diets for growing rabbits

In this review, the methods used to measure fibre and soluble fibre fractions are briefly presented and the effects of the soluble fibre content in diets for growing rabbits reviewed by a meta-analysis of studies available in literature, with the aim of elucidating the relationships with other dietary nutrients. Soluble fibre was assumed as the difference between total dietary fibre (TDF) and neutral detergent fibre (NDF), as it is simple to obtain and has been measured in numerous studies. Dietary soluble fibre content affects the digestive utilisation of soluble and insoluble fibre fractions and its increase is associated with reduced mortality in growing rabbits affected by epizootic rabbit enteropathy. This effect could be attributed to the high fermentability of soluble fibre, the consequent changes in the intestinal microbiota and an enhanced gut barrier function just after weaning. A supply of 12-14% of soluble fibre (as-fed) is recommended in diets for post-weaning and growing rabbits containing around 30% NDF and 18% acid detergent fibre. The positive effects of increasing dietary soluble fibre are linked to the use of sugar beet pulp as primary source of soluble fibre and should be confirmed with other sources of soluble fibre.

Dietary fibre fractions in cereal foods measured by a new integrated AOAC method

The reliable determination of soluble, insoluble and total dietary fibre in baked goods and cereal flours is an important issue for research, nutritional labelling and marketing. We compared total dietary fibre (TDF) contents of selected cereal based foods determined by AOAC Method 991.43 and the new AOAC Method 2009.01. Fifteen bread and bakery products were included in the study. Our results showed that TDF values of cereal products determined by AOAC Method 2009.01 were always significantly higher than those determined by AOAC Method 991.43. This was explained by the inclusion of low molecular weight soluble fibre fractions and resistant starch fractions in the TDF measurement by AOAC 2009.01. This documents that nutritional labelling of cereal products poses the challenge how to update TDF data in nutrient databases in a reasonable time with an acceptable expenditure.

Molecular weight distribution of soluble fiber fractions and short chain fatty acids in ileal digesta of growing pigs.

The effect of dietary fiber source on molecular weight (MW) distribution of soluble fiber fractions and short chain fatty acids (SCFA) in ileal digesta of 7 post valve T-cecum (PVTC) cannulated growing pigs was studied. Pigs were fed semisynthetic diets with sugar beet (Beta vulgaris) pulp (SBP) or chicory (Cichorium intybus) forage (CFO) as fiber sources of which the soluble nonstarch polysaccharide (NSP) fraction originated mainly from pectin. Three MW intervals were selected-large MW (MWL): 10,000,000 to 1,000,000 g/mol, medium MW (MWM): 1,000,000 to 200,000 g/mol, and small MW (MWS): 200,000 to 10,000 g/mol-and the relative distribution (% of total) of molecules in each interval was calculated. The MWM fraction was higher (P < 0.05) in ileal digesta of pigs fed diet SBP and the MWS fraction was higher (P < 0.05) in ileal digesta of pigs fed diet CFO. The mole/100 mole of propionic acid (HPr) was higher (P < 0.010) in pigs fed diet SBP whereas pigs fed diet CFO had higher (P < 0.010) mole/100 mole of acetic acid (HAc). The proportion of the MWL and MWM fractions in ileal digesta were negatively correlated to HAc (r = -0.52, P = 0.05, and r = -0.62, P = 0.02, respectively). The proportion of MWM in ileal digesta was positively correlated to HPr (r = 0.83; P = 0.001) whereas MWS and HPr were negatively correlated (r = -0.76; P = 0.002). In conclusion, the bacterial degradation of the soluble NSP fraction is selective and MW distribution may explain differences in SCFA production.

Effects of simulated digestion in vitro on cell wall polysaccharides from kiwifruit (Actinidia spp.)

Cell wall polysaccharides are resistant to digestion and absorption in the human small intestine and are considered to be delivered to the colon in a chemically unaltered state. In this paper, pulp from green and gold kiwifruit was subjected to in vitro upper-intestinal tract digestion and the chemical and physical changes to cell wall polysaccharides (dietary fibre) were investigated. Yields of insoluble fibre decreased slightly with simulated digestion while soluble fibre yields increased. Constituent sugar and glycosyl linkage analysis of the soluble and insoluble fibre fractions revealed that the chemical composition and structure of the non-starch polysaccharides remained largely unchanged. However, the degree of methylesterification of galacturonic acid residues present in the pectin-rich soluble fibre fractions of both fruit decreased with treatment; size-exclusion chromatography detected changes in the molecular weight profiles of these fractions. These changes may affect the physicochemical properties and fermentability of kiwifruit dietary fibre in the large intestine.

