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1.
A negative relationship between dough strength and dough extensibility would pose a problem for breeding hard wheats, as both dough strength and dough extensibility are desirable. We derived 77 recombinant inbred lines (RIL) from a cross between hard red spring wheat cultivars McNeal and Thatcher. McNeal produces flour with stronger dough and lower extensibility than does Thatcher. RIL were evaluated for strength‐related properties using mixograph analysis and extensibility parameters using the Kieffer attachment to the TA.XT2 texture analyzer. Additionally, the RIL were test baked. Measurements using the mixograph and the Kieffer attachment were highly heritable. Maximum dough extensibility (Extmax) was negatively correlated with resistance to extension (Rmax) (r = ‐0.74) and with mixograph tolerance (r = ‐0.45). Loaf volume was correlated with both Rmax (r = 0.42) and area under the extensigraph curve (r = 0.44) based on partial correlation analysis adjusted for protein differences. Extmax was negatively correlated with loaf volume (r = ‐0.26). The McNeal allele for polymorphism at the Gli1‐B1 locus on chromosome 1BS caused high dough‐mixing tolerance and low dough extensibility. Our results suggest that traditional selection criteria in hard red spring wheat, including tolerance to dough mixing and high loaf volume, may result in reduced dough extensibility.  相似文献   

2.
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   

3.
Dough extensibility affects processing ease, gas retention, and loaf volume of finished products. The Kieffer dough extensibility test was developed to assess extensibility of small dough samples and is therefore adapted for use in breeding programs. Information is lacking on relationships between wheat growing environments and dough properties measured by the Kieffer dough extensibility test. This study documents the variability of dough extensibility (Ext), maximum resistance to extension (Rmax), and area under the extensibility curve (Area) in relation to breadmaking quality, and the effect of wheat growing environments. Mixograph, Kieffer dough extensibility, and bake tests were performed on flour milled from 19 hard red spring wheat (Triticum aestivum L.) genotypes grown during three growing seasons (2007‐2009) at six South Dakota locations. Although both genotype and environment had significant effects on Kieffer dough extensibility variables, environment represented the largest source of variation. Among genotype means, Area was most correlated (r = 0.63) with loaf volume, suggesting that by selecting lines with increased Area, loaf volume should improve. Rmax was positively correlated (r = 0.58) with loaf volume among genotype means but negatively correlated (r = –0.80) among environmental means. Ext was positively correlated (r = 0.90) with loaf volume among environmental means. Weather variables were correlated with Rmax, Ext and loaf volume and therefore could help predict end‐use quality.  相似文献   

4.
The effect on physical dough properties of nitrogen and sulfur fertilizer applied during cultivation was observed in two trials using the bread wheat (Triticum aestivum) cultivar Otane. Wheat flours from both trials were evaluated for physical dough properties under laboratory conditions and also under industrial conditions in the second trial. The laboratory and industrial optimum mechanical dough development (MDD) work input (WI) significantly increased when nitrogen (N) fertilizer was applied without sulfur fertilizer (S) during crop cultivation. With combined N and S fertilization, laboratory and industrial WI remained close to levels for grain grown without fertilizer. Reductions in extensigraph resistance to extension (Rmax) and increases in extensigraph extensibility (Ext) due to S fertilization also were observed. None of the observed changes in WI, Rmax, or Ext due to S fertilization significantly affected end‐product quality as measured by loaf volume, crumb grain, and bake score. The nexus between WI and Rmax was weakened by combined N and S fertilization in the first trial, but remained strong in the second trial. Both WI and Rmax increased as N fertilizer and flour nitrogen increased, but at different rates. This observation indicated that by applying N fertilizer to improve dough strength, a disproportionate and disadvantageous increase in WI also resulted, which could be tempered by S fertilization. In this regard, an optimum N:S fertilizer ratio of 3:1 was indicated, although this ratio would be dependent on the balance of available N and S in the soil. Flour N:S ratios <12.5 kept WI to levels desirable in an industrial MDD bakery. Correlations between laboratory WI, mixograph development time (except in the SN1 trial), and farinograph development time were significant. The 125‐g MDD mixers appeared to be more responsive when measuring mixing requirements than the mixograph and farinograph to variations in quality due to environmental and agronomic influences and correlated better with industrial performance.  相似文献   

