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1.
Oatrim (oat β‐glucan amylodextrins) was evaluated as a fat substitute in a cake system. The physical and rheological properties of cakes containing shortening replaced with 20, 40, and 60% by weight of Oatrim were characterized. The increase in the specific gravity of the cakes and the decrease in the viscosity as more shortening was replaced with Oatrim were correlated with the change in the cake volume. The number of air bubbles present in the cake batters varied significantly; however, the size of the observed bubbles did not change. The cakes containing more Oatrim displayed a higher starch gelatinization temperature due to the amylodextrins in the Oatrim. The dynamic rheological properties of the cakes were investigated during baking and correlated with the differential scanning calorimetry results. The oscillatory shear storage moduli decreased upon initial heating, then increased due to starch gelatinization, and finally reached a plateau value that varied based on the sample composition. Moreover, increased replacement of shortening with Oatrim resulted in higher observed oscillatory shear storage moduli. The cakes prepared with up to 20% by weight of Oatrim did not evidence significant changes in softness (P < 0.01) and generally exhibited similar physical properties to the control cake.  相似文献   

2.
Germination can be used to improve the texture and flavor of cereals. However, germination generally causes breakdown of β‐glucans, which is undesirable with respect to the functional properties of β‐glucan. Our aim was to assess possibilities of germinating oat without substantial loss of high molecular weight β‐glucan. Two cultivars, hulled Veli and hull‐less (naked) Lisbeth were germinated at 5, 15, and 25°C and dried by lyophilization or oven drying. Elevated germination temperatures led to an increase in Fusarium, aerobic heterotrophic bacteria, Pseudomonas spp., lactic acid bacteria, enterobacteria, and aerobic spore‐forming bacteria. Therefore, the germination temperature should be kept low to avoid excessive growth of microbes. Of the samples germinated at 15°C, only one contained low amounts of the Fusarium toxin deoxynivalenol (52 μg/kg). Germination led to the breakdown of β‐glucans, but the decrease in the molecular weight of β‐glucan was initially very slow. A short germination schedule (72 hr, 15°C) terminated with oven drying was developed to produce germinated oat with retained β‐glucan content. Compared with the native oat, 55–60% of the β‐glucan could be retained.  相似文献   

3.
Hydration of oat bran including fermentation by rye sourdough was studied. Three types of oat bran suspensions were prepared (a control, one with whole meal rye flour added, and one with rye starter added). The suspensions were incubated for 1, 2, 3 and 4 hr. β‐Glucan content and solubilities of protein and β‐glucan were analyzed. Viscosity of the supernatants of oat bran suspensions was determined. Neither the rye sourdough nor the rye flour alone had a significant effect on the total β‐glucan content of oat bran suspensions. However, the addition of rye, either as whole meal rye flour or as sourdough starter, markedly increased the solubility of β‐glucan and proteins and simultaneously decreased the viscosity of the water‐soluble fraction of oat bran suspension. This suggests that a hydrolysis of β‐glucan had occurred that could change the rheological properties of oat bran in baking and the physiological potential of oat bran in nutrition.  相似文献   

4.
Rheological properties of raw oat flour slurries were determined in experimental high β‐glucan (≤7.8%) and traditional oat lines (4–5% β‐glucan) grown in two consecutive years. Three different media were used to disperse oat flours: deionized water, silver nitrate solution (to inactivate endogenous enzymes), and alkali solution (to solubilize both water‐soluble and water‐insoluble β‐glucans). Significant correlations (P < 0.05) between viscosity of slurries and β‐glucan concentration obtained in either deionized water (r = 0.833), silver nitrate (r = 0.940), or alkali (r = 0.896) solutions showed that β‐glucans were the main contributor to oat extract viscosity. The highest correlation was obtained in silver nitrate solution, suggesting that inactivating endogenous enzymes is important to obtain high correlations. Predictive models of oat β‐glucan concentration based on the viscosity profile were developed using partial least squares (PLS) regression. Prediction of β‐glucan concentration based on viscosity was most effective in the silver nitrate solution (r = 0.949, correlation coefficient of predicted vs. analyzed β‐glucans) and least effective in the alkali solution (r = 0.870). These findings demonstrate that the β‐glucan in oat could be predicted by measuring the viscosity of raw flours in silver nitrate solution, and this method could be used as a screening tool for selective breeding.  相似文献   

