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1.
Bread made partially with soy may represent a viable alternative for increasing soy consumption in populations consuming Western diets. The potential health‐promoting activity of soy isoflavones may depend on their abundance and chemical form. The objective of this study was to characterize the changes in isoflavone distribution and β‐glucosidase activity during the soy breadmaking process. Soy bread ingredients were combined and mixed to form a dough that was subsequently proofed at 48°C for 1–4 hr and baked at 165°C for 50 min to produce breads. The isoflavone composition and β‐glucosidase activity in bread ingredients, doughs, and breads were monitored. Soy ingredients and wheat flour (not bread yeast) were the major contributors of the β‐glucosidase activity in bread. No degradation of isoflavones was observed during breadmaking but the isoflavone distribution was largely altered. Proofing and baking have important but different roles in changing the isoflavone distribution. Proofing converted isoflavone β‐glucosides to aglycones by highly specific β‐glucosidase activity. Thermal treatment during baking significantly decreased the isoflavone malonylglucosides and increased isoflavone β‐glucosides. Enzyme activity during proofing and the balance between formation and deconjugation of isoflavones during baking determine the isoflavone content and composition in the final product.  相似文献   

2.
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   

3.
Twin‐screw extrusion of wheat flour and the effects on the flour proteins were studied using flour samples containing 9, 20, and 30% protein. Vital gluten containing 70% protein was used to achieve the flour protein levels. The three flour samples were extruded with a twin‐screw extruder at a combination of processing parameters (exit die temperatures of 120, 140, and 160°C, and screw speeds of 240, 320, and 400 rpm). Increasing extruder exit die temperatures resulted in increased sulfhydryl content of the 9 and 20% protein content flour samples, but appeared to have little or no effect on the 30% protein content flour sample. Similarly, disulfide content decreased, albeit disproportionately, following the same trend. Both sulfhydryl and disulfide contents of extruded samples were lower than those of the nonextruded samples and could imply denaturation of protein, aggregation through intermolecular disulfide bonds, or oxidation during extrusion processing. Total cysteine content of extruded samples decreased by ≈16% relative to nonextruded samples, but otherwise remained almost unchanged among all extruded samples. The loss of total cysteine in extruded samples could represent the generation of hydrogen sulfide, volatile organic compounds, or flavor compounds during extrusion. SDS‐PAGE analysis of total proteins showed a shift from the higher to lower molecular weight regions for certain protein bands. Both depolymerization and protein aggregation occurred at higher shear forces during extrusion.  相似文献   

4.
The objective of this work was to evaluate extrusion cooking as a means to improve the nutritional properties of Phaseolus vulgaris L. that had been stored either at 42 degrees C and 80% relative humidity for 6 weeks or for periods >1 year in cereal stores in tropical conditions. Storage under these conditions resulted in an increase in cooking time increased (7.7- and 12-fold, respectively) as a result of development of the hard-to-cook (HTC) defect. Single-screw extrusion of the milled beans was carried out at four barrel temperatures and two moisture contents. The extrudate bulk density and water solubility index decreased with increasing temperature, whereas the water absorption index increased due to the higher proportion of gelatinized starch in the extruded samples. Both fresh and HTC beans contained nutritionally significant amounts of lectins, trypsin, and alpha-amylase inhibitors, which were mostly inactivated by extrusion. Extrusion also caused a considerable redistribution of insoluble dietary fiber to soluble, although the total dietary fiber content was not affected. Changes in solubility involved pectic polysaccharides, arabinose and uronic acids being the main sugars involved. Stored beans subjected to extrusion cooking showed physical and chemical characteristics similar to those of extrudates from fresh beans.  相似文献   

