Influence of the particle size on the rheological behaviour of chestnut flour doughs

The rheological properties of chestnut flour (CF) doughs with different particle size were studied using a controlled stress rheometer. The mixing curves and heating–cooling cycle responses were previously obtained from the Mixolab® apparatus. Shear measurements (0.1–10 s⁻¹), oscillation measurements (1–100 rad s⁻¹ at 0.1% strain), temperature sweep (30–100 °C) to achieve the gelatinization temperatures and creep-recovery tests (loading of 50 Pa for 60 s) were conducted in the rheometer. Mixolab® showed that CF samples with smaller particle size needed more water absorption to reach a consistency of 1.1 Nm. Shear viscosities of CF doughs exhibited a Newtonian plateau at low shear rate and shear thinning behaviour at higher shear rate. Apparent viscosity increased with increasing average particle size and steady-flow curves were fitted using Cross model. Oscillatory measurements of CF dough showed that the storage modulus, G′, was greater than loss modulus, G″, for all samples in the tested angular frequency range. CF samples with smaller particle size presented lower G′ and G″ values. Creep-recovery tests of these flours showed that elasticity was limited and unrecoverable proportion was very high. Gelatinization temperatures measured using Mixolab® and rheometer were practically coincident.     

Effect of β-Glucan Concentrate on the Water Uptake,Rheological and Textural Properties of Wheat Flour Dough

The effects of the addition of β-glucan concentrate (2.5–10 g/100 g flour) and water (58–70 mL/100 g flour) on the rheological and textural properties of wheat flour doughs were studied. Various empirical (farinograph, extensograph, dough inflation, and dough stickiness) and fundamental rheological tests (oscillatory and creep-recovery) were employed to investigate composite dough structure and an attempt was made to correlate the data obtained from different instrumental measurements. The water absorption increased with the addition of β-glucan concentrate into wheat flour. An increase in mixing time and stability were recorded upon addition of β-glucan concentrate (≤ 5 g/100 g flour), and the extensibility decreased at similar condition. The composite dough exhibited predominating solid-like behavior. The mechanical strength, dough stickiness, the peak dough inflation pressure decreased with increasing water content but those parameters increased with β-glucan concentrate incorporation within the studied concentration range. Creep-recovery tests for 5 g β-glucan concentrate/100 g flour doughs recorded less resistance to deformation with an increase in water level and data were well described by the Burger model. Thermal scanning of doughs revealed that the protein denaturation peak was significantly influenced by water content, and the values were ranged between 110 and 124°C. Significant relationships between empirical and fundamental rheological testing methods were found.     

Rheology of commercial chestnut flour doughs incorporated with gelling agents

The rheological properties of chestnut flour (CF) doughs incorporated with agar, hydroxypropylmethyl cellulose (HPMC) and xanthan at different concentrations (0.5, 1.0, 1.5, 2.0%, flour basis) were determined at 30 °C using a controlled stress rheometer. The mixing behavior at the same temperature was achieved by the Mixolab^® apparatus. The tests conducted in the rheometer were shear (0.01–10 s⁻¹), oscillatory (1–100 rad s⁻¹ at 0.1% strain), creep-recovery (loading of 50 Pa for 60 s) and temperature sweep (30–100 °C) measurements. These rheological properties were significantly modified by the type and content of gelling agent added. The values of apparent viscosity in all tested shear rate range as well as the values of storage (G′) and loss (G″) moduli of CF doughs in the tested angular frequency decreased with increasing agar and HPMC concentration and increased with xanthan addition. Flow curves and storage and loss moduli of assayed doughs were satisfactorily fitted using Cross model and a potential model, respectively. The initial gelatinization temperature decreased with agar and increased with xanthan as well as the gelatinization temperatures range with HPMC addition was shorter. This pasting trend was also noticed using Mixolab^®. Creep-recovery data, successfully fitted using Burgers model, showed that elasticity of doughs improved significantly with HPMC and xanthan addition.     