5.
Use of saturated Ba(OH)2 to extract rye β‐glucan led to a depolymerized product. Similar depolymerization of β‐glucan was observed when oat bran was extracted with this reagent. Isolated oat β‐glucan, detarium xyloglucan, guar galactomannan, and wheat and rye arabinoxylan were also depolymerized by treatment with the barium reagent. The degree of depolymerization was related to time of contact with, and concentration of, the barium. Rye β‐glucan of two different molecular weights (MW) were isolated and characterized. The structure of rye β‐glucan, as evaluated from the ratio of (1→3)‐linked cellotriosyl to (1→3)‐linked cellotetraosyl primary structural units, most closely resembles barley β‐glucan. Analytical variability of this ratio is discussed. A freshly prepared solution (2%) of the higher MW sample showed shear thinning behavior typical of cereal β‐glucans. The lower MW sample at 2% was not shear thinning, but on further purification, after storage for seven days, a 6% solution had gelled as shown by the mechanical spectrum.  相似文献   

6.
Muffins containing different amounts and molecular weights (MW) of β‐glucan were evaluated for the effect of β‐glucan on the physical characteristics of the muffins and on in vitro bile acid binding and fermentation with human fecal flora. Wheat flour muffins were prepared with the addition of β‐glucan extracts with high‐, medium‐, or low‐MW. For oat flour muffins, the native oat flour contained high‐MW β‐glucan; the oat flours were treated to create medium‐ and low‐MW β‐glucan within the prepared muffin treatments. For each 60‐g muffin, the amounts of β‐glucan were 0.52, 0.57, and 0.59 g for high‐, medium‐, and low‐MW β‐glucan wheat flour muffins, and 2.38, 2.18, and 2.23 g for high‐, medium‐, and low‐MW β‐glucan oat flour muffins, respectively. The lower the MW of the β‐glucan in muffins, the lower the height and volume of the muffins. The oat flour muffins were less firm and springy than the wheat flour muffins as measured on a texture analyzer; however, MW had no effect on muffin texture. The oat flour muffins bound more bile acid than did the wheat flour muffins. The muffins with high‐MW β‐glucan bound more bile acid than did those with low‐ and medium‐MW β‐glucan. Muffin treatment affected the formation of gas and total short‐chain fatty acids (SCFA) compared with the blank without substrate during in vitro fermentation. There were no differences in pH changes and total gas production among muffin treatments. The high‐MW β‐glucan wheat flour muffins produced greater amounts of SCFA than did the wheat flour muffin without β‐glucan and the oat flour muffins; however, there were no differences in SCFA production among muffins with different MW. In general, the β‐glucan MW affected the physical qualities of muffins and some potential biological functions in humans.  相似文献   

7.
The impact of extrusion on physical and sensory properties and on the in vitro bile acid (BA) binding was examined for N979 and Jim oat (Avena sativa) lines with 8.1 and 4.8% β‐glucan, respectively. Based on hardness and edibility of products made from Jim oats, moisture concentrations of 16–25% and temperatures of 165–180°C were selected for N979 extrusion. Jim‐based cereal had a significantly greater (P < 0.05) expansion ratio than did N979‐based cereal at most moistures. N979 cereal was browner, but not harder, than Jim cereal. Extruded products from N979 and Jim oats had 5.29–5.99% and 3.38–3.94% β‐glucan, respectively. Changing extrusion temperature or moisture content did not affect β‐glucan concentration in the products. N979 cereal made at 165°C and 16% moisture had greater BA binding than at other conditions, and had crunchiness comparable to cereals made at other conditions. BA binding of Cheerios brand breakfast cereal was close to that of N979 cereal made at 180°C and 18% moisture, but lower than cereals made at other conditions. Cereals made from Jim and N979 oats were browner, harder, coarser, and crunchier than Cheerios breakfast cereal. Proper processing and preparation techniques should be considered when producing extruded products from high β‐glucan oats.  相似文献   

8.
The aim was to study the effect of concentration and molecular weight of four different β‐glucan preparations on the perceived sensory quality of a beverage prototype. The correlations between sensory and instrumental measures were investigated. Two of the preparations were brantype containing high molecular weight β‐glucan, two were more‐processed low molecular weight β‐glucan preparations. Twelve beverage samples containing 0.25–2% β‐glucan and one reference sample thickened with carboxymethyl cellulose (CMC) were profiled by a sensory panel and analyzed by instrumental measurements (viscosity and molecular weight). Sensory profiles of the beverages varied at the same concentration of β‐glucan, depending on β‐glucan preparation. Beverages made with the bran‐type preparations were more viscous and had higher perceived thickness than beverages made with more‐processed, low molecular weight preparations. Moderate correlations were obtained between perceived thickness and sliminess and instrumental viscosity at all shear rates between 26 and 100/sec (r = 0.63–0.78; P ≤ 0.001). Technologically, more‐processed β‐glucan preparations are easier to add into a beverage in amounts sufficient for achieving a physiologically functional amount of β‐glucan in a product.  相似文献   

