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1.
The enrichment of liquid food matrix with wheat bran has not yet been explored. This study investigated the impact of disintegrating wheat bran preparations on their stability at high moisture content. Three wheat bran preparations – standard bran, peeled bran and aleurone rich fraction – were modified by dry grinding, enzymatic degradation, wet grinding and microfluidization. The sedimentation of processed preparations was evaluated in water solution and related to their physical structure, solubilized compounds and suspension viscosity. In dry ground preparations mixed in water (5% w/w), most of the particles sedimented already in 5 min. Wet grinding disintegrated the physical structure of bran preparations (d50 = 10–16 μm), causing improvement of particle stability due to reduction of gravitational sedimentation. Enzymatic treatment with xylanase efficiently increased the total solubility of the bran preparations (from 18–24% to 40–50%), but the higher solubility was not related to the better stability of particles. Microfluidization of peeled bran and aleurone increased the viscosity and stability of dispersions. The higher viscosity of the microfluidized dispersions was likely correlated with the better homogenisation of the particles, and also with the modified microstructure of treated bran preparations. Disintegrated wheat bran preparations showed high potential for beverage applications.  相似文献   

2.
Biscuits contain high amount of fat and sugar thus having high calorie but low nutrient density. Wheat bran is a good source of dietary fibre (DF) and protein and is thus a good candidate for nutritional enrichment of cereal foods. The aim of this study was to understand the effect of bran incorporation and particle size reduction on biscuit microstructure, texture and in vitro starch digestibility. Five different biscuits containing 5–15% DF were produced. Two different particle sized wheat brans were used: coarse (450 μm) and fine (68 μm). Bran particle size reduction increased the elastic modulus and hardness of biscuits. Biscuits containing fine bran had visually more compact structure without any surface or internal defects than those with coarse bran. Fine bran containing sample had the highest hardness value. Sensory evaluation showed that roughness and breakdown of biscuits in the mouth was significant for the coarse bran with highest level of bran addition. The instrumental elastic modulus, stress and hardness were closely related to sensory hardness and strength to break. Increasing DF content from 5 to 15% increased hydrolysis index by 16%, from 32 to 37.  相似文献   

3.
The objective of this study was to produce wholegrain wheat flour on a laboratory-scale with particle size distributions similar to commercially-milled samples without re-milling the bran. The moisture contents of four hard winter wheat cultivars were adjusted to 7.29–7.98% (by drying), 9.00–10.6% (“as is”), and 15.6% (by tempering) prior to milling into wholegrain flour. The moisture treatments appeared to affect the partitioning of wholegrain flour particles into each of three categories: fine (<600 μm), medium (600–849 μm) and coarse (≥850 μm). When the distributions of particles were grouped into these categories, wholegrain flours made from dried and “as is” wheat fell within the values for commercial wholegrain flours, while that from tempered wheat contained more coarse particles than even the coarsest commercial wholegrain flour. Loaf volumes and crumb firmness were not significantly different between bread made from wholegrain flour that had been produced from dried or “as is” wheat, but loaf volume was significantly lower and bread crumb firmness was significantly higher when wholegrain flour from tempered wheat was used. These results show that wheat may be milled without tempering to produce wholegrain flour with particle size similar to some commercially-milled flours without needing to re-grind the bran.  相似文献   

4.
In this study 7 bran fractions were produced by grinding coarse durum wheat bran followed by sieving to achieve median particle size ranges between 115 and 1497 μm. These bran fractions were incorporated into pasta at 1, 5, 10 and 20% and the phytochemical and technological properties evaluated. Higher incorporation of bran, especially at 20%, reduced pasta quality, but a reduced impact was seen at the same degree of incorporation using finer bran. Bran increased antioxidants (by up to 65%), ferulic acid (up to 400%) and phytosterols (up to 130%) in pasta, parameters which were insensitive to bran particle size above 10% incorporation except for ferulic acid, which was higher in particles between 248 and 1497 μm. It is recommended to use finer fractions if bran is added to pasta at 20% and higher, since they provide a better quality pasta while still delivering enhancements in phytochemical content above regular semolina pasta.  相似文献   

