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1.
The impact of dietary fiber (DF) mixtures on dough thermal properties needs to be investigated when designing high‐fiber wheat bread. Effects of flour replacement at different levels (6–34%) by soluble (inuline [FN]), partially soluble (sugar beet [FX], pea cell wall [SW]), and insoluble (pea hull [EX]) DF on wheat dough thermal profiles have been investigated by simulating baking, cooling, and storage in differential scanning calorimetry (DSC) pans. In general, DF incorporation into water‐flour systems delayed endothermic transition temperatures for both gelatinization and retrogradation phenomena except for the peak temperature (Tp) of retrogradation. With some exception, the pattern of the enthalpy of amylopectin retrogradation was lower and slower (lower constant of proportion, k) over 10 days of storage in gelatinized hydrated flour‐fiber blends when compared with control without DF. FX, a partially soluble fiber, provided major effects on gelatinization (Tp decrease and ΔH increase) and retrogradation kinetics (the Avrami exponent, n, increase). Single presence of EX allowed a significant reduction in the Avrami exponent n leading to slower kinetics for amylopectin retrogradation when included in the blends.  相似文献   

2.
The dough properties and baking qualities of a novel high‐amylose wheat flour (HAWF) and a waxy wheat flour (WWF) (both Triticum aestivum L.) were investigated by comparing them with common wheat flours. HAWF and WWF had more dietary fiber than Chinese Spring flour (CSF), a nonwaxy wheat flour. Also, HAWF contained larger amounts of lipids and proteins than WWF and CSF. There were significant differences in the amylose and amylopectin contents among all samples tested. Farinograph data showed water absorptions of HAWF and WWF were significantly higher than that of CSF, and both flours showed poorer flour qualities than CSF. The dough of WWF was weaker and less stable than that of CSF, whereas HAWF produced a harder and more viscous dough than CSF. Differential scanning calorimetry data showed that starch in HAWF dough gelatinized at a lower temperature in the baking process than the starches in doughs of WWF and CSF. The starch in a WWF suspension had a larger enthalpy of gelatinization than those in HAWF and CSF suspensions. Amylograph data showed that the WWF starch gelatinized faster and had a higher viscosity than that in CSF. The loaves made from WWF and CSF were significantly larger than the loaves made from HAWF. However, the appearance of bread baked with WWF and HAWF was inferior to the appearance of bread baked with CSF. Bread made with WWF became softer than the bread made with CSF after storage, and reheating was more effective in refreshing WWF bread than CSF bread. Moreover, clear differences in dough and bread samples were revealed by scanning electron microscopy. These differences might have some effect on dough and baking qualities.  相似文献   

3.
Hydrothermal treatments, which are routine in oat processing, have profound effects on oat flour dough rheological properties. The influence of roasting and steam treatments of oat grain on dough mixing and breadbaking properties was investigated when hydrothermally treated oat flour was blended with wheat flour. Roasting of oat grain (105°C, 2 hr) resulted in oat flours that were highly detrimental to wheat flour dough mixing properties and breadbaking quality. Steaming (105°C, 20 min) or a combination of roasting and steaming of oat grain significantly improved the breadbaking potential of the oat flours. The addition of oat flours increased water absorption and mixing requirements of the wheat flour dough and also decreased bread loaf volume. However, at the 10% substitution level, steamed oat flours exhibited only a gluten dilution effect on bread loaf volume when wheat starch was used as a reference. Oat flour in the breadbaking system decreased the retrogradation rate of bread crumb starch. The results indicate that adequate hydrothermal treatments of oat grain are necessary for oat flour breadbaking applications. Steamed oat flours used at a 10% level retarded bread staling without adversely affecting the loaf volume.  相似文献   

