Effect of solvents and supercritical-CO2 extraction of lipids on physico-chemical,functional, pasting and rheological properties of hard,medium hard and soft wheat varieties

This study was conducted to compare the effect of lipids removal using supercrital-CO₂ extraction and organic solvents (hexane and isopropanol) from hard and soft wheat flour varieties. Flours were evaluated for physicochemical properties (protein, ash, hunter colour), sodium dodecyl sulphate-polyacrylamide gel electrophoresis, foaming properties, water and oil absorption capacity, pasting, farinographic and dynamic rheology. Protein content of flours increased after defatting and supercritical fluid extracted (SCE) wheat flours showed the highest increase. SCE flours showed higher peak viscosity than native and hexane extracted (HE) and isopropyl alcohol extracted (IPAE) flours. Functional properties improved upon defatting and the highest increase in functional properties was observed for SCE flours. Empirical and fundamental rheological measurements were affected by defatting and SCE flours showed the highest change in visco-elasticity. SC-CO2 was proved better alternative technique over conventional organic solvent methods to remove lipids from flours that brought desirable changes in some functional properties.     

Effect of flour blending on functional, baking and organoleptic characteristics of bread

Soybean (full‐fat and defatted) and barley flours were incorporated into wheat flour at 5, 10, 15 and 20% substitution levels. The gluten content, sedimentation value and water absorption capacity of the flour blends and the mixing time of the dough decreased with increase in the level of soybean and barley flour separately and in combinations. Protein and glutelin contents increased significantly on blending of soyflour (full‐fat and defatted) to bread wheat flour. The breads prepared from the blends also varied in their loaf weight, loaf volume and sensory characteristics. The bread volume decreased with increasing amount of non‐wheat flour substitution. The crumb colour changed from creamish white to dull brown and a gradual hardening of crumb texture was observed as the addition of soybean (full‐fat and defatted) and barley flours increased. At the higher levels, the acceptability declined because of the compact texture of the crumb and the strong flavour of the product. The addition of 10% of soyflour (full‐fat and defatted) or 15% of barley flour, full‐fat soy + barley or defatted soy + barley flour to bread flour produced acceptable bread.     

馒头坯在汽蒸过程中水分迁移特性研究

研究了不同加水量的馒头坯在汽蒸过程中水分的迁移特性。结果表明：在汽蒸过程中．随着加水量的增加,馒头坯总的吸水量呈先上升后下降,然后趋于平缓。加水量与馒头坯不同部分的水分含量呈显著正相关,汽蒸时间与馒头坯不同部分水分含量之间的相关性不显著。另外,加水量与馒头坯不同部分的吸水量之间的相关性不显著,在汽蒸前6min,水分向馒头坯内部各部分迁移的速率最快;在汽蒸过程中,馒头坯各部分的水分含量关系始终为表皮部分大于瓤部分,瓤部分大于中心部分。     

Rheological and Breadmaking Properties of Wheat Flours Supplemented with Octenyl Succinic Anhydride-Modified Waxy Maize Starches

The feasibility of emulsifying starches as bread improvers was investigated by incorporating starch sodium octenyl succinate (OSA-st), pre-gelatinized OSA-st and hydrolysed spray-dried OSA-st at 2.5, 5 and 10 % into wheat flour. Dough rheological properties (creep and recovery measurements; Mixolab, Alveograph) and bread quality parameters (specific loaf volume, crust and crumb colour, crumb moisture, crumb grain features, texture) were evaluated. The substituted flours, except hydrolysed OSA-st, significantly increased water absorption measured by Mixolab. The study on the rheological behaviour of doughs containing emulsifying starches, performed using a rheometer and an Alveograph, showed that OSA-st incorporation yielded strengthened dough, whereas pre-gelatinized and hydrolysed OSA-st addition led to more extensible dough. With regard to the thermal behaviour, investigated in water-limited systems by Mixolab, doughs prepared from pre-gelatinized OSA-st and hydrolysed OSA-st exhibited lower maximum peak torque, whilst all three examined starches increased cooking stability and decreased the setback value. Specific volumes of loaves baked from the substituted flours increased, and the highest effect was observed with pre-gelatinized OSA-st, which consequently produced bread crumbs with the largest mean gas cell area. The bread crumbs baked with octenyl succinate starches were whiter and softer. Although upon 1 day of storage no significant moisture retention capacity of emulsifying starches was noticed, the firmness values of OSA-st and pre-gelatinized OSA-st-supplemented bread crumbs, after 24 h of storage, were similar to or significantly lower than those of the control determined 2 h after baking. The obtained results indicate a requirement for further optimization of the octenyl succinate starch-supplemented doughs in terms of the combination of different types and levels of modified starches in order to obtain maximum bread quality.     

