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1.
While consumption of diets high in fiber is perceived to result in undesirable gastrointestinal symptoms, the fermentation of undigested carbohydrate in the large intestine may, in fact, have beneficial health effects. In this study, we compared the effects of oats, barley, and their extracts with a glucose control for 24 hr on breath hydrogen and methane production as a marker of colonic fermentation and also assessed gastrointestinal symptoms. Nine men and 11 women (35–57 yr) consumed 1 g/kg of body weight of carbohydrate as glucose or 0.66 g/kg of body weight sugar and 0.33 g/kg of body weight as oat bran, barley flour, oat extract, or barley extract (Nu‐trimX) in a Latin square design. Expired alveolar breath samples were collected after instruction at fasting, 2, 4, 5, 6, 7, 8, 9, 10, and 24 hr after consumption of the test meals. All test meals increased breath hydrogen and methane (both P < 0.0001). Hydrogen, but not methane, responses to barley, oats, and extracts of each were higher (barley > oats, P < 0.05) than responses to glucose (P < 0.0001). Reported gastrointestinal symptoms were not related to specific test meals. Oats and barley, as well as their extracts, can be consumed in greater amounts by Americans to increase soluble fiber and lower fat intake, and thus lower risk factors for chronic disease.  相似文献   

2.
Abstract

Oat (Avena sativa L.) and waxy hulless barley (Hordeum vulgare L.) are important sources of water soluble plant fiber (ß‐glucan) needed in human diets to lower serum cholesterol. Recent studies have shown grain ß‐glucan content is influenced by soil type and environment, however, nitrogen (N) response data for oat and waxy hulless barley are lacking. In this study, we evaluated N effects on grain ß‐glucan content and yield; grain yield, protein content, and test weight; and total dry matter production and N utilization of oat and waxy hulless barley. Rates of applied N were 0, 34, 67, and 101 kg N/ha at three field environments in central Montana during 1989 and 1990. Nitrogen increased all variables except test weight and ß‐glucan content. Waxy hulless barley grain yields fluctuated from 0.82 to 4.11 Mg/ha, ß‐glucan content from 62 to 76 g/kg, and ß‐glucan yields from 51 to 354 kg/ha. Oat yields ranged from 0.85 to 3.83 Mg/ha, ß‐glucan content from 37 to 51 g/kg, and ß‐glucan yields from 35 to 178 kg/ha. Oat ß‐glucan content was positively related to grain protein content, and waxy hulless barley ß‐glucan content was positively related to test weight. ß‐glucan content appeared more related to environmental factors other than N.  相似文献   

3.
The suitability of the falling number method for oats was studied using samples of oat groats, oat bran, oat endosperm flour, and rolled oats. Sample sizes of 4.5–8 g were tested. The results showed that a standard 7‐g sample falling number determination would be suitable for oats, the falling number of samples varying from 328 to 721 sec. Due to high gelatinization temperature of oat starch, falling number values <300 sec showed greater variation than those >300 sec. Oat groat samples from two separate kiln drying processes showed that kiln drying increased the falling number values by 30–89%. The falling number determination is a potential tool for estimating the adequacy of kiln drying of oats. However, further modifications of the method should be developed to better consider the pasting properties of oat starch.  相似文献   

4.
Samples of hull-less oat genotypes from the Cooperative Naked Oat Test grown in Ottawa, ON, and Aberdeen, ID, were analyzed for their potential as a food malt. Malted oats had a lower concentration of petroleum ether-extractable lipid, but a much higher percentage of the lipid was in the form of free fatty acids. About 5% less starch and slightly more N was found in malted oats than in unmalted. Malted oats contained ≈8% soluble carbohydrate. During the germination phase of malting, nearly all the β-glucan was degraded. α-Amylase activity of malted oats approached that of malting barleys, but diastatic power was much lower. Groats of hulled cultivars grown at Madison, WI, were malted and analyzed with similar results. Because the increased levels of free fatty acids in the malted grains may lead to the development of rancid flavors, a method to curtail their increase or selections of genotypes with a minimum increase during malting may be necessary to produce a useful malted food product.  相似文献   

