Wholemeal Rye Bread Research Articles

Lipolysis and Sterol Stability and Bioaccessibility of Wholemeal Rye Bread Enriched with Plant Sterols Subjected to Adult and Elderly Digestion Conditions.

This study evaluated the impact of different digestion conditions (adult and senior) on lipolysis and bioaccessibility of plant sterols (PS) and phytosterol oxidation products (POPs) in PS-enriched wholemeal rye bread. Under adult digestion conditions, the addition of gastric lipase (GL) reduced lipolysis products (by 6.1% for free fatty acids and 11.7% for monoacylglycerols) and the bioaccessibility of PS by 6.7%, compared to the control. In digestion with both GL and cholesterol esterase (CE), these reductions were 12.9, 20.1, and 11.3%, respectively. Both modifications (GL and GL + CE) increased the bioaccessibility of POPs by 4.5-4.0%. When simulating the elderly digestion, the modified gastric and intestinal phases did not alter PS bioaccessibility but decreased POPs bioaccessibility by 21.8% compared to control, along with reduced lipolysis. Incorporating GL and CE thus approached physiological conditions and influenced lipid digestion. Elderly simulated digestion conditions resulted in a positive outcome by maintaining PS bioaccessibility while reducing potentially harmful POPs.

Human Oral Phase Coupled with In Vitro Dynamic Gastrointestinal Digestion for Assessment of Plant Sterol Bioaccessibility from Wholemeal Rye Bread.

A dynamic gastrointestinal digestion system (simgi) after a human oral phase was used, for the first time, to assess the bioaccessibility of plant sterols (PS) from wholemeal rye bread (74.8 ± 2.2 mg of PS/100 g d.m.) and PS-enriched wholemeal rye bread (PS-WRB) (1.6 ± 0.04 g of PS/100 g of fresh bread). The use of these solid food matrices requires a novel adaptation of the gastric phase of the system. The PS identified in the breads are campesterol, campestanol, stigmasterol, β-sitosterol, sitostanol, Δ5-avenasterol, Δ5,24-stigmastadienol, Δ7-stigmastenol, and Δ7-avenasterol. The bioaccessibility of the total PS, only quantifiable in PS-WRB, is 19.9%, with Δ7-avenasterol being the most bioaccessible and Δ5-avenasterol being the least (p < 0.05). As shown in this study, PS-WRB can be considered to be a good choice to include in the daily diet. Furthermore, although the use of dynamic digestion methods for evaluating bioaccessibility implies high costs and technical complexity, their application means a closer approximation to in vivo scenarios.

Chemopreventive Effect of an In Vitro Digested and Fermented Plant Sterol-Enriched Wholemeal Rye Bread in Colon Cancer Cells.

Diet is crucial for the prevention of colorectal cancer. Whole grains are the source of beneficial compounds for this, such as fiber. The enrichment of wholemeal rye bread with plant sterols (PSs) could increase its beneficial effects. This study aimed to assess the potential antiproliferative effect of this enriched food on colon adenocarcinoma cells (Caco-2) compared with a non-enriched one. After a human oral chewing, simulated semi-dynamic gastrointestinal digestion and colonic fermentation in a simgi® system, fermentation liquids (FLs) obtained were used as treatment for cells. Cytotoxicity assay showed that samples diluted 1/5 (v/v) with DMEM are not toxic for non-tumoral cells, whereas they damage tumoral cells. Samples with PS (FLPS) produced a higher chemopreventive effect (vs. blank) in MTT and apoptosis assays, as well as higher gene expression of TP53 and Casp8. Nevertheless, FL0 (without PS) produced a higher chemopreventive effect in a cell cycle and reduced glutathione and calcium assays, besides producing higher gene expression of Casp3 and lower CCND1. The distinct antiproliferative effect of both FLs is attributed to differences in PSs, short chain fatty acids (lower concentration in FLPS vs. FL0) and antioxidant compounds. These results may support wholemeal rye bread consumption as a way of reducing the risk of colorectal cancer development, although further research would be needed.

