R. Havenaar

Bioprocessing of Wheat Bran in Whole Wheat Bread Increases the Bioavailability of Phenolic Acids in Men and Exerts Antiinflammatory Effects ex Vivo

Whole grain consumption has been linked to a lower risk of metabolic syndrome, which is normally associated with a low-grade chronic inflammation. The benefits of whole grain are in part related to the inclusion of the bran, rich in phenolic acids and fiber. However, the phenols are poorly bioaccessible from the cereal matrix. The aim of the present study was to investigate the effect of bioprocessing of the bran in whole wheat bread on the bioavailability of phenolic acids, the postprandial plasma antioxidant capacity, and ex vivo antiinflammatory properties. After consumption of a low phenolic acid diet for 3 d and overnight fasting, 8 healthy men consumed 300 g of whole wheat bread containing native bran (control bread) or bioprocessed bran (bioprocessed bread) in a cross-over design. Urine and blood samples were collected for 24 h to analyze the phenolic acids and metabolites. Trolox equivalent antioxidant capacity was measured in plasma. Cytokines were measured in blood after ex vivo stimulation with LPS. The bioavailabilities of ferulic acid, vanillic acid, sinapic acid, and 3,4-dimethoxybenzoic acid from the bioprocessed bread were 2- to 3-fold those from the control bread. Phenylpropionic acid and 3-hydroxyphenylpropionic acid were the main colonic metabolites of the nonbioaccessible phenols. The ratios of pro-:antiinflammatory cytokines were significantly lower in LPS-stimulated blood after the consumption of the bioprocessed bread. In conclusion, bioprocessing can remarkably increase the bioavailability of phenolic acids and their circulating metabolites, compounds which have immunomodulatory effects ex vivo.

Ferulic acid from aleurone determines the antioxidant potency of wheat grain (Triticum aestivum L.).

Grain is an important source of phytochemicals, which have potent antioxidant capacity. They have been implicated in the beneficial health effect of whole grains in reducing cardiovascular disease and type 2 diabetes. The aim of the present study was to identify the most important antioxidant fractions of wheat grain. It was found that the aleurone content of these fractions was highly correlated with the antioxidant capacity of the fractions (r = 0.96, p < 0.0001). Ferulic acid appeared to be the major contributor to the antioxidant capacity in fractions with higher antioxidant capacity. The contribution of protein was rather limited. It was concluded that the antioxidant potency of wheat grain fractions is predominantly determined by aleurone content, which can be attributed to the presence of relatively large amounts of phenolic compounds, primarily ferulic acid.

Effects of a high fat meal matrix and protein complexation on the bioaccessibility of blueberry anthocyanins using the TNO gastrointestinal model (TIM-1)

The TNO intestinal model (TIM-1) of the human upper gastrointestinal tract was used to compare intestinal absorption/bioaccessibility of blueberry anthocyanins under different digestive conditions. Blueberry polyphenol-rich extract was delivered to TIM-1 in the absence or presence of a high-fat meal. HPLC analysis of seventeen anthocyanins showed that delphinidin-3-glucoside, delphinidin-3-galactoside, delphinidin-3-arabinoside and petunidin-3-arabinoside were twice as bioaccessible in fed state, whilst delphinidin-3-(6″-acetoyl)-glucoside and malvidin-3-arabinoside were twice as bioaccessible under fasted conditions, suggesting lipid-rich matrices selectively effect anthocyanin bioaccessibility. TIM-1 was fed blueberry juice (BBJ) or blueberry polyphenol-enriched defatted soybean flour (BB-DSF) containing equivalent amounts of free or DSF-sorbed anthocyanins, respectively. Anthocyanin bioaccessibility from BB-DSF (36.0±10.4) was numerically, but not significantly, greater than that from BBJ (26.3±10.3). Ileal efflux samples collected after digestion of BB-DSF contained 2.8-fold more anthocyanins than same from BBJ, suggesting that protein-rich DSF protects anthocyanins during transit through upper digestive tract for subsequent colonic delivery/metabolism.

