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1.
Wheat bran was extruded in a twin‐screw extruder at five specific mechanical energy (SME) levels (0.120, 0.177, 0.234, 0.291, and 0.358 kWh/kg, dwb) and the cholesterol‐lowering effects were compared with those of unprocessed wheat bran when fed to four‐week‐old male golden Syrian hamsters (n = 10/treatment) for three weeks. Diets contained 10% total dietary fiber, 10.3% fat, 3% nitrogen, and 0.4% cholesterol. Plasma total cholesterol and very‐low‐density lipoprotein cholesterol were significantly lower with 0.120 kWh/kg extruded wheat bran diet compared with the unextruded wheat bran control. Total triglycerides were significantly lower with 0.120 and 0.177 kWh/kg wheat bran diets compared with those fed 0.291 and 0.358 kWh/kg extruded wheat bran diets. Cholesterol digestibility, total liver cholesterol, and total liver lipids were significantly lower with all the extruded wheat bran diets compared with the unextruded wheat bran control. Cholesterol digestibility for the 0.291 kWh/kg wheat bran diet was also significantly lower than all other extruded diets. Significantly more sterols were excreted with diets containing 0.291 and 0.358 kWh/kg extruded wheat bran compared with the unextruded wheat bran control. Wheat bran extruded with 0.291 kWh/kg diet resulted in a 13% reduction in plasma cholesterol and a 29% reduction in low‐density lipoprotein cholesterol. Considering lowest cholesterol digestibility, significantly higher sterol excretion, desirable plasma lipo‐protein cholesterol profile, significantly lower liver weight, total liver lipids, and liver cholesterol, the wheat bran extruded at 0.291 kWh/kg appeared to have the most desirable healthful potential. Data suggest that cholesterol‐lowering potential of wheat bran could be enhanced by optimizing the energy input used in the extrusion process.  相似文献   

2.
The in vitro bile acid binding by rice, oat, wheat, and corn brans was determined using a mixture of bile acids normally secreted in human bile at a physiological pH of 6.3. The objective of the study was to relate bile acid binding of cereal brans to health promoting properties. Three experiments were conducted testing substrates on an equal weight (dry matter) basis, an equal total dietary fiber (TDF) basis, and an equal TDF and equal fat basis. Each experiment was repeated to validate the results (for a total of six experiments). The relative in vitro bile acid binding of the cereal brans on an equal TDF basis considering cholestyramine as 100% bound was rice bran 51%, wheat bran 31%, oat bran 26%, and corn bran 5%. The data suggest that cholesterol lowering by rice bran appears to be related to bile acid binding. The primary mechanism of cholesterol lowering by oat bran may not be due to bile acid binding by soluble fiber. Bile acid binding did not appear to be proportional to the soluble fiber content of the cereal brans tested. Bile acid binding by wheat bran may contribute to cancer prevention and other healthful properties.  相似文献   

3.
The present study was performed to investigate calcium-binding characteristics of different brans under simulated gastrointestinal pH conditions and to explore the significance of dietary fiber, oxalate, and phytate for calcium binding. Different brans (rice, rye, soy, fine wheat, coarse wheat, and oat) and CaCl(2) solution containing (45)Ca were incubated at 37 degrees C at gastric pH (2.2) followed by buffering steps of 1 degree from pH 3.0 to pH 8.0. Total calcium binding and calcium-binding capacity of the pH 2.2 soluble bran fraction were determined. Additionally, oxalate and phytate contents of brans and solubility profiles of phytic acid were investigated. Calcium-binding capacities of brans showed a clear pH dependence. At gastric pH calcium binding was low in all brans, ranging from 0.022 to 0.040 mmol of calcium/g of bran. Soy bran, nearly phytate-free, showed higher binding values up to pH 4.0 and lower values between pH 5.0 and 8.0. In all other brans, binding values increased strongly with increasing pH in the quantitative order rice bran > coarse wheat bran > fine wheat bran > rye bran > oat bran. The solubility profiles indicate that in the cases of rye, wheat, and rice bran phytate accounts for 70-82% of their total calcium-binding capacities. The results suggest that dietary fiber makes no important contribution to calcium binding, except for soy and oat brans. Oxalate plays only a minor role in calcium binding by brans.  相似文献   

