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1.
Breadmaking properties such as bread height and specific volume were improved in bread from wheat flour with added disulfides such as dimethy disulfide (M2S2), diethyl disulfide (E2S2), dipropyl disulfide (Pro2S2), and dibutyl disulfide (B2S2). However, the amount of disulfides for maximum breadmaking properties was various and strongly related to the number of carbons (C) in the disulfide. Brabender farinographs of disulfide‐wheat flour showed an interesting profile, and the properties of the modification of the width of the tail. Size‐exclusion high performance liquid chromatography (SE‐HPLC) of the wheat proteins in the control and the disulfide‐added flours showed profiles of low, medium, and high molecular weight peaks. The area of the high molecular weight peak was larger in the disulfide‐added flours than in the control, indicating that this protein was important for the improvement of breadmaking properties.  相似文献   

2.
Studies were conducted with two newly developed gluten‐free bread recipes. One was based on corn starch (relative amount 54), brown rice (25), soya (12.5), and buckwheat flour (8.5), while the other contained brown rice flour (50), skim milk powder (37.5), whole egg (30), potato (25), and corn starch (12.5), and soya flour (12.5). The hydrocolloids used were xanthan gum (1.25) and xanthan (0.9) plus konjac gum (1.5), respectively. Wheat bread and gluten‐free bread made from commercial flour mix were included for comparison. Baking tests showed that wheat and the bread made from the commercial flour mix yielded significantly higher loaf volumes (P < 0.01). All the gluten‐free breads were brittle after two days of storage, detectable by the occurrence of fracture, and the decrease in springiness (P < 0.01), cohesiveness (P < 0.01), and resilience (P < 0.01) derived from texture profile analysis. However, these changes were generally less pronounced for the dairy‐based gluten‐free bread, indicating a better keeping quality. Confocal laser‐scanning microscopy showed that the dairy‐based gluten‐free bread crumb contained network‐like structures resembling the gluten network in wheat bread crumb. It was concluded that the formation of a continuous protein phase is critical for an improved keeping quality of gluten‐free bread.  相似文献   

3.
Robust ionic liquid–based dispersive liquid–liquid microextraction (IL-DLLME) is a fast and simple method for extraction and preconcentration of metal ions from samples with high salt content. This method can solve the problems associated with the limited application of the conventional IL-DLLME in these samples. In this procedure, the hydrophobic chelate of chromium with ammonium pyrrolidinedithiocarbamate (APDC) was extracted into the fine droplets of 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF6]), which was dispersed into the aqueous sample solution. Several factors that influence the microextraction efficiency were investigated. In optimum conditions a linear calibration graph in the range of 0.5–70 μg L?1 of Cr in the initial solution with r = 0.9998 was obtained. Detection limit was 0.16 μg L?1 and relative standard deviation (RSD) for 20 μg L?1 of Cr was 2.68% (n = 10), respectively. The proposed method was successfully applied for the determination of Cr(VI) in water samples and food additives.  相似文献   

4.
Lactic acid bacteria (LAB) were obtained from durum wheat flour samples and screened for roseoflavin-resistant variants to isolate natural riboflavin-overproducing strains. Two riboflavin-overproducing strains of Lactobacillus plantarum isolated as described above were used for the preparation of bread (by means of sourdough fermentation) and pasta (using a prefermentation step) to enhance their vitamin B2 content. Pasta was produced from a monovarietal semolina obtained from the durum wheat cultivar PR22D89 and, for experimental purposes, from a commercial remilled semolina. Several samples were collected during the pasta-making process (dough, extruded, dried, and cooked pasta) and tested for their riboflavin content by a high-performance liquid chromatography method. The applied approaches resulted in a considerable increase of vitamin B2 content (about 2- and 3-fold increases in pasta and bread, respectively), thus representing a convenient and efficient food-grade biotechnological application for the production of vitamin B2-enriched bread and pasta. This methodology may be extended to a wide range of cereal-based foods, feed, and beverages. Additionally, this work exemplifies the production of a functional food by a novel biotechnological exploitation of LAB in pasta-making.  相似文献   

