Effect of soybean lipoxygenase on baking properties of wheat flour

Changes in bread-baking properties of wheat flour caused by soybean lipoxygenase and polyunsaturated fatty acids were studied. A positive effect of soybean flour added during dough kneading in an amount of 2% was demonstrated. A method for dough fermentation increasing the loaf volume and improving organoleptic characteristics and total bread-baking estimate is recommended.     

Thiol oxidase and disulfide reductase activities of the wheat Triticum aestivum L. caryopsis and its technological quality

Activities of oxygen-dependent thiol: O2 oxidoreductase (EC 1.8.3.2) and glutathione-dependent thiol: protein-disulfide oxidoreductase (EC 1.8.4.2) as well as technological value of seven soft spring wheat cultivars grown on different soil under contrasting climatic conditions (Krasnodar krai and Irkutsk oblast) were studied. It was found that the ratio of these enzymatic activities correlated positively with dough physical properties and flour bread-baking quality.     

Thiol oxidase and disulfide reductase activities of wheatTriticum aestivum L. caryopsis and its technological quality

Activities of oxygen-dependent thiol: O₂ oxidoreductase (EC 1.8.3.2) and glutathione-dependent thiol: protein-disulfide oxidoreductase (EC 1.8.4.2) as well as technological value of seven soft spring wheat cultivars grown on different soil under contrasting climatic conditions (Krasnodar krai and Irkutsk oblast) were studied. It was found that the ratio of these enzymatic activities correlated positively with dough physical properties and flour bread-baking quality.     

Rates of Shrinkage and Growth of Air Bubbles Entrained in Wheat Flour Dough

The rates of shrinkage at constant temperature, and growth under a temperature rise below 100°C, of bubbles entrained in wheat flour dough were analyzed and compared with those of a bubble in water. The rate of shrinkage of bubbles in flour dough was controlled by the diffusion of dissolved air from the surface of bubbles to the bulk of flour dough. The apparent diffusion coefficient of the dissolved air in wheat flour dough with the water fraction of 0.49 calculated from the shrinkage of bubbles, was (3.2 ± 1.5) × 10^1?1 m²/sec (19°C), and (6.4 ± 2.0) × 10^?11 m²/sec (42°C). However, the growth behavior of bubbles in flour dough under a temperature rise was very different from that predicted from the diffusion theory. The critical radius of bubbles to grow was larger than that estimated from the diffusion theory. The mechanism of growth of bubbles in wheat flour dough, which was different from that of a bubble in water, is a subject that needs to be clarified.     

The genetic control of milling yield, dough rheology and baking quality of wheat

Improving the end-use quality of wheat is a key target for many breeding programmes. With the exception of the relationship between glutenin alleles and some dough rheological characters, knowledge concerning the genetic control of wheat quality traits is somewhat limited. A doubled haploid population produced from a cross between two Australian cultivars ‘Trident’ and ‘Molineux’ has been used to construct a linkage map based largely on microsatellite molecular makers. ‘Molineux’ is superior to ‘Trident’ for a number of milling, dough rheology and baking quality characteristics, although by international standards ‘Trident’ would still be regarded as possessing moderately good end-use quality. This population was therefore deemed useful for investigation of wheat end-use quality. A number of significant QTL identified for dough rheological traits mapped to HMW and LMW glutenin loci on chromosomes 1A and 1B. However, QTL associated with dough strength and loaf volume were also identified on chromosome 2A and a significant QTL associated with loaf volume and crumb quality was identified on chromosome 3A. A QTL for flour protein content and milling yield was identified on chromosome 6A and a QTL associated with flour colour reported previously on chromosome 7B was confirmed in this population. The detection of loci affecting dough strength, loaf volume and flour protein content may provide fresh opportunities for the application of marker-assisted selection to improve bread-making quality.     