5.
Relationships between flour functional properties and protein composition were studied using a set of 138 Argentinean wheat samples. Among different protein groups, the incremental increase of gliadin with increasing grain protein content was highest followed by polymeric protein with albumin‐globulin content much lower. Functional properties could be divided into two groups based on dependence on protein composition. Properties such as dough extensibility and bake test loaf volume correlated highly with the percentage of polymeric protein in the grain. Properties such as mixograph dough development time were best correlated with the percentage of polymeric protein in the protein (PPP). Alveograph tenacity showed no significant dependence on PPP. as found previously for extensigraph maximum resistance, but it was correlated with the percentage of unextractable polymeric protein in the protein. Energy (W) appeared to be a more useful alveograph parameter for predicting flour quality.  相似文献   

6.
A modified extensigraph method reduced sample quantity to 100 g from 300 g and testing time by half with easy dough preparation compared to the AACC standard extensigraph method, which challenges wheat breeding programs where the sample size is small and evaluations of large numbers of samples are demanded. Correlation coefficients (r) for 93 pairs of each of six extensigraph dough characteristics of 31 different tested wheat samples were r = 0.95 for resistance‐to‐extension, r = 0.80 for extensibility, r = 0.93 for ratio of resistance‐to‐extension to extensibility, r = 0.92 for ratio of maximum resistance‐to‐extension to extensibility, and r = 0.81 for area under the curve (energy). Correlation coefficients for the measurements of extensigraph dough characteristics at each of three rest‐time tests between the modified and standard methods were significant. Some dough mixing characteristics and bake tests correlated better with dough extension characteristics when determined by the modified method. Repeatability of the modified method test was good. The modified extensigraph method can be a useful alternative to the standard method for the milling and baking industries, crop quality surveys, and wheat quality research.  相似文献   

7.
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   

8.
Dough strength is needed for efficient breadmaking quality. This property is strongly influenced in wheat (Triticum aestivum L.) by gluten seed storage proteins and, in particular, by high‐molecular‐weight (HMW) glutenin subunit composition. Experiments were designed to elevate expression of a key native HMW glutenin subunit (1Dy10) via genetic engineering and to determine whether resultant flours can be used in sponge and dough applications, the most common commercial bread‐baking procedure. Both unblended and blended samples from transgenic and nontransgenic sister lines were tested, with blended samples being formed by addition to a control sample. Dough properties, as determined by farinograph evaluation, were improved by the transgene‐encoded increases in 1Dy10 in both undiluted and blended flours. Mean farinograph stability of transgenic samples was twice that of the control, and blends with transgenic samples demonstrated increases in stabilities proportional to the amount of transgenic flour included. Mean farinograph quality numbers of transgenic samples, and of all blends containing transgenic flour, were significantly higher than both the control and all nontransgenic treatments. In the sponge and dough bake procedure, undiluted transgenic samples induced lower scores, relative to both control and undiluted nontransgenic samples, for water absorption, crumb body firmness, and loaf volume. In blends, however, the transgenic samples resulted in improvements in some sponge and dough loaf attributes, including loaf symmetry and crumb color score, without any concomitant loss of loaf volume in transgenic blends. These improved variables relate to finished product appearance and to consumer selection in markets. The use of transgenic flours with increased 1Dy10 glutenin content in commercial blends could provide advantages in sponge and dough bake applications.  相似文献   

9.
《Cereal Chemistry》2017,94(2):270-276
The extensigraph is an internationally accepted method for measurement of physical properties of dough subjected to mechanical handling and resting. Standard extensigraph methods ( 1 , ISO 5530‐2) use the farinograph for the preparation of dough in the presence of 2% salt at reduced water absorption (farinograph absorption minus 2–3%). However, the dough so prepared is usually underdeveloped and drier than typically seen in common baking processes. In addition, the standard extensigraph test is time consuming and requires a large sample size. In this study, an alternate dough preparation protocol is proposed, consisting of a Swanson‐type pin mixer at reduced salt (1%) and elevated water absorption (farinograph absorption plus 4%). With the alternate method, dough is fully developed and similar to bread dough in physical properties. 1 is followed for dough rounding, molding, resting, and stretching by using the Brabender Extensograph‐E instrument. Strong correlations for resistance to extension (r = 0.90) and area (r = 0.92) were found between the modified and standard dough preparation methods. This protocol requires much less flour sample and significantly increases sample throughput.  相似文献   