5.
The baking properties of oats are poor, mainly due to the lack of gluten matrix and hence the surface properties of the aqueous phase are crucial for the gas retention in oat dough. Our aim was to study the composition and foaming properties of the water‐soluble fraction from differently processed oats. A water extract from kilned oats contained nonpolar triglycerides and had poor foaming properties, whereas removing lipids with hexane extraction improved the foaming capacity and foam stability. A water extract from supercritical carbon dioxide extracted oats (CO2‐oats) was free from nonpolar lipids and had good foam stability and excellent foaming capacity. Moreover, oat lipid‐binding proteins, tryptophanins, were highly concentrated in the CO2‐oats‐derived foam and apparently played an important role in the foam structure. Supplementing CO2‐oats extract with small quantities (<0.05%) of nonpolar lipids of oats destructed its foaming properties. In a preliminary baking trial, the addition of the nonpolar lipids to CO2‐oats and wheat‐starch‐based baking recipes resulted in baked goods with reduced volume. The study showed that nonpolar triglycerides were present in the aqueous phase of oat in a quantity that impaired foaming. Moreover, this was the first study showing that tryptophanins, lipid‐binding proteins of oats, were highly concentrated in foams prepared of oats free of water‐extractable nonpolar lipids. In conclusion, tryptophanins can be considered as the foam‐active proteins of oats that prevent the lipid‐induced destabilization of foam structures which could improve the baking properties of oats.  相似文献   

6.
Films for potential food use were prepared from aqueous solutions of β‐glucan extracted from hulled barley, hull‐less barley, and oats. The extracts (75.2–79.3% β‐glucan) also contained proteins, fat, and ash. Glycerol was used as a plasticizer. The films were translucent, smooth, and homogeneous in structure on both sides. Water vapor permeability of films prepared from 4% solutions of β‐glucan extracts were higher than those from 2% solutions, despite similar values for water vapor transmission rate. Mechanical properties were influenced by both β‐glucan source and concentration. The oat β‐glucan films showed higher tensile strength and water solubility, and lower color, opacity, and deformation values than those of barley. Films prepared from hull‐less barley cv. HLB233 remained intact upon immersion in water for 24 hr.  相似文献   

7.
The antioxidant activities of oat groat extracts using different solvents were investigated. For acetone, hexane, and methanol extracts, the total phenolic compound contents were 12.83, 8.56, and 26.17 μg of catechin equivalent/g, respectively. Their corresponding free radical scavenging activities measured using the DPPH (2,2'‐diphenyl‐1‐picrylhydrazyl) method were 0.68, 0.35, and 0.79 μmol of Trolox equivalent/g, respectively. All oat extracts presented significantly greater capability in preventing cholesterol oxidation than the control (no extract added) during heating at the three levels of addition (1, 5, and 10 mg). The capability of the hexane or acetone extract in preventing cholesterol oxidation was not as effective as the methanol extract. In the docosahexaenoic acid (DHA, C22:6) oxidation test, all oat extracts at the level of 5 and 10 mg had greater inhibition capability on DHA oxidation than the control (DHA only). No significant inhibition was found for the hexane and acetone extract at the level of 1 mg, except for the methanol extract. The capabilities of oat extracts to inhibit oxidation of cholesterol and DHA from high to low was methanol, acetone, and hexane extract, which agreed with their free radical scavenging activities and total phenolic compound contents.  相似文献   

8.
Oat β‐glucan enriched extruded cereals with molecular weights (MWs) ranging from 2,180,000 to 326,000 were produced. Test meals composed of 31 g of available carbohydrate, 8.3–8.7 grams of β‐glucan, and milk were administered to subjects and their postprandial blood glucose levels monitored for 2 hr. White bread plus milk and a control wheat bran cereal plus milk were administered, and white bread alone served as a reference food for estimation of glycemic index (GI) of the cereals, after adjusting for the effect of adding milk to white bread. Both oat bran and wheat bran cereals significantly reduced peak blood glucose rise (PBGR) and area under the curve (AUC) versus white bread alone or white bread plus milk. There was a significant inverse relationship between AUC and log10[weight average MW] (r2 = 0.96, P = 0.0192). There was a significant inverse relationship between PBGR and log10[viscosity] of in vitro extracts from all cereals, including the wheat control (r2 = 0.96, P = 0.0031). However, no significant differences in glycemic responses among the oat bran cereals were found with pairwise comparisons. All cereals were low GI (<55) and were significantly lower than white bread alone or white bread plus milk. Among the oat bran cereals, palatability was positively correlated with MW (r2 = 0.98, P = 0.0110).  相似文献   

