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Date fruits (Phoenix dactylifera) of ten varieties, collected in the United Arab Emirates, were studied to determine their dietary fiber content and composition. Fourier transform infrared (FTIR) spectroscopy indicated that the dietary fiber components in all the date fruit varieties was similar. The major dietary fiber components, including cellulose, hemicellulosic components, lignin, and pectin, were analyzed by the Uppsala method. The total dietary fiber content in the date fruits analyzed (5.2%–8.3%) is comparable to commonly consumed dried fruits and is correlated with the content of lignin. The lignin was the main determinant of the total dietary fiber content in dates and its content was higher in semi-hard and hard fruit varieties.

Material disintegration is the primary step in β-glucan determination in cereal grains. This study investigated the effect of disintegration approach on β-glucan content, determined by an enzymatic method in mature kernels of barley and oat. Milling with a coffee grinder was found to be relevant only for pre-disintegration and homogenization of the grain (4.6% and 3.2% β-glucan content was found in barley and oats, respectively). Ball milling appeared to be the most efficient approach for reducing material particle size, but resulted in samples with underestimated β-glucan content (4.6% and 3.3% in barley and oats, respectively). Grinding with mortar and pestle in liquid nitrogen and repeated centrifugal milling were found to be the optimal disintegration methods for barley kernels (5.2% and 4.7–4.8% β-glucan content, respectively). Grinding with mortar and pestle (either in dry state or in liquid nitrogen) and single centrifugal milling were the optimal disintegration methods for oat kernels (3.6–3.9% and 3.3–3.4% β-glucan content, respectively).

Date fruits vary widely in the hardness of their edible parts and they are classified accordingly into soft, semi-dry, and dry varieties. Fruit texture, a significant parameter in determining consumer acceptance, is related to the tissue structure and chemical composition of the fruit, mainly the ratio of sucrose to reducing sugars. This study aimed to understand the relationship between the chemical composition, microstructure, and texture profile of 10 major Emirati date fruits. The soluble sugars, glucose and fructose, represent ca 80 g/100 g of the fruits on the basis of dry weight (DW) while the dietary fiber contents varied 5.2–7.4 g/100 dg D.W. with lignin being the main determinant of the variability. The textures of the samples were studied using instrumental texture profile analysis. While no correlation was found between the soluble sugar and texture parameters in this study, the different fiber constituents correlated variably with the different parameters of date fruit texture. Lignin, arabinoxylan, galactomannan, and pectin were found to correlate significantly with fruit hardness and the related parameters, gumminess and chewiness. Both lignin and arabinoxylan correlated with resilience, and arabinoxylan exhibited a strong correlation with cohesiveness.

In this study, 50% sifted barley flour from six different varieties and 50% refined wheat flour was used to bake bread. The flour mixture and the bread crumb and crust were analysed for content and composition of total dietary fibre, arabinoxylan, fructan, β-glucan, starch and resistant starch. Total dietary fibre content and extractability were not changed significantly by bread making. The extractability of mixed-linkage (1 → 3), (1 → 4)- β-D-glucan (β-glucan) increased with baking, while the average molecular weight of β-glucan decreased. However in one variety, SLU 7, higher average molecular weight was maintained and a different pattern was apparent in the molecular weight distribution. SLU 7 is thereby promising for inclusion in bread where a higher molecular weight of β-glucan is preferred, especially since the content of β-glucan in SLU 7 is high. The resistant starch formed positively correlated with amylose content. The high amylose variety yielded 2.9% resistant starch in the bread crumb, making an important contribution to total dietary fibre.

Wheat bran and rye bran are mostly used as animal feed today, but their high content of dietary fiber and bioactive components are beneficial to human health. Increased use of bran as food raw material could therefore be desirable. However, bran mainly contains unextractable dietary fiber and deteriorates the sensory properties of products. Processing by extrusion could increase the extractability of dietary fiber and increase the sensory qualities of bran products. Wheat bran and rye bran were therefore extruded at different levels of moisture content, screw speed and temperature, in order to find the optimal setting for increased extractability of dietary fiber and positive sensory properties. A water content of 24% for wheat bran and 30% for rye bran, a screw speed of 400 rpm, and a temperature of 130 °C resulted in the highest extractability of total dietary fiber and arabinoxylan. Arabinoxylan extractability increased from 5.8% in wheat bran to 9.0% in extruded wheat bran at those settings, and from 14.6% to 19.2% for rye bran. Total contents of dietary fiber and arabinoxylan were not affected by extrusion. Content of β-glucan was also maintained during extrusion, while its molecular weight decreased slightly and extractability increased slightly. Extrusion at these settings is therefore a suitable process for increasing the use of wheat bran and rye bran as a food raw material.