10.
This study measured the relationship between bread quality and 49 hard red spring (HRS) or 48 hard red winter (HRW) grain, flour, and dough quality characteristics. The estimated bread quality attributes included loaf volume, bake mix time, bake water absorption, and crumb grain score. The best‐fit models for loaf volume, bake mix time, and water absorption had R2 values of 0.78–0.93 with five to eight variables. Crumb grain score was not well estimated, and had R2 values ≈0.60. For loaf volume models, grain or flour protein content was the most important parameter included. Bake water absorption was best estimated when using mixograph water absorption, and flour or grain protein content. Bake water absorption models could generally be improved by including farinograph, mixograph, or alveograph measurements. Bake mix time was estimated best when using mixograph mix time, and models could be improved by including glutenin data. When the data set was divided into calibration and prediction sets, the loaf volume and bake mix time models still looked promising for screening samples. When including only variables that could be rapidly measured (protein content, test weight, single kernel moisture content, single kernel diameter, single kernel hardness, bulk moisture content, and dark hard and vitreous kernels), only loaf volume could be predicted with accuracies adequate for screening samples.  相似文献   

11.
Growers are targeting hard red spring wheat (Triticum aestivum L.) (HRSW) for frozen dough end uses. Consequently, it is important to determine whether increasing nitrogen (N) fertilizer rates and grain protein content (GPC) improve frozen dough quality. Four HRSW cultivars were grown in low‐N soils at three locations over two years in North Dakota and fertilized with N rates of 0 kg/ha, 67.2 kg/ha, and 134.4 kg/ha. End use characteristics were analyzed using farinograph, extensigraph, and baking tests. Fresh and frozen doughs were analyzed to determine the effects of N treatments on frozen storage. A cultivar × N treatment interaction existed for extensigram curve area of fresh dough. A significant increase in GPC existed between the 0 and 67.2 kg/ha N treatments. Farinograph water absorption, arrival times, and peak times increased significantly at the 67.2 kg/ha N treatment. Bread loaf volume of fresh dough increased significantly with all treatments, while loaf volume of frozen dough increased significantly only at the 67.2 kg/ha N treatment. Therefore, aside from fresh dough loaf volume, there appears to be no improvement in frozen dough quality with the use of higher than typical N application.  相似文献   

12.
Bread yield is economically important to commercial bakers. Flour was replaced with 2.5% citrus peel fiber or 0.23% pectin. Pectin increased water absorption by 0.6% in the farinograph, 2% in the mixograph, and 4% in baking. Citrus peel fiber had a greater effect, increasing water absorption by 6.5% in the farinograph, 7% in the mixograph, 6.4% in the mixolab, and 10% in baking. Citrus peel fiber strengthened dough while pectin had a weakening effect. Loaves containing citrus peel fiber had decreased loaf volume but crumb grain characteristics similar to control loaves. Pectin did not affect loaf volume but had a deleterious effect on the crumb grain. Neither citrus peel fiber nor pectin affected bread firming. Citrus peel fiber increased loaf weight by increasing water absorption, indicating that low levels of citrus peel fiber in the bread formula is an effective way to increase bread yield.  相似文献   

13.
Bread loaf volume is an important economic criterion. Breeders, millers, and bakers need measurements allowing them to evaluate dough performance during processing. Strain hardening is an important dough property. It describes the stability of the gas cell walls and the ability of cells to expand further; therefore, the higher the strain hardening index (n), the better the baking performance. Dough exhibits strain hardening during uniaxial extensibility tests. However, obtaining n from an extensibility test is time consuming. The objectives of this study were to identify the extensibility parameters that contribute to n. Three parameters were retained in the model (R2 = 0.90): dough strength (Rmax), extensional delay (EDiff), and initial slope of the curve (Ei). Rmax was the largest contributor and was proportional to the dough strain hardening properties. EDiff and Ei had a detrimental effect on n. The appropriateness of the model was validated with two sample sets (19 genotypes, 12 environments). Significant correlations were found between loaf volume and n (r = 0.52–0.64) for 7 of the 12 environments. The strain hardening index was found to be a good predictor for baking performance as judged by loaf volume.  相似文献   

14.
Cations of differing chaotropic capacities (LiCl, NaCl, and KCl) were used in small‐scale mixing and extensigraph studies to assess functional changes in dough behavior of wheat cultivars varying in total protein content and HMW glutenin composition. Salt addition, regardless of cationic type, caused an increase in dough strength and stability. The smaller (hydrated) and least chaotrophic cations (Li+<Na+<K+) effected the greatest increase in mixing time (MT) and resistance to extension (Rmax) and produced the most stable resistance breakdown (RBD). The effects of different cations on mixing and extensions indicated strong intercultivar variation; differential responses to salt addition were further shown when the cultivars were grouped according to protein content and Glu‐1D or Glu‐1B genome composition. Increases in dough strength parameters due to the addition of salt were consistently more significant for cultivars showing an overexpression of Bx7 (>12% protein). In the absence of genotypic variation, a significant interactive effect of cultivar type, protein amount, and salt addition was found for all functional dough parameters except extensibility. During mixing, there was a decrease in the amount of apparent unextractable polymeric protein (%UPP) in the dough. This phenomenon was ameliorated by the presence of salt in doughs formed from weaker flours and was most pronounced early on in the mixing process (t = 100–200 sec). Results show the importance of refining 2‐g mixograph studies to include salt in the “flour and water” dough formula.  相似文献   