5.
Breadmaking properties were determined for formulations that included durum, soft, and spring wheat flour, using a pound-loaf sponge-dough baking procedure. Up to 60% durum or soft wheat flour plus 10% spring wheat flour could be incorporated at the sponge stage for optimum dough-handling properties. At remix, the dough stage required 30% spring wheat flour. Bread made with 100% spring wheat flour was used as a standard for comparison. Bread made with 60% durum flour exhibited internal crumb color that was slightly yellow. When storing pound bread loaves for 72 hr, crumb moisture content remained unchanged. Crumb firmness and enthalpy increased the most in bread made with 60% soft wheat flour. Crumb firmness increased the least in bread made with 100% spring wheat flour. Enthalpy changed the least in bread made with 60% durum flour. Crumb moisture content was significantly correlated with crumb firmness (r = -0.82) and enthalpy (r = -0.65). However, crumb moisture content was specific for each type of flour and a function of flour water absorption; therefore, these correlations should be interpreted with caution. Crumb firmness and enthalpy were significantly correlated (r = 0.65). Ball-milling flour resulted in an increase in water absorption of ≈2% and in crumb moisture content of ≈0.5% but had no effect on either crumb firmness or enthalpy.  相似文献   

6.
The effects of rice flour on the physicochemical properties of the raw material system and the quality of extruded potato–rice noodles were studied. The results demonstrated that the amylose content, pasting viscosities, storage modulus (G′), and loss modulus (G″) gradually increased with the included levels of rice flour, whereas the swelling power, solubility, and pasting temperature decreased with increasing rice flour content. The extruded potato–rice noodles exhibited desirable cooking qualities and textural properties with rice flour contents of up to 40%. Additionally, sensory evaluations revealed that the scores for chewiness, firmness, slipperiness, elasticity, and overall acceptability increased gradually with increasing rice flour content in the blends. Additionally, the results indicated the possibility of replacing potato flour with rice flour at a ratio of 6:4 to produce extruded potato–rice noodles of acceptable quality.  相似文献   

7.
Prime starch was extracted from soft and hard wheat flours and ballmilled to produce 100% damaged starch. Small amounts of the ball-milled starch or a pregelatinized starch were added to sugar-snap cookie formulations. Other cookie doughs were produced from prime starch only (no flour) with small amounts of the ball-milled starch added. Starch damages of the resulting substituted soft and hard wheat flours and soft and hard wheat prime starches were determined and compared to diameters of sugarsnap cookies produced from the control and treatments. Soft wheat flour and starches produced larger diameter cookies than their hard wheat counterpart at all levels of damaged starch. Both sources of damaged starch (ball-milled or pregelatinized starch) had similar effects on cookie diameter. Cookies produced from all starch (no flour) were similar to their respective flour controls at ≈8% damaged starch. To produce the same size cookie as that produced by soft wheat flour and starch, hard wheat flour and starch cookie formulations required less damaged starch and had lower alkaline water retention than did the soft wheat flour and starch cookie formulations. Other flours were treated with chlorine gas to pH 4.8. Pregelatinized starch (≈5%) was required to reduce the cookie diameter as much as chlorine treatment did. Results suggest unique quality differences between soft and hard wheat starch as they function in sugar-snap cookie baking. The functional results of those differences are not adequately quantified by the estimation of damaged starch level.  相似文献   

8.
Variations in physical and compositional bran characteristics among different sources and classes of wheat and their association with bread‐baking quality of whole grain wheat flour (WWF) were investigated with bran obtained from Quadrumat milling of 12 U.S. wheat varieties and Bühler milling of six Korean wheat varieties. Bran was characterized for composition including protein, fat, ash, dietary fiber, phenolics, and phytate. U.S. soft and club wheat brans were lower in insoluble dietary fiber (IDF) and phytate content (40.7–44.7% and 10.3–17.1 mg of phytate/g of bran, respectively) compared with U.S. hard wheat bran (46.0–51.3% and 16.5–22.2 mg of phytate/g of bran, respectively). Bran of various wheat varieties was blended with a hard red spring wheat flour at a ratio of 1:4 to prepare WWFs for determination of dough properties and bread‐baking quality. WWFs with U.S. hard wheat bran generally exhibited higher dough water absorption and longer dough mixing time, and they produced smaller loaf volume of bread than WWFs of U.S. soft and club wheat bran. WWFs of two U.S. hard wheat varieties (ID3735 and Scarlet) produced much smaller loaves of bread (<573 mL) than those of other U.S. hard wheat varieties (>625 mL). IDF content, phytate content, and water retention capacity of bran exhibited significant relationships with loaf volume of WWF bread, whereas no relationship was observed between protein content of bran and loaf volume of bread. It appears that U.S. soft and club wheat bran, probably owing to relatively low IDF and phytate contents, has smaller negative effects on mixing properties of WWF dough and loaf volume of bread than U.S. hard wheat bran.  相似文献   