Aging-related gastrointestinal conditions decrease the bioaccessibility of plant sterols in enriched wholemeal rye bread: in vitro static digestion.

The prevention of cardiovascular disease using foods fortified with plant sterols (PS), with a hypocholesterolemic effect, is important for the elderly population. This study aimed at identifying the different PS present in PS-enriched wholemeal rye bread (WRB) and in the ingredient source of PS, to evaluate their bioaccessibility in WRB by simulated static digestion. The gastrointestinal conditions of the elderly were adapted, and the results were compared with the adult population. Nine PS were identified, and a total amount of 2.18 g/100 g WRB was determined. Bioaccessibility was reduced in the elderly model with gastrointestinal adaptation vs. the adult model (11.2 vs. 20.3%), but no differences were observed when adapting only the gastric phase. Even though there was lower bioaccessibility of PS in the elderly, they could benefit from the consumption of WRB as it has a good nutritional profile. Further investigation including in vivo assays is needed to strengthen the results.

Enrichment of Wholemeal Rye Bread with Plant Sterols: Rheological Analysis, Optimization of the Production, Nutritional Profile and Starch Digestibility.

Bread is one of the staple foods of many countries, and its enrichment with bioactive compounds is trending. This phenomenon is focused on breads with a good nutritional profile, such as wholemeal rye bread (WRB), in which enrichment with plant sterols (PSs) is allowed in accordance with European regulations. The objective of the present study was to optimize the production of a WRB enriched with PS (PS-WRB) and to evaluate the proximate composition and starch digestibility as an indicator of nutritional quality. The rheological analysis showed that the bread dough presents satisfactory farinographic properties (dough development time 6 min; stability 4 min; degree of softening 100 Brabender units) but high water absorption (67%). The PS-WRB is high in dietary fiber and low in protein (20.4 and 7.7% w/w, dry basis, respectively) compared with other cereals reported in the scientific literature. In turn, a low starch proportion was hydrolyzed during the simulated digestion (59.9% of total starch), being also slowly hydrolyzed, as deduced from the rapidly digestible starch value (56.5% of total starch). In conclusion, WRB is a suitable matrix for PS enrichment, which allows for obtaining a product with a good nutritional profile and potential health benefits.

Bioaccessibility of Plant Sterols in Wholemeal Rye Bread Using the INFOGEST Protocol: Influence of Oral Phase and Enzymes of Lipid Metabolism.

Bioaccessibility of plant sterols (PS) in an enriched wholemeal rye bread was evaluated, for the first time, using the INFOGEST protocol without gastric lipase (GL) and cholesterol esterase (CE), with GL or GL + CE. Moreover, human chewing and an in vitro oral phase (simulated salivary fluid and α-amylase) were evaluated for this purpose. The addition of GL decreased the bioaccessibility of total PS (from 23.8 to 18.5%), whereas the use of GL + CE does not significantly affect PS bioaccessibility. The in vitro oral phase resulted in an ineffective homogenization of the fresh vs partially dried and milled bread, reducing the bioaccessibility of total (from 20.2 to 12.8%) and individual PS. The INFOGEST digestion including the use of GL and CE, as well as an oral phase with human chewing, is proposed for the assessment of PS bioaccessibility in a solid matrix such as wholemeal rye bread since it more closely approximates the in vivo situation.

Developing lactic acid bacteria starter cultures for wholemeal rye flour bread with improved functionality, nutritional value, taste, appearance and safety.