15.
《Cereal Chemistry》2017,94(4):760-769
The interrelationships between flour quality and the variability in the dough physical properties and bread loaf characteristics were investigated under reduced salt conditions using partial least squares (PLS) regression analysis. Seventy‐two percent of the variability in dough physical properties was explained by the flour quality using a three‐factor PLS model. Damaged starch content (DS), protein content, and farinograph dough development time (DDT) explained the variability of dough creep‐recovery behavior along PLS‐1. Farinograph absorption (FAB), located along PLS‐2, was strongly related to dough adhesiveness, in which adhesiveness was highly correlated to dough stickiness (r = 0.91). Eighty‐nine percent of the variability in bread loaf characteristics was explained by the flour quality using a four‐factor PLS model; the first two PLS factors explained 66% of the variability. The loaf volume was related to a high number of loaf cells, whose expansion resulted in a greater loaf height. The relation between loaf volume and loaf height was expressed more in PLS‐3 than PLS‐1 and PLS‐2. Mean cell wall thickness and mean cell diameter were closely related negatively along PLS‐1, for which DS and farinograph dough stability explained much of the variability in these loaf characteristics. Along the third PLS factor, FAB explained the variability in loaf weight.  相似文献   

16.
Undermixing or overmixing the dough results in varied experimental loaf volumes. Bread preparation requires a trained baker to evaluate dough development and determine the stop points of the mixer. Instrumentation and electronic control of the dough mixer would allow for automatic mixing. This study used a 200 g mixer that provided an output signal during dough mixing to evaluate potential mixing stop points. The effect of varied mixing time on the baked loaf volume was tested by using three flours with protein contents of 10.6, 12.4, and 13.8%. Dough samples were undermixed, mixed to peak, and overmixed. Overmixing by 0.6 min reduced the loaf volume in all flours tested, by 16–50 cm3 at 90 rpm and by 29–68 cm3 at 118 rpm. When the high‐protein flour sample was undermixed, the largest baked loaves were produced, with an average volume of 922 cm3. A second objective studied the similarities and differences between a 200 g mixer and a 35 g mixograph. The same flours were mixed on both units. The mixing peaks for the 200 g mixer were normalized with the 35 g mixograph peaks. When flour and water were used, the mixing times for the 200 g mixer averaged 0.7, 1.2, and 1.6 min shorter than the 35 g mixograph, at 90, 104, and 118 rpm, respectively. Although both the 200 g mixer and the 35 g mixograph system look mechanically similar, they both have unique mechanical motion, speeds, and sample sizes. Their results may show similar trends, but their measured values are usually different. However, when other baking ingredients were included in the 200 g mixer at 90 rpm, the mixing times were within 0.2 min of the 35 g mixograph times for three of four flours.  相似文献   

17.
The advantages of using the mixograph to determine dough mixing properties include minimal flour requirements (2–35 g) and an efficient mixing process that rapidly resolves mixing peaks. A disadvantage to using this instrument is that it lacks an objective absorption measurement. This article describes an analysis system, RsMix, that objectively determines water absorption and statistically evaluates (R2 and probability values) this measurement. The RsMix system also exports files that produce response surface plots. These plots illustrate the response of the dough to different combinations of mixing time and absorption. Each data set analyzed by the RsMix system was composed of an absorption series run at 2% absorption increments. The RsMix system attempts to maximize power input over data collected over absorption and time ranges. These data can be input manually or automatically acquired from MixSmart data files. To measure the precision of the RsMix system, a replicated absorption series composed of four to six different amounts of added water was analyzed. Depending on the mixer and formulation used, calculated standard deviations for optimum absorptions ranged from 0.8 to 2.0%. A regression comparing flour protein content to 2-g mixograph absorption had r2 = 0.80. A similar regression comparing 2-g mixograph to 50-g farinograph absorption had r2 = 0.81. Mixograph parameters could also account for 90% or more of the variation in bake absorption, bread volume, and total bread scores.  相似文献   