Physicochemical and functional properties of full fat and defatted cashew kernel flours

Full fat and defatted cashew kernel flours were prepared and analysed for their physicochemical and functional properties. There were significant increase in protein and carbohydrate contents of the flour as a result of defatting. The defatted flour possessed higher Ca, P, Na and K contents. It had improved gel strength, foaming and emulsion properties. Foam capacity for the full fat and defatted flours increased from 42% to 50% and 55% to 57% with increased NaCl concentration up to 0.25 and 0.05  m , respectively. The foam capacity and stability of the flours were also pH dependent. The emulsion activity and stability of both flours decreased with increasing NaCl concentration. Minimum and maximum protein solubility were at pH 4 and 8, respectively for the full fat and defatted flours. These results suggest that defatted cashew flour may have potential application as a functional ingredient and as a supplement in foods.     

Functional Properties of Defatted and Detoxified Madhuca (Madhuca butyraceae) Seed Flour

Functional properties of defatted and detoxified Madhuca (Madhuca butyraceae) seed flours were determined and compared with those of soybean flour. Soybean and detoxified Madhuca flours had higher water absorption capacities than defatted Madhuca flour. Due to the presence of saponins, the defatted Madhuca flour showed higher foaming capacity than the soybean and detoxified Madhuca flours.     

Hard Winter Wheat and Flour Properties in Relation to Breadmaking Quality of Straight-dough Bread： Flour Particle Size and Bread Crumb Grain

Samples of 12 hard winter wheats and their flours that produced breads varying in crumb grain scores were studied for 38 quality parameters including： wheat physical and chemical characteristics; flour ash and protein contents, starch damage, swelling power, pasting characteristics, and flour particle size distribution; dough properties determined by a mixograph; and breadmaking properties for pup loaves （100g flour）. Only two parameters, the protein content of wheat and the granulation of flour, showed significant correlations with bread crumb grain scores. Protein content of wheat ranging 12.9%- 14.5% determined by an NIR method showed a weak inverse relationship （r =-0.61, p〈0.05） with bread crumb grain score. Flour particle size distribution measured by both Alpine Air Jet Sieve and NIR methods revealed that the weight wt % of particles less than 38 μ m in size and representing 9.6% - 19.3 % of the flour weights was correlated positively （r =0.78, p 〈 0.01） with crumb grain score, whereas wt % of flour particles larger than 125μm had an inverse relationship （r =-0.60, p〈0.05） with crumb grain score.     

Physicochemical,Pasting, and Functional Properties of Amaranth Seed Flours: Effects of Lipids Removal

The present work was carried out to evaluate physicochemical (composition, hunter color, and sodium dodecyl sulfate–polyacrylamide gel electrophoresis [SDS‐PAGE]), pasting, and functional properties (foaming, emulsification, water, and fat absorption capacity) of amaranth full‐fat flours from 6 lines/cultivars (AFs), and to see the effects of lipid removal/defatting on these properties. Protein, ash, and lipid content of AFs ranged between 12.5% to 15.2%, 3.0% to 3.5%, and 7.1% to 8.0%, respectively. The flours showed a number of bands between 97 and 7 kDa, with main subunits of approximately 58, 37, 33, 31, 23, and 16 kDa in the SDS‐PAGE profiles. The protein content and L* value increased, while b* values decreased following defatting for most of the lines/cultivars. The defatted flours (DAFs) had higher final viscosity and stability (lower breakdown viscosity) as compared to counterpart AFs. The protein profiling of the flours was not affected with the lipid removal/defatting. However, water absorption capacity and foam stability of the flours improved upon defatting. Principal component analysis revealed that pasting temperature was positively related to lipid content, while breakdown viscosity was negatively related to protein content. Foaming properties (capacity and stability) showed negative relationship with lipid content, and positive with protein content, ash content, water, and fat absorption capacity.     