Starter cultures composed of lactic acid bacteria (LAB) were developed based on the genotypic and phenotypic characterisation of isolates belonging to dominant groups of bacteria in spontaneous rye wholemeal sourdoughs. Combinations of strains have been evaluated on an industrial scale in the sourdough fermentation process. Wholemeal rye bread was prepared using sourdoughs obtained with 3 new starter cultures, and compared to bread made using the commercial culture (LV2). All newly developed cultures used for the preparation of wholemeal rye bread allowed to obtain better quality products as compared to the LV2 based bread. The best results were obtained when the culture containing Lactiplantibacillus plantarum 2MI8 and exopolysaccharide (EPS)-producing Weissella confusa/cibaria 6PI3 strains was applied. The addition of yeast during sourdough breads production, especially the one prepared from mentioned above starter culture, significantly improved their organoleptic properties, their volume and crumb moisture was increased, and also the crumb acidity and hardness was reduced. Fermentation of rye wholemeal dough, especially without the yeast addition, resulted in a significant reduction in the content of higher inositol phosphates as compared to the applied flour, which is associated with improved bioavailability of minerals. The results of this study prove that the investigated new starter cultures can be successfully applied in wholemeal rye bread production.

Effects of fibre-rich rye milling fraction on the functional properties and nutritional quality of wholemeal rye bread

The goal was to assess the effects of partial replacement of wholemeal rye flour with 30%, 40% and 50% of the high-fibre rye flour (HFRF) on nutritional quality and sensory and physicochemical characteristics of breads. The HFRF supplemented breads (SB30, SB40, SB50) were compared in their nutrients and energy contents, physicochemical and sensory properties, and in vitro digestibility to the control bread (CB). There were no significant differences in shape and volume of loaves, crusts and crumbs appearance, taste and smell of two supplemented breads (SB30 and SB40) and the CB. Compared to the CB, all supplemented breads contained significantly more soluble and insoluble fibre, arabinoxylan and β-glucan, but less available saccharides, including rapidly available glucose. Bread with 40% HFRF (SB40) yielded both, improved nutritional quality and acceptable sensory characteristics comparable to the CB. An in vitro overall digestibility of the SB40 was lower than that of the CB but the losses of dietary fibre and its components after enzymatic digestion were comparable between both breads. In conclusion, rye bread supplemented with 40% of the HFRF had improved nutritional quality and acceptable sensory and physicochemical characteristics and could be considered as an option to commonly consumed wholemeal rye bread.

Procedures for Breadmaking Quality Assessment of Rye Wholemeal Flour.

The aim of this study was to evaluate the baking value of rye flours from industrial mills and to indicate which rye flour quality parameters are the most important predictors of wholemeal rye bread quality for commercially milled rye grains. Ten wholemeal rye flours, which were characterized by ash content ranging from 1.43% to 2.42% d.m. (dry mass), were used for the study. The parameters that characterize the flour properties and the baking test were assessed. The study revealed that for the analyzed commercial rye flours, the falling number test and the amylograph properties are insufficient parameters for predicting the quality of wholemeal rye bread. The manufacture of good quality wholemeal bread requires the use of rye flour with superior quality, such as fine granulation, low protein content, low total and insoluble pentosans content, and, in particular, a high percentage of water-soluble pentosans content. Breads with a higher volume were obtained from rye flours that were generally characterized by lower protein content, lower total and insoluble pentosans content, and higher water-soluble pentosans content. Flour granulation and the percentage of water-soluble pentosans content especially, had a significant impact on bread’s hardness of crumb and the hardness of crumb’s increase during bread storage.

Mastication-induced release of compounds from rye and wheat breads to saliva

Mastication initiates digestion, disintegrating food structure and mixing it with saliva. This study aimed to provide understanding about the first step of bread digestion by exploring release of compounds from bread matrix during mastication. Furthermore, the aim was to identify compound groups that differentiate rye and wheat breads.Fifteen participants masticated whole-meal rye bread, endosperm rye bread, endosperm rye bread with added gluten and wheat bread. The masticated samples were studied with non-targeted LC-MS metabolic profiling.A great number of compounds were released from bread matrices in mastication, and the identified compounds differed largely between bread types. Specifically, rye bread samples were characterized by a greater release of peptides and amino acids, whereas sugars and nucleosides were characteristic for wheat bread. These compounds could potentially act as signal molecules in the alimentary tract and may explain, at least partly, the postprandial physiological effects of the breads identified in earlier studies.