9.
Lipids, especially polar lipids, can improve loaf volume, grain and texture, and delay staling in bread. Oats (Avena sativa L.) are rich in total and polar lipids. We have investigated the effect of oat lipids in a bread formulation on loaf volume, appearance, and bread staling. Oat oil was fractionated into polar and nonpolar fractions by water‐degumming. Crude oat oil and shortening (at 3%) increased loaf volume by ≈11% over the zero lipid formulation. The polar lipid fraction increased loaf volume by nearly the same amount when added at only a 0.5% level. The addition of 3% crude oat oil or 0.7% oat oil polar fraction significantly delayed bread firming and starch retrogradation; the difference between oat lipids and shortening was more evident at the end of a four‐day storage period. Oat lipids had a stronger relative effect on bread from a weak flour (10% protein) than from a strong flour (14% protein). The effects of oat oil in the bread formulation could be related to the amphipathic character of polar lipids in oats that enables them to interact with starch, proteins, and other bread components.  相似文献   

10.
Oats, different oat fractions as well as experimental and commercial oat‐based foods, were extracted with hot water containing thermostable α‐amylase. Average molecular weight and molecular weight distributions of β‐glucan in extracts were analyzed with a calibrated high‐performance size‐exclusion chromatography system with Calcofluor detection, specific for the β‐glucan. Oats, rolled oats, oat bran, and oat bran concentrates all had high Calcofluor average molecular weights (206 × 104 to 230 × 104 g/mol) and essentially monomodal distributions. Of the oat‐containing experimental foods, extruded flakes, macaroni, and muffins all had high average molecular weights. Pasteurized apple juice, fresh pasta, and teacake, on the other hand, contained degraded β‐glucan. Calcofluor average molecular weights varied from 24 × 104 to 167 × 104 g/mol in different types of oat bran‐based breads baked with almost the same ingredients. Large particle size of the bran and short fermentation time limited the β‐glucan degradation during baking. The polymodal distributions of β‐glucan in these breads indicated that this degradation was enzymatic in nature. Commercial oat foods also showed large variation in Calcofluor average molecular weight (from 19 × 104 g/mol for pancake batter to 201 × 104 g/mol for porridge). Boiling porridge or frying pancakes did not result in any β‐glucan degradation. These large differences in molecular weight distribution for β‐glucan in different oat products are very likely to be of nutritional importance.  相似文献   

11.
Oat hull fiber is an insoluble source of dietary fiber, derived from the outermost layer of the oat grain. The effect of oat hull fiber on colonic function and serum lipids was investigated by conducting a controlled study on 10 healthy males, aged 20–37, who ate, for two three-week periods, a controlled low fiber diet (13.1 g of nonstarch polysaccharide [NSP]/day), and the same diet with 25 g of oat hull fiber per day incorporated into foods, providing 17 g of NSP/day. Fecal weight increased from 113 ± 10.4 to 155 ± 10.8 g/day (P < 0.001) with no change in transit time or serum lipids. Fermentation of oat hull fiber was studied by analysis of feces for NSP. Excretion of NSP increased from 2.0 g/day excreted to 19.7 g/day, indicating that no degradation had occurred. Oat hull fiber is therefore resistant to fermentation in the human colon, has no effect on serum lipids, and provides no energy to the body  相似文献   

12.
A better understanding of the impact of fertilizer nitrogen (N) on biomass and N accumulation, and their partitioning into different plant components is needed to optimize crop yield and quality. A field experiment with spring wheat (Triticum aestivum), hulless (Avena nuda), and hulled (Avena sativa) oats was conducted for 3 years in Ottawa, ON, Canada, to determine the crop responses to N addition (0, 75, and 150 kg N ha–1). Biomass, N, and phosphorus (P) accumulation and partitioning into different plant components were examined during the growth season. Lodging score was determined for all crops when it occurred and again at harvest. During the growth season, both hulless and hulled oats and the wheat cultivar showed almost similar patterns of N and P accumulation with maximum contents at late grain filling or at harvest. Plant N concentration was up to 60 g kg–1 during the seedling stage, decreased gradually with advancing growth stages, and was lowest at harvest. Nitrogen treatments significantly increased plant N and P contents. At heading stage, N treatments enhanced dry matter (24%–45%), N (35%–135%), and P (27%–45%) contents in plant components (i.e., culm, leaf, and head), but also enhanced crop lodging, especially in oats. Both hulled and hulless oats had higher total plant N (5%–35%), N : P ratio, and dry‐matter content in leaf (6%–43%) and head (0%–129%) along with higher P (up to 27%) in culm than the wheat cultivar. The wheat cultivar accumulated greater dry matter and higher N content in kernels than both hulled and hulless oats at harvest. Both hulled and hulless oat cultivars exhibited similar lodging susceptibility to N addition (75 or 150 kg N ha–1), produced lower dry weight and lower kernel N, and hence lower grain yield than the wheat cultivar. The larger vegetative dry‐matter accumulation at heading coupled with higher P content in culms under high‐N‐supply conditions may be related to severe lodging in oat cultivars.  相似文献   