4.
This study was undertaken to evaluate the lipidemic response of rice bran and the possible enhancement of its healthful properties by using raw or processed white or brown rice in place of corn starch. All diets contained 10% total dietary fiber, 15% fat, and 0.5% cholesterol. Weanling male golden Syrian hamsters were fed cellulose control (CC), processed corn starch (PCS), cellulose with processed brown rice (CPBR), rice bran (RB), RB with white rice (RBWR), RB with processed white rice (RBPWR), RB with brown rice (RBBR), and RB with processed brown rice (RBPBR) diets. After three weeks, the PCS diet significantly lowered total plasma cholesterol (TC) compared with the CC, CPBR, RBWR, and RBPBR diets. RB and RBBR diets significantly lowered TC and LDL‐C compared with CPBR diet. All the RB‐containing and PCS diets significantly lowered liver cholesterol and liver lipid content. Processing white rice increased TDF content 240% and insoluble dietary fiber (IDF) 360%, whereas soluble dietary fiber (SDF) decreased by 25%. Uncooked brown rice contained 7 times as much TDF as uncooked white rice. Processing brown rice decreased its TDF, IDF and SDF contents by 12, 6, and 42%, respectively. The data suggest that a possible mechanism for cholesterol‐lowering by rice bran, with or without added raw or processed rice (white or brown), is by decreasing lipid digestibility and increasing neutral sterol excretion, whereas cholesterol‐lowering by processed corn starch is mediated through other mechanisms.  相似文献   

5.
Four-week-old male golden Syrian hamsters were fed diets containing cellulose (control, CC), cellulose + soy protein (CS), CS + vitamin E, (CSE), rice bran (RB), RB + vitamin E (RBE), oat bran (OB), and OB + vitamin E (OBE) for six weeks (n = 10/treatment). Diets contained (by weight) 10% total dietary fiber, 3% N, 20% fat, 0.5% cholesterol, and some diets had an additional 0.1% vitamin E. After six weeks, RB and OB diets resulted in significantly higher weight gain than the CC diet. Plasma low-density lipoprotein cholesterol (LDL-C) values and the LDL-C/high-density lipoprotein cholesterol ratio in hamsters fed CSE, RBE, OB, and OBE diets were significantly lower than in those fed CC diet. There were no significant differences in total plasma cholesterol values among the hamsters fed any of the diets. Liver cholesterol in animals fed OB and OBE diets was significantly lower than in all other groups. Foam cell areas in the inner bend of the aortic arch in animals fed all treatment diets were significantly reduced when compared with that in animals fed CC diet. The level of additional dietary vitamin E did not result in further significant reductions in foam cell area. The results of this study suggest that diets containing rice bran, oat bran, or soy protein significantly reduced the development of atherosclerosis in hypercholesterolemic hamsters.  相似文献   

6.
The in vitro bile acid binding by rice bran, oat bran, dehulled barley, and β‐glucan enriched barley was determined using a mixture of bile acids at a duodenal physiological pH of 6.3. Six treatments and two blank incubations were conducted testing substrates on an equal protein basis. The relative in vitro bile acid binding of the cereal brans on an equal total dietary fiber (TDF) and insoluble dietary fiber (IDF) basis considering cholestyramine as 100% bound was rice bran 45 and 49%; oat bran 23 and 30%; dehulled barley 33 and 57%; and β‐glucan enriched barley 20 and 40%, respectively. Bile acid bindings on equal protein basis for the respective cereals were 68, 26, 41, and 49%. Bile acid binding by rice bran may account to a great extent for its cholesterol‐lowering properties, while bile acid binding by oat bran suggests that the primary mechanism of cholesterol lowering by oat bran is not due to the bile acid binding by its soluble fiber. Bile acid binding was not proportional to the soluble fiber content of the cereal brans tested. Except for dehulled barley, bile acid binding for rice bran, oat bran, and β‐glucan enriched barley appear to be related to their IDF content. Highest relative bile acid binding values for rice bran and β‐glucan enriched barley were observed on an equal protein basis, whereas highest values for dehulled barley were based on IDF. Data suggest that of all four cereals tested, bile acid binding may be related to IDF or protein anionic, cationic, physical and chemical structure, composition, metabolites, or their interaction with active binding sites.  相似文献   