Glycaemic and insulin index of four common German breads.

German-style breads are recommended as a lower glycaemic index (GI) alternative, yet little data is available. Our aim was to test the GI and insulin index (II) of four breads and rolls commonly consumed in Germany. Four German bread products were tested for their GI and II in 12 healthy subjects according to the International Standard Organization guidelines. Only the wholemeal rye bread with visible intact grains and sunflower seeds was identified as low GI (GI=55). Both the wholemeal spelt wheat (GI=63) and the rye wheat sourdough bread (GI=62) were classified as medium GI, whereas soft pretzel was high GI (GI=80, P<0.05 compared with other products). The II of soft pretzels (II=102) was also highest and differed significantly from wholemeal rye (II=70) and rye sourdough bread (II=72) but not from wholemeal spelt wheat (II=77). Contrary to popular belief, these German-style breads are medium to high GI, with the exception of the rye bread with intact grains and seeds. The results highlight the need to test, rather than 'guestimate', the GI of local products, and develop a broader range of low-GI breads.

The effect of fermentation and addition of vegetable oil on resistant starch formation in wholegrain breads

Resistant starch has potential health benefits but the factors affecting its formation in bread and baked products are not well studied. Here, the formation of resistant starch in wholemeal bread products was evaluated in relation to the processing conditions including fermentation time, temperature and the inclusion of palm oil as a vitamin source. The effects of each the factor were assessed using a full factorial design. The impact on final starch content of traditional sourdough fermentation of wholemeal rye bread, as well as the bulk fermentation process of wheat and wheat/oat blends of wholemeal bread, was also assessed by enzyme assay. Palm oil content was found to have a significant effect on the formation of resistant starch in all of the breads while fermentation time and temperature had no significant impact. Sourdough fermentation of rye bread was found to have a greater impact on resistant starch formation than bulk fermentation of wheat and wheat blend breads, most likely due the increased organic acid content of the sourdough process.

HEALTH BENEFITS OF KVASS MANUFACTURED FROM RYE WHOLEMEAL BREAD

Kvass based on traditional technology completely disappeared from polish market. It was replaced by drinks, prepared from malt concentrates, wrongly named kvass. The aim of this study was therefore to obtain traditional bread kvass (by fermentation), using the mash prepared from commercial wholemeal rye bread, produced by 5-phase dough fermentation method, and to determine the quality of this kvass in terms of consumer acceptance, chemical composition and antioxidant activity. It has been demonstrated that based on the traditional wholemeal rye bread, it is possible to produce good quality bread kvass, with similar organoleptic qualities to the commercial kvasses, which contain several added flavours and preservatives. Natural bread kvass can be consumed by consumers of all ages, since it contains only trace amounts of alcohol, and it has almost double the dietary fibre content and three times lower content of reducing sugars as compared to the commercial kvasses. Laboratory made kvasses by natural fermentation also showed an increase in antioxidant activity by 60%, when compared to commercial kvasses.

Effects of wheat and rye bread structure on mastication process and bolus properties

Chemical composition, baking process and structure of breads influence their degradation in digestion leading to different postprandial responses. Rye bread has a very different structure as compared to wheat bread, and rye breads are known to induce lower postprandial insulin responses than wheat bread. The aim of this study was to find out potential differences in mastication and initial starch hydrolysis rate of rye and wheat breads. Three rye breads (wholemeal rye, endosperm rye and endosperm rye with gluten) and wheat bread were masticated by fifteen participants and the process was monitored using electromyography. The particle size distribution and initial in vitro starch hydrolysis of the bread boluses were analysed. Specific volume correlated negatively and closed porosity of breads correlated positively with work required for mastication. When compared to wheat bread, wholemeal rye bread required more work for mastication process (p=0.004). Rye breads were degraded to smaller particles than wheat bread during mastication. There was a trend (p=0.098) towards slower in vitro starch hydrolysis rate in rye bread boluses than in wheat bread boluses. The results indicate that the digestion process of rye breads differs from that of wheat bread already in the early phase of digestion. This may be one reason behind the unique postprandial responses reported for rye breads.