Natural fermentation of lentils. Functional properties and potential in breadmaking of fermented lentil flour

The effects of fermentation on functional properties of lentil flour and rheological properties of doughs and breads produced from blends of wheat and fermented lentil flour were studied. Lentil protein solubility was higher at neutral pH than acid pH; the lowest and highest protein solubility values were observed at pH 4.0 and pH 7.0, respectively. Water hydration capacity and fat binding capacity of fermented lentil flour (FLF) were always higher than those of non-fermented lentil flour (NFLF), irrespective of fermentation temperature (28–42°C) and flour concentration (79–221 g/l). Emulsifying properties of NFLF were similar to the properties of other legume flours in the range used in experiment. In contrast, the emulsion capacity and stability of FLF were very low and flours fermented at 42°C did not even form emulsion. Rheological properties of doughs made from wheat-fermented lentil blends were similar to those from wheat flour with the addition of other legume flours such as pea and bean. Good quality breads were produced at 2.5 to 10% NFLF and FLF supplementation (except for bread with 10% FLF addition which was middle quality).     

The Effect of Hybrid Carrageenan on the Thermo-rheological Properties of Gluten-Free Flour Doughs Using a Modified Kneading Protocol

Thermo-rheological behaviour of chestnut flour doughs supplemented with kappa/iota-hybrid carrageenan (HC) (up to 2.0%, flour basis (f.b.)) and sodium chloride (1.8%, f.b.) was determined at both target (C1) and final (C5) mixing peaks. For this purpose, small amplitude oscillatory shear (0.01 to 100 Hz), creep–recovery (loading of 50 Pa for 60 s, 30 °C), temperature sweeps (from 30 up to 180 °C) and heating/cooling cycles (between 30 and 60 °C) were conducted on a controlled stress rheometer. Previously, the thermal-mixing behaviour at proposed mixing temperature (50 °C) was conducted on Mixolab® apparatus. Results showed that the dough stability (from 2.2 to 5.8 min) in mixing stage and starch heat resistance to dough processing were significantly improved at proposed mixing temperature, even in the absence of HC. No statistical differences in rheological properties were observed for doughs evaluated in C1; however, those analysed in C5 were significantly modified in the presence of HC, mainly in terms of viscous behaviour (from 52.1 × 10⁶ to 39.1 × 10⁶ Pa s). Creep–recovery data sets, successfully fitted using Burgers model, revealed that the elasticity (J _r/J _max from 73.3 to 87.6%) of doughs analysed in C5 improved with HC addition. Thermal tests showed that the starch transitions were significantly promoted and stabilized with HC addition.     

Functional,Thermal and Rheological Properties of High Fibre Fresh Pasta: Effect of Tiger Nut Flour and Xanthan Gum Addition

Tiger nut flour (TNF) is a rich source of dietary fibre with potential to be used in cereal-based products. However, research on improving the rheological properties of tiger nut-based doughs is limited. In this paper, the significance of TNF and xanthan gum (X) incorporation into fresh egg pasta, in terms of its thermal and dynamic rheological properties, has been investigated. Plain semolina pasta (DWS) was used as control. High fibre doughs (20 and 40% TNF) with or without X (0 and 1%) were assessed. Both fundamental (dynamic oscillatory and creep tests) and empirical (texture profile analysis) tests were performed to assess the viscoelasticity of TNF-DWS composite blends. Raw solids (TNF, DWS) were characterised in terms of their chemical composition, particle size distribution and functional properties. For both fresh and cooked pasta, water activity, water content and gelatinisation temperatures were estimated. The results from the rheological tests revealed that partial replacement of DWS by TNF lead to less cohesive and weaker structures due to the lower presence of a gluten network. X significantly improved the rheological response of the TNF-based doughs. Thermal analysis showed a single endothermic peak in the temperature range between 60 and 78 °C during heating, which corresponds to the amylopectin gelatinisation. However, when replacing 40% of DWS by TNF, two-phase transitions were observed, probably associated to the starch tiger nut gelatinisation or the formation of amylose-lipid complexes. The optimum cooking time for the tiger nut pasta was 2 min as determined by a calorimetric analysis.     