7.
This study examined the effects of various cereal fibers and various amounts of β-glucan on cholesterol and bile acid metabolism. Hamsters were fed semisynthetic diets containing 0.12% cholesterol, 20% fat, and either 16% total dietary fiber (TDF) from wheat bran (control) or 10% TDF from oat bran, 13% TDF from oat bran concentrate or barley grains, 16% TDF from oat fiber concentrate, barley flakes, or rye bran. After five weeks, plasma total cholesterol and liver cholesterol concentrations were significantly lower (20 and 50%, respectively) only in hamsters fed rye bran. Diets containing any of the oat ingredients or barley had no effect on total cholesterol. Changes in the pattern of biliary bile acids occurred in hamsters fed 16% TDF from barley flakes or 10% TDF from oat bran. Hamsters fed rye bran had a significantly higher fecal bile acid excretion when compared with controls fed wheat bran. Because rye bran caused the most pronounced lowering effect of total cholesterol despite the lowest content of β-glucan and soluble fibers, components other than β-glucan and soluble fibers seem to be involved in its hypocholesterolemic action. Since the effects of the oat and barley ingredients were not solely correlated to the β-glucan content, structural changes occurring during processing and concentrating of the products may have impaired the hypocholesterolemic potential of the β-glucans, and other factors such as solubility and viscosity of the fiber components seem to be involved.  相似文献   

8.
The contents of free and total phenolic acids and alk(en)ylresorcinols were analyzed in commercial products of eight grains: oat (Avena sativa), wheat (Triticum spp.), rye (Secale cerale), barley (Hordeum vulgare), buckwheat (Fagopyrum esculentum), millet (Panicum miliaceum), rice (Oryza sativa), and corn (Zea mays). Avenanthramides were determined in three oat products. Free phenolic acids, alk(en)ylresorcinols, and avenanthramides were extracted with methanolic acetic acid, 100% methanol, and 80% methanol, respectively, and quantified by HPLC. The contents of total phenolic acids were quantified by HPLC analysis after alkaline and acid hydrolyses. The highest contents of total phenolic acids were in brans of wheat (4527 mg/kg) and rye (4190 mg/kg) and in whole-grain flours of these grains (1342 and 1366 mg/kg, respectively). In other products, the contents varied from 111 mg/kg (white wheat bread) to 765 mg/kg (whole-grain rye bread). Common phenolic acids found in the grain products were ferulic acid (most abundant), ferulic acid dehydrodimers, sinapic acid, and p-coumaric acid. The grain products were found to contain either none or only low amounts of free phenolic acids. The content of avenanthramides in oat flakes (26-27 mg/kg) was about double that found in oat bran (13 mg/kg). The highest contents of alk(en)ylresorcinols were observed in brans of rye (4108 mg/kg) and wheat (3225 mg/kg). In addition, whole-grain rye products (rye bread, rye flour, and whole-wheat flour) contained considerable levels of alk(en)ylresorcinols (524, 927, and 759 mg/kg, respectively).  相似文献   

9.
Chemical composition and in vitro digestion properties of select whole grains, before and after processing, and their components were measured. Substrates included barley, corn, oat, rice, and wheat. In addition to whole grain flours, processed substrates also were tested as were corn bran, oat bran, wheat bran, and wheat germ. Processing of most substrates resulted in higher dry matter and digestible starch and lower resistant starch concentrations. Dietary fiber fractions varied among substrates with processing. Digestion profiles for most substrates correlated well with their chemical composition. Corn bran and rice substrates were the least fermentable. Extrusion rendered barley, corn, and wheat more hydrolytically digestible and barley and oat more fermentatively digestible. Except for corn bran, all components had greater or equal fermentability compared with their native whole grains. Understanding digestion characteristics of whole grains and their components will allow for more accurate utilization of these ingredients in food systems.  相似文献   