5.
The objective of this study was to examine the effects of whole-wheat flour (WWF) particle size on the quality attributes of WWF tortillas. WWF samples of different particle size distributions from commercial U.S. hard white (median diameters: 175.7, 128.6, 120.0, 108.5 and 102.4 μm), hard red winter (median diameters: 173.7, 133.6, 124.3, 110.8 and 104.2 μm) and hard red spring (median diameters: 173.7, 132.1, 124.7, 112.9, 106.3 μm) wheat classes were obtained by fine grinding of bran and shorts and re-combining with the rest of fractions. For all three wheat classes, as WWF median particle size decreased, the L* (lightness) value decreased but the adjusted damaged starch, polyphenol oxidase activity, and a* and b* values increased. Mixolab data showed that development time decreased as WWF particle size was reduced, while stability time and starch retrogradation increased. As for WWF tortilla quality, the breaking force and extensibility increased with decreasing particle size from ∼175 to 129–134 μm, but diameter and thickness were not significantly affected. The results indicated that reducing the median particle sizes of WWFs from ∼175 μm to ∼130 μm would significantly improve the WWF tortilla quality.  相似文献   

6.
The objective of this study was to produce wholegrain wheat flour on a laboratory-scale with particle size distributions similar to commercially-milled samples without re-milling the bran. The moisture contents of four hard winter wheat cultivars were adjusted to 7.29–7.98% (by drying), 9.00–10.6% (“as is”), and 15.6% (by tempering) prior to milling into wholegrain flour. The moisture treatments appeared to affect the partitioning of wholegrain flour particles into each of three categories: fine (<600 μm), medium (600–849 μm) and coarse (≥850 μm). When the distributions of particles were grouped into these categories, wholegrain flours made from dried and “as is” wheat fell within the values for commercial wholegrain flours, while that from tempered wheat contained more coarse particles than even the coarsest commercial wholegrain flour. Loaf volumes and crumb firmness were not significantly different between bread made from wholegrain flour that had been produced from dried or “as is” wheat, but loaf volume was significantly lower and bread crumb firmness was significantly higher when wholegrain flour from tempered wheat was used. These results show that wheat may be milled without tempering to produce wholegrain flour with particle size similar to some commercially-milled flours without needing to re-grind the bran.  相似文献   

7.
Wheat bran is one of the major dietary fiber sources widely used in the food industry in order to produce fiber-rich foods. The effects of particle size and addition level of wheat bran on the quality of flour and of dry white Chinese noodles (DWCN) were investigated. Results suggested that increasing wheat bran concentration and particle size decreased midline peak value (MPV). However, the MTxW and MPT increased as particle size increased. Peak viscosity, trough, final viscosity, area of viscosity, breakdown, and setback of blends decreased significantly with increasing bran levels from 5% to 20%, but there were no significant differences in the impact of particle size on pasting properties. For the 5% and 10% addition levels, there was no distinct effect in breaking strength of the noodles when bran size was 0.21 mm and 0.53 mm. Hardness, gumminess and chewiness of cooked DWCN showed a downtrend with increasing addition levels and particle size, while adhesiveness showed uptrend. The total score of DWCN showed a downtrend with increasing of addition level and particle size. For the 5% bran level, the scores of cooked DWCN were more than 83 when wheat bran particle size was 0.21 mm and 0.53 mm. By using 5–10% fine bran or using 5% medium bran in wheat flour, it is possible to satisfactorily produce fiber-rich DWCN.  相似文献   

8.
Ultra-fine grinding increases the antioxidant capacity of wheat bran   总被引：1，自引：0，他引：1  
In order to study the influence of wheat bran particle size on its antioxidant capacity, the wheat bran was ground under normal and cryogenic conditions with variable intensity to produce ten fractions with different physical structures. The high energy grinding increased 3-fold the specific surface of the bran fractions and also the proportion of particles smaller than 50 μm assimilated to the proportion of disrupted aleurone cells. All the ground bran fractions presented similar total ferulic acid concentration and chemical form (free, conjugated, linked). A positive effect of the grinding on the antioxidant capacity of the bran fractions was noticed. The antioxidant capacity increased from 30 to 45 mmol TEAC/kg when the specific surface increased from 0.09 to 0.26–0.30 m2/g. The antioxidant capacity of the bran fractions was linearly correlated with the specific surface, with the D50 values and with the proportion of particles smaller than 50 μm. In in vitro gastric conditions, the finely ground bran inhibited the accumulation of conjugated dienes more efficiently than coarse bran. In conclusion, the bran structure affects its antioxidant capacity. This effect remained in gastric conditions showing that grinding can be used to produce wheat bran fractions with higher nutritional value.  相似文献   