Changes During Accelerated Storage in Millet–Wheat Composite Flours for Bread

Two millet–wheat composite flours, CF1 and CF2, were formulated based on the rheological and textural properties of dough using response surface methodology. The optimized contents of composite flour CF1 were 61.8% barnyard millet flour, 31.4% wheat flour, and 6.8% gluten, respectively. The optimized components of the composite flour CF2 were barnyard millet flour 9.1%, finger millet flour 10.1%, proso millet flour 10.2%, and wheat flour 70.6%. Millet–wheat composite flours were stored in three different packaging materials, namely, low-density polyethylene (LDPE), high-density polyethylene (HDPE), and metallized polyester (MP), at 90% RH and 40 °C temperature for 90 days. For the packaging of millet–wheat composite flour CF1, MP was found best among the tested packaging materials, where moisture gain in samples was minimum (55%) as compared with materials LDPE (124%) and HDPE (100%). Vitamin loss among the different packaging materials was not significantly different at the 5% level of significance. The shelf lives of the composite flours were estimated based on their critical moisture contents. After 90 days of storage of CF1, the highest retention of starch (91.85%) was recorded in MP packaging followed by HDPE (87.5%) and LDPE (84.8%). However, in CF2, the retention was not significant in all three packaging materials (P?相似文献   

Influence of water and barley β-glucan addition on wheat dough viscoelasticity

The effects of the addition of two barley β-glucan isolates (0.2–1.0% of wheat flour), differing in molecular weight, and water (53–63% in a poor breadmaking wheat flour, cv. Dion, and 58–68% in a good breadmaking wheat flour, cv. Yekora) on the viscoelastic properties of wheat flour doughs were investigated. A response surface model (CCF) was used to evaluate the effects observed on the dynamic and creep-recovery parameters of the dough. The evaluation was done separately for each combination of β-glucan isolate (BG1 of ～10⁵ Da and BG2 of ～2 × 10⁵ Da) and flour type. Besides the contents of β-glucan and water, the molecular size of the polysaccharide and the flour quality were important determinants of the dough’s viscoelastic behavior. Compared to BG1, the higher molecular weight β-glucan (BG2) brought about major changes on all the rheological responses of the fortified doughs. The addition of appropriate levels of β-glucans and water in the poor breadmaking cultivar (Dion) doughs could yield similar viscoelastic responses to those observed by a non-fortified good breadmaking quality flour dough (Yekora).     

不同粒径小米粉对面团流变特性及馒头质构特性的影响

为研究小米粉添加对面团流变特性和馒头制品质构特性的影响,分别选取不同粒径的粳性和糯性小米粉,利用损伤淀粉测定仪、快速黏度分析仪等对不同小米粉的损伤淀粉含量和糊化特性进行分析,通过流变仪测定小米面团的流变学特性,结合扫描电镜观察小米面团微观结构变化,并利用质构仪测定小米馒头的质构特性。结果表明：随着小米粉粒径的减小,多数品种小米粉（除冀谷39和汇华金米）损伤淀粉的碘吸收率增加;受直支比的影响,相同目数下,粳性小米粉的峰值黏度、谷值黏度、最终黏度和回生值较糯性小米粉大。流变学研究表明,除汇华金米和冀谷39,储能模量与损耗模量随角频率增加总体上升。扫描电镜观察发现小米粉的添加使面团结构更加松散。小米粉的添加会对馒头质构性质中硬度、咀嚼性和弹性等有一定程度的负面影响。主成分分析表明馒头咀嚼性、损伤淀粉、峰值黏度、谷值黏度、最终黏度、崩解值和回生值可作为区分粳糯品种和馒头品质特征的指标。     