5.
The objective of this study was to evaluate protein composition and its effects on flour quality and physical dough test parameters using waxy wheat near‐isogenic lines. Partial waxy (single and double nulls) and waxy (null at all three waxy loci, Wx‐A1, Wx‐B1, and Wx‐D1) lines of N11 set (bread wheat) and Svevo (durum) were investigated. For protein composition, waxy wheats in this study had relatively lower albumins‐globulins than the hard winter wheat control. In the bread wheats (N11), dough strength as measured by mixograph peak dough development time (MDDT) (r = 0.75) and maximum resistance (Rmax) (r = 0.70) was significantly correlated with unextractable polymeric protein (UPP), whereas in durum wheats, moderate correlation was observed (r = 0.73 and 0.59, respectively). This may be due to the presence of high molecular weight glutenin subunits (HMW‐GS) Dx2+Dy12 at the Glu‐D1 locus instead of Dx5+Dy10, which are associated with dough strength. Significant correlation of initial loaf volume (ILV) to flour polymeric protein (FPP) (r = 0.75) and flour protein (FP) (r = 0.63) was found in bread wheats, whereas in durum wheats, a weak correlation of ILV was observed with FP (r = 0.09) and FPP (r =0.51). Significant correlation of ILV with FPP in bread wheats and with % polymeric protein (PPP) (r = 0.75) in durum lines indicates that this aspect of end‐use functionality is influenced by FPP and PPP, respectively, in these waxy wheat lines. High ILV was observed with 100% waxy wheat flour alone and was not affected by 50% blending with bread wheat flour. However, dark color and poor crumb structure was observed with 100% waxy flour, which was unacceptable to consumers. As the amylopectin content of the starch increases, loaf expansion increases but the crumb structure becomes increasingly unstable and collapses.  相似文献   

6.
Pup‐loaf bread was made with 10, 30, and 50% substitution of flour with wheat starch phosphate, a cross‐linked resistant starch (XL‐RS4), while maintaining flour protein level at 11.0% (14% mb) by adding vital wheat gluten. Bread with 30% replacement of flour with laboratory‐prepared XL‐RS4 gave a specific volume of 5.9 cm3/g compared with 6.3 g/cm3 for negative control bread (no added wheat starch), and its crumb was 53% more firm than the control bread after 1 day at 25°C, but 13% more firm after 7 days. Total dietary fiber (TDF) in one‐day‐old bread made with commercial XL‐RS4 at 30% flour substitution increased 3–4% (db) in the control to 19.2% (db) in the test bread, while the sum of slowly digestible starch (SDS) plus resistant starch (RS), determined by a modified Englyst method, increased from 24.3 to 41.8% (db). The reference amount (50 g, as‐is) of that test bread would provide 5.5 g of dietary fiber with 10% fewer calories than control bread. Sugar‐snap cookies were made at 30 and 50% flour replacement with laboratory‐prepared XL‐RS4, potato starch, high‐amylose (70%) corn starch, and commercial heat‐moisture‐treated high‐amylose (70%) corn starch. The shape of cookies was affected by the added starches except for XL‐RS4. The reference amount (30 g, as‐is) of cookies made with commercial XL‐RS4 at 30% flour replacement contained 4.3 g (db) TDF and 3.4 g (db) RS, whereas the negative control contained 0.4 g TDF and 0.6 g RS. The retention of TDF in the baked foods containing added XL‐RS4 was calculated to be >80% for bread and 100% for cookies, while the retention of RS was 35–54% for bread and 106–113% for cookies.  相似文献   