4.
《Cereal Chemistry》2017,94(6):991-1000
Wheat, an important crop in North Dakota and the United States, is often used for bread. Health concerns related to chronic diseases have caused a shift toward consumption of whole wheat bread. There has been some indication that the rate and amount of starch digestibility of whole wheat breads may be lower than for their refined flour counterparts. This research investigated the components of whole wheat bread that may reduce starch digestibility and impact nutritional quality. Six formulations of flour were used, which included two refined flours, two whole wheat flours, and two whole wheat flours with added starch. The starch was added to whole wheat flours to increase the starch level to that of the refined flour so that we can determine whether or not the dilution of the starch in whole wheat bread was a factor in lowering the estimated glycemic index (eGI) of whole wheat bread. White and whole wheat flours and breads were evaluated for chemical composition, baking quality by 1 , and eGI by the Englyst assay. Whole wheat breads had significantly (P < 0.05) higher mineral, protein, arabinoxylan, and phenolic acid contents, as well as significantly (P < 0.05) lower eGI. The starch molecular weight was also significantly (P < 0.05) higher for whole wheat and whole wheat + starch breads compared with white breads. The eGIs of refined flour breads were 93.1 and 92.7, whereas the eGIs of whole wheat and whole wheat + starch breads ranged from 83.5 to 85.1. Overall, several factors in the whole wheat bread composition can be found to affect the quality and starch hydrolysis.  相似文献   

5.
The effect of addition of flours from the highly nutritious Andean crops quinoa (Chenopodium quinoa), kañiwa (Chenopodium pallidicaule), kiwicha (Amaranthus caudatus), and tarwi (Lupinus mutabilis) has been investigated in wheat doughs and fresh bread quality. The thermomechanical profile of wheat doughs and bread quality has been explored by increasing substitution of wheat flour at 0–100% by Andean crop flours. Dough blends were evaluated using the Chopin Mixolab device, whereas bread quality assessment comprised sensory (overall acceptability) and physicochemical (moisture, specific volume, texture, color) determinations in composite breads. In general, no breads with aerated crumb structure could be obtained from 100% Andean crop flours, with the exception of quinoa breads that had overall sensory values about half a completely perfect score, and which were not significantly different from the breads made from a 50:50 blend of wheat and quinoa. Replacement of wheat flour by ≤12.5% (tarwi), 25% (kañiwa), and 50% (kiwicha), respectively, still produced breads with good sensory acceptability but variable color and doughs with acceptable thermomechanical patterns. Partial substitution of wheat flour by Andean crop flours constitutes a viable option to improve the nutritional value of the breads, with acceptable technological performance of dough blends and composite breads.  相似文献   

6.
Barley is rich in nutritionally positive compounds, but the quality of bread made of wheat–barley composite flours is impaired when a high percentage of barley is used in the mixture. A number of enzymes have been reported to be useful additives in breadmaking. However, the effect of β‐glucanase on breadmaking has scarcely been investigated. In this paper, the influence of different levels (0.02, 0.04, 0.06, and 0.08%, based on composite flour) of β‐glucanase (100,000 U/g) on the properties of dough and bread from 70% wheat, 30% barley composite flour were studied. Although dough development time, dough stability, and protein weakening value decreased after β‐glucanase addition, dough properties such as softness and elasticity as well as bread microstructure were improved compared with the control dough. β‐Glucanase also significantly improved the volume, texture, and shelf life of wheat–barley composite breads. The use of an optimal enzyme concentration (0.04%) increased specific volume (57.5%) and springiness (21%), and it reduced crumb firmness (74%) and staling rate. Bread with added β‐glucanase had a better taste, softness, and overall acceptability of sensory characteristics compared with the control bread. Moreover, the quality of wheat–barley composite bread after addition of 0.04% β‐glucanase was nearly equal to the quality of pure wheat bread. These results indicate that dough rheological characteristics and bread quality of wheat–barley composite flour can be improved by adding a distinct level of β‐glucanase.  相似文献   