Fungi in flour and refrigerated dough products

Summary Fungal counts of 19 flour samples and 11 wheat samples from 11 flour mills of the Kansas-Nebraska and Pacific Northwest wheat-growing areas were made over a period of 2 years. In addition, 50 spoiled and 22 fresh samples of refrigerated dough products were examined for their fungal content. Methods for obtaining counts of fungi from flour and refrigerated dough were improved through the use of tetracycline as a bacterial inhibitor. Fungal counts ranged from 85 to 8,100 per gram in flour and from 90 to 1,400 in wheat. Generally, mold counts were higher in the flour than in the wheat. Judging from earlier reports, improved handling of wheat and better milling practices are effecting a gradual reduction in fungal counts in commercial flours. More than 500 fungi were isolated from the flours and doughs and were identified. Except for a few Fungi Imperfecti and Mucorales, the majority of the species from the flours belong in the generaAspergillus andPenicillium. Not only do they belong to these genera, but to specific groups in each. In the genusAspergillus, representatives of theA. candidus, A. glaucus, A. flavus-oryzae, andA. versicolor groups were the only ones present. InPenicillium the series commonly found wereP. cyclopium, P. citrinum, andP. urticae, and the remaining species were scattered among various series. Fungal counts of both fresh and spoiled dough samples were comparatively low. Essentially, the fungal flora of the doughs was a reflection of the flour microflora. Spoilage of the dough products did not appear to be of fungal origin.This is a laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

The effect of seaweed composite flour on the textural properties of dough and bread

Seaweeds as food and seaweed-derived food flavors, colors, and nutrients are attracting considerable commercial attention. In the baking industries, hydrocolloids are of increasing importance as bread making improvers, where their use aims to improve dough handling properties, increase the quality of fresh bread, and extend the shelf life of stored bread. Seaweeds contain a significant amount of soluble polysaccharides and have the potential function as a source of dietary fiber. In this study, red seaweed (Kappaphycus alvarezii) powder was incorporated (2–8 %) with wheat flour and used to produce bread. The effect of seaweed composite flour on dough rheological properties and the quality of bread was investigated using various techniques. Farinograph tests were applied to determine the effect of seaweed powder on the rheological properties of wheat flour dough, while texture profile analysis (TPA) was used to measure the textural properties of dough as well as the final product. The results showed that the additions of seaweed powder (2–8 %) increased the water absorption of the dough. TPA results showed that the addition of seaweed powder decreased stickiness properties. Bread produced with seaweed composite flour showed higher values of firmness.     

Analysis of dough functionality of flours from transgenic wheat

The rheological properties of flours from five different lines of transgenic wheat that either express or over-express subunits 1Ax1 and 1Dx5 were analyzed by mixograph assays and SDS sedimentation tests. In one case, the over-expression of subunit 1Dx5 resulted in a ca. 2-fold increase in mixing time, associated with a significant improvement in dough strength, and a lower resistance breakdown, suggesting an important increase in dough stability. However, the flour failed to develop properly without mixing with control flour because the rate of mixing was insufficient to develop the dough, i.e., the flour was overstrong. In two wheat transgenic lines, the expression of 1Ax1 and 1Dx5 transgenes, associated with silencing of all the endogenous high-molecular-weight glutenin subunits, resulted in flours with lower mixing time, peak resistance and sedimentation volumes, suggesting a lower gluten strength.     

Distribution of Zinc in Euglena gracilis Wild and Mutant Cells Cultured in Zinc Enriched Medium as Proved by X-Ray Microanalysis

As a part of the study of bubble expansion in wheat flour dough under temperature rise, the critical radius for expansion, and the time course of expansion of an isolated bubble were investigated. As the required physical properties for the calculation of the critical bubble radius for expansion and the time course of bubble expansion, the authors measured the surface tension of the liquid phase of wheat flour batter as a function of concentration and temperature, and the apparent diffusion coefficients of air in wheat flour dough as a function of temperature. The critical radius for expansion and the time course of expansion of the isolated bubble under temperature rise were compared with the theoretical values calculated from the diffusion theory. At constant temperature, the time course of bubble shrinkage in wheat flour dough was described well by diffusion theory with the surface tension and the apparent diffusion coefficient, indicating that the bubble shrinkage would be rate-limited by the diffusion in the liquid phase of wheat flour dough of air out of the bubble. Under temperature rise from 3°C to 43°C, every bubble larger than the critical radius expanded. This result is physically admissible. On the other hand, the calculated time course of the bubble radius under temperature rise was not in agreement with the experimental data.     