10.
Several oat brans (crunchy oat bran, oat bran alone, and oat breakfast cereal) and wheat brans (wheat bran alone, wheat bran powder, wheat bran with malt flavor, bran breakfast cereal, tablet of bran, and tablet of bran with cellulose) used as dietary fiber supplements by consumers were evaluated as alternative antioxidant sources (i) in the normal human consumer, preventing disease and promoting health, and (ii) in food processing, preserving oxidative alterations. Products containing wheat bran exhibited higher peroxyl radical scavenging effectiveness than those with oat bran. Wheat bran powder was the best hydroxyl radical (OH*) scavenger. In terms of hydrogen peroxide (H2O2) scavenging, wheat bran alone was the most effective, while crunchy oat bran, oat bran alone, and oat breakfast cereal did not scavenge H2O2. The shelf life of fats (obtained by the Rancimat method for butter) increased most in the presence of crunchy oat bran. When the antioxidant activity during 28 days of storage was measured by the linoleic acid assay, all of the oat and wheat bran samples analyzed showed very good antioxidant activities. The Trolox equivalent antioxidant capacity (TEAC) assay was used to provide a ranking order of antioxidant activity. The wheat bran results for TEAC (6 min), in decreasing order, were wheat bran powder > wheat bran with malt flavor > or = wheat bran alone > or = bran breakfast cereal > tablet of bran > tablet of bran with cellulose. The products made with oat bran showed lower TEAC values. In general, avenanthramide showed a higher antioxidant level than each of the following typical cereal components: ferulic acid, gentisic acid, p-hydroxybenzoic acid, protocatechuic acid, syringic acid, vanillic acid, vanillin, and phytic acid.  相似文献   

11.
The steryl ferulate contents of rye and wheat grains and their milling fractions were analyzed using a reversed-phase high-performance liquid chromatographic (HPLC) method. HPLC-mass spectrometry was used for identification. In addition, steryl ferulates of some selected milling byproducts were determined. The total steryl ferulate contents of rye and wheat grains were 6.0 and 6.3 mg/100 g, respectively. Uneven distribution of steryl ferulates in the grains led to considerable differences in the milling products; their steryl ferulate contents ranged from trace amounts in flours with low ash content to 20 and 34 mg/100 g in rye and wheat brans, respectively. Campestanyl ferulate and sitostanyl ferulate were the main components, followed by campesteryl ferulate and sitosteryl ferulate, whereas sitosterol was the main component in total sterols. Among the other samples, a byproduct of rice milling (pearling dust) was the best source of steryl ferulates, its total steryl ferulate content being 119 mg/100 g, whereas no measurable amounts of steryl ferulates were measured in oat bran or pearling dust of barley. The results indicated that rye and wheat and especially their bran fractions are comparable to corn as steryl ferulate sources.  相似文献   

12.
The aim of the present work was to evaluate the cholesterol-lowering potency of the different milling fractions of whole wheat flour, by investigating the effects of these wheat fractions (white flour, whole flour, and bran) on digestive fermentations and lipid metabolism in Wistar rats. Compared to the control, which was fiber-free, the different cereal fractions did not affect the daily food intake or weight gain. The white flour and whole flour diets markedly enlarged the cecum and elicited acidic fermentations (pH approximately 6.2), whereas bran was less effective. It appears that white flour rather promoted propionate-rich fermentations (+62%), whereas bran favored butyrate-rich fermentations (+178%). White flour or bran did not significantly affect total steroid excretion, but whole flour was effective (+41%). Both white flour and whole flour decreased cholesterol in the d < 1.040 fraction, but only whole flour significantly lowered cholesterolemia. However, all the cereal diets significantly decreased liver lipids, whole flour being the most potent (-54%). In conclusion, the totality of the wheat grain is important for cholesterol- and triglyceride-lowering effects, and the splitting up of the grain alters its health effects.  相似文献   