9.
Experimental oat lines high in β‐glucan (6–7.8%) and traditional lines (3.9–5.7% β‐glucan) were used to evaluate the effect of β‐glucan on pasting (by rapid viscoanalysis) and thermal properties (by differential scanning calorimetry) of oat flours. Significant correlations established between β‐glucan concentration and the pasting parameters after amylolysis demonstrated the role of β‐glucans in oat pasting. The relative decrease of peak viscosity (PV) observed after enzymatic removal of β‐glucans was correlated with β‐glucan concentration (r = 0.880, P < 0.010) and reconfirmed their contribution to pasting. A significant increase of PV with β‐glucan concentration obtained under conditions of either autolysis (deionized water used for dispersion) (r = 0.89, P < 0.010) or inhibition (silver nitrate solution used for dispersion) (r = 0.91, P < 0.001) might be explained by an increase in water retention capacity caused by the β‐glucans. Predictive models of β‐glucan concentration based on the whole pasting profile or selected profile regions were developed using partial least squares (PLS) regression.Prediction of β‐glucan based on the whole profile obtained in the silver nitrate solution was the most effective (r = 0.93, correlation coefficient of predicted vs. analyzed β‐glucans, P < 0.050). No correlations were observed between the thermal properties of oat flours and the β‐glucan concentration.  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.
Extraction protocols for β‐glucan from oat flour were tested to determine optimal conditions for β‐glucan quality testing, which included extractability and molecular weight. We found mass yields of β‐glucan were constant at all temperatures, pH values, and flour‐to‐water ratios, as long as sufficient time and enough repeat extractions were performed and no hydrolytic enzymes were present. Extracts contained about 30–60% β‐glucan, with lower proportions associated with higher extraction temperatures in which more starch and protein were extracted. All commercial starch hydrolytic enzymes tested, even those that are considered homogenous, degraded β‐glucan apparent molecular weight as evaluated by size‐exclusion chromatography. Higher concentration β‐glucan solutions could be prepared by controlling the flour‐to‐water ratio in extractions. Eight grams of flour per 50 mL of water generated the highest native β‐glucan concentrations. Routine extractions contained 2 g of enzyme‐inactivated flour in 50 mL of water with 5mM sodium azide (as an antimicrobial), which were stirred overnight, centrifuged, and the supernatant boiled for 10 min. The polymer extracted had a molecular weight of about 2 million and was stable at room temperature for at least a month.  相似文献   

12.
The main nonstarch polysaccharide of rye is arabinoxylan (AX), but rye contains significant levels of (1→3)(1→4)‐β‐d ‐glucan, which unlike oat and barley β‐glucan, is not readily extracted by water, possibly because of entrapment within a matrix of AX cross‐linked by phenolics. This study continues objectives to improve understanding of factors controlling the physicochemical behavior of the cereal β‐glucans. Rye β‐glucan was extracted by 1.0N NaOH and increasing concentrations of ammonium sulfate were used to separate the β‐glucan from AX and prepare a series of eight narrow molecular weight (MW) distribution fractions. Composition and structural characteristics of the isolated β‐glucan and the eight fractions were determined. High‐performance size‐exclusion chromatography (HPSEC) with both specific calcofluor binding and a triple detection (light scattering, viscometry, and refractive index) system was used for MW determination. Lichenase digestion followed by high‐performance anion exchange chromatography of released oligosaccharides, was used for structural evaluation. The overall structure of all fractions was similar to that of barley β‐glucan.  相似文献   

13.
Oats (Avena sativa L.) have received significant attention for their positive and consistent health benefits when consumed as a whole grain food, attributed in part to mixed‐linkage (1‐3,1‐4)‐β‐d ‐glucan (referred to as β‐glucan). Unfortunately, the standard enzymatic method of measurement for oat β‐glucan is costly and does not provide the high‐throughput capability needed for plant breeding in which thousands of samples are measured over a short period of time. The objective of this research was to test a microenzymatic approach for high‐throughput phenotyping of oat β‐glucan. Fifty North American elite lines were chosen to span the range of possible values encountered in elite oats. Pearson and Spearman correlations (r) ranged from 0.81 to 0.86 between the two methods. Although the microenzymatic method did contain bias compared with the results for the standard streamlined method, this bias did not substantially decrease its ability to determine β‐glucan content. In addition to a substantial decrease in cost, the microenzymatic approach took as little as 6% of the time compared with the streamlined method. Therefore, the microenzymatic method for β‐glucan evaluation is an alternative method that can enhance high‐throughput phenotyping in oat breeding programs.  相似文献   