Complementary Approaches To Gauge the Bioavailability and Distribution of Ingested Berry Polyphenolics

Two different strategies for investigating the likely fate, after ingestion, of natural, bioactive berry constituents (anthocyanins and other non-nutritive flavonoids) are compared. A model of the human gastrointestinal tract (TIM-1) that mimicked the biological environment from the point of swallowing and ingestion through the duodenum, jejunum, and ileum (but not the colon) was used to monitor the stability and bioaccessibility of anthocyanins from both maqui berry and wild blueberry. TIM-1 revealed that most anthocyanins were bioaccessible between the second and third hours after intake. Alternatively, biolabeled anthocyanins and other flavonoids generated in vitro from berry and grape cell cultures were administered to in vivo (rodent) models, allowing measurement and tracking of the absorption and transport of berry constituents and clearance through the urinary tract and colon. The advantages and limitations of the alternative strategies are considered.

Effect of bioprocessing of wheat bran in wholemeal wheat breads on the colonic SCFA production in vitro and postprandial plasma concentrations in men.

The health benefits of whole grain consumption can be partly attributed to the inclusion of the bran or outer-layers of the grain rich in dietary fibre. Fibre is fermented in the colon, leading to the production of beneficial metabolites, such as short-chain fatty acids (SCFA). The effect of five different types of bread on the SCFA production was studied in an in vitro model of human colon. Additionally, the postprandial effects of two selected breads on the SCFA plasma concentrations were investigated in men. A higher in vitro production of butyrate was induced by wholemeal wheat bread with bioprocessed bran than by native bran. The increase in butyrate seemed to be in exchange for propionate, whilst the total SCFA production remained similar. However, differences between the two breads in the postprandial butyrate concentrations could not be detected in peripheral blood of men, probably due to an effective utilisation by colonocytes.

Anti-inflammatory effect of breads in relation to the bioavailability of phenolic compounds

Phenolic compounds (PC) are food-derived bioactive compounds contained in the daily diet. PC have been claimed to help prevent cancer, degenerative diseases and chronic and acute inflammation. A possible mechanism of anti-inflammatory action is by their effect on the redox sensitive transcription factor nuclear factor kappaB, inducible nitric oxide synthase expression and cyclooxygenase inhibition. The anti-inflammatory effects of PC are evident in vitro using high concentrations; however, physiological concentrations are dependent on their bioavailability from the food source, which is often limited. Cereal products contribute substantially to the total intake of PC. Most of the PC in the cereal grain are concentrated in the outermost part, the bran. Therefore, wholemeal breads containing either native or bioprocessed bran were tested for their post-prandial effects on an inflammatory response ex vivo. The objective of this investigation was to evaluate the anti-inflammatory effect of PC in relation to their bioavailability from a natural dietary source, such as bread. The study design was: crossover, with 8 healthy men undergoing 3-days low phenolic diet prior to intervention and at least 1 week of wash-out period between the two intervention days. Blood was drawn before bread ingestion (t0 or baseline), and at 1 h 15 min, 6 h and 12 h after ingestion. Whole blood was incubated with LPS (1 ng/ml) for 24 h and TNF-a, IL-6, IL-1b and IL-10 were determined. The PC quantified in plasma were: ferulic acid, vanillic acid, p-coumaric acid, sinapic acid and their colonic metabolites: phenylpropionic acids, phenylacetic acids, and benzoic acids with different grades of hydroxylation. The ratio of pro-/anti-inflammatory cytokines at 1 h 15 min, 6 h and 12 h after bread ingestion was lower than baseline (t0). The bread with bioprocessed bran showed a stronger effect than the one with native bran, which could be associated with an increase in the bioavailability of PC by the bioprocessing.