13.
Rye bran and aleurone, wheat bran and aleurone, and oat bran and cell wall concentrate were compared in their in vitro gut fermentation patterns of individual phenolic acids and short-chain fatty acids, preceded by enzymatic in vitro digestion mimicking small intestinal events. The formation of phenolic metabolites was the most pronounced from the wheat aleurone fraction. Phenylpropionic acids, presumably derived from ferulic acid (FA), were the major phenyl metabolites formed from all bran preparations. The processed rye, wheat, and oat bran fractions contained more water-extractable dietary fiber (DF) and had smaller particle sizes and were thus more easily fermentable than the corresponding brans. Rye aleurone and bran had the highest fermentation rate and extent probably due to high fructan and water-extractable arabinoxylan content. Oat samples also had a high content of water-extractable DF, β-glucan, but their fermentation rate was lower. Enzymatic digestion prior to in vitro colon fermentation changed the structure of oat cell walls as visualized by microscopy and increased the particle size, which is suggested to have retarded the fermentability of oat samples. Wheat bran was the most slowly fermentable among the studied samples, presumably due to the high proportion of water-unextractable DF. The in vitro digestion reduced the fructan content of wheat samples, thus also decreasing their fermentability. Among the studied short-chain fatty acids, acetate dominated the profiles. The highest and lowest production of propionate was from the oat and wheat samples, respectively. Interestingly, wheat aleurone generated similar amounts of butyrate as the rye fractions even without rapid gas production.  相似文献   

14.
An experiment was conducted to determine the effects of extrusion conditions on chemical composition and in vitro hydrolytic and fermentative digestion of barley grits, cornmeal, oat bran, soybean flour, soybean hulls, and wheat bran. Extrusion conditions altered crude protein, fiber, and starch concentrations of ingredients. Organic matter disappearance (OMD) increased for extruded versus unprocessed samples of barley grits, cornmeal, and soybean flour that had been hydrolytically digested. After 8 h of fermentative digestion, OMD decreased as extrusion conditions intensified for barley grits and cornmeal but increased for oat bran, soybean hulls, and wheat bran. Total short-chain fatty acid production decreased as extrusion conditions intensified for barley grits, soybean hulls, and soybean flour. These data suggest that the effects of extrusion conditions on ingredient composition and digestion are influenced by the unique chemical characteristics of individual substrates.  相似文献   

15.
The effect of wheat bran (AACC hard red) and bran particle size on fat and fiber digestibility and gastrointestinal tract measurements were investigated with diets containing 5.7–10.7% dietary fiber. Fifty‐six male weanling Sprague‐Dawley rats were randomly assigned to four diets containing 5% cellulose (C5); 10.5% cellulose (C10); 21.5% coarse (2 mm) wheat bran (CB); or 22.2% fine (0.5 mm) wheat bran (FB) in a sixweek study. Dietary fiber digestibilities were significantly different (P < 0.05) among treatment diets (CB > FB > C5 > C10) but there was no effect in fat digestibility among treatments. High‐fiber diets fed to rats resulted in significantly greater wet and dry fecal weights than low‐fiber diets. Bran diets resulted in significantly higher fecal moisture than cellulose diets. Cecum lengths increased significantly with bran diets compared with cellulose diets. The CB diet resulted in significantly higher stomach weights than with cellulose diets. Stomachs were heavier and cecal lengths were greater with bran diets than with cellulose diets; however, a high‐cellulose diet resulted in increased colon weight. Except for higher fiber digestibility of coarse bran, bran particle size had no significant effects. Healthful effects of wheat bran may be associated with gastrointestinal morphology and function. Fecal bulking and decreased intestinal transit time can prevent constipation and may dilute or reduce absorption of toxic or carcinogenic metabolites, thus improving gastrointestinal health and lowering the risk of tumor development and cancer.  相似文献   

16.
This study investigated the antioxidant content and activity of phenolic acids, anthocyanins, α-tocopherol and γ-oryzanol in pigmented rice (black and red rice) brans. After methanolic extraction, the DPPH free radical scavenging activity and antioxidant activity were measured. The pigmented rice bran extract had a greater reducing power than a normal rice bran extract from a long grain white rice. All bran extracts were highly effective in inhibiting linoleic acid peroxidation (60-85%). High-performance liquid chromatography (HPLC) analysis of antioxidants in rice bran found that γ-oryzanol (39-63%) and phenolic acids (33-43%) were the major antioxidants in all bran samples, and black rice bran also contained anthocyanins 18-26%. HPLC analysis of anthocyanins showed that pigmented bran was rich in cyanidin-3-glucoside (58-95%). Ferulic acid was the dominant phenolic acid in the rice bran samples. Black rice bran contained gallic, hydroxybenzoic, and protocatechuic acids in higher contents than red rice bran and normal rice bran. Furthermore, the addition of 5% black rice bran to wheat flour used for making bread produced a marked increase in the free radical scavenging and antioxidant activity compared to a control bread.  相似文献   