In this study, β-glucan in samples of sifted flour from six barley varieties was sequentially extracted with water and NaOH obtaining three fractions: water-extractable (WE), NaOH- extractable (NaE) and residual (Res). β-Glucan isolates were incubated with lichenase and oligomers released were analysed with high performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). A higher ratio of 3-O-β-cellobiosyl-D-glucose (DP3) to 3-O-β-cellotriosyl-D-glucose (DP4) is reported in WE, NaE and Res fractions in variety SLU 7 (shrunken endosperm) compared to the other varieties, suggesting a more packed β-glucan structure. Water-extractable and water-unextractable β-glucan fractions were incubated with wheat extract and effects of wheat β-glucanase on the structure was assessed after lichenase digestion and analysis with HPAEC-PAD. Findings suggest that wheat β-glucanase manifests a selective hydrolysis towards β-glucan with lower DP3/DP4 ratio and that β-glucan of SLU 7 is composed of a population with higher DP3/DP4 ratio and hence with a more tighten structure which may be more resistant to enzymic action. Overall, the results obtained are of interest to characterise barleys differing in starch and dietary fibre composition, specifically shrunken endosperm barley SLU 7 in the perspective of its inclusion in the production of β-glucan enriched foods.

Whole grain wheat and rye are important sources of many bioactive compounds and contribute significantly to the total intake of cereals in many countries. Alkylresorcinols, benzoxazinoids, lignans, phenolic acids, phytosterols and tocols are common bioactive compounds present in these cereals. In this review, we report recent findings (mainly from 2010 onwards) regarding their content, composition, effects of food processing and their uptake, elimination and bioactivities with implications for health.

Oat β-glucan has been shown to have cholesterol, insulin and glucose lowering effects, which are related to increased viscosity of the intestinal contents. Some important factors influencing the viscosity are molecular weight, structure and concentration. To study the effect of variety and environment on β-glucan content and molecular weight of β-glucan, four oat varieties were grown in 11 different environments (location × year combinations) in a field experiment. The β-glucan content varied between 2.3 and 3.2% and the average molecular weight of β-glucan between 1.73 and 2.02 × 10 6 g mol −1 . There was a significant difference between varieties and environments for both β-glucan content and molecular weight of β-glucan. The effect of environment was much greater on molecular weight (71%) than on β-glucan content (42%), while the effect of variety was greater on β-glucan content (23%) than on molecular weight (4%). There was also a positive significant correlation between β-glucan content and molecular weight of β-glucan ( p r = 0.46). These results show that β-glucan content is a better target for plant breeding than molecular weight. However, both factors are important for the physiological effects of β-glucan, and selection for high β-glucan content will probably also give higher molecular weight.

The alkylresorcinol (AR) content and relative homologue composition were determined in Norwegian flours and bread. The following average values for total AR content (μg/g dm) were found: wholegrain wheat flour available only to bakers (490) and to both consumers and bakers (710), refined wheat flour (36), wheat bran (3625), wholegrain spelt wheat flour (650), refined spelt wheat flour (80), wholegrain rye flour (972), refined rye flour (90) and rye bran (2753). The C17:0/C21:0 ratio was 0.1 for wheat and 0.8–0.9 for rye, confirming that it can be used to distinguish between wheat and rye. The AR content of Norwegian refined wheat flour was higher than that of Swedish, due to a consistently higher milling extraction rate in Norway. The content of AR varied from 27 to 2766 μg/g dm in hard bread and 21 to 548 μg/g dm in soft bread. The highest contents were found in bread with a high proportion of wholegrain flour and/or bran, in agreement with earlier studies. There was a good correlation (r = 0.91) and a high compliance between calculated and analysed AR levels in soft bread, confirming that AR can be used as a biomarker for wholegrain wheat and/or rye content in a cereal product.

BACKGROUND: Alkylresorcinols (AR) are amphiphilic phenolic compounds found in high amounts in wheat, durum wheat and rye, with different homologue composition for each cereal. The effect of different amounts of added AR from these cereals on bread volume, height, porosity and microstructure was studied. Breads with added rye bran (with high levels of AR) or acetone-extracted rye bran (with low levels of AR) were also baked, as well as breads with finely milled forms of each of these brans. RESULTS: Breads with high amounts of added AR, irrespective of AR homologue composition, had a lower volume, a more compact structure and an adverse microstructure compared with breads with no or low levels of added AR. AR were also shown to inhibit the activity of baker's yeast. There was no difference in bread volume and porosity between bread baked with rye bran and acetone-extracted rye bran or with brans of different particle size. CONCLUSION: Irrespective of homologue composition, AR had a negative effect on wheat bread properties when added in high amounts as purified extracts from wheat, durum wheat and rye. Natural levels of AR in rye bran, however, did not affect the volume and porosity of yeast-leavened wheat breads. Copyright © 2010 Society of Chemical Industry