7.
To alleviate the adverse effects (grittiness and high crumb firmness) caused by the inclusion of sorghum flour in composite breads, sorghum grain was malted with the aim of decreasing the gelatinization temperature and increasing the water‐holding capacity of sorghum flour. Four different heat treatments were investigated: drying the malt at high temperatures (50–150°C), stewing, steaming, and boiling before drying the malt at 80°C. Malting decreased the pasting temperature of sorghum to values approaching those of wheat flour, but the paste viscosity was very low. Increasing the malt drying temperature inactivated the amylases but gave malts of darker color and bitter taste. Stewing, steaming, and boiling the malt before drying almost completely inactivated the amylases and increased the enzyme‐susceptible starch content and the paste viscosity of malt flours. Bread made with boiled malt flour (30%) had an improved crumb structure, crumb softness, water‐holding capacity, and resistance to staling, as well as a fine malt flavor compared with the bread made with grain sorghum flour (30%). Consumers preferred the malted sorghum bread over the bread made with plain sorghum flour.  相似文献   

8.
The influence of bran particle size on bread‐baking quality of whole grain wheat flour (WWF) and starch retrogradation was studied. Higher water absorption of dough prepared from WWF with added gluten to attain 18% protein was observed for WWFs of fine bran than those of coarse bran, whereas no significant difference in dough mixing time was detected for WWFs of varying bran particle size. The effects of bran particle size on loaf volume of WWF bread and crumb firmness during storage were more evident in hard white wheat than in hard red wheat. A greater degree of starch retrogradation in bread crumb stored for seven days at 4°C was observed in WWFs of fine bran than those of coarse bran. The gels prepared from starch–fine bran blends were harder than those prepared from starch–unground bran blends when stored for one and seven days at 4°C. Furthermore, a greater degree of starch retrogradation was observed in gelatinized starch containing fine bran than that containing unground bran after storage for seven days at 4°C. It is probable that finely ground bran takes away more water from gelatinized starch than coarsely ground bran, increasing the extent of starch retrogradation in bread and gels during storage.  相似文献   

9.
Bread was prepared from wheat flour and wheat flour fortified with either 3, 5, and 7% legume hulls or insoluble cotyledon fibers, or with 1, 3, and 5% soluble cotyledon fibers isolated from pea, lentil, and chickpea flours. Incorporation of hulls or insoluble fibers resulted in increases in dough water absorption by 2–16% and increases in mixing time of dough by 22–147 sec. Addition of soluble fiber resulted in decreases in water absorption as the substitution rate increased and similar mixing times to the control dough. Loaf weights of breads containing hulls or insoluble fibers were generally higher than that of control bread at 149.4–166.5 g. However, the loaf volume of breads fortified with legume hulls and fibers (685–1,010 mL) was lower than that of the control bread (1,021 mL). Breads containing soluble fibers were more attractive in terms of crumb uniformity and color than breads containing either hulls or insoluble fibers. Breads fortified with legume hulls and fibers were higher in moisture content than control bread regardless of the type, source, or fortification rate. Bread fortified with up to 7% hulls or insoluble cotyledon fibers or up to 3% soluble cotyledon fibers, with the exception of 7% insoluble pea fiber, exhibited similar firmness after seven days of storage compared with the control bread, despite their smaller loaf volume. Breads containing hull fibers exhibited the lowest starch transition enthalpies as determined by DSC after seven days of storage, while the starch transition enthalpies of breads containing added soluble or insoluble fiber were not significantly different from the control bread.  相似文献   

10.
Refined wheat flours commercially produced by five different U.S. and Mexican wheat blends intended for tortilla production were tested for quality and then processed into tortillas through the hot‐press forming procedure. Tortilla‐making qualities of the flour samples were evaluated during dough handling, hot pressing, baking, and the first five days on the shelf at room temperature. The predominant variables that affected the flour tortilla performance were wet gluten content, alveograph W (220–303) and P/L (0.70–0.94) parameters, farinograph water absorption (57%) and stability (10.8–18.7 min), starch damage (5.43–6.71%), and size distribution curves (uniform particle distribution). Flours produced from a blend of Dark Northern Spring (80%) and Mexican Rayon (20%) wheat had the highest water absorption, and tortillas obtained from this blend showed the highest diameter and lowest thickness. The whitest and best textured tortillas were obtained from the flour milled from three hard types of Mexican wheat blend. A Mixolab profile was generated from the best tortilla flours, those produced by mills 3 and 4. The Mixolab profile showed that a good flour for hot‐press tortillas had a relatively lower absorption and short dough mix time compared with a bread flour and should have a significantly higher gluten compared with an all‐purpose flour. Compared with bread flour, the tortilla flour had higher retrogradation and viscosity values. The Mixolab profile proved to be a good preliminary test to evaluate flours for hot‐press tortillas.  相似文献   