17.
The protective effects of whole grain cereals against heart disease and certain cancers may be due, at least partly, to the antioxidant effects of phenolics concentrated in the bran. However, it is unclear to what extent these phenolics are absorbed, and whether these phenolics exert significant physiological antioxidant effects. Thus, this study aimed to compare total phenolics (TP) and antioxidant potential (AOP) in the plasma and urine of humans following consumption of a single meal of unprocessed wheat bran or a refined cereal (ground white rice). Using a randomized cross‐over design, 17 adults consumed ≈93 g of wheat bran or ground rice after an overnight fast. Baseline and postmeal plasma and urine samples were analyzed for TP (Folin‐Ciocalteu method) and AOP (FRAP method). Compared with ground rice, wheat bran gave significantly (P < 0.05) higher plasma TP at 1 hr, and significantly (P < 0.001) higher plasma AOP from 0.5 to 3 hr. Furthermore, compared with ground rice, wheat bran led to consistently higher TP and AOP in urine, and these differences were significant (P < 0.05) at 2 hr. Comparisons with data from a range of other phenolic‐rich foods indicated that wheat bran phenolics are relatively well absorbed and may enhance antioxidant status.  相似文献   

18.
膨化玉米作啤酒辅料的可行性试验研究   总被引:8,自引:5,他引:8  
探讨了用不脱胚玉米挤压膨化物作啤酒辅料的可行性。指出:挤压膨化不脱胚玉米的绝干浸出率大于不膨化脱胚玉米的绝干浸出率,接近不膨化大米的绝干浸出率。可以用挤压膨化不脱胚玉米,代替目前传统工艺中不膨化的大米或脱胚玉米,作为酿制啤酒的辅料。同时使脱胚玉米辅料用量减少8%左右,麦芽用量减少10%左右。  相似文献   

19.
The present study examined the cholesterol-lowering activity of algal powder (AP), algal lipids (AL), and algal residue (AR) and their interaction with genes of transporters, receptors, and enzymes involved in cholesterol absorption and metabolism. In this experiment, 48 hamsters were fed either control diet or one of the three experimental diets containing 2% AP, 1.0% AL, or 1.0% AR for 6 weeks. Plasma total cholesterol (TC) and non-high-density-lipoprotein-cholesterol (non-HDL-C) were significantly decreased in the AP and AL groups but not in the AR group compared with those in the control hamsters. It was found that the cholesterol-lowering activity of AP and AL was associated with down-regulation of hepatic 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, low-density lipoprotein receptor (LDLR), and intestinal Niemann-Pick C1-like 1 (NPC1L1) transporter. It was concluded that the alga possessed the cholesterol-lowering activity and its lipids were the active ingredients. The mechanisms underlying the cholesterol-lowering activity of algae were mediated most likely by increasing the sterol excretion and decreasing the cholesterol absorption and synthesis.  相似文献   

20.
Decorticating sorghum to concentrate healthy phytochemicals   总被引:3,自引:0,他引:3  
The growing prominence of nutrition-related health problems demands strategies that explore nontraditional natural ingredients to expand healthy food alternatives. Specialty sorghums were decorticated using a tangential abrasive dehulling device (TADD) to remove successive bran layers, which were collected at 1 min intervals and analyzed for phenols, tannins, 3-deoxyanthocyanins, dietary fiber, and antioxidant activity. The first two bran fractions had the highest levels of phenols and antioxidant activity (3-6 times as compared to whole grain). Brown (tannin-containing) and black sorghums had at least 10 times higher antioxidant activity than white sorghum or red wheat brans. Black sorghums had the highest 3-deoxyanthocyanin content (up to 19 mg/g bran). Dietary fiber in sorghum brans ranged between 36 and 45%, as compared to 48% for wheat bran. Specialty sorghum brans are rich in valuable dietary components and present promising opportunities for improving health attributes of food.  相似文献   

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