9.
Milling of wheat produces co-products rich in dietary fiber, micronutrients and phytochemicals which can be used to integrate healthy functional foods. In the study different co-products including bran, shorts, and red dog were identified by physicochemical and functional analyses. The results showed that the fat, protein and starch contents decreased in order of red dog > shorts > bran (P < 0.05). The ash, neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, water and oil holding capacities (WHC, OHC) were in order bran > shorts > red dog, respectively (P < 0.05). Antioxidant capacity was in order red dog > shorts > bran (P < 0.05). The bran was selected as the co-product with the highest fiber that was finely grounded to four different fractions (>355, 250–355, 180–250, <180 μm) and they were characterized more detail. The fat, protein and starch contents decreased with increasing bran particle size (P < 0.05). The ash, crude fiber, NDF, ADF, hemicellulose and WHC and OHC increased with the increasing bran particle size (P < 0.05). DPPH radical scavenging activity increased with increasing particle size (P < 0.05). The bran fractions 250–355 and >355 μm can be used as high fiber ingredients rich in antioxidants to generate functional foods.  相似文献   

10.
White, blue, black and purple red wheat bran powders were prepared by ultrafine grinding to the particle size distribution of 0.5–100 μm. The effects of wheat bran addition on the qualities of dry Chinese noodles were investigated. Rapid Visco Analyzer results suggested that peak viscosity, hot paste viscosity, cool paste viscosity, breakdown viscosity and setback viscosity of the blends decreased with the increasing bran levels from 2.0% to 6.0% (P < 0.05). Color of dough sheet (L*) decreased with the addition of wheat bran, while a* and b* values increased distinctly. Water absorption and firmness of the cooked noodles showed up trends with increasing addition of bran, while cooking loss showed a downtrend. Tensile strength and elongation rate decreased when bran addition was 2.0%, but increased when bran addition reached 4.0%–6.0%. Storage modulus (E′) and loss modulus (E″) showed decreasing trends with increases in bran addition at frequencies of 0.1–10 Hz. SEM revealed that bran presence could slightly decrease surface connectivity between starch granules and gluten. It is possible to produce fiber-rich noodles by using 2.0%–6.0% ultrafine-ground bran in wheat flour.  相似文献   

11.
An effect of freeze-milling on processing properties of beta-glucan oat bran has been evaluated. A comparison with existing, patented methods of high molecular weight oat beta-glucan has been carried out. The new method employs raw material pre-treatment with freezing and milling in a hammer mill, resulting in significant reduction of particle size – 89% was between 80 and 50 μm in comparison with initial material when 79% were between 250 and 200 μm. Reduction of particle size also improved some process parameters of extraction technology – 30% improvement in fat removal during first stage of beta-glucan recovery was observed. The achieved pilot plant yield of product containing beta-glucan extraction was 64,03%, purity (ie. beta-glucan content), of achieved product was 84,4% and average molecular weight was about 69,500 g/mol.  相似文献   

12.
The present study explored the effect of size reduction by superfine grinding on the performance and rheological properties of bran-enriched dough. Coarse (D50 = 328.98 μm) and superfine-ground (D50 = 50.76 and 28.37 μm) wheat brans were incorporated into the wheat dough to replace 10–30% of plain flour. Both fundamental and empirical tests were performed to assess the mixing properties, pasting properties, large deformation rheology, small deformation rheology, and stickiness of the dough. With the increasing amount of bran added, dough water absorption capacity increased, while the dough became less sticky and more rigid. Superfine grinding reduced the water retention capacity of the bran by 17–20%. Dough fortified with the finest bran (D50 = 28.37 μm) showed an overall better stability and uniaxial extensibility. However, the results suggested that superfine grinding not necessarily improve every aspect of dough performance, particularly the pasting properties. High peak and final viscosity were observed for dough fortified with superfine bran, indicating their end products, such as noodle, might exhibit high stickiness after cooking, and a high degree of starch retrogradation. Results of this study contributed to a better understanding of the modification effect of superfine grinding on dietary fibre.  相似文献   