USE OF THE FARINOGRAPH IN PREDICTING BAKING QUALITY OF UNCHLORINATED AND CHLORINATED FLOURS

The viscoelastic properties of six Coker 916 flours with different protein contents were analyzed along with their baking properties. The wheat grain was grown under different amounts of nitrogen, which resulted in the variation of protein content. A portion of each flour sample was chlorinated, and comparisons were made between viscoelastic properties and baking quality. The farinograph was used to link the data derived from the flour analysis with baking quality. The stability, mixing tolerance index (MTI) and peak time (PT) correlated significantly with baking performance and were also good predictors when testing quality of chlorinated flour. Chlorination increased the absorbency of the flour, which contributed to a firmer crumb and a stable baked product.     

Impact of brown foxtail millet (Setaria italica) flour on thermo-mechanical properties of flours from different rice varieties

The physical, functional and thermo-mechanical properties of rice flours prepared from long, round and medium rice grain and of foxtail millet (Setaria italica) flour were investigated. The impact of foxtail millet flour addition on the thermo-mechanical properties to the rice flours was also explored. Rice flour from long grain had higher amylose content (26.37%), while the rice flour from round grain had better hydration properties compared to the other rice flours. The dough from long grain rice flour exhibited higher starch gelatinisation temperature and cooking stability and lower starch retrogradation compared to the other investigated rice flours. Foxtail millet flour addition to the rice flours exerted a lower impact on the thermo-mechanical properties of the dough based on rice flour from long grain compared to the other investigated rice flours. These differences might be due to the differences in terms of starch properties and proximate composition of the flour samples.     

Significance of microbial transglutaminase on the sensory, mechanical and crumb grain pattern of enzyme supplemented fresh pan breads

The impact of microbial transglutaminase (TGM) on the sensory, mechanical and crumb grain pattern of fresh pan breads has been investigated in white and wholemeal flour sponge dough samples supplemented with amylolytic-(NMYL) and non-amylolytic (PTP) enzymes. Assessment of bread performance has been carried out by physico-chemical measurements, texture profile analysis, sensory evaluation, digital image analysis and multivariate data handling. Improving effects of TGM addition were prominent when added to low extraction rate flours (increased cohesiveness by 11%, volume, aroma intensity by 31%, typical taste and crumb to cell ratio by 25% and decreased cell number by 17%). For white and whole flours, NMYL addition to TGM breads led to 16% softer breads. For the pool of enzyme supplemented samples tested, it was observed that the higher the specific volume of breads, the lower the acidification power, the better the mechanical behaviour with high cohesiveness and low hardness values and the higher the sensory scores for visual and textural attributes.     

Flour lipids and their effects in baking

Wheat flour lipid was separated into five fractions by selective elution from silica gel. The two earlier eluted fractions, which contained mainly non-polar components, depressed loaf volume when added to defatted flour. The three other fractions contained polar components and these maintained or increased loaf volume. The effects of the fractions as foam stabilizers paralleled their effects on loaf volume, supporting the theory that flour lipids exert their action in baking through their role as surfactants in stabilizing or destabilizing the gas bubble structure during expansion of the loaf. Evidence points to a classification of flour lipids into three groups according to their effects in baking. The polar galactolipids and phospholipids increase loaf volume, compounds of intermediate polarity depress loaf volume while the more non-polar compounds such as triglycerides have little effect in the absence of other lipids but have beneficial effects when other lipids are present. Thin-layer chromatography showed clear differences in composition between lipid extracts from wheat, rye and maize flours and these could be correlated with effects on the baking behaviour of defatted wheat flour.     