14.
The soluble fiber, β‐glucan, in oat products is an active hypolipidemic component that is responsible for lowering plasma lipids. Quantitative analysis of β‐glucan in oat hydrocolloids such as Oatrim, Nutrim, and C‐Trim was performed to measure the total β‐glucan content and molecular weight distribution. For the measurement of total β‐glucan content, both modified flow‐injection analysis (FIA) method and the standard AACC enzymatic method were employed. FIA method uses the enhanced fluorescence produced when β‐glucan forms complexes with Calcofluor. Experimental results of both the modified FIA method and the standard AACC enzymatic method revealed very good coincidence with each other. This result confirms the applicability of either technique for the quantitative evaluation of β‐glucan in hydrocolloids. Molecular weight (MW) distribution of β‐glucan was determined by size‐exclusion chromatography with postcolumn detection. Experimental results revealed that the molecular weight of β‐glucan in the Trim products was decreased during the manufacturing process. This result was ascribed to the rigorous processing condition of jet‐cooking.  相似文献   

15.
《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   

16.
Several food regulatory agencies around the world have approved health claims for oat‐derived β‐glucan for cholesterol lowering and glycemic control. The biological efficacy of β‐glucan appears to depend both on daily intake and on physicochemical properties, such as molecular weight and viscosity. The objective of this study was to determine the effects of oat processing, genotype, and growing location on the physicochemical properties of β‐glucan. Five oat genotypes (HiFi, Leggett, CDC Dancer, Marion, and CDC Morrison) grown in two locations (Saskatoon and Kernen) were dehulled (untreated) and processed in a pilot facility through kilning (kilned, not flaked) and subsequent steaming and flaking (kilned, flaked). Untreated groats gave a relatively low Rapid Visco Analyzer (RVA) apparent viscosity (164 cP) and a low extractable β‐glucan molecular weight (332,440) but exhibited high β‐glucan solubility (90.49%). Compared with untreated groats, the kilned (not flaked) samples had significantly increased RVA apparent viscosity (314 cP) and extractable β‐glucan molecular weight (604,710). Additional processing into kilned and flaked products further increased RVA apparent viscosity (931 cP) and β‐glucan molecular weight (1,221,760), but β‐glucan solubility (63.83%) was significantly reduced. Genotype and growing environment also significantly affected β‐glucan viscosity and molecular weight, but no significant interaction effects between processing, genotype, and environment were found. Results indicate that there is potential for processors to improve the physicochemical and nutritional properties of oat end products through processing of specific oat genotypes from selected growing locations.  相似文献   

17.
Fermentation by human fecal bacteria of fractions of wheat bran prepared by preprocessing technology were examined and compared with a β‐glucan‐rich oat bran and a purified β‐glucan (OG). The wheat fractions were essentially a beeswing bran (WBA), mainly insoluble dietary fiber, and an aleurone‐rich fraction (WBB) containing more soluble fiber and some β‐glucan (2.7%). The oat bran (OB) had more endosperm and was very rich in β‐glucan (21.8%). Predigestion of WBB and OB to mimic the upper gastrointestinal (GI) tract gave digested wheat bran fraction B (WBBD) and digested oat bran (OBD), respectively. These predigested fractions were fermented in a batch technique using fresh human feces under anaerobic conditions. Changes in pH, total gas and hydrogen production, short chain fatty acids (SCFA), and both soluble and insoluble β‐glucan and other polysaccharide components, as determined from analysis of monosaccharide residues, were monitored. Fractions showed increasing fermentation in the order WBA < WBBD < OBD < OG. Variations in SCFA production indicated that microbial growth and metabolism were different for each substrate. Polysaccharide present in the supernatant of the digests had disappeared after 4 hr of fermentation. Fermentability of oat and wheat β‐glucan reflected solubility differences, and both sources of β‐glucan were completely fermented in 24 hr. Although the overall patterns of fermentation indicated the relative amounts of soluble and insoluble fiber, the anatomical origin of the tissues played a major role, presumably related to the degree of lignification and other association with noncarbohydrate components.  相似文献   