9.
Brans from rice, oats, corn, and wheat were cooked in a twin-screw extruder at either high or low energy input, and their cholesterol-lowering effects were compared with those of unprocessed brans when fed to four-week-old male golden Syrian hamsters (n = 10 per treatment) for three weeks. Peanut oil was added to oat, corn, and wheat bran during the extrusion process to match the oil content of rice bran. Diets contained 10% total dietary fiber, 10.3% fat, 3% nitrogen, and 0.3% cholesterol. Plasma and liver cholesterol and total liver lipids were significantly lower with low-energy extruded wheat bran compared with unprocessed wheat bran. Extrusion did not alter the hypocholesterolemic effects of rice, oat, or corn brans. Plasma and liver cholesterol levels with corn bran were similar to those with oat bran. Relative cholesterol-lowering effects of the brans, determined with pooled (extruded and unextruded) bran data, were rice bran > oat bran > corn bran > wheat bran. Rice bran diets resulted in significantly lower levels of total plasma cholesterol and very low density lipoprotein cholesterol compared with all other brans. Total liver cholesterol and liver cholesterol concentrations (mg/g) were significantly lower with high-energy extruded rice bran compared with the cellulose control group. Plasma cholesterol and total liver cholesterol values with low-energy extruded wheat bran were similar to those with rice bran (unextruded or extruded) diets. Lowered cholesterol with rice bran diets may result in part from greater lipid and sterol excretion with these diets. Results with low-energy extruded wheat bran suggest that this type of processing may improve the potential for lowering cholesterol with wheat bran products.  相似文献   

10.
The objective of this study was to evaluate the chemical, physicochemical, and functional properties of agrowastes derived from okara ( Glycine max), corn cob ( Zea mays sp.), wheat straw ( Triticum sp.), and rice husk ( Oryza sativa) for potential applications in foods. The fibrous materials (FM) were treated with alkali to yield fibrous residues (FR). Rice husk contained the highest ash content (FM, 8.56%; FR, 9.04%) and lowest lightness in color (FM, 67.63; FR, 63.46), possibly due to the abundance of mineral constituents. Corn cob contained the highest amount of soluble dietary fiber (SDF), whereas okara had the highest total dietary fiber (TDF). The high dietary fiber fractions of corn cob and okara also contributed to the highest water- and oil-holding capacities, emulsifying activities, and emulsion stabilities for both FM and FR samples. These results indicate that these agrowastes could be utilized as functional ingredients in foods.  相似文献   

11.
Jet milling is a fluid energy impact‐milling technique generally used for the ultrafine reduction of higher value materials. The efficiency of jet milling combined with air classification appears very efficient to separate starch from other wheat flour aggregate components and to produce wheat starch with very low residual protein content. Indeed, residual protein content of the starch‐rich fraction can be reduced to <2% db with a series of successive grinding and air classification operations. Lipid and pentosan contents were also reduced in the starch‐rich fraction. Nevertheless, jet milling cannot eliminate grinding differences observed between different types of wheat. Wheat hardness continues to have an effect on milling and classification yields and on the composition of air classification fractions. To obtain starch‐rich fraction with only 2% protein content, hard wheat flour required a series of at least five grinding steps, whereas only three steps are necessary for soft wheat flour. Under these conditions, hard wheat flours give 24% mass yield with 12% starch damage compared with 39% yield and a low starch damage content (6.4%) for soft wheat flour. These results highlight new prospects for the development of cereal flours, especially soft wheat flours.  相似文献   