Identification of α-Tocotrienolquinone Epoxides and Development of an Efficient Molecular Distillation Procedure for Quantitation of α-Tocotrienol Oxidation Products in Food Matrices by High-Performance Liquid Chromatography with Diode Array and Fluorescence Detection

The aim of this study was to investigate the most important oxidation products of α-tocotrienol (α-T3) along with other tocochromanols in lipid matrices and tocotrienol-rich foods. For this purpose, an efficient molecular distillation procedure was developed for the extraction of analytes, and α-T3-spiked and thermally oxidized natural lipids (lard and wheat germ oil) and α-T3-rich foods (wholemeal rye bread and oil from dried brewer's spent grain) were investigated through HPLC-DAD-F. The following α-T3 oxidation products were extractable from lipid matrices along with tocochromanols: α-tocotrienolquinone (α-T3Q), α-tocotrienolquinone-4a,5-epoxide (α-T3Q-4a,5-E), α-tocotrienolquinone-7,8-epoxide (α-T3Q-7,8-E), 7-formyl-β-tocotrienol (7-FβT3), and 5-formyl-γ-tocotrienol (5-FγT3). Recovery rates were as high as 88% and enrichment factors up to 124. The proposed method allows the investigation of α-T3Q, α-T3Q-4a,5-E, α-T3Q-7,8-E, 7-FβT3, and 5-FγT3 in small quantities (<0.78 μg/g) in lipid matrices, which is necessary for the investigation and analysis of the formation kinetics of these oxidation products in fat, oils, and tocotrienol-rich foods.

Chemopreventive effects of in vitro digested and fermented bread in human colon cells

Bread as a staple food product represents an important source for dietary fibre consumption. Effects of wheat bread, wholemeal wheat bread and wholemeal rye bread on mechanisms which could have impact on chemoprevention were analysed in colon cells after in vitro fermentation. Effects of fermented bread samples on gene expression, glutathione S-transferase activity and glutathione content, differentiation, growth and apoptosis were investigated using the human colon adenoma cell line LT97. Additionally, apoptosis was studied in normal and tumour colon tissue by determination of caspase activities. The expression of 76 genes (biotransformation, differentiation, apoptosis) was significantly upregulated (1.5-fold) in LT97 cells. The fermented bread samples were able to significantly increase glutathione S-transferase activity (1.8-fold) and glutathione content (1.4-fold) of the cells. Alkaline phosphatase activity as a marker of differentiation was also significantly enhanced (1.7-fold). The fermented bread samples significantly inhibited LT97 cell growth and increased the level of apoptotic cells (1.8-fold). Only marginal effects on apoptosis in tumour compared to normal tissue were observed. This is the first study which presents chemopreventive effects of different breads after in vitro fermentation. In spite of differences in composition, the results were comparable between the bread types. Nevertheless, they indicate a potential involvement of this staple food product regarding the prevention of colon cancer.

Comparative study of colorectal health related compounds in different types of bread: Analysis of bread samples pre and post digestion in a batch fermentation model of the human intestine