Effect of extrusion parameters on some properties of dietary fiber from lemon (Citrus aurantifolia Swingle) residues

Approximately 50% of the original whole fruit mass, after citrus processing for juice, consist of the peel, membranes and seeds. Citrus residues consist mainly of insoluble fiber (celluloses) and a small proportion of soluble fiber (hemicelluloses and pectin). For this reason, citrus residues could be considered as a potential high fiber ingredient that is used for food industry. In this study, lemon residues were extruded to modify and increase their soluble fiber fraction. Surface response methodology with six central points and six axial points was used to evaluate the changes in dietary fiber fractions in lemon residues. The independent variables studied were extrusion temperature (from 59.77 to 110.63°C), moisture content of the sample (from 33.18 to 66.82%) and screw speed (from 3.18 to 36.82). The extrusion process increased the soluble fiber from 38.60% in unprocessed lemon residues to 40.00 to 50.01% in extruded samples. The highest content of soluble fiber was 50.00% when operating conditions were high in temperature (100°C), low in moisture content (40%) and low in screw speed (10 rpm). The results of this study indicate that extrusion is a process that has the capability to transform insoluble fiber to soluble fiber in lemon residues. Key words: Lemon residues, extrusion, dietary fiber.

Effect of extrusion parameters on some properties of dietary fiber from lemon (Citrus aurantifolia Swingle) residues

Approximately 50% of the original whole fruit mass, after citrus processing for juice, consist of the peel, membranes and seeds. Citrus residues consist mainly of insoluble fiber (celluloses) and a small proportion of soluble fiber (hemicelluloses and pectin). For this reason, citrus residues could be considered as a potential high fiber ingredient that is used for food industry. In this study, lemon residues were extruded to modify and increase their soluble fiber fraction. Surface response methodology with six central points and six axial points was used to evaluate the changes in dietary fiber fractions in lemon residues. The independent variables studied were extrusion temperature (from 59.77 to 110.63°C), moisture content of the sample (from 33.18 to 66.82%) and screw speed (from 3.18 to 36.82). The extrusion process increased the soluble fiber from 38.60% in unprocessed lemon residues to 40.00 to 50.01% in extruded samples. The highest content of soluble fiber was 50.00% when operating conditions were high in temperature (100°C), low in moisture content (40%) and low in screw speed (10 rpm). The results of this study indicate that extrusion is a process that has the capability to transform insoluble fiber to soluble fiber in lemon residues. Key words : Lemon residues, extrusion, dietary fiber.

The ferulic acid esterases of Chrysosporium lucknowense C1: Purification, characterization and their potential application in biorefinery

Three ferulic acid esterases from the filamentous fungus Chrysosporium lucknowense C1 were purified and characterized. The enzymes were most active at neutral pH and temperatures up to 45 °C. All enzymes released ferulic acid and p-coumaric acid from a soluble corn fibre fraction. Ferulic acid esterases FaeA1 and FaeA2 could also release complex dehydrodiferulic acids and dehydrotriferulic acids from corn fibre oligomers, but released only 20% of all ferulic acid present in sugar beet pectin oligomers. Ferulic acid esterase FaeB2 released almost no complex ferulic acid oligomers from corn fibre oligomers, but 60% of all ferulic acid from sugar beet pectin oligomers. The ferulic acid esterases were classified based on both, sequence similarity and their activities toward synthetic substrates. The type A ferulic acid esterases FaeA1 and FaeA2 are the first members of the phylogenetic subfamily 5 to be biochemically characterized. Type B ferulic acid esterase FaeB2 is a member of subfamily 6.

A study of the recovery of the dietary fibres from olive mill wastewater and the gelling ability of the soluble fibre fraction

A novel method of the recovery of a dietary fibre containing material from olive mill wastewater (OMW) was developed. Extraction was based on thermal treatment with mixtures of ethanol and acids, prior to the isolation of the alcohol insoluble residue (AIR). Different mixtures were tested and the extracted residues were characterized. The maximum AIR recovery accounted 64.8 g/100 g OMW dry matter, while the corresponding total fibre content was 5.1 g/100 g of the AIR. Despite the high potassium (8.4 g/100 g) and the low galacturonic acid content (3.3 g/100 g), AIR was able to form gels after a simple isolation and concentration of the soluble fraction. The soluble fibres were exclusively composed of pectin (93.9 and 6.1 mol/100 mol galacturonic acid and arabinose, respectively) with 59 mol/100 mol GalA degree of methylation. The viscoelastic properties of the gels were evaluated as a function of galacturonic acid content, where the gel rigidity and elasticity was found to increase exponentially with this parameter. A further treatment of the pectin material with citric acid during its concentration, allowed the formation of more rigid, but less elastic gels.