13.
Incorporation of insoluble fibers into extruded cereals severely limits their expansion and reduces crispness. The specific objective of this work was to investigate how corn bran and its fractions mixed with cornmeal affect rheology and extrudate expansion. Alkali-treated bran (ATB) and alkaline-soluble bran (ASB) were prepared from unmodified corn bran (UMB). Mixtures of the different corn bran fractions and degermed cornmeal having a 26% (w/w) of total dietary fibers were extruded in a twin screw extruder and expansion of the extrudates was determined. Melt shear rheology of mixtures of cornmeal and different corn bran fractions having a 20% total dietary fiber was determined using a capillary rheometer at 120 °C while the extensional rheology was determined using lubricated squeezing flow. The expansion of extrudates containing ATB was larger than those containing UMB, while extrudates containing ASB showed a greater expansion that was close to that of the control. Addition of UMB to cornmeal increased shear and extensional viscosity significantly as compared to the control. ATB addition increased the shear viscosity of the mixture to a small extent but showed the highest extensional viscosity amongst the samples. Addition of ASB resulted in mixtures having lower shear and extensional viscosities than the control.  相似文献   

14.
Rye and wheat brans are valuable sources of bioactive compounds, which could be used for the development and commercialization of high added value functional ingredients such as dietary antioxidants. The aim of this study was to evaluate antioxidant potential of rye and wheat bran using different polarity solvents. Cereal brans were ground to four different particle size fractions and extracted at 10.3 MPa pressure and 80 °C temperature by consecutive application of hexane, acetone and methanol:water (80:20%). The highest extract yield was obtained from rye bran using methanol-water; particle size in most cases had a significant effect. Antioxidant potential of extracts was assessed by ABTS+•, DPPH• scavenging, ORAC and total phenols content (TPC) assays. Extraction solvent had a major influence on TPC and antioxidant activity of the extracts. The most active extracts were obtained using methanol:water; rye bran extracts, in general, were stronger antioxidants than wheat bran extracts. For the majority of assays, reduction of particle size resulted in higher antioxidant activity values. However, ABTS+• scavenging was found to decrease by decreasing particle size of rye bran used for extraction.  相似文献   

15.
Wheat bran is an undervalued by-product of white flour and has great nutritional potential due to its high content in fibres and bioactive compounds. Micronized bran could be used as a food ingredient to improve the nutritional potential of cereal products, or be used as a starting material for other processes (bioactive compound extraction or bran fractionation). The aim of this work was to find a way to efficiently decrease the particle size of bran. The influence of the grinding temperature (ambient or cryogenic grinding) on the granulometric distribution of particles, their composition, and their microstructure was studied, at lab-scale and pilot-scale. It showed that the intrinsic characteristics of bran (glass transition within intermediate layers at −46 °C) had more influence on its grinding behaviour than the type of grinding device used: the particles size distributions obtained after grinding at lab-scale and pilot-scale were very similar. At both scales, the granulometric curves were narrow for cryogenic grinding, while for ambient grinding they were spread over the whole particle size range. Ultrafine particles were obtained in both ambient and cryogenic conditions. Negative temperatures, by increasing the material’s brittleness, favoured a fast fragmentation of bran: one step of cryogenic grinding allowed a median particle size of nearly 50 μm to be reached, whereas three successive steps of ambient grinding were needed for the same result. On the other hand, ambient temperature favoured the dissociation of the different constituent layers of wheat bran, and produced less composite particles than cryogenic grinding.  相似文献   

16.
The particle size of waxy (amylose-reduced) wheat (Triticum aestivum L.) starch was determined at isothermal temperatures by laser diffraction analysis. Flour samples were suspended in deionized water at temperatures ranging from 30 to 90 °C for 20–60 min. At 30 °C, all of the flour particles exhibited trimodal size distributions, i.e., the particles in the first, second, and third modes were <10 μm, 10–50 μm, and 51–300 μm, respectively. Control experiments with isolated starch indicated that the first and second modes were associated mainly with starch granules, whereas the third mode may have been related to gluten and gluten adhesion. The particle size distributions of waxy segregant wheat flours were temperature dependent. At 60 °C, there were significant changes in the particle size and distribution of waxy flours, which indicated the swelling of starch granules in response to elevated temperature. As the temperature increased, the peak particle size of waxy segregant wheat flours increased in different ways. The results suggest that variations in the swelling properties of selected waxy genotype flours may be due to the strength of starch–protein interaction and the capacity for starch granule gelatinization.  相似文献   