Effects of protein removal on the physicochemical properties of waxy maize flours

The effects of protein removal on the physicochemical properties of waxy maize flours were investigated. Protein removal caused significant reduction in the P and S contents of starches. Starch granules had a smoother surface and low protein content (<6 g/kg) compared with the flours. Both flours and starches had a typical A‐type X‐ray diffraction pattern, with a crystallinity range of 29.8–32.2% and 27.7–30.6%, respectively. Flours had higher swelling power and solubility, and lower light transmittance than starches. The gelatinization enthalpy and onset temperature of starches were higher compared with those of their counterpart flours. The retrogradation of flours was significantly greater compared with that of starches. Protein removal increased the peak viscosity, trough viscosity, final viscosity, and breakdown, whereas it decreased the setback and pasting temperature. Genotypic differences in those maize were related to the physicochemical characteristics of the flours and starches.     

Physicochemical characterization of corn–sorghum nixtamalized flours as a function of the steeping time

This work focused on the study of the physicochemical properties of nixtamalized corn and sorghum flours, as well as combined nixtamalized corn–sorghum flours with 10, 20, and 30 % of sorghum. The removal of the sorghum pericarp during nixtamalization depends on the steeping time and strongly influences the water and calcium uptake. The absence of the waxy layer in sorghum grain allows a faster water uptake in relation to corn grain. Changes in the pericarp structure during the steeping time govern the Ca absorption in sorghum grain. The partial removal of the pericarp and the most external layers of the endosperm produce the decrease in phosphorous content for corn and sorghum. The Ca/P ratio of nixtamalized corn/sorghum flours is greater than 1 for steeping time up to 3 h. Therefore, this fact could help the increase of Ca in the daily diet. Amylopectin is the predominant macromolecule in both starches. The pasting profiles showed a decrease in peak viscosity when the sorghum fraction increases; this is due to increases in fiber.     

Effects of binary organic solvents and heating on lipid removal and the reduction of beany odour in Bambara groundnut (Vigna subterranean) flour

Effects of various binary organic solvents at different temperatures on the removal of lipids and beany or grassy odour of Bambara groundnut flour were studied. The highest lipid removal was achieved at 60 °C (P < 0.05), regardless of binary organic solvents used. Under the optimal temperature, chloroform/methanol showed the highest lipid removal (87%), followed by hexane/isopropanol (78%). All binary solvents containing methanol had higher efficiency in removal of phospholipids, and inactivation of lipoxygenase and trypsin inhibitors, as compared to isopropanol containing solvents (P < 0.05). Based on FTIR spectra, lipids removed by methanol containing solvents had high content of phospholipids. The flours defatted by methanol containing solvents exhibited the lowest peroxide value, thiobarbituric acid-reactive substances and beany odour intensity than the non-defatted flour and those defatted by isopropanol containing solvents throughout the storage (P < 0.05) of 30 days at refrigerated and room temperatures. In general, chloroform/methanol was the most effective in inactivating lipoxygenase and trypsin inhibitors, retarding lipid oxidation as well as beany odour development in flour. Therefore, chloroform/methanol could be used to lower beany or grassy odour in Bambara groundnut flour.     

Chemical compositions,functional properties,and microstructure of defatted macadamia flours

The objective of this research was to study the chemical compositions, functional properties, and microstructure of partially defatted flours (PDF, 12–15% fat, dry basis (db)) and totally defatted flours (TDF, 1% db fat) from three macadamia cultivars, PY 741, DS 344, and DS 800, grown in Northern Thailand. The defatted flours were high in protein (30.40–36.45% db) and carbohydrate (49.29–57.09% db). For each macadamia cultivar, while emulsion activities and emulsion stabilities of the TDF tended not to be different from those of the PDF (p > 0.05), TDF had significantly greater water absorption capacities (WAC), oil absorption capacities and foaming capacities (FC), but had significantly lower foaming stability (FS) than the PDF (p ? 0.05). The TDF from PY 741 cultivar possessed the highest WAC and FC but the lowest FS. The variation in the functional properties of the defatted flours could mainly arise from the difference in the quantity and characteristics of the proteins in the flours. Structure determination of macadamia flours showed that the proteins bodies and starch granules were embedded in kernel tissues. The starch granules were oval and approximately 10 μm in diameter.     