Particle Size Fractionation of High-Amylose Rice (Goami 2) Flour as an Oil Barrier in a Batter-Coated Fried System

The particle size effects of high-amylose rice (Goami 2) flour on quality attributes of frying batters were characterized in terms of physicochemical, rheological, and oil-resisting properties. High-amylose rice flours were fractionated into four fractions (70, 198, 256, and 415 μm) of which morphology was also analyzed by scanning electron microscopy. Rice flour with smaller particle size exhibited a higher degree of starch gelatinization, giving rise to increased pasting parameters. When the rice flours were incorporated into frying batters, higher steady shear viscosity was observed in the batters with finer rice flour, which could be well characterized by the power law model. In addition, the dynamic viscoelastic properties of the batters were enhanced by the use of rice flour with smaller particle size, which also caused an increase in batter pickup. When subjected to deep fat frying, the batters with finer rice flour exhibited reduced moisture loss. Furthermore, the oil uptake was found to have a positive correlation with the particle size of rice flour (R ²?=?0.88), even showing the reduction of oil uptake by 15%. It could be synergistically attributed to the formation of outer starch granular layers, high batter viscosity/pickup, and reduced moisture loss by finer rice flour.     

Physicochemical and Rheological Properties of Taro (Colocasia esculenta) Flour Affected by Cormels Weight and Method of Peeling

The present study investigated the effect of peeling and cormels weight on physicochemical and rheological properties of taro (Colocasia esculenta) flour. The cormels were divided by the weight into four classes: size?<?170 g, 170?<?size?<?214 g, 214 g?<?size?<?284 g, and size?>?284 g. Each one of these classes contains half of peeled and unpeeled cormels. The results showed a difference between the flour derived from different taro cormels weight in term of the physicochemical, morphological, and rheological properties. However, no difference was observed in terms of the thermal properties. The study revealed that taro flours are mainly made of dietary fibers. The granule size of the flour varied significantly within each different cormels weight in the same method of peeling and the mean flour diameters are around 204 μm. For both form of peeling, potassium was found to be the higher mineral and sodium was the lower one. Concerning phytate, the peeled samples have the lowest values of 5.76 and 4.79 mg/g dry matter, respectively, for cormels size?<?170 g and 170 g?<?size?<?214 g. Finally, we observed that peeling methods and weight of taro cormels have an influence on some physicochemical composition of flour and rheological properties of flours suspensions.     

Rheological properties of commercial chestnut flour doughs with different gums

Rheology of chestnut flour (CF) doughs with arabic gum (AG), carboxymethyl cellulose (CMC), guar gum (GG) and tragacanth gum (TG) at different concentrations (up to 2.0%) were determined at 30 °C using a controlled stress rheometer. The mixing characteristics at 30 °C were achieved using Mixolab^® apparatus. Shear (0.01–10 s^?1), oscillatory (1–100 rad s^?1 at 0.1% strain), creep‐recovery (50 Pa for 60 s) and temperature sweep (30–100 °C) tests were performed. Rheological properties were significantly modified by gum added. Apparent viscosity of CF doughs, storage and loss moduli increased at content of AG (above 0.5%), CMC (at 1.0%), GG (above 1.5%) and TG (at 1.0%). Flow curves and mechanical spectra were fitted using Cross model and power models, respectively. The gelatinisation temperatures increased with gums. The same pasting trend was noticed using Mixolab^®. Creep‐recovery data, fitted by Burgers model, showed that elasticity of CF doughs improved with GG.     

RHEOLOGY OF WHEAT DOUGHS FOR FRESH PASTA PRODUCTION: INFLUENCE OF SEMOLINA-FLOUR BLENDS AND SALT CONTENT

Dynamic measurements were made with a controlled stress rheometer to study the viscoelastic properties (G', G', δ) of wheat doughs (45% wb water content) for fresh pasta production prepared with different blends of durum wheat semolina and common wheat flour with different concentrations of sodium chloride. Increasing the semolina and sodium chloride content, increased the strength and the solid-like behaviour of semolina-flour blends. The physical properties of dough were strongly dependent on particle size distribution and salt addition. By manipulating semolina-flour ratio and ionic strength, it was possible to obtain semolina-flour doughs with a rheological behaviour close to that of pure semolina dough.     