12.
High‐amylose wheat flour was used to substitute for normal wheat flour in breadmaking and formation of resistant starch (RS) in bread during storage was determined. Substitution with high‐amylose wheat flour (HAF) decreased peak and final viscosities, breakdown, and setback. Doughs with HAF substitutions were weaker and less elastic, and absorbed more water than those of the normal wheat flour. After baking, RS contents in breads with 10, 30, and 50% HAF substitutions were 1.6, 2.6, and 3.0% (db), respectively, higher than that of the control (0.9%, db). The levels of RS increased gradually during storage for one, three, and five days. With substitutions of 30 and 50% HAF, the total levels of dietary fiber (DF) and RS in bread after five days of storage were 15.5 and 16.8% (db), respectively, as compared to 13.0% (db) in bread from the normal wheat flour. The loaf volumes and appearances of bread crumbs made from HAF substitutions of 10 and 30% were not significantly different from those of the control, whereas the substitution with 50% HAF decreased loaf volume and resulted in inferior appearance of breadcrumbs. The firmness of breadcrumbs increased along with increase in the level of HAF substitutions after baking. During storage, the firmness of breadcrumb with 10% HAF substitutions was higher than that of the control, whereas breads with 30 and 50% HAF substitutions had similar firmness to the control. As a result, HAF might be used to substitute for up to 50% normal wheat flour to make bread with acceptable bread quality and significantly high amount of RS.  相似文献   

13.
A soybean angiotensin I converting enzyme (ACE) inhibitory peptide fraction was reported to have antihypertensive activity in a rat study. The purpose of the present study was to examine if the presence of isoflavones in the soybean ACE inhibitory peptide fraction may contribute to the blood-pressure-lowering property. The isoflavone concentration in soybean samples was analyzed on a C 18 reverse-phase column using a two-step gradient solvent system. Producing soybean hydrolysate led to a nearly 40% loss of isoflavones compared with the original soybean flour, but the isoflavone composition did not change and the dominant isoflavone chemicals remained as 6'-O-malonylgenistin and 6'-O-malonyldaidzin. Ion exchange chromatography affected significantly both the content and the composition of the isoflavones. The dominant isoflavones in the ion-exchanged fraction were aglycones and nonacylated isoflavones, accounting for 95.8% of the total amount of 987.7 microg/g. It was calculated that the isoflavone content in the soybean ACE inhibitory peptide fraction was 25 times less than the minimal effective isoflavone dose reported. In vitro study also showed that adding isoflavones into both soybean flour hydrolysate and soybean ACE inhibitory peptide samples to a concentration of as high as 31.5% (w/w) did not affect ACE inhibitory activity (IC 50 values). The findings along with previously published results indicated that the contribution of isoflavones in soybean ACE inhibitory peptide fraction to the blood-pressure-lowering property in a short-term feeding study might be negligible.  相似文献   

14.
Sensory evaluation showed panelists could detect small differences in gloss and translucency in boiled white salted noodles (WSN) but sensory evaluation requires significant resources. Methods for the measurement of noodle gloss and translucency in boiled WSN were developed and the effects of hardness, protein, water addition, and vacuum mixing on these visual sensory characteristics and color (as measured by CIE L*, a*, and b*) were investigated. Noodles derived from hard wheats at low flour protein contents were more translucent than noodles from soft wheat flour at low protein. This trend changed at the highest flour protein contents observed. Translucency of the soft wheat noodles increased to levels equal to or exceeding the translucency of high protein hard wheat noodles. Translucency of all noodle varieties increased as flour protein increased. CIE L* decreased, a* increased, and b* increased when water addition to dough increased from 30 to 35%, but there was no further effect on color when water addition was increased to >35% for raw soft and hard WSN. Boiled noodle translucency was significantly increased when water addition to the dough was increased from 35 to 38% and when noodles made from soft wheat flour were mixed under vacuum. Vacuum mixing significantly increased gloss of boiled noodles made from soft wheat flours.  相似文献   