Physicochemical and functional properties of full‐fat and defatted Moringa oleifera kernel flour

Full‐fat and defatted Moringa oleifera kernel flours were analysed for their functional properties. The effect of pH and NaCl concentrations on the functional properties of the flours was investigated following standard procedures. The protein content of full‐fat and defatted flour was 36.18 and 62.76 g/100 g, respectively. The concentrations of other proximate constituents of the defatted flour were higher than those of the full‐fat flour. Nitrogen solubility was lowest at pH of 4.0 and 9.0, respectively, with maximum solubility occurring at pH of 6.0. Defatting increased the water absorption and fat absorption capacities of Moringa oleifera kernel flour. The foaming capacity and foam stability of the defatted flour were 86.0% and 82.0 mL, whereas that of full‐fat flour were 20.6% and 18.5 mL respectively. The defatted flour showed better emulsification (97.2 mL g^?1) than full‐fat flour (66.0 mL g^?1). The least gelation concentration of the defatted and full‐fat flours was 14% and 16% (w/v) respectively. Moringa oleifera kernel flour can be a valuable source of vegetable protein in fortified food products formulation.     

Response Surface Methodology in the Development of Rice Flour Yeast Breads: Sensory Evaluation

Yeast breads were developed from rice flour (80%) and potato starch (20%). Using sensory measurement from a trained panel, response surface methodology (RSM) was applied to find carboxymethylcel-lulose (CMC), hydroxypropylmethylcellulose (HPMC), and water level combinations for gluten-free breads from three different rice flours. Formulations resulted in rice breads that met wheat bread reference standards for moistness, cohesiveness, yeasty flavor, adhesiveness, aftertaste, top crust and crumb color, cell size uniformity and predominant cell size. Medium grain rice flour breads met more sensory reference standards than long grain rice flour breads.     

Adequacy of wholegrain non-wheat flours for layer cake elaboration

Flours (white and wholegrain flours) from wheat, rye, triticale, barley and tritordeum were used to elaborate layer cakes. The pasting properties (RVA) and the water-absorption (doughLab) of flours were analyzed. The batter characteristics (density, G′, G″, tan δ, consistency and flow index), and the cake characteristics (cake volume, crumb and crust colour and texture after 1 and 7 days) were studied. A sensorial evaluation of the cakes was also performed. Wholegrain flours showed higher pasting temperature and water-absorption, but lower peak time and viscosity than white flours. Its batters showed lower density and consistency and higher G′, G″, tan δ and n values. Wholegrain cakes showed lower specific volume, symmetry, colour characteristics, and staling rate but higher initial firmness. Considering the different cereals, barley showed the most different behaviour in flour, batter and cake characteristics. DoughLab analysis was very interesting to understand the adequacy of flours to cake elaboration, since significant correlations were found between water-absorption and specific volume, symmetry and firmness. Little differences in the consumer test were obtained between wheat and non-wheat cakes. Wholegrain non-wheat cakes could be a good alternative to white flour wheat cakes, due to their adequate technological properties and their nutritional advantages.     

Some observations on wheat gluten solubilities

A study of wheat protein solubilities in dilute acetic acid is presented. Up to 4% more protein can be extracted from defatted flours than from the non-defatted flour. High-speed homogenisation can render up to 88% of flour protein and up to 97% of dough protein soluble. One criterion for optimum fatty acid or lipid protein interaction (causing protein insolubility) is that the fatty acids or lipids should contain C7-C9 hydrocarbon chain lengths.