11.
One nonwaxy (covered) and two waxy (hull-less) barleys, whole grain and commercially abraded, were milled to break flour, reduction flour, and the bran fraction with a roller mill under optimized conditions. The flour yield range was 55.3–61.8% in whole grain and increased by 9–11% by abrasion before milling. Break flours contained the highest starch content (≤85.8%) independent of type of barley and abrasion level. Reduction flours contained less starch, but more protein, ash, free lipids, and total β-glucans than break flours. The bran fraction contained the highest content of ash, free lipids, protein, and total β-glucans but the lowest content of starch. Break flours milled from whole grain contained 82–91% particles <106 μm, and reduction flours contained ≈80% particles <106 μm. Abrasion significantly increased the amount of particles <38 μm in break and reduction flours in both types of barley. Viscosity of hot paste prepared with barley flour or bran at 8% concentration was strongly affected by barley type and abrasion level. In cv. Waxbar, the viscosity in bran fractions increased from 428 to 1,770 BU, and in break flours viscosity increased from 408 to 725 BU due to abrasion. Sugar snap cookies made from nonwaxy barley had larger diameter than cookies prepared from waxy barley. Cookies made from break flours were larger than those made from reduction flours, independent of type of barley. Quick bread baked from nonwaxy barley had a loaf volume similar to that of wheat bread, whereas waxy barley bread had a smaller loaf volume. Replacement of 20% of wheat flour by both waxy and nonwaxy barley flour or bran did not significantly affect the loaf volume but did decrease the hardness of quick bread crumb.  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.
We used modified wheat starches in gluten-starch flour models to study the role of starch in bread making. Incorporation of hydroxypropylated starch in the recipe reduced loaf volume and initial crumb firmness and increased crumb gas cell size. Firming rate and firmness after storage increased for loaves containing the least hydroxypropylated starch. Inclusion of cross-linked starch had little effect on loaf volume or crumb structure but increased crumb firmness. The firming rate was mostly similar to that of control samples. Presumably, the moment and extent of starch gelatinization and the concomitant water migration influence the structure formation during baking. Initial bread firmness seems determined by the rigidity of the gelatinized granules and leached amylose. Amylopectin retrogradation and strengthening of a long-range network by intensifying the inter- and intramolecular starch-starch and possibly also starch-gluten interactions (presumably because of water incorporation in retrograded amylopectin crystallites) play an important role in firming.  相似文献   

14.
Flour qualities of polished wheat flours of three fractions, C‐1 (100–90%), C‐5 (60–50%), and C‐8 (30–0%), obtained from hard‐type wheat grain were used for the evaluation of four kinds of baking methods: optimized straight (OSM), long fermentation (LFM), sponge‐dough (SDM) and no‐time (NTM) methods. The dough stability of C‐5 in farinograph mixing was excellent and the maturity of polished flour doughs during storage in extensigraph was more improved than those of the commercial wheat flour (CW). There were no significant differences in the viscoelastic properties of CW dough after mixing, regardless of the baking method, while those of polished flour doughs were changed by the baking method; this tendency became clear after fermentation. The polished flours could make a better gluten structure in the dough samples after mixing or fermentation using LFM and SDM, as compared with other baking methods. Baking qualities such as specific volume and storage properties of breads from all polished flours made with SDM increased more than with other methods. In addition, viscoelastic properties of C‐5 and C‐8 doughs fermented by SDM were similar to those of CW, and the C‐5 breadcrumb showed softness similar to that of the CW. Also, SDM could make C‐5 bread with significantly higher elasticity and cohesiveness after storage for five days when compared with CW bread. Therefore, SDM with long fermentation, as compared with other baking methods, was considered suitable for use with polished flours to give better effects on dough properties during fermentation, resulting in more favorable bread qualities.  相似文献   