15.
Pharmacokinetic studies of soybean isoflavones have shown that following oral ingestion, the two major isoflavones, daidzin and genistin, are hydrolyzed in the intestine, rapidly absorbed into the peripheral circulation, and eliminated from the body with a terminal half-life of 7-8 h. These characteristics make maintenance of steady-state plasma isoflavone concentrations difficult to attain unless there is repeated daily ingestion of foods or supplements containing isoflavones. In an attempt to sustain more constant plasma isoflavone concentrations, a new slow-release formulation of a soybean isoflavone extract was prepared by microencapsulation with a mixture of hydroxypropylcellulose and ethylcellulose to alter its dissolution characteristics. In vitro experiments confirmed slow aqueous dissolution of isoflavones from this formulation when compared with the conventional isoflavone extract. The pharmacokinetics of this slow-release isoflavone extract was studied in 10 healthy postmenopausal women after oral administration of a single capsule containing the equivalent of 22.3 mg of genistein and 7.47 mg of daidzein expressed as aglycons. A comparison of the key pharmacokinetic parameters obtained in this study with those established in extensive studies performed previously in this laboratory indicated that the mean residence time of genistein and daidzein increased 2-fold with microencapsulation. These findings are indicative of a decreased rate of absorption, consistent with the observed slow in vitro dissolution rate. These findings show that it is feasible to employ polymer matrices that slow the aqueous dissolution for preparing sustained-release formulations of soy isoflavones. Further studies to optimize such formulations are warranted.  相似文献   

16.
A combination of analytical techniques was used to examine and quantify seed compositional components such as protein, lipid, free sugars, isoflavones, and soyasaponins during soybean development and maturation in two Korean soybean cultivars. Protein accumulation was rapid during reproductive stages, while lipid content was only relatively moderately increased. The major carbohydrate saccarides sucrose and stachyose constantly increased during the reproductive stage. Previously published results suggest that the free sugar and lipid content reached their maximal concentrations at a relatively early stage of seed development and remain constant in comparison to other chemical components. The malonylglucosides were the predominant isoflavone form followed by the glucosides, acetyl glucosides, and aglycone forms. As soybean seed matures, total soyasaponin concentration was constantly decreased until the R8 stage. Soyasaponin beta(g) was the major soyasaponin in DDMP-conjugated group B soyasaponins, followed by the non-DDMP counterpart soyasaponin I and soyasaponin A1. The ratio of total isoflavone to total soyasaponin in the developing soybean increased from 0.06 to 1.31. Protein, lipid, and free sugar contents in the developing soybean seeds showed significant positive correlations with conjugated isoflavones and total isoflavone concentration, while the lipid contents showed a negative correlation with the isoflavone aglycone. Protein, lipid, and free sugar contents showed a negative correlation with total group A and B soyasaponins and total soyasaponins; however, only the soyasaponin A content was significantly negatively correlated with free sugar content. Total soyasaponin content was negatively correlated with isoflavone content (r = -0.828 at p < 0.01).  相似文献   