The influence of soluble and insoluble lupin non-starch polysaccharides on the digestibility of diets fed to rainbow trout ( Oncorhynchus mykiss)

This study examined the effect of increasing inclusion levels of soluble and insoluble lupin ( Lupinus angustifolius) fibres, and purified cellulose on the dry matter, protein and energy digestibility of diets fed to rainbow trout ( Oncorhynchus mykiss). Soluble and insoluble fibre fractions from lupin kernel meal were produced using differential pH solubilities. There were significant differences among the digestibility parameters of the diets with different inclusion levels of each of the different fibre types, except for the soluble lupin fibre, which had limited effect on any digestibility parameters. Differences among diets in dry matter and energy digestibility were most distinct. Using an ANOVA analysis no significant differences were noted for diet protein digestibilities with any of the fibre types. However, regression analysis of the effect of fibre inclusion levels showed significant effects on all digestibility parameters, including protein digestibilities. The lupin insoluble NSP also had a greater effect on dry matter and energy digestibilities than that of cellulose, with findings suggesting that it also affected the digestibility of additional nutrients in the diet to a degree not seen with cellulose. These results show that different fibre classes can have distinctly different effects on diet digestibility parameters.

Soluble fiber extracted from potato pulp is highly fermentable but has no effect on risk markers of diabetes and cardiovascular disease in Goto-Kakizaki rats

The cholesterol-lowering and hypoglycemic effect of dietary fiber are commonly attributed to soluble fiber fractions. By enzymatic treatment of potato pulp, which is rich in cellulose and pectin, we prepared 3 fractions with different chemical composition and solubility, and compared their effects with commercially available crystalline cellulose (negative control) on central parameters related to risk factors of diabetes mellitus and cardiovascular disease in diabetic prone Goto-Kakizaki rats. Forty male rats were fed a semisynthetic Western-type diet containing 5% dietary fiber in the form of concentrated potato fiber (CF), insoluble potato fiber (IF), soluble fiber (SF), or cellulose (CEL) ad libitum for 4.5 weeks to study weight change and induce diabetic conditions. This was followed by 16 days of slightly restricted feeding, for the measurement of fecal organic matter digestibility, fecal dry matter, urinary glucose excretion, and fasting blood glucose. Finally, the rats were euthanized 2 hours postprandial for measurement of postprandial glucose, triacylglycerol and cholesterol levels, and cecal fermentation pattern to assess any relation between digestion processes and hematological risk markers. Diet SF had higher fecal organic matter digestibility and led to a significantly larger pool of organic acids with a higher proportion of propionate than the other diets. There was no difference in hematological parameters except for a small but significant reduction in postprandial plasma triacylglycerol concentration of rats fed diet SF compared to diet CEL and diet CF. In conclusion, increased fermentation and production of propionate with diet SF did not reduce plasma cholesterol or glycemic response.

Arabinoxylan Fibre Consumption Improved Glucose Metabolism, but did not Affect Serum Adipokines in Subjects with Impaired Glucose Tolerance

The consumption of arabinoxylan, a soluble fibre fraction, has been shown to improve glycemic control in type 2 diabetic subjects. Soluble dietary fibre may modulate gastrointestinal or adipose tissue hormones regulating food intake. The present study investigated the effects of arabinoxylan consumption on serum glucose, insulin, lipids, leptin, adiponectin and resistin in subjects with impaired glucose tolerance. In a randomized, single-blind, controlled, crossover intervention trial, 11 adults consumed white bread rolls as either placebo or supplemented with 15 g arabinoxylan for 6 weeks with a 6-week washout period. Fasting serum glucose, insulin, triglycerides, unesterified fatty acids, apolipoprotein A1 and B, adiponectin, resistin and leptin were assessed before and after intervention. Fasting serum glucose, serum triglycerides and apolipoprotein A-1 were significantly lower during arabinoxylan consumption compared to placebo (p=0.029, p=0.047; p=0.029, respectively). No effects of arabinoxylan were observed for insulin, adiponectin, leptin and resistin as well as for apolipoprotein B, and unesterified fatty acids. In conclusion, the consumption of AX in subjects with impaired glucose tolerance improved fasting serum glucose, and triglycerides. However, this beneficial effect was not accompanied by changes in fasting adipokine concentrations.