15.
The purpose of this research was to find out the effect of flour extraction rate on the antioxidative properties of traditional rye bread and then to compare the bioactive compounds content and antioxidant properties of rye breads with commercial wheat roll. Four types of rye flour with different extraction rates of 100 (whole meal dark flour), 95 (brown flour), 90 (brown flour), and 70% (light flour) originated from Warko rye cultivar were used for traditional bread baking with sourdough fermentation. Four types of the respective rye breads were analyzed for their potentially beneficial components, including tocopherols and tocotrienols, total phenolics and flavonoids, reduced glutathione, and inositol hexaphosphates. Moreover, the phenolic acids profile was provided. The Trolox equivalent antioxidant capacity (TEAC) of the breads was evaluated using free radical scavenging activities of 80% methanol extracts against ABTS*+ radical cation (ABTS radical cation decolorization method) whereas radical scavenging activity (RSA) was determined against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH*). The superoxide dismutase-like activity (SOD-like activity) was evaluated as free radical scavenging activities of PBS extracts against superoxide anion radicals (O2*-). The results were compared to whole meal rye bread as well as to wheat roll taken as representative example of wheat based bakery product. The studies showed that flour extraction rates strongly affected the content of bioactive compounds and antioxidative properties of traditionally baked rye breads. The incorporation of the rye flours with extraction rates from 100 down to 70% in the formulation caused decrease in tocopherol (T), tocotrienol (T3), inositol hexaphosphate (IP6), and phenolic compound (TPC) contents in rye breads. No changes in reduced glutathione (GSH) contents were noted between each type of rye bread. A significant decrease in Trolox equivalent antioxidant capacity and radical DDPH scavenging activity was also found in bread formulated on flour with an extraction rate of 70% in comparison to the breads formulated on flour with extraction rates from 100 to 90%. The highest SOD-like activity was noted for rye bread formulated on flour with an extraction rate of 70%. The four types of rye breads showed better antioxidative properties and higher antioxidant contents when compared to wheat roll with one exception made to tocopherols and tocotrienols.  相似文献   

16.
Starch, protein, and temperature effects on bread staling were investigated using visible and near‐infrared spectroscopy (NIRS) and differential scanning calorimetry (DSC). Bread staling was mainly due to amylopectin retrogradation. NIRS measured amylopectin retrogradation accurately in different batches. Three important wavelengths, 970 nm, 1,155 nm, and 1,395 nm, were associated with amylopectin retrogradation. NIRS followed moisture and starch structure changes when amylopectin retrograded. The amylose‐lipid complex changed little from one day after baking. The capability of NIRS to measure changes in the retrograded amylose‐lipid complex was limited. Two important wavelengths, 550 nm and 1,465 nm, were key for NIRS to successfully classify the starch‐starch (SS) and starch‐protein (SP) bread based on different colors and protein contents in SS and SP. Low temperature dramatically accelerated the amylopectin retrogradation process. Protein retarded bread staling, but not as much as temperature. The starch and protein interaction was less important than the starch retrogradation. Protein hindered the bread staling process mainly by diluting starch and retarding starch retrogradation.  相似文献   