Structural changes of arabinoxylans in refrigerated dough

Wheat flour mainly consists of the starchy endosperm of the kernel, and contains starch, proteins, lipids and non-starch polysaccharides. Arabinoxylans (AXs) are the main non-starch polysaccharides found in wheat flour. Studies showed that degradation of AXs in refrigerated dough has negative effect on quality. The objectives of this research were to structurally characterize the AXs from refrigerated dough samples and determine any correlations between the AX structural changes and variation in dough quality. We observed that the molecular weight of the AXs was changing during the extended storage, and we detected variation in arabinose to xylose ratio for water extractable and unextractable AXs. The ratio of unsubstituted xylose in water extractable AXs increased during storage. These results showed that changes in AX chemistry is correlated to the refrigerated dough quality.     

Use of selected enterococci and Rhizopus oryzae proteases to hydrolyse wheat proteins responsible for celiac disease

Aims:  This work aimed at using a pool of selected enterococci and fungal proteases to hydrolyse wheat gluten during long-time fermentation.
Methods and Results:  A liquid dough made with wheat flour (20% w/w) was fermented with three Enterococcus strains (dough A) or with the combination of enterococci and Rhizopus oryzae proteases (dough B). After 48 h of fermentation, dough A and B had a concentration of water-soluble peptides approximately threefold higher than the chemically acidified dough (CAD), used as the control. The same was found for the concentration of free amino acids, being higher in dough B with respect to dough A. SDS-PAGE analysis showed that albumin and glutenin fractions were partially hydrolysed, while gliadins almost disappeared in dough A and B, as confirmed by two-dimensional electrophoresis, RP-HPLC and R5-ELISA analyses.
Conclusions:  The combined use of enterococci and fungal proteases showed a decrease of the gluten concentration of more than 98% during long-time fermentation.
Significance and Impact of the Study:  The use of the mixture of selected enterococci and R. oryzae proteases should be considered as a potential tool to decrease gluten concentration in foods.     

Microbial transformation of phytosterol in corn flour and soybean flour to 4-androstene-3,17-dione by Fusarium moniliforme Sheld

A strain that was capable of transforming the phytosterol in corn flour and soybean flour was isolated from soil and identified as Fusarium moniliforme Sheld. The main transformation product was purified by high performance liquid chromatography (HPLC), and was characterized by nuclear magnetic resonance (NMR), mass spectrum (MS), and infrared spectrum (IR). The results indicated that the product was 4-androstene-3,17-dione (AD). The production of AD was increased with the increase of initial concentration of corn flour while the yield of AD was decreased. The yield of AD was lower in the media with only soybean flour. Sulfate–phosphate–ferric method (SPF) was first used for determination of the total phytosterol content in corn flour or soybean flour. The measured value by SPF method matched reasonably well with that by HPLC, which indicated the validity of SPF method.     

Effect of arabinogalactan isolated from Siberian larch on the baking value of soft wheat flour and bread quality

Using additives of arabinogalactan (AG) isolated from Siberian larch, we examined the soft wheat flour quality and quantity of gluten, physical properties of the dough, and quality of finished bread depending on the quantity of the added polysaccharide. In the case of the addition of 1–3% of AG to flour, its content decreases in the final product. An excess amount of AG inhibits yeast growth, which leads to a decrease in bread quality. The optimum addition of AG to flour is 1%, at which the technological properties of flour and dough do not change significantly, but the quality of bread becomes remarkably better; furthermore, arabinogalactan is fully consumed in the course of bread preparation. The use of AG is recommended in the optimum dose for increasing the quality of baked goods.     