Antioxidant and anti-inflammatory potency of different wheat varieties and fractions

IrNo QuaLirv oJ Ltre Po Box t*tl!ioolt;;,1;,,!:,,1;i;yi,!:ri:;,2n,niversirtrtJ Meta;*icttr Po tsor 6t6 Risk factors for diet-related disorders are oxiclative stress and chlonic intlarnmation. Wheat is a source of phytochernicals with antioxiclant activity that might play a role in the observed protection of whole-grain diets against metabolic disorders The aims of the present study were first to investigate the bioaccessibility of antioxidant and anti-inflammatory activity tom difterent wheat fractiolls during gastrointestinal (Gl) transit and second to demonstrate the contribution of wheat cornpounds to these health factors Experiments were perforned in the TIM system, which is a dynamic computer-controlled model consisting of gastric, duodenal, je.lunal and ileal colnpartlnents simulating conditions in the human GI tract(r2). Samples were collected in I h aliquots tbr 6h fionr the dialysates of the jejunal and ileal colnpartlnents to measure the kinetics of bioaccessibility of antioxidant capacity and anti-inflanrnl?rtory responses. Antioxidant capacity (Trolox equivalent antioxidant capacity assay) and ferulic acid, polyphenol and prorein conterits were de[ennined. Anti-inflanrmatory effects were measured in extmcts and TIM samples nsing a hunran rnacroplrage cell systenl with lipopolysirccharide (LPS)-induced TNFa and IL-6 secretion. Antioxidant capacity was unevenly distlibuted within the whear fractions (aleurone tiactions>bran tiactions>flour fractions), without difTerences between cultivars (Tiger and Crousty). Antioxidant capacity was conelated rvith the f-erulic acid content (/l 0.9(r, P<0.00001) Ferulic acid was the rnajor contributor to the antioxidant capacity in bran and aleurone fiactions (-50-607c). However, fÞrulic acid did not reduce TNFo and IL-6 levels in a dose-dependent lnanner. The TIM experirnents showed that the antioxidant capacity was bioaccessible during CI digestion. [n the case of the blan and aleurone fiactions the bioaccessibility was significantly lower (20-30a/o initial aritioxiclant capacity) than that frorn the flour fraction. The bioaccessibility of ferulic acid was sirnilarly low fronr the bran ancl aleurone fractions. In experiments with flour terulic acid was below the detection limit in the dialysate sarnples, because of the low initial level ât oml intake The dialysates samples collected from TlM showed reduced levels of TNFq, for the bran and aleurone fiactions, reaching nraxirnal inhibition at the 2nd hour and 3rd hour (Figure). These data corresponded with the maxirnuin levels of the bioaccessibility ol the antioxidant capacity from these fractions.

New methods for assessment of nutritional and health effects of cereal products.

ABSTRACT Insight in physiological and molecular mechanisms linking diet to health benefits is rapidly growing. New techniques can significantly contribute to our understanding of “what is going on in the intestinal black box” after intake of cereal products. Bioassays are used to study potential beneficial health effects of whole grain products. These bioassays, in combination with modern instrumental analytical techniques like LCMS, can aid in identifying those fractions which show biological activity and can be investigated further for stability, bioavailability and activity in the gastrointestinal (GI) tract. Validated in vitro model systems mimicking the entire GI tract (TIM systems) have created a powerful tool for monitoring the impact of product structure and whole grain compounds (e.g. dietary fibres, phenolics, tocols, folate, trace elements) on viscosity of the GI content, glycaemic response, availability and interactions of nutrients and bioactive molecules as well as bioconversion by the intestinal microflora. In a recent model study on fermentation in the large intestine the presence of fermentable carbohydrates proved to be essential to counteract the negative impact on intestinal health of high protein diets, such as the Dr. Atkins diet. Studies in GI model systems can also be combined with chemical analysis and bioassays to study effects on chronic inflammatory events. Newly developed analytical tools used in our studies are: total antioxidant capacity and several specific cell lines to determine the antioxidant action on inflammatory parameters, such as interleukines, TNF-alpha, hsCRP and effects on NF-kappa B/I-kappa B alpha. This approach can significantly support R&D for designing products contributing to reduced risk for cardio-vascular diseases, type-2 diabetes and other disorders related to inflammation.