18.
《Cereal Chemistry》2017,94(4):723-732
Blending wheat or flour to meet end‐use requirements is a critical part of the production process to deliver consistent quality products. The functionality of commercial Canadian hard red wheat flour (HWF) and soft red wheat flour (SWF) blends with ratios of 100:0, 75:25, 50:50, 25:75, and 0:100 (HWF/SWF, w/w) was investigated with new and standard methods to discern which functional properties may be indicators of bread quality and processing performance. Rheological characteristics including farinograph water absorption behavior, dough development time (DT), stability, extensigraph extensibility, and gluten aggregation of wheat flours were significantly influenced by the proportion of HWF in blends of SWF and HWF (P < 0.05). The SWF content in the blends had negative linear relationships with the protein content, lactic acid solvent retention capacity, water absorption, and GlutoPeak peak torque. Polynomial relationships were observed for sodium dodecyl sulfate sedimentation volume, DT, stability, extensibility, resistance, GlutoPeak peak time, and bread loaf volume with the amount of SWF in blends. The results indicate that linear responses may be more closely tied to protein content, whereas polynomial responses may be more indicative of protein quality and baking performance. The GlutoPeak peak time was sensitive to the addition of HWF in the blends, showing a significant change in gluten aggregation kinetics between the 0 and 25% HWF samples. Principal component analysis (PCA) confirmed that GlutoPeak peak time was a significant factor in differentiating the 0% HWF. Protein secondary structures identified in the final baked bread were also PCA factors differentiating the 0% HWF sample. Although the 0% bread sample did not deviate from the observed polynomial trend for bread loaf volume, the differences in bread protein secondary structures may translate into differences in processing tolerance in commercial settings.  相似文献   

19.
Dough rheological characteristics obtained by alveograph testing, such as extensibility and resistance to extension, are important traits for determination of wheat and flour quality. A challenging issue that faces wheat breeding programs and some wheat research projects is the relatively large flour sample size of 250 g required for the standard alveograph method (AACCI Approved Method 54‐30.02). A modified dough preparation procedure for a small flour sample size was developed for the alveograph test method. A dough was prepared by mixing 80 g of flour with 60% water absorption (2.5% salt solution) for 4 min in a 100 g pin mixer; it was then sheeted and cut into three patties of defined thickness. Data generated by the modified dough preparation method were significantly correlated with the results from the approved alveograph method. The correlation coefficients (r) for each of six alveograph dough characteristics of 40 different advanced breeding lines and wheat varieties were 0.92 for P (mm H2O), 0.73 for L (mm), 0.83 for W (10–4 J), 0.90 for P/L, 0.90 for le (%), and 0.76 for G. The modified dough preparation was easier and more convenient than the approved method, and test time for the modified dough preparation was shorter by 20–25 min. This modified dough preparation procedure for the alveograph may be useful for wheat breeding programs as well as an alternative to the approved alveograph method for milling and baking industries and wheat quality research.  相似文献   

20.
Improvement of food processing quality has become a major breeding objective in China. Nineteen Chinese leading winter wheat cultivars with improved quality and two Australian cultivars with high bread and noodle-making qualities were sown in four locations for two years to investigate dough properties, pan bread, and Chinese white salted noodle (CWSN) qualities, and their association with the quantity of protein fractions. The results indicated that genotype, environment, and genotype-by-environment interaction significantly affected most of quality traits and amount of protein fractions. Genotype mainly determined the quantity of gluten protein fractions and pan bread quality parameters, while environment was the most important source of variation for the noodle quality parameters. Chinese cultivars were characterized by acceptable protein content (11.1–13.4%), medium to strong dough strength (maximum resistance 176.9–746.5 BU), medium to poor dough extensibility (166.5–216.4 mm), fair to very good pan bread qualities, and good to very good CWSN qualities. Gliadin contributed more in quantity to protein content (r = 0.80, P < 0.001), however, glutenin and its subgroups were more important to dough strength. The quantity of glutenin, HMW-GS, and LMW-GS were highly and significantly correlated with dough strength-related traits such as farinograph development time, stability, extensigraph maximum resistance, and extension area (r = 0.70–0.91, 0.65–0.89, and 0.70–0.91, respectively; P < 0.001). The quantity of LMW-GS could explain 82.8% of the total variation of dough maximum resistance. The quantity of gliadin and the ratio of HMW-GS to LMW-GS determined dough extensibility (r = 0.75 and r = –0.59, respectively; P < 0.001 and P < 0.01, respectively). Higher quantity of glutenin and lower ratio of gliadin to glutenin resulted in higher bread score with r = 0.70 (P < 0.001) and r = –0.74 (P < 0.001), respectively. However, protein content and its fractions have a moderate undesirable effect on CWSN parameters such as color, firmness, and taste. Therefore, both allelic variation and quantity of storage protein fractions should be considered in breeding cultivars with improved pan bread making quality.  相似文献   

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