Utilization of Unfermented Cassava Flour for the Production of an Indigenous African Fermented Food, Agbelima

Summary Unfermented cassava flour, also called high quality cassava flour (HQCF) is used as a partial substitute for wheat flour in the baking industry. This work was carried out to produce an indigenous fermented cassava dough, agbelima, from high quality cassava flour in order to diversify uses for the flour. An isolate of each of the dominant species of lactic acid bacteria isolated from agbelima, was used to ferment reconstituted HQCF dough into agbelima, whilst pH changes, population on MRS, and the organoleptic quality were assessed. The antimicrobial properties of the fermenting samples against three enteric pathogens were also investigated. Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus fermentum and Leuconostoc mesenteroides were isolated at levels of 10¹⁰, 10⁹, 10⁹ and 10⁸ c.f.u. g⁻¹ respectively in agbelima. All isolates and a control sample, produced agbelima with pH of between 4.11 and 3.82 in 48 h, and ANOVA showed no significant difference between the pH of the samples at P ≤ 0.05. Spontaneous fermentation of the reconstituted dough was possible, because the flour was found to contain Lactobacillus plantarum at a level of 10⁶ c.f.u. g⁻¹ as well as the other species isolated from agbelima. Counts of Gram-positive catalase-negative rods and cocci on MRS in all the fermented samples were at levels of 10⁸ to 10⁹ c.f.u. g⁻¹, with ANOVA showing no significant difference between the populations at P ≤ 0.05. Three enteric pathogens, Salmonella typhimurium 9, Echerichia coli D2188 and Vibrio cholerae C-230, inoculated into the samples at 10⁶ to 10⁷ c.f.u. g⁻¹ at the start of fermentation, could not be detected in 10 g of any of the samples at the end of 48 h fermentation. A taste panel preferred banku - a stiff porridge made from a combination of fermented maize dough and fermented cassava dough – prepared with fermented HQCF dough to banku prepared with a market sample of agbelima or reconstituted agbelima flour. Processing the highly perishable cassava roots into high quality cassava flour, therefore, offers a means for preserving cassava, which can subsequently be used for both industrial and traditional purposes.     

Efficient production of protopectinases by Bacillus subtilis using medium based on soybean flour

We have developed a culture system for efficient production of protopectinases (PPases) by Bacillus subtilis. PPase shows the pectin-releasing activity and is expected to be utilized in the enzymatic cotton scouring. B. subtilis IFO3134 was cultivated using defatted soybean flour as a main component of culture media. This strain produced three different types of PPases, namely, PPase-C, -N and -R performing endo-arabinase activity, pectate-lyase activity and pectin-lyase activity, respectively. The effects of alkaline solubilization and autoclave treatments to extract nutrients from soybean flour and initial soybean flour concentration (20-80g/l) on production of PPases in batch fermentation were investigated. Alkaline solubilization of soybean flour with NaOH remarkably reduced enzyme productivity. In addition, a higher initial concentration of soybean flour reduced the enzyme productivity of cells. The pectin-releasing activity was the largest and reached up to 2200-2400U/ml, when the culture medium containing an initial soybean flour concentration of 40g/l was autoclaved for 45-60min without alkaline solubilization treatment.     

Immunoblotting detection of lectins in gluten and white rice flour

The gluten lectin was isolated by affinity chromatography, separated by sodium dodecyl sulphate-gel electrophoresis together with purified wheat germ agglutinin (WGA) and electrotransferred to nitrocellulose filters. The binding pattern of anti-WGA to the blotted filters confirmed the presence of WGA in gluten. A lectin from rice bran and white rice flour, respectively, was isolated by affinity chromatography. Both lectins reacted with anti-WA in immunoblotting. As patients with coeliac disease are known to tolerate rice flour, the finding of a WGA-like lectin questioned the suggestion that WGA in gluten is involved in the pathogenesis of coeliac disease. A second lectin was also isolated from rice flour which reacted only with antibodies against soybean lectin on immunoblots. This may indicate a contamination of soybean proteins in rice flour.     