17.
《Cereal Chemistry》2017,94(1):98-103
Dehulled and/or germinated black bean flours were physicochemically characterized, including pasting properties, along with the trypsin inhibitor and antioxidant phenolics. To our best knowledge, this is the first study that, using nonparametric correlations and principal component analysis, identifies the parameters affecting the pasting properties of germinated black bean flour. The carbohydrate loss observed after black bean germination was indirectly correlated with the crude fiber content. Therefore, germination increased the protein and crude fiber contents compared with raw seeds (from 19.1 and 2.4% to 24.0 and 5.1%, respectively). Additionally, the highest protein digestibility was obtained in dehulled germinated black bean flour (78.4%), followed by whole germinated seed flour (74.1%). The dehulling process increased the total starch content 13.5 and 18.8% compared with raw and germinated whole bean flours, respectively. Dehulling decreased both trypsin inhibitor activity and antioxidant phenolics. Germination reduced by twofold the peak and final viscosities of black bean flours. Interestingly, both viscosities were negatively correlated with protein and positively correlated with fat and insoluble dietary fiber. Although resistant starch content was not affected by germination or dehulling, its interactions with fat and insoluble dietary fiber were responsible of the changes observed in pasting properties of germinated black bean flour.  相似文献   

18.
The objective of this research was to evaluate the effect of thermomechanical extrusion and particle size (PS) reduction on the bioconversion rate of corn fiber for ethanol production. Extrusion was conducted at a screw speed of 300 rpm, feed rate of 120 g/min, feed moisture content of 30%, melt temperature of 140°C, and die diameter of 3 mm. Raw and extruded corn fiber were separated into three different PSs (1 > PS ≥ 0.5, 0.5 > PS ≥ 0.3, and 0.3 > PS ≥ 0.15 mm) with a wire sieve. Extrusion pretreatment and PS reduction resulted in a significant (P < 0.05) difference in physical properties and color values of extruded corn fiber as a result of accelerated degradation of corn fiber structure. Significant increase in water solubility index of extruded corn fiber at 0.3 > PS ≥ 0.15 mm was an indication of high degradation of starch during extrusion for higher release of polysaccharides. Moreover, extruded corn fiber at PS reduction 0.3 > PS ≥ 0.15 mm also significantly increased (P < 0.05) ethanol yield (69.11 g/L) and conversion (68.18%) by increasing protein digestibility and free amino nitrogen, which are essential for higher fermentation efficiency.  相似文献   

19.
The Rheo Extrusion Meter (REM) measures the time for vertical upward extrusion of wheat flour dough (subsequently referred to as extrusion time, ET) as a measure of its consistency. ET evidently increases with dough consistency. ETs are highly reproducible and sensitive to differences in dough moisture content. A single REM analysis takes 20 min, and the measured ET can be converted into the correct baking absorption at a given temperature. The heights of the extruded dough pieces are negatively correlated with straight‐dough bread loaf specific volume, both when comparing different flour samples and when adjusting moisture content of dough prepared from a given flour sample. The REM also allows determination of the consistency of complex wheat flour based systems and the impact of vital wheat gluten or ascorbic acid thereupon. Furthermore, in contrast to the farinograph, it detects the impact of endoxylanases hydrolyzing water‐extractable arabinoxylan on dough consistency.  相似文献   

20.
Wet okara (soy milk residue), as a functional ingredient, was evaluated to be added to a coconut‐based snack at 10, 20, 30, 40, and 50% levels to replace dry coconut in the formula. Certain physicochemical, nutritional, and sensory properties of the samples were evaluated. A coconut‐based, soft, baked snack with incorporated okara showed higher total fiber and much lower fat content than the control, which significantly improved the nutritional profile of the samples. Samples 3 and 4 (which had 30 and 40% replacement of coconut with wet okara, respectively) received the highest overall sensory score (8.4), which was significantly higher than the score of a control sample (7.5). Sample 3 also had a significantly improved nutritional profile per serving size, such as an increased fiber content of 6.11 ± 0.04 g/100 g and a decreased fat content of 17.57 ± 0.02 g/100 g, and sample 4 had an increased fiber content of 6.19 ± 0.03 g/100 g and a decreased fat content of 15.64 ± 0.03 g/100 g compared with the control sample. The appearance, color, flavor, physical measurements (instrumental texture profile analysis), and water activity of samples 3 and 4 were not significantly different from the control sample and demonstrated potential application of this formulation in the baking industry, proving that the wet okara can be successfully used as a value‐added functional ingredient.  相似文献   

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