Advances in pasture plant breeding for animal productivity and health

Plant breeding has had a substantial effect on the productivity and health of ruminant animals in New Zealand by improving the quantity, quality and reliability of grazed temperate pastures. Genetic changes have affected annual pasture productivity, seasonal growth, digestibility, protein/energy balance, level of rumen undegradable protein, leaf properties affecting intake, resistance to foliar diseases, and reductions in compounds that have an adverse impact on the health, welfare and reproductive fertility of ruminant animals. Most plant improvement programmes have achieved genetic gains in excess of 1% per year for a variety of target traits, and these gains are likely to continue given the high genetic variation available within forage plants. Significant heritable variation exists to improve forage quality, particularly for soluble carbohydrate and fibre fractions in grasses, and in the rate at which these change during the season. Deleterious animal health and welfare effects can be alleviated through the use of non-toxic endophytes in grasses, that do not produce lolitrem B and ergovaline. Use of improved cultivars, with the appropriate management, can add value to animal products.

Repeated dose oral toxicological evaluation of concentrated barley β-glucan in CD-1 mice including a recovery phase

The cholesterol-lowering effect observed following consumption of oats and barley is attributable to the β-glucan component of the soluble fiber fraction of these cereal grains. β-Glucan has also been reported to modulate immune activity, however, few studies have evaluated the hematological effects of β-glucan following oral exposure. In the current study, a concentrated β-glucan (64%) preparation from barley (Barley Betafiber) was blended into mouse feed at concentrations of 1, 5, or 10% (corresponding to approximately 0.7, 3.5, and 7% β-glucan) and evaluated in CD-1 mice. Plasma was collected for clinical chemistry and hematological measurements at the initiation of the study and again following 14 and 28 days of exposure. Plasma was also collected from animals that consumed the same diets for 28-days but were switched to control diet (containing no supplemental β-glucan) for an additional 14-day period to evaluate reversibility or delayed occurrence of treatment-related changes. Half of the animals were sacrificed for histopathologic analysis following the 28-day exposure period and the other half were evaluated following the recovery period. Histopathologic analysis focused on primary lymphoid organs and lymph nodes proximal and distal to the route of exposure. An additional group of untreated animals (naı̈ve) was bled and sacrificed at day 0, 14, 27 and 41 for comparison of the hematology parameters with those of the control group because it was not known if multiple blood draws would affect hematology parameters. Compared to animals consuming the control diet, no treatment-related adverse effects were observed in hematological or clinical chemistry measurements or in organ weights and immunopathology in either sex following consumption of concentrated barley β-glucan for 28-days or following the recovery period. Likewise, no differences were observed between the naı̈ve and control groups. Results from this study showed that consumption of concentrated barley β-glucan did not cause treatment-related inflammatory or other adverse effects in CD-1 mice.

Efeito hipoglicêmico de rações à base de berinjela (Solanum melongena,L.) em ratos

Os objetivos do presente trabalho foram verificar se dietas ricas em berinjela apresentam efeito hipoglicêmico, se contribuem para o retardamento de absorção da glicose pós-prandial e se a fração fibra solúvel está correlacionada com estes efeitos. Os experimentos foram realizados com ratos Wistar machos adultos, normais e diabéticos, que receberam rações à base de caseína, berinjela com casca e sem casca, e de casca de berinjela por um período de 42 dias. A glicose sangüínea foi determinada no início do experimento e aos 13, 21, 34 e 42 dias. Os testes orais de tolerância à glicose (TOTG) foram realizados no final do experimento. Os resultados mostraram que as rações à base de farinha de berinjela com casca e de casca de berinjela apresentaram redução nos níveis de glicose. Este efeito não foi significativo para a ração à base de farinha de berinjela sem casca. Os animais do grupo diabético que receberam ração à base de berinjela com casca apresentaram menor área sob a curva de glicose, do que os dos grupos controle (ração à base de caseína e de berinjela com casca) e do que o do grupo diabético que recebeu a ração de caseína. Este efeito não foi observado nos animais que receberam ração à base de berinjela sem casca e casca de berinjela. Estes resultados indicam a presença de um composto responsável pelo efeito hipoglicêmico na casca de berinjela e que a pectina solúvel da ração não foi suficiente para promover tal efeito, mas que a administração contínua de pectina solúvel contribuiu para a melhora da TOTG.