7.
以GB14880-1994中规定的谷物食品强化L-赖氨酸(Lys)标准的下限值(0.8 g/kg)为基准,设计在小麦粉中分别强化相当于Lys下限值0.55、1.10和1.65倍的L-赖氨酸锌(LZn)+L-赖氨酸-L-谷氨酸盐(LG),Zn强化参照国家“公众营养与发展中心”(PNDC)规定的下限值,与空白对照组比较,作了流变学特性(粉质、拉伸)等基础分析,并制作了馒头、面条或面包。研究结果表明:在小麦粉中适度强化LZn+LG复合盐,对改善小麦粉的品质特性有明显的促进作用;使用较高的LZn+LG强化量时,所制馒头的外观及内部结构特性都有明显改善;强化LZn+LG对制作的面条没有不良影响;强化LZn+LG的面包总分明显高于对照组,在面包体积、表皮及包心色泽、内部纹理结构等方面表现尤为突出。该研究为L-赖氨酸复合盐的在谷物食品中的应用提供了重要依据。  相似文献   

8.
The stress relaxation behaviors of soft and bread‐type wheat kernels were studied using the generalized Maxwell model. The data showed two phases, a fast phase at short times of about 1.52–16.88 sec (τ1 and τ2) and a slow phase with longer times of about 81.28–793.81 sec (τ3 and τ4). The shorter decay of σ1 can be explained by very weak forces that affect mainly the rheological properties. The slow decay (σ4) located at longer relaxation times resulted from strong forces. The first derivative obtained from the stress relaxation curve of intact wheat kernels was quite similar in shape to the dough farinograms. The stress relaxation parameters showed differences in springs, relaxation times, and viscosities of bread wheat compared with soft‐type wheat kernels. The stresses σ1 and σ4 were correlated with wheat kernel, flour, rheological, and breadmaking properties; so especially were the elasticity of the spring (σ0) and viscosity of the fourth Maxwell element (η4), which were significantly correlated with all the quality properties, whereas σ2, σ3, η1, and η2 did not show correlation at all, except that η2 was correlated with falling number and volume of CO2.  相似文献   

9.
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   

10.
The practical applications of flour from waxy (amylose‐free) hexaploid wheat (Triticum aestivum L.) were assessed. The applications evaluated were bread, cakes, white salted noodles, and pasta for gyoza. An excessive addition of waxy hexaploid wheat flour to total wheat flour (>20%) resulted in poorer functional properties (sticky, lumpy, or less crispy textures) in almost every end use product. However, incorporation of <20% waxy hexaploid wheat flour, produced considerable improvement in shelf‐life characteristics. After one day of storage, the bread from flour including waxy hexaploid wheat flour maintained moistness, softness, and stickiness. This application of waxy hexaploid wheat flour as an antistaling ingredient was also confirmed in cake products. Tests were also conducted on alimentary pasta products. In alimentary pasta, waxy hexaploid wheat flour was most effective when utilized for frozen fried dumplings (gyoza). By using flour including 30 or 50% waxy hexaploid wheat flour, the problem of firmness was solved without other ingredients. In conclusion, flour from waxy hexaploid wheat may be useful in developing more increased staling‐ and freezing‐tolerant grain‐based foods. Starch properties could be responsible for these improved characteristics.  相似文献   

11.
Measurements of creep‐recovery of flour‐water doughs were made using a dynamic mechanical analyzer (DMA) in a compression mode with an applied probe force of 50 mN. A series of wheat flour and blend samples with various breadmaking potentials were tested at a fixed water absorption of 54% and farinograph optimum water absorption, respectively. The flour‐water doughs exhibited a typical creep‐recovery behavior of a noncross‐linked viscoelastic material varying in some parameters with flour properties. The maximum recovery strain of doughs with a fixed water absorption of 54% was highly correlated (r = 0.939) to bread loaf volume. Wheat flours with a large bread volume exhibited greater dough recovery strain. However, there was no correlation (r = 0.122) between maximum creep strain and baking volume. The maximum recovery strain of flour‐water doughs also was correlated to some of the parameters provided by mixograph, farinograph, and TA‐XT2 extension.  相似文献   