Fortification of wheat flour with black soldier fly prepupae. Evaluation of technological and nutritional parameters of the intermediate doughs and final baked products

Bread wheat flour presents specific nutrient deficiencies, such as some essential amino acids and this drawback could be tackled by adding ingredients that contain them in high amounts. Therefore, this study aims at developing new types of flours as well as at analysing enriched flours and baked derived products, which combine the compositional and sensory characteristics of wheat bread with some peculiar nutritional properties of black soldier fly prepupae (Hermetia illucens). These composite flours were obtained by mixing “Italian type 1” semi-whole wheat flour (W = 300) with flour obtained from prepupae of black soldier fly (20 g and 40 g/1 kg composite flour). Chemical, physical, and rheological analyses were carried out for each of the flour mixtures. Moisture, ash, gluten, total protein content, falling number, strength, tenacity, extensibility, amino acid profile of doughs and breads were analysed as well. An increase in the content of essential amino acids in doughs and baked products was obtained and also led to an improvement in bread texture.     

Promoting dough viscoelastic structure in composite cereal matrices by high hydrostatic pressure

The impact of high hydrostatic pressure (HP) treatment on dough viscoelastic reinforcement of highly-replaced wheat cereal matrices has been investigated. The gelatinisation/pasting and gelling profiles of HP hydrated oat, millet, sorghum and wheat flours, and the small and large deformation rheological parameters of blended wheat/non-wheat doughs were determined. Oat, millet, sorghum and wheat hydrated flours, at dough yield (DY) 160 and 200, were treated for 10 min at 0.1, 200, 350 or 500 MPa. Regardless the nature of the cereal, HP changes flour viscometric features, particularly in softer doughs (DY 200), leading to increased values for viscosity parameters, concerning pasting and paste cooking. Incorporation of 350 MPa pressure-treated flours into bread dough formulation provided increased dynamic moduli values, particularly for wheat and oat/wheat blends, associated to a reinforced dough structure. Highly-replaced composite dough samples treated at 500 MPa proved to be extremely stiff, resistant to stretch, low cohesive and low extensible, and thus not suitable for breadmaking.     

Technological Assessment of Chestnut Flour Doughs Regarding to Doughs from Other Commercial Flours and Formulations

The technological assessment of chestnut flour doughs was studied using Mixolab® apparatus, establishing a comparison with gluten (soft, hard and whole wheat) and gluten-free (rice and yellow corn) flour doughs as well as corn starch pastrymaking and breadmaking formulations. This equipment measures the torque in function of temperature and time, firstly at 30 °C (mixing curve) and secondly the mixing during heating (4 °C/min up to 90 °C) and cooling (4 °C/min up to 50 °C) steps (complete curve). Different hydrations of doughs ranging from 41.4% to 68.5% (flour basis) were necessary to reach the torque of 1.10?±?0.07 Nm. Parameters of mixing such as water absorption, development time, stability and mixing tolerance index were obtained. Parameters of heating and cooling cycle related to weakening of proteins, gelatinization starch, amylase activity and starch retrogradation as well as range of gelatinization temperatures were also determined. Chestnut flour showed suitable parameters in the mixing stage such as arrival time (1.93?±?0.1 min), stability (12.1?±?0.4 min) and departure time (14.0?±?0.3 min). In the heating cycle, chestnut flour exhibited close behaviour to soft wheat flour with cooking stability of 1.12?±?0.01 min and seems to be suitable for pastrymaking products. Finally, in the cooling cycle the behaviour revealed that products of this flour can present problems of staling and crumbs firmness due to high values (2.88 Nm) of C5 parameter.     