Cereal alkylresorcinols (ARs), a group of phenolic lipids mainly found in the outer parts of wheat and rye kernels, are currently being studied for possible use as biomarkers of intake of whole grain wheat and rye foods. Several different techniques have been used for quantitative AR analysis over the years, but with limited attempts to compare them. In this present study, two commonly used methods, gas chromatography and colorimetry, were evaluated and compared. Gas chromatographic and the colorimetric methods showed good agreement. The GC-method provides the total amount of AR and relative homologue composition, whereas the colorimetric method, which is based on azo-coupling of a Fast Blue salt to the hydroxyl group(s) in the alkylresorcinol molecule, only provides the total amount, but is much faster and does only requires a UV-spectrophotometer.

Milling fractions of hull-less barley, and dough and bread with hull-less barley flour (40%) and wheat flour (60%) were analysed in an investigation of how the properties of (1→3, 1→4)-β-glucan were affected by milling, dough formation and bread making. Calcofluor average molecular weight ( M ¯ cf ) and molecular weight distribution and the cellotriosyl/cellotetraosyl ratio of the (1→3, 1→4)-β-glucan were determined. Four different hull-less barley samples were milled to produce straight-run white flours, shorts, bran and whole-meal flours. The molecular weight distributions were unimodal for all fractions, and the ( M ¯ cf ) range was between 117×104 and 188×104. These parameters were similar for all barleys, although ( M ¯ cf ) was somewhat lower in white flour and bran fractions and somewhat higher in shorts and whole-meal. The cellotriosyl/cellotetraosyl ratio (1.5–1.8) was also similar in all fractions. Doughs and breads were made to study how flour type (sifted or whole-meal barley flour), water content, yeast, mixing time and fermentation time affect (1→3, 1→4)-β-glucan. The molecular weight distribution of (1→3, 1→4)-β-glucan was polymodal with two or three populations for all doughs and breads, and the ( M ¯ cf ) decreased with increasing mixing and fermentation time. These results indicated that (1→3, 1→4)-β-glucan was degraded by endogenous β-glucanases in the barley and/or wheat flour. The molecular weight was not significantly affected by bread-baking and other factors. After mixing and fermentation the cellotriosyl/cellotetraosyl ratio was about 1.7–1.8 and was thus not significantly different from that of the flour blends. Thus to retain high molecular weight (1→3, 1→4)-β-glucan, which is important for its cholesterol-lowering effect, it is thus important to keep the mixing and fermentation time as short as possible when baking hull-less barley bread.

A high-performance size-exclusion chromatography system (HPSEC) was set up with detection based on the specific binding of Calcofluor to β-glucan for determination of amount and molecular weight of β-glucan in different cereal extracts. To calibrate the HPSEC system, a purified β-glucan was fractionated into narrow molecular weight ranges and the average molecular weight was determined before analysis on the HPSEC system. The detector response was similar for β-glucans from oats and barley and appeared to be independent of molecular weight. Four different methods for extraction of β-glucan from different cereal products were tested: two alkaline, one with hot water and added α-amylase, and one with water and added xylanase. Inactivation of endogenous β-glucanase was crucial for the stability of the extracts, even when extracting at high temperature or pH. Yields varied widely between the different extraction methods but average molecular weight and molecular weight distribution were similar. Extr...

The effects of different inoculum-loading rates and pre-treatment of wheat straw with formic acid and hot water (50 °C) on the establishment of Phanerochaete chrysosporium on unsterile straw were studied in laboratory scale and in a 1.5-m3 bioreactor. The establishment of P. chrysosporium on unsterile straw was satisfactory. Phanerochaete chrysosporium and other fungi, which developed simultaneously, were able to produce the activity necessary to degrade two herbicides, bentazon and MCPA (4-chloro-2-methylphenoxyacetic acid) in 20 days (65 and 75%, respectively). The decrease of both herbicides coincided with the presence of the activity of the lignin-degrading enzymes lignin peroxidase and manganese peroxidase/laccase. Extensive growth of P. chrysosporium or other lignin-degrading fungi on unsterile straw would be excellent for inexpensive solid substrate systems intended for degradation of pesticides.