12.
Nine laboratories analyzed samples of whole grain, intermediate, and ready-to-eat products for ethylene dibromide (EDB) residues. Supplied samples of wheat, rice, and flour contained both fortified and incurred EDB; corn bread mix, baby cereal, and bread contained only fortified EDB. The whole grains and intermediates were analyzed by the same basic procedural steps as in the official method for multifumigants: They were extracted by soaking in acetone-water (5 + 1). The baby cereal and bread were analyzed by a modification of the Rains and Holder hexane co-distillation procedure. EDB was determined by electron capture gas chromatography operated with an SP-1000 column. All products contained 3 different levels of EDB and were analyzed as blind duplicates. Overall mean recoveries ranged from 85.2% for 69.6 ppb to 105.0% for 4.35 ppb, both in baby cereal. Interlaboratory relative standard deviations ranged from 5.7% for 869 ppb in wheat to 20.2% for 69.6 ppb in baby cereal, both fortified. Mean levels of incurred EDB in wheat, rice, and flour were 926.7, 982.0, and 49.9 ppb, respectively; corresponding relative standard deviations were 9.9, 7.7, and 13.1%. The method was adopted official first action.  相似文献   

13.
Preharvest sprouted wheat is often characterized by the falling number (FN) test. FN decreases in preharvest sprouted wheat as enzymatic degradation of the starchy endosperm increases. Wheat with FN values <250–275 is often discounted at the time of sale. The intent of this investigation was to evaluate the effects of debranning or pearling on the flour quality traits of five samples of wheat rated as low, med‐low, medium, med‐high, and sound that exhibited a range in FN values of 62–425 sec. Replicates of each sample were pearled for 30, 60, and 120 sec to remove portions of the outer bran layers before milling. FN was highly correlated with α‐amylase activity (r > ‐0.97) in the med‐low, medium, and med‐high FN sample sets as pearling time increased. FN increased in the medlow, medium, and med‐high FN samples by 128, 123, and 80%, respectively, after 120 sec of pearling. Pearling had no effect on flour FN of the low FN sample but α‐amylase activity was significantly decreased. Pearling had little or no effect on FN and α‐amylase activity of the sound sample. FN was moderately to strongly correlated with Rapid Visco Analyser (RVA), alveograph, and farinograph properties, and poorly correlated with protein content, flour yield, and bread loaf volume. In subsequent breadmaking studies, bread loaf volume, and crumb characteristics of flour from pearled wheat were not significantly different from loaf volume and crumb characteristics of flour from the corresponding nonpearled wheat.  相似文献   

14.
《Cereal Chemistry》2017,94(4):670-676
Wheat grain may be attacked by different insect species. Among them, some Heteroptera species (e.g., Aelia spp. and Eurygaster spp.) reduce wheat breadmaking quality; others, such as Nysius simulans , commonly extract water and nutrients from soy plants. The aim of this study was to assess the effect of N. simulans infestation on breadmaking quality of different bread wheat cultivars. Twelve wheat cultivars (damaged and undamaged by N. simulans ) were studied. Infested grain percentage varied between 51 and 78%, depending on cultivar. Protein and gluten quantity and quality were significantly reduced in damaged flours, as shown by gluten index, solvent retention capacity, and SDS sedimentation index. SDS‐PAGE from water‐extractable proteins evidenced an important proteolytic activity in damaged samples. Dough rheological properties showed a reduced dough viscoelasticity in damaged samples. Microbread specific volume changed from 3.26 cm3/g for samples made with undamaged flour to 2.77 cm3/g for bread made with damaged flour. No evidence for modification in starch properties was found. The infestation by N. simulans reduced wheat breadmaking quality in all cultivars studied, as a result of proteolytic activity occurring after dough hydration. Results suggest that the presence of N. simulans should be considered as a factor affecting wheat crops, mainly those located next to soy crop areas, which is the usual host for this insect.  相似文献   