Seven different types of wheat and rye bread were analysed for colorectal health related compounds, pre and post digestion, in batch fermentation model of the human intestine. Pre digestion, higher amounts of colorectal health-related dietary fibre compounds (soluble/insoluble/total dietary fibre, arabinoxylans, β-glucans) and phytochemicals (mono-/di-phenolic acids, phytic acid, hydroxymethylfurfural) were detected in wholemeal than in refined flour types of bread, as well as in rye flour types than in wheat flour types of bread. Post digestion, faecal bacterial metabolites of colorectal health promoting (acetate/propionate/butyrate, lactate, free mono-/di-phenolic acids) and impairing (amino metabolites, bile acid metabolites) activities were found in fermentation supernatants of bread samples. All types of bread positively affected faecal bacterial metabolism; among the different types of bread, the highest stimulation of organic acid production (acetate/propionate/butyrate, lactate) and the lowest detrimental bacterial enzyme activities (β-glucuronidase, urease) were detected for wheat flour bread, whereas the strongest retardation of bacterial bile acid degradation and the strongest stimulation of phenolic acid metabolite release (phenylpropionic/phenylpropenoic acid derivatives) were induced by wholemeal rye bread. This study for the first time presents a qualitative and quantitative overview over the broad spectrum of colorectal health related compounds in high- and low-fibre types of bread, pre and post in vitro digestion, and highlights the significance of bread for the preventive nutritional intervention of colorectal cancer.

The role of pentosans and starch in baking of wholemeal rye bread

Abstract In case of rye wholemeal with low enzymatic activity, high bread volume is obtained in cases, when pentosan fraction contains many water extractable polymers, and there is an optimum ratio of water extractable pentosans to starch, which should be in the range 1:16–1:20. This is also accompanied by starch properties such as high amylose content, good swelling capacity (big swelling factor) and consequently high solubility and pasting temperature. Moisture content of wholemeal rye bread is mainly controlled by the level of fiber, including soluble pentosans, compared to the amount of starch. Starch properties which seem to be important for establishing this value are amylose content, and the susceptibility to swelling and gelatinization. Hardness of wholemeal rye bread is influenced by the level of fiber, including soluble pentosans. Decline of bread texture is observed in the presence of extractable pentosans with high molecular weight. Use of starch with high amylose level, high swelling factor and low molecular weight is accompanied by increased crumb hardening.

Effect of commercial rye whole-meal bread on postprandial blood glucose and gastric emptying in healthy subjects

BackgroundThe intake of dietary fibre has been shown to reduce the risk of developing diabetes mellitus. The aim of this study was to compare the effects of commercial rye whole-meal bread containing whole kernels and white wheat bread on the rate of gastric emptying and postprandial glucose response in healthy subjects.MethodsTen healthy subjects took part in a blinded crossover trial. Blood glucose level and gastric emptying rate (GER) were determined after the ingestion of 150 g white wheat bread or 150 g whole-meal rye bread on two different occasions after fasting overnight. The GER was measured using real-time ultrasonography, and was calculated as the percentage change in antral cross-sectional area 15 and 90 minutes after completing the meal.ResultsNo statistically significant difference was found between the GER values or the blood glucose levels following the two meals when evaluated with the Wilcoxon signed rank sum test.ConclusionThe present study revealed no difference in postprandial blood glucose response or gastric emptying after the ingestion of rye whole-meal bread compared with white wheat bread.Trial registrationNCT00779298

Long-term intake of iron fortified wholemeal rye bread appears to benefit iron status of young women

The efficacy of intake of iron fortified, wholemeal rye bread on iron status of young women with low iron stores was evaluated in a 5 month single-blind intervention study. Two parallel groups of women (20–38 y) were given 144 g of rye bread/d either fortified with 6 mg iron as ferrous fumarate/100 g bread (i.e. 8.6 mg iron/d) ( n=21) or unfortified ( n=22) in addition to their normal diet. Blood samples were taken at 0, 2.5 and 5 months. Serum ferritin in the control group changed significantly from 0 mo: 24.6 [21.0–28.8] μg/l to 5 mo: 20.2 [17.5–23.3] μg/l. There was no change in serum ferritin in subjects given iron fortified bread. Haemoglobin was unchanged in the control group, 124±8 g/l. In the fortification group, there was a non-significant increase from 0 to 5 months: 124±6 and 126±8 g/l. Intake of fortified wholemeal rye bread resulted in a stabilisation of iron stores of young women with poor iron status which were otherwise reduced by intake of the unfortified control bread.