17.
The aim of this study was to evaluate the effect of particle size distribution on composition, properties rheological, pasting, microstructural and baking properties of whole grain wheat flour (WGWF) of three different particles sizes (194.9 μm, 609.4 μm and 830.0 μm). The quantification of free sulfhydryl groups (-SH) of WGWF samples, together with the effects observed in the behavior of the dough and bread showed that particle size influences the functionality of the gluten network in a differentiated way. Firmer and lower breads volume compared to refined wheat flour (RF) were correlated with the quality of the gluten network. In the sample of finer particles, more pronounced adverse effects in quality (dough rheology, bread volume and texture) compared to the medium and coarse particle size sample suggests that the larger contact surface and the increased release of reactive compounds due to cell rupture interact with the gluten-forming proteins changing their functionality.  相似文献   

18.
In this study, the effect of steam explosion (SE) treatment on microstructure, enzymatic hydrolysis and baking quality of wheat bran was investigated. Coarse and fine bran were treated at different steam temperatures (120–160 °C) and residence times (5 or 10 min) and then hydrolysed with carbohydrase enzymes. The SE treatment increased water extractable arabinoxylan (WEAX) content from 0.75 to 2.06% and reducing sugars from 0.92 to 2.41% for fine bran. The effect was more pronounced with increased SE temperature and residence time. The highest carbohydrate solubilisation was observed in fine bran at SE treatment of 160 °C, 5 min. WEAX content increased to 3.13% when this bran was incubated without enzyme, while WEAX content increased to 9.14% with enzyme addition. Microscopic analysis indicated that cell wall structure of wheat bran was disrupted by severe SE conditions. Supplementation of SE treated (150 °C, 10 min) bran at 20% replacement level decreased the baking quality of bread. However SE followed by enzymatic hydrolysis increased specific volume and decreased crumb hardness (on the day of baking and after three days of storage). Phytic acid content of bread supplemented with SE treated bran was lower than the one supplemented with untreated bran.  相似文献   

19.
The reduction of particle size can facilitate the extraction of phytochemical compounds. In this study was evaluated the effect of rice bran particles size in the yield and characteristics of γ-oryzanol compound. The γ-oryzanol extraction was realized with hexane and isopropanol solvents and quantification by spectrophotometric method. The γ-oryzanol extracts were characterized in relation of theirs majority components in HPLC-UV and the antioxidant capacity verified by the free radical DPPH● consumption. The γ-oryzanol yield varied of 0.10–1.54 mg/g of bran, and the highest yield was obtained in particles smaller than 0.39 mm. The γ-oryzanol majority components presence (cycloartenyl ferulate, 2,4-methylenecycloartanyl ferulate, campesteryl ferulate e β-sitosteryl ferulate) in the extracts was confirmed and verified differences in the profile of this components in function of different particles sizes. The γ-oryzanol extract obtained from particle sizes between 0.73 and 1.67 mm demonstrated most specific inhibition of DPPH radical (6.7%) and IC50 6.63 μg/mL. When the particle size is reduced, the access surface to the extraction solvent is increased resulting in more γ-oryzanol extraction, however the extract from larger particles was more efficient as antioxidant.  相似文献   

20.
There is no data on the lipid profile of Fagopyrum tataricum grain and its milling products. Therefore, we aimed to assess the phytosterol and tocopherol content and fatty acid profile of the samples of F. tataricum. Grain was milled, then the milling product separated to hull, bran, and two flour fractions, differing in particle size. The highest level of lipids (total fatty acids – 83%, with dominant oleic acid – 40%) was observed in the bran fraction (380 μm > GA > 180 μm). All samples contained some natural cis fatty acids, such as vaccenic acid (C18:1 n-7; ~2.8%) and tocopherol (α-, β-, δ- and γ-tocopherol). The highest content of total tocopherol was also detected in the bran fraction (0.1% of lipids). The content of lipid soluble bioactive substances was different and depended on the size of obtained fraction, therefore properly designed grain processing technology can be used to produce food with high nutritional value.  相似文献   

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