15.
Introduction of high molecular weight glutenin subunits (HMW‐GS) from the Glu‐D1d locus of wheat into triticale restores the genetic constitution of high molecular weight glutenin loci to that of wheat and subsequently improves the breadmaking quality of triticale. One means of achieving such restoration of the genetic constitution is through the use of translocation lines. The aim of this study was to evaluate and compare the performance of translocations 1A.1D and 1R.1D with HMW‐GS 5+10 and 2+12 in terms of physical dough tests and baking quality using four different sets of triticale lines, GDS7, Trim, Rhino, and Rigel. In general, significantly lower milling quality (flour yield), very low mixing times with lower loaf volume were typical of all the triticales studied except 1A.1D 5+10 lines, when compared to hard wheat flour (Pegaso). Among the lines studied, significantly higher loaf volume, mixograph dough development time (MDDT), and maximum resistance to extension (Rmax) were observed with 1A.1D 5+10 lines indicating that translocation of the Glu‐D1d allele with HMW‐GS 5+10 was beneficial in terms of improving the quality attributes. Although pure triticale flour from these lines did not possess the functional characteristics for good quality bread, the translocation 1A.1D that contains HMW glutenin subunits 5+10 showed significant improvement in quality characteristics, and could reasonably be expected to yield commercially satisfactory bread loaves when combined with bread wheat flour. Significantly higher UPP, Rmax, and MDDT values along with a lower gliadin‐to‐glutenin ratio in 1A.1D 5+10 of GDS7 and Rigel sets indicate that the molecular weight distribution was shifted to higher molecular weights, resulting in greater dough strength associated with 5+10 subunits.  相似文献   

16.
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   

17.
Karkade (Hibiscus sabdariffa) was blended with wheat flour to make bread. When 0.5% Karkade was blended with wheat flour, maximum bread height and specific volume (cm3/g) were obtained (pH 4.8–5.0); these properties gradually deteriorated with increased Karkade. The pH of the bread crumb decreased with increased Karkade, reaching pH 3.35 when blended with 10% Karkade. The pH of Karkade alone was 2.5, which was adjusted to ≈5.0 by the addition of alkali just before blending with wheat flour and making bread. Control of the Karkade pH resulted in bread height and specific volume recovering to the original optimal levels. In addition, the deep reddish purple color (513 nm) of the bread crumb changed to a brownish color crumb. The Fe content was 0.14 mg of Fe/gram of dry crumb, or 6.22 mg of Fe/60 g of fresh bread when 5% Karkade was blended with wheat flour.  相似文献   

18.
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   

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.
The objective of this study was to evaluate how Rhyzopertha dominica infestation of stored wheat grain affects the rheological and baking properties of bread made with the milled flour. Wheat samples were infested with R. dominica and stored for up to 180 days at room temperature. Every 45 days, samples of wheat were collected and evaluated for insect population and flour yield. Flour milled from these wheat samples was evaluated for color reflectance, pH, fat acidity, and rheological properties which were measured by a farinograph. Loaves of bread were baked using a straight-dough procedure. Volume, height, and weight of the loaves were evaluated. None of the analyses performed on the control wheat flours showed any changes during the storage period, and they were similar to the initial wheat. The insect population increased during storage of the wheat up to 90 days, and the flour yield decreased with the storage up to 180 days. Flours from insect-infested wheat absorbed more water than did flours from control wheat. Dough stability and dough development times of infested flours decreased. Bread volume showed a progressive decline throughout the storage experiment. In conclusion, flour from insect-infested wheat exhibited changes in rheological properties such as dough stability, dough development times, water absorption, and mixing stability; bread had an offensive odor; and volume and loaf characteristics were negatively affected.  相似文献   

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