Eight different barleys, including covered and naked samples containing low, normal and high amylose starches as well as a sample with low starch and high β-glucan content and a malting barley, were examined both from a chemical and physical perspective. In the chemical characterisation of the samples, analyses of nutrients were performed, while in the physical characterisation, weight of individual kernels, sieving fractions, bulk density, terminal velocity by pneumatic classification and parameters from a Single Kernel Characterization System (SKCS) were analysed. Results were evaluated by principal component analysis (PCA). The major trend found was that hull content and endosperm composition varied independently of each other. Constituents found mainly in the hull were positively correlated with each other, but negatively with bulk density and the 95% quantile of terminal velocity. There was a positive correlation between average value and standard deviation of grain mass, fat and starchy endosperm components such as extractable dietary fibre residues and β-glucan. The latter variables were negatively correlated to β-glucan extractability. © 1999 Society of Chemical Industry

The wheat grain comprises three groups of major components, starch, protein, and cell wall polysaccharides (dietary fiber), and a range of minor components that may confer benefits to human health. Detailed analyses of dietary fiber and other bioactive components were carried out under the EU FP6 HEALTHGRAIN program on 150 bread wheat lines grown on a single site, 50 lines of other wheat species and other cereals grown on the same site, and 23−26 bread wheat lines grown in six environments. Principal component analysis allowed the 150 bread wheat lines to be classified on the basis of differences in their contents of bioactive components and wheat species (bread, durum, spelt, emmer, and einkorn wheats) to be clearly separated from related cereals (barley, rye, and oats). Such multivariate analyses could be used to define substantial equivalence when novel (including transgenic) cereals are considered.

Alkylresorcinols (AR), phenolic lipids found in high amounts in whole grain wheat and rye, can be used as biomarkers for these cereals. The content (on a dry matter basis) and homologue composition of AR were determined in 26 wheat varieties grown in Hungary in 2005-2007, as well as in the United Kingdom, France, and Poland in 2007. There was a significant effect of year, location, and variety on both total AR and individual AR homologue content (p

The effects of genotype and environment on the content of bioactive components in rye were determined with four varieties being grown on one site for three years and on three additional sites in the third year and a fourth variety being included in all trials except year 1. Clear differences were observed in the extent to which the contents of dietary fiber components (arabinoxylan, beta-glucan, total dietary fiber) and phytochemicals (folates, alkylresorcinols, sterols, tocols, phenolic acids) varied between varieties and between the same varieties grown in different sites (United Kingdom, France, Hungary, Poland) and years (2005-2007 in Hungary), with sterols being the most stable and phenolic acids the least. However, no single variety could be selected as having the highest overall level of bioactive components or as being more stable in comparison across environments.

Analysis of the contents of bioactive components (tocols, sterols, alkylresorcinols, folates, phenolic acids, and fiber components) in 26 wheat cultivars grown in six site × year combinations showed that the extent of variation due to variety and environment differed significantly between components. The total contents of tocols, sterols, and arabinoxylan fiber were highly heritable and hence an appropriate target for plant breeding. However, significant correlations between the contents of bioactive components and environmental factors (precipitation and temperature) during grain development also occurred, with even highly heritable components differing in amount between grain samples grown in different years on different sites.

Ten different barley varieties grown in one location were studied for their content of tocols, folate, plant sterols, alkylresorcinols, and phenolic acids, as well as dietary fiber components (arabinoxylan and beta-glucan). The samples included hulled and hull-less barley types and types with normal, high-amylose, and waxy starch. The aim was to study the composition of raw materials, and therefore the hulls were not removed from the hulled barleys. A large variation was observed in the contents of all phytochemicals and dietary fibers. Two varieties from the INRA Clermont Ferrand barley program in France (CFL93-149 and CFL98-398) had high content of tocopherols and alkylresorcinols, whereas the variety Dicktoo was highest in dietary fiber content and phenolics. Positive correlations were found between 1000 kernel weight, alkylresorcinols, and tocols, as well as between dietary fiber content and phenolic compounds. The results demonstrate that the levels of phytochemicals in barley can likely be affected by breeding and that the contents of single phytochemicals may easily be adjusted by a right selection of a genotype.

The levels and compositions of a range of phytochemicals (sterols, tocols, avenanthramides, folates, phenolic acids) and dietary fiber components were determined in five oat cultivars (four husked and one naked) grown on a single site in 2005. The total levels of tocols, phenolic acids, and avenanthramides varied by over 2-fold between cultivars, but less variation occurred in total sterols and total folates. Limited variation was also observed in the dietary fiber content and composition of the four husked lines. These results indicate that it may be possible to selectively breed for lines with high contents of dietary fiber and specific groups of phytochemicals.