13.
《Cereal Chemistry》2017,94(3):625-632
Six Australian milling oat cultivars grown over two growing seasons were characterized for differences in (1,3)(1,4)‐β‐glucan (β‐glucan) viscosity, solubility, molecular weight (Mw), and the effect of processing. Oat cultivars grown in 2012 had significantly higher extracted β‐glucan viscosity from oat flour than the same oat cultivar grown in 2011 (P < 0.05, mean 137 and 165 cP, respectively). Noodle β‐glucan mean viscosity for 2012 (147 cP) was significantly higher than for 2011 (128 cP). β‐Glucan from ‘Williams’ and ‘Mitika’ oats had the highest viscosity (P < 0.05) in flour (5.92 and 5.25%, respectively) and noodles (1.64 and 1.47%, respectively) for both years, compared with the other oat cultivars. β‐Glucan (Mw) of Williams for 2012 and ‘Kojonup’ for both years were the least affected by processing, with an average drop of 33% compared with a maximum of 63% for other cultivars. Therefore, Williams showed superior β‐glucan properties to other oat cultivars studied, and can potentially provide improved health benefits. High and low β‐glucan Mw populations were found in the same elution peak after processing. Oat cultivars chosen for processing should be those with β‐glucans that are more resistant to processing, and that maintain their physiochemical properties and, therefore, bioactivity.  相似文献   

14.
High-fiber, high-carbohydrate diets, including foods with low glycemic index, have been associated with prevention and treatment of diseases such as coronary heart disease and diabetes. β-glucan, a soluble, viscous polymer found in oat and barley endosperm cell wall, was incorporated into pasta test meals. Five fasted adult subjects were fed test meals of a barley and durum wheat blend pasta containing 100 g of available carbohydrate, 30 g of total dietary fiber (TDF) and 12 g of β-glucan, or an all durum wheat pasta containing the same amount of available carbohydrate, 5 g of TDF, and negligible β-glucan. The β-glucan and durum wheat pasta resulted in a lower glycemic response as measured by average total area and maximum increment of the blood glucose curves. Lower insulin response to the β-glucan and durum wheat pasta was also indicated by lower average area and increment characteristics of the insulin curves. Barley β-glucans may be an economical and palatable ingredient for processed food products formulated to modify glycemic and insulin response.  相似文献   

15.
The cholesterol-lowering effect of cereal grains has been associated with the soluble fiber component of dietary fiber. β-Glucan is the major soluble fiber component of barley (Hordeum vulgare L.) and oat (Avena sativa L.). Much research has been conducted to determine the β-glucan content of barley and oat genotypes from many different countries. However, genotypes of both crops always were grown in separate experiments, making direct comparisons between the two crops difficult. This study compares in the same experiment the β-glucan content of nine barley and 10 oat genotypes grown at two locations in each of two years (i.e., four environments) in North Dakota. Averaged across genotypes, total β-glucan content of barley and oat groat was similar. Soluble β-glucan content of oat groat was greater than barley, and oat groat had a greater ratio of soluble-to-total β-glucan than barley. The soluble β-glucan content and ratio of soluble to total β-glucan content of the “best” barley genotypes were less than that of oat genotypes with the highest levels of these two traits.  相似文献   

16.
Test weight or bulk density of oats (Avena sativa L.) has a major influence on the monetary value of oat grain. We hypothesize that test weight can be attributed to grain density and packing efficiency. We have measured oat grain volume and density by a sand‐displacement method and derived the packing factor for six oat cultivars grown in three environments. Volumes of individual grains were 31–38 mm3 and were highly correlated with grain mass. Grain densities were 0.96–1.03 g/cm3. Packing efficiency, defined as the space proportion occupied by the grains, was 53–55%. Regression analysis suggested that 78% of the variation in test weight could be attributed to grain density. Size fractionation of grain by sieving and analysis by digital image analysis indicated that smaller grains within an oat sample packed more efficiently than larger grains and larger grains in a sample were less dense than the smaller grains. Analysis of oat grain components indicated groat densities were ≈1.29 g/cm3 and hull densities were ≈0.69 g/cm3. The difference in densities between groat and hull provide a physical basis for the recognized relationship between groat percentage and test weight.  相似文献   