The antimicrobial effect of organic acids, sour dough and nisin against Bacillus subtilis and B. licheniformis isolated from wheat bread

Prevention of growth in wheat bread for more than 6 d of approximately 10⁶ rope-producing Bacillus subtilis spores per gram of dough was achieved by addition of propionic or acetic acids at levels of 0·10% v/w (based on flour weight), or by addition of 15% sour dough fermented with Lactobacillus plantarum C11, Lact. brevis L62, Lact. plantarum ('vege-start 60'), Lact. plantarum (ch 20), Lact. maltaromicus (ch 15), or the commercial sour dough starter culture, Lact. sanfrancisco L99. These cultures resulted in an amount of total titratable acids above 10 in the sour dough and a pH value below 4·8 in the final bread. Bacteriocin-producing lactic acid bacteria added as starter cultures in wheat dough and nisin (Nisaplin) at levels up to 100 p.p.m. g⁻¹ flour had no effect against B. subtilis and B. licheniformis strains, despite the fact that nisin-producing strains of Lactococcus lactis ssp. lactis among 186 strains of lactic acid bacteria had demonstrated inhibitory activity against B. subtilis and B. licheniformis in an agar spot assay.     

Effectiveness of enzyme preparations of fodder in the degradation of nonstarch polysaccharides from grain substrates

The effects of commercial and laboratory preparations were compared in the course of treatment of components of compound fodder. The most potent preparations were selected for the treatment of soybean flower, sunflower meal, and wheat and barley flour. Preparation 181–1008, which had a high proteinase activity, provided the highest yield of protein from soybean flour and sunflower meal. Preparations aGA, AG20X, and VR, characterized by high activities of pectinase and α-galactosidase, as well as laboratory preparation B2000Mix with a high activity of α-galactosidase, provided the highest yield of sugars from soybean flour. Preparations with high α-galactosidase activity were the most potent in hydrolyzing soluble carbohydrates from soybean flour. The highest yield of reducing sugars was observed after treatment of wheat and barley flour with preparations B2000Mix and aGA. Xylanase activity of these preparations was lower than that of preparations 3.130.2 and TG20X. Preparations 3.130.2 and TG20X were the most potent in hydrolyzing wheat middlings.     

Effectiveness of enzyme preparations of fodder in the degradation of nonstarch polysaccharides from grain substrates

The effects of commercial and laboratory preparations were compared in the course of treatment of components of compound fodder. The most potent preparations were selected for the treatment of soybean flower, sunflower meal, and wheat and barley flour. Preparation 181-1008, which had a high proteinase activity, provided the highest yield of protein from soybean flour and sunflower meal. Preparations aGA, AG20X, and VR, characterized by high activities of pectinase and alpha-galactosidase, as well as laboratory preparation B2000Mix with a high activity of alpha-galactosidase, provided the highest yield of sugars from soybean flour. Preparations with high alpha-galactosidase activity were the most potent in hydrolyzing soluble carbohydrates from soybean flour. The highest yield of reducing sugars was observed after treatment of wheat and barley flour with preparations B2000Mix and aGa. Xylanase activity of these preparations was lower than that of preparations 3.130.2 and TG20X. Preparations 3.130.2 and TG20X were the most potent in hydrolyzing wheat middlings.     

Medium optimization for the production of thermal stable beta-glucanase by Bacillus subtilis ZJF-1A5 using response surface methodology

Polysaccharides, such as barley flour, dextrin and soluble starch, were better carbon sources than monosaccharides and disaccharides, such as glucose and maltose, for cell growth of Bacillus subtilis ZJF-1A5 and beta-glucanase production. beta-Glucanase produced by B. subtilis ZJF-1A5 was associated partially with cell growth and increased significantly when cells entered stationary phase; yeast extract was the best nitrogen source, followed by soybean flour. All inorganic nitrogen sources chosen in the experiments were not favorable for cell growth and enzyme production. A fractional factorial design (2(6-2)) was applied to elucidate medium components that significantly affect beta-glucanase production. The concentration of barley flour, corn flour and soybean flour in medium were significant factors. The steepest ascent method was used to locate the optimal domain and a central composite design was used to estimate the quadratic response surface from which the factor levels for maximum production of beta-glucanase were determined. The composition of fermentation medium optimized with response surface methodology was (g/l): barley flour, 63.5; corn flour, 44.8; KH2PO4, 1.0; MgSO4 x 7H2O, 0.1; CaCl2, 0.1. beta-Glucanase activity was 251 U/ml at 48 h using optimized medium, 1.4 times higher than that in original medium.