17.
Double‐null partial waxy wheat (Triticum aestivum L.) flours were used for isolation of starch and preparation of white salted noodles and pan bread. Starch characteristics, textural properties of cooked noodles, and staling properties of bread during storage were determined and compared with those of wheat flours with regular amylose content. Starches isolated from double‐null partial waxy wheat flours contained 15.4–18.9% amylose and exhibited higher peak viscosity than starches of single‐null partial waxy and regular wheat flours, which contained 22.7–25.8% amylose. Despite higher protein content, double‐null partial waxy wheat flours, produced softer, more cohesive and less adhesive noodles than soft white wheat flours. With incorporation of partial waxy prime starches, noodles produced from reconstituted soft white wheat flours became softer, less adhesive, and more cohesive, indicating that partial waxy starches of low amylose content are responsible for the improvement of cooked white salted noodle texture. Partial waxy wheat flours with >15.1% protein produced bread of larger loaf volume and softer bread crumb even after storage than did the hard red spring wheat flour of 15.3% protein. Regardless of whether malt was used, bread baked from double‐null partial waxy wheat flours exhibited a slower firming rate during storage than bread baked from HRS wheat flour.  相似文献   

18.
The properties of frozen and unfrozen water in two different wheat flours (hard and soft), and in their main components (gluten, starch, damaged starch, water‐soluble and water‐insoluble pentosans), were described using modulated differential scanning calorimetry (DSC). As a reference, enthalpy values of crystallization (298 J/g) and melting (335 J/g) of pure water were determined from the total heat flow curves. The separation of thermal events between the reversing and nonreversing heat flows with modulated DSC was not effective due to disturbances in the modulated temperature scan. For wheat flours and their components, linear regressions described well the changes in frozen water content calculated from enthalpies of freezing (R2 = 0.970–0.982) or melting (R2 = 0.783–0.996). The unfrozen water content (UFWC) calculated for the hard wheat flour (29–31%, db) was close to that calculated for the soft wheat flour (30–32%). The UFWC of wheat gluten (38–47%), starch (38–42%), damaged starch (37–40%), water‐soluble pentosans (51%), and water‐insoluble pentosans (40–44%) were higher than the corresponding values for the flours. The simple summation of the contributions of each component cannot be used to estimate the overall behavior of flours.  相似文献   

19.
Spelt wheat seeds (Triticum aestivum subsp. spelta cv. Ostro) were used to obtain white spelt flour (64.5% yield), wholemeal spelt flour (100% yield), and scalded spelt wheat kernels. From these materials, white spelt wheat bread (WSB), wholemeal spelt wheat bread (WMSB), and spelt wheat bread with scalded spelt wheat kernels (SSKB) were made and were compared to the reference white wheat bread (WWB). The spelt wheat flours and breads contained more proteins in comparison to wheat flour and bread. Among the samples the highest rate of starch hydrolysis was noticed in WSB. During the first 30 min of incubation this particular bread was shown to have significantly more (P < 0.05) rapidly digestible starch than the WMSB and later on also more starch than in WWB and SSKB, respectively. The WMSB had the lowest hydrolysis index (HI = 95.7). However, the result did not differ significantly from that in the reference common wheat bread. On the other hand, the most refined spelt wheat flour resulted in a bread product (WSB) that was statistically withdrawn (P < 0.05) as one with the highest HI (112.6).  相似文献   

20.
One commercial bread wheat flour with medium strength (11.3% protein content, 14% mb) was fractionated into starch, gluten, and water solubles by hand‐washing. The starch fraction was separated further into large and small granules by repeated sedimentation. Large (10–40 μm diameter) and small (1–15 μm diameter) starch fractions were examined. Flour fractions were reconstituted to original levels in the flour using composites of varying weight percentages of starch granules: 0% small granules (100% large granules), 30, 60, and 100% (0% large granules). A modified straight‐dough method was used in an experimental baking test. Crumb grain and texture were significantly affected. The bread made from the reconstituted flour with 30% small granules and 70% large granules starch had the highest crumb grain score (4.0, subjective method), the highest peak fineness value (1,029), and the second‐highest elongation ratio (1.55). Inferior crumb grain scores and low fineness and elongation ratios were observed in breads made from flours with starch fractions with 100% small granules or 100% large granules. As the proportion of small granules increased in the reconstituted flour, it yielded bread with softer texture that was better maintained than the bread made from the reconstituted reference flour during storage.  相似文献   

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