17.
Oat products are abundant in β-glucan, which could lower the glycemic index of products or foods. A low glycemic index is beneficial in the control of postprandial glycemia. The study examined the hypoglycemic effects of oat products that had the same percentage of oat β-glucan and were added into the diet fed to streptozotocin-induced diabetic mice for 6 weeks, and potential mechanisms are discussed here. Oat products significantly decreased fasting blood glucose and glycosylated serum protein (p < 0.05), but the hypoglycemic effect was not more than that of metformin (p > 0.05). Oat products increased glycogen, hormone, and nuclear receptor levels (p < 0.05), decreased free fatty acid content and succinate dehydrogenase activity (p < 0.05), and inhibited pancreatic apoptosis (p < 0.05). The results showed oat products had hypoglycemic effects. Hypoglycemic effects of oat products might be regulating glucose and fat metabolisms, stimulating hormone secretion, activating the nuclear receptor, and protecting organ function.  相似文献   

18.
The content and molecular weight (MW) of β-glucan in extracts from a selection of oat and barley cultivars were compared using flow-injection analysis and high-performance size-exclusion chromatography. From 60 to 75% of the β-glucan was extracted from oat and waxy barley by hot water (90°C) containing heat-stable α-amylase, whereas just 50–55% was extracted from nonwaxy barley. Consecutive extractions with hot water and dimethylsulfoxide (DMSO) extracted 65% (nonwaxy barley) or 75–80% (oat and waxy barley) of the total β-glucan. An extraction with sodium hydroxide and sodium borohydride (NaOH/NaBH4) increased the percentage of β-glucan extracted to 86–100% but decreased the MW. The MW of β-glucan in the oat cultivars selected was significantly higher than those in the barley cultivars. The β-glucan extracted from the nonwaxy barley cultivars showed significantly higher peak MW than that from the waxy barley cultivars.  相似文献   

19.
Oat (Avena sativa L.) kernels appear to contain much higher polar lipid concentrations than other plant tissues. We have extracted, identified, and quantified polar lipids from 18 oat genotypes grown in replicated plots in three environments to determine genotypic or environmental variation in these lipids. Validation experiments indicated a solid phase silica gel extraction step elution provided excellent and clean separation of extracted lipids into neutral lipid, glycolipid, and phospholipid fractions. Analysis of phospholipids by HPLC (normal phase, diol column) indicated phosphatidylethanolamine, phosphatidylcholine, phosphatidic acid, phosphatidylglycerol, phosphatidylinositol, and lyso‐ forms but very little genotypic or environmental variation. Di, tri and tetragalactosyl‐diacylglycerols were quantified in the glycolipids, along with their mono‐, di‐, and triacyl estolides. Most of these exhibited significant genotypic variation. Molecular species analysis of the glycolipids in the Morton cultivar by direct infusion electrospray ionization tandem mass spectrometry confirmed the enormous diversity of galactosyl‐lipids in oats. Analyses indicated total lipid of ≈8.3% (dry weight basis), of which ≈10% was phospholipid and 11% was glycolipids. These results indicate that oats are a rich source of polar lipids and contain an extremely rich diversity of galactosyl‐lipids.  相似文献   

20.
Effects of hydrothermal treatments (steaming, roasting) of oat grain on β-glucan extractability and rheological properties were tested on oat cultivars with low (Robert) and high (Marion) β-glucan content. Steaming of grain reduced the amount of β-glucan that could be extracted, compared with raw or roasted grain, but the extracts from steamed grain had much greater viscosity. Increased extraction temperatures increased the amount and the average relative molecular mass (M r) value of β-glucan extracted. In boiling water extractions, the average M r values among raw, roasted and steamed oat samples were equivalent, but extracts from steamed oat grain had significantly higher intrinsic viscosity than the extracts from roasted or raw oat grains. β-glucan solutions purified from steamed grain extracts were very viscous and highly pseudoplastic, as described by the power law equation. Oat β-glucan from steamed samples were more viscoelastic than β-glucan from roasted or raw oat samples. Because viscous properties of β-glucan from boiling water extracts are influencedhydrothermal treatments without affecting polymer molecular weight, polymer interaction with the solvent must be affected. Steaming may disrupt intramolecular cross-linkings in native β-glucan, allowing a linear chain configuration to generate greater viscosity.  相似文献   

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