Human milk oligosaccharides are resistant to enzymatic hydrolysis in the upper gastrointestinal tract

Human milk oligosaccharides (HMOs) show a complexity and variety not found in milk of any other species. Although progress has been made in the past 3 decades with regard to identification and structural characterization of HMOs, not much is known about the physiologic functions of HMOs. As a prerequisite for biological activity in infant metabolism, HMOs have to resist enzymatic hydrolysis in the gastrointestinal tract. To assess the extent to which selected HMOs are hydrolyzed, we carried out in vitro digestion studies using enzyme preparations of human and porcine pancreas and intestinal brush border membranes (BBMs). Fractions of HMOs, including structurally defined isolated oligosaccharides, were digested for up to 20 h with human pancreatic juice and BBMs prepared from human or porcine intestinal tissue samples. HMOs were incubated by using a porcine pancreatic homogenate and BBMs as enzyme sources. HMOs and digestion products were identified by mass spectrometry and anion-exchange chromatography. Additionally, free D-glucose, L-fucose, and N-acetylneuraminic acid were determined enzymatically. Whereas maltodextrin (control) was rapidly and completely hydrolyzed, neutral and acidic HMOs showed a profound resistance against pancreatic juice and BBM hydrolases. However, cleavage of most of the HMOs was achieved by using a pancreatic homogenate containing intracellular, including lysosomal, enzymes in addition to secreted enzymes. The results of this study strongly suggest that HMOs are not hydrolyzed by enzymes in the upper small intestine. Although intact HMOs may be absorbed, we postulate that a majority of HMOs reach the large intestine, where they serve as substrates for bacterial metabolism. Therefore, HMOs might be considered the soluble fiber fraction of human milk.

Teas and Other Beverages Suppress D-Galactosamine-Induced Liver Injury in Rats

We compared the effects of various types of beverages (teas, coffee, and cocoa) on D-galactosamine-induced liver injury by measuring plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in 7-wk-old male Wistar rats. The effects of five fractions extracted with different organic solvents from green tea, different types of dietary fibers, and some short chain fatty acids were also investigated. All of the beverages tested significantly suppressed D-galactosamine-induced enhancement of plasma enzyme activities when powdered beverages were added to the diet (30 g/kg) and fed to rats for 2 wk. Plasma ALT activities were 1155 ± 82 μmol/(min⋅L), control], 289 ± 61 (green tea), 626 ± 60 (roasted green tea), 471 ± 84 (puerh tea), 676 ± 69 (oolon tea), 423 ± 76 (black tea), 829 ± 53 (coffee), and 885 ± 89 (cocoa). The profile of AST activities was similar. The caffeine-containing fraction from green tea had no significant effect, whereas the other four fractions, including the soluble fiber fraction, significantly suppressed liver injury. In addition to tea fibers, many other types of dietary fiber (hemicellulose, chitin, chitosan, alginate, pectin, guar gum, glucomannan, and inulin, but not cellulose) had liver injury-preventive effects when added to the diet (30 g/kg), suggesting that liver injury-prevention may be one of the general effects of dietary fibers. Of three short-chain fatty acids tested (acetate, propionate, and butyrate), only acetate prevented liver injury when added to the diet (15 g/kg), supporting the possibility that the liver injury-preventive effect of dietary fibers may be mediated at least in part by certain organic acids. These results suggest that several beverages possess preventive effects on certain types of liver injury, such as that induced by D-galactosamine, and that different constituents of high and low molecular weights contribute to the liver injury-preventive effects of green tea.

In vitro calcium availability from brassica vegetables ( Brassica oleracea L.) and as consumed in composite dishes

In vitro calcium availability from four varieties of Brassica oleracea L. (broccoli, cauliflower, green cabbage and kale) was evaluated. The effect of including some brassica vegetables in composite dishes (macaroni and broccoli, macaroni and cauliflower) was also studied. Brassica vegetables were rich in calcium (20.6–35.3 mg/100 g) and in organic acids. Dietary fibre content in brassica vegetables (2.4 g/100 g) was lower than in composite dishes, the latter having a higher content of the soluble fraction. Uronic acids represented 50% of the soluble fibre fraction of brassica vegetables and only 24% of that of composite dishes. Approximately 25% of the total calcium of brassica vegetables was dialysable; ionic dialysable calcium was about 7% of the total calcium. The addition of macaroni to vegetables significantly lowered only calcium dialysability ( p<0.001). Unlike vegetables, composite dishes had a percentage of soluble calcium higher ( p<0.001) than that of dialysable calcium. The presence in dialysates of higher amounts of bound calcium compared to free ionic calcium implies that most of the absorbable calcium was bound to low molecular weight compounds. Organic acids might constitute the main association of calcium in brassica vegetables. Brassicaceae can be regarded as a good source of available calcium; their consumption in the diet may contribute to an adequate calcium nutriture.