18.
Barley β‐glucan concentrate shows great potential as a functional food ingredient, but few product applications exist. The objectives of this study were to formulate a functional beverage utilizing barley β‐glucan concentrate, and to make a sensory evaluation of beverage quality in comparison to pectin beverages and to assess shelf stability over 12 weeks. Three beverage treatments containing 0.3, 0.5, and 0.7% (w/w) barley β‐glucan were developed in triplicate. Trained panelists found peely‐ and fruity‐orange aroma and sweetness intensity to be similar (P > 0.05) for all beverages tested. Beverage sourness intensity differed among beverages (P ≤ 0.05). Panelists evaluated beverages containing 0.3% hydrocolloid as similar (P > 0.05), whereas beverages with 0.5 and 0.7% β‐glucan were more viscous (P ≤ 0.05) than those with pectin at these levels. Acceptability of beverages was similar according to the consumer panel. Shelf stability studies showed no microbial growth and stable pH for all beverages over 12 weeks. Colorimeter values for most beverages decreased (P ≤ 0.05) during the first week of storage, mostly stabilizing thereafter. With an increase in concentration, β‐glucan beverages became lighter in color (P ≤ 0.05) and cloudier, but these attributes for pectin beverages were not affected (P > 0.05). β‐Glucan beverages exhibited cloud loss during the first three weeks of storage. β‐Glucan can therefore be successfully utilized in the production of a functional beverage acceptable to consumers.  相似文献   

19.
Oat consumption is regarded as having significant health benefits. The enrichment of white salted noodles with oat flour would provide a potential health benefit but may affect the texture and sensory quality. Oat cultivars grown in Western Australia (Yallara, Kojonup, Mitika, Carrolup, and new line SV97181‐8) and a commercial oat variety were milled into flour and added to wheat flour at 10, 20, and 30% to produce oat‐enriched white salted noodles. The purpose of the study was to determine the quality characteristics of the oat flours and to assess the influence the oat flour blends had on noodle texture, color, and sensory characteristics. In addition, another goal was to determine whether the different oat cultivars had similar potential to provide health benefits by measuring the β‐glucan content before and after processing. The results indicated that protein, ash content, and noodle firmness increased with the increased percentage of oat flour in the noodle formulations, whereas the pasting properties of the noodle wheat–oat flour blends did not differ significantly. The color of raw noodle sheets and boiled noodles changed significantly with oat incorporation and resulted in lower lightness/brightness, higher redness, lower yellowness, and lower color stability in comparison to standard wheat white salted noodles. Noodles made with the lowest oat percentage (10%) scored highest for all sensory parameters and were significantly different in appearance, color, and overall acceptability compared with noodles made with 20 and 30% oat flour. The β‐glucan content of the flour blends increased with the increase in the level of oat incorporation but subsequently decreased during processing into noodles. The decrease in the β‐glucan content varied across the different oat cultivars and levels of incorporation into the noodles. A new oat cultivar, SV97181‐8, exhibited the least β‐glucan loss during processing. In this study, the quality characteristics of white salted noodles enriched with oat flour from Western Australian cultivars were determined to provide essential information for the commercial development of healthier noodles.  相似文献   

20.
Shortening in a conventional yellow layer cake was replaced by maltodextrin (MD), amylodextrin (AD), octenyl succinylated amylodextrin (OSAD), or mixtures (MD+AD and MD+OSAD). The physical and sensory characteristics of the shortening‐free cakes were investigated. The specific gravity and viscosity of the cake batter, and the volume index of the baked cake were significantly reduced by MD, whereas the cake with added AD or OSAD showed a higher volume index than the control cake containing the shortening. An equivalent mixture of MD and AD, or MD and OSAD, however, produced cakes with a volume index and color defined as ΔE*(ab) that was similar to the control cake. Sensory evaluation revealed that the cakes containing AD or OSAD had significantly higher firmness than the control, but the cakes containing a mixture of MD and AD had firmness, springiness, and overall flavor scores similar to that of the control cake. According to instrumental texture profile analysis (TPA), MD addition, either alone or mixed with AD or OSAD, reduced firmness, whereas AD addition made the cake significantly firmer. When the shortening‐free cakes were stored for eight days at 4°C, TPA revealed greater changes in cake firmness and adhesiveness for MD alone. Cakes made from mixtures of dextrins (MD+AD and MD+OSAD) showed textural change with storage similar to that of the control cake, although the MD+AD cake remained softer than the control.  相似文献   

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