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Effect of ascorbic acid on the rheological properties of wheat fermented dough
2003
M. Hrušková | D. Novotná
The effect of ascorbic acid on the rheological properties of wheat fermented dough from forty three wheat flour samples, represented two groups of flours, characterised (according to the ash content, protein content and Zeleny sedimentation value) the main Czech flour type has been studied. Standard analytical parameters (ash and protein contents, wet gluten, falling number, Zeleny sedimentation value), rheological investigation (maturograph, oven rise recorder), and laboratory baking test were used for the characterisation of flours and doughs. It was stated that the influence of the ascorbic acid addition on the fermented dough behaviour depends on the flour composition particularly in the proofing stage. Oven rise characteristics of dough and specific bread volume revealed smaller changes without significant differences between flours with lower (up to 0.6%) and higher (up to 0.7%) ash contents. An important correlation (r = 0.51-0.68) significant at 0.01 level has been found between specific bread volume and final rise of dough.
Mostrar más [+] Menos [-]Effect of malt flour addition on the rheological properties of wheat fermented dough
2003
M. Hrušková | I. Švec | I. Kučerová
The bread-making quality of forty three wheat flour samples, divided into two groups according to the ash content (up to 0.6% and 0.7%), and its changes by fortification with malt flour were studied in the form of fermented dough. Standard analytical measurements (ash and protein contents, wet gluten, falling number, Zeleny sedimentation value), rheological investigations (amylograph, maturograph, oven rise recorder), and laboratory baking test were used for the characterisation of flour and dough. The influence of the malt flour addition on the fermented dough behaviour depends on the flour composition and was found more significant in flours with a lower ash content ("bright" type). Amylograph characteristics of flour-water suspensions were affected in the same extent by the malt addition. Maturograph behaviour changed significantly only in proofing stability (without influence by the flour type) and dough firmness was affected by malt only in the case of flours with lower ash contents. Oven rise characteristics of dough and the specific bread volume showed important changes in both sets of samples with significant differences between flours with lower and higher ash contents. A strong correlation (r = 0.62-0.75) significant at 0.01 level exists between the specific bread volume and all oven rise parameters of dough from both sets of samples.
Mostrar más [+] Menos [-]Effect of accelerated ageing on the content and composition of polyphenolic complex of wheat (Triticum aestivum L.) grains
2003
J. Lachman | J. Dudjak | M. Orsák | V. Pivec
The influence of accelerated ageing test (AAT), i.e. of higher temperature and humidity, on the content and composition of phenolic compounds in the grains of five cultivars of wheat (Triticum aestivum L.) was studied in the years 1998 and 1999. Total polyphenols were determined spectrophotometrically by Folin-Ciocalteau's phenolic reagent and free phenolic acids by an HPLC method in control samples and after deterioration treatment (AAT) in the Ebi, Estica, Nela, Samanta and Šárka cultivars. Statistical significance of deterioration treatment, cultivar, cultivation site, and harvest year was proved. Content of total polyphenols increased during deterioration and levels of the individual free phenolic acid changed depending on their structures. Mean contents of total polyphenols varied from 600 to 960 mg/kg of dry matter. The increase caused by the AAT ranged between 0-20%, the greatest mean increase was observed in the cultivar Nela (by 19%). Sinapic acid (as high as 540 mg/kg of dry matter), 3-hydroxy-benzoic acid and 7-hydroxycoumarin were determined as the major phenolic acids and coumarins. A decrease of free phenolic acids containing methoxy groups in their molecules (sinapic and vanillic acids) and an increase of phenolic acids with free hydroxy groups (caffeic and gallic acids) was observed after deterioration treatment. Statistically significant (P ≤ 0.05) effect of AAT on the content of free phenolic acids was observed.
Mostrar más [+] Menos [-]Effects of different organic amendment on winter wheat yields under long-term continuous cropping
2003
B. Procházková | J. Hrubý | J. Dovrtěl | O. Dostál
The observations were conducted on chernozem soil in a sugar-beet production region in 1971-2002. Six variants of organic amendment were examined: l - straw harvest, 2 - straw harvest + green manuring, 3 - straw incorporation, 4 - straw incorporation + green manuring, 5 - straw burning, 6 - straw burning till 1977 + intercrop, incorporation of farmyard manure at 10 t/ha since 1978. The effect of organic amendment on winter wheat continuous cropping was statistically significant. On average of the whole period (32 years), the highest yields were produced in variants with straw burning (var. 5) - 6.04 t/ha and with green manuring (var. 2) - 6.03 t/ha, and lower yields in variants with straw incorporation into soil (var. 3) - 5.65 t/ha, (var. 4) - 5.67 t/ha. The smallest differences between variants were found in the first decade of the experiment. Over time (in the second and third decades), the differences increased and positive effects of green manuring and straw burning and adverse effects of straw incorporation into soil increased. The yield level of winter wheat continuous cropping was high under the given conditions. The yield for the whole period of the experiment averaged 5.85 t/ha, the yields 5.19, 6.54 and 5.76 t/ha were obtained in the first, second and third decade, respectively.
Mostrar más [+] Menos [-]Wpływ gęstości wysiewu oraz poziomu agrotechniki pszenicy jarej na strukturę zachwaszczenia jej łanu
2003
Marian Wesołowski (Autor) | Maria Dąbek-Gad (Autor) | Agnieszka Stępień (Autor) | Cezary Kwiatkowski (Autor)
Report of a Working Group on Wheat: First meeting, 8-10 November 2001, Prague-Ruzyne, Czech Republic
2003
Maggioni, L. | Faberová, I. | Le Blanc, A. | Lipman, E. | European Cooperative Programme for Plant Genetic Resources | International Plant Genetic Resources Institute
The Impact of Canadian Wheat Imports on Regional U.S. Wheat Prices
2003
McNew, Kevin | Smith, Vincent H.
Investigation on economic threshold of Russian wheat aphid in wheat crop
2003
Nourbakhsh, Sayyed Habibollah | Rezvani, Ali | Taheri, Mahmoud
During 1999-2000 economic threshold of Duraphis noxia(mordvilko) was investigated . The experiments were carried out in form of randomized complete block design with 5 treatments and 3 replicates. In 1999 the treatments were four rate of contaminating wheat plants as, 1,2,3,5 percent and check plot. In 2000 the treatments were four rate of contaminating wheat plants as, 1,3,5,10 percent and check plot. The check plots were sprayed with Oxidimeton methyl every 10 days. Contaminating were carried out in two growth stages of wheat include tillering and stem elongation. The plots were visited weekly and number of infested plants was numbered. Yield per plot was determined after harvesting. The results of contamination in tillering stage in 1999 has no significant difference (f=2.286 and ل=0.132) but the result of contamination in stem elongation stage in this year has a significant difference (f= 6.389 and ل=0.002). In the second year the results of two stages has no significant difference (f=0.558 and ل=0.07) and (f= 0.083 and ل=0.986). Also the weight of 10000 seeds of the yield of each plot has no significant difference (f=1.288 and ل=0.084) in seco
Mostrar más [+] Menos [-]The effect of mixing and wheat protein/gluten on the gelatinization of wheat starch
2003
Mohamed, Abdellatif A. | Rayas-Duarte, Patricia
Protein was extracted with 0.1 M acetic acid and gluten was isolated from durum and Hard Red Spring (HRS) wheat. The extracted and isolated proteins were used to investigate their effect on the gelatinization of starch using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Starch and protein in different ratios were mixed with water using a spatula in test tubes and tested in a Brabender Farinograph. The data showed that mixing was an important factor, affecting starch DSC gelatinization parameters, TGA profile path and final weight loss of the blends. The starch onset and peak temperatures and ΔH of the mixed blend were compared with the unmixed blend. Mixing increased the onset and the peak temperatures of the starch gelatinization and decreased the ΔH. Higher amounts of protein in the blend increased the onset and peak temperatures and decreased the ΔH of the starch gelatinization. Protein extract and gluten were found to interact differently with starch and influence its gelatinization parameters and water evaporation, as measured by DSC and TGA, respectively.
Mostrar más [+] Menos [-]Research progress on resistance of wheat to russian wheat aphid, diuraphis noxia (mordvilko)
2003
Duan Canxing | Zhu Zhendong | Wang Xiaoming(CAAS, Beijing (China), Institute of Crop Germplasm Resources)