Biscuit making properties of flours from hard and soft milling single variety wheats

Bench scale baking tests for two types of biscuits,¹ a hard sweet (HS) and a short sweet (SS), have been used to examine the biscuit making properties of a large number of flour samples from wheats grown in four consecutive years (1980–1983). Multiple regression models for prediction of biscuit properties using a range of standard cereal laboratory tests as independent variables on results from 1980–1981 harvest wheats confirmed earlier observations that such tests are of limited commercial value for biscuit flour specification. However the results of baking tests, with both types of biscuit, from single wheat varieties grown during 1981–1983 showed that flours from soft milling wheats (SMW) required less water to give biscuit doughs of standard consistency (measured instrumentally) than did flours from hard milling wheats (HMW). In addition biscuit doughs made with SMW flours gave greater oven spring, i.e. biscuits of lower bulk density, than doughs made from HMW flours. In each season the difference in the mean values of both parameters for flours milled from SMW and HMW was highly significant (P<0.001). With one exception the variability of the measured parameters within seasons was not significantly different between SMW and HMW. However within both SMW and HMW varieties highly significant differences (P<0.001) were observed between seasons for the mean values of both measured biscuit parameters. The effect of flour particle size on the biscuits was studied by regrinding a number of flours. With flours from both SMW and HMW reduction in particle size resulted in HS biscuits of higher density but SS biscuits of lower density.     

Influence of Flour Particle Size on Quality of Gluten-Free Rice Cakes

There is a growing interest in developing gluten-free bakery products in recent time. In cake making, gluten network formation is not essential, but hardly any information exists about the influence of the gluten-free flour characteristics affecting the final cake product. This study analyses the influence of two different rice cultivars (short and long) with different flour particle size in batter characteristics (specific volume, viscosity and internal structure) and in sponge and layer cake formulas (volume, shape, texture and colour). During starch gelatinization, the finest flours (median particle size finer than 100 μm) increased their viscosity and reached the peak viscosity (RVA) later than the coarsest flours. Moreover, the finest flours gave batters with lower specific volumes but with an air distribution in smaller and uniform bubbles in both formulas. These flours also produced higher volume and lower firmness in sponge cakes and greater symmetry index both in sponge and layer cakes. The rice type also influenced batter and cakes characteristics but in a lesser extent. The different results obtained depending on the rice flour particle size, type flour and cake formulation indicate the need to define them both in industrial specifications and in research studies.     

Rheological and thermal properties of blend systems of rice flour and potato starch

The rheological and thermal properties of blends of rice flour (RF) with potato starch (PS) at different RF/PS ratios (9/1, 8/2, 7/3, 6/4, and 5/5) were examined. Steady and dynamic shear rheological tests indicated that the consistency index, yield stress, and dynamic moduli (G′ and G″) values of the RF-PS blends increased with an increase in the mixing ratio of PS. All blend samples exhibited high shear-thinning fluid characteristics. Tan δ values of all the blends were lower than those of RF and PS, showing that the presence of PS increased the elastic property of RF. DSC studies showed that the transition temperatures and enthalpies of gelatinization of the blends appeared to be greatly influenced by the addition of PS. In general, these results suggest that the presence of PS in RF modified the rheological and thermal properties, and that these modifications were dependent on the mixing ratio of PS.     

Water Content, Water Soluble Fraction, and Mixing Affect Fundamental Rheological Properties of Wheat Flour Doughs

Fundamental rheological behavior of wheat flour doughs were compared with empirical results from a farinograph. Water contents of 42-47% and mixing times of 8, 16, and 24 min were examined. The storage modulus, G′, decreased when water content was increased from 42 to 45%. Dough produced from water extracted flours had high G′ and low δ. Increasing water content or mixing time decreased G′. There was a linear relationship (slope = 0.30) between G′ and the farinogram peak height for the reconstituted (water-soluble fraction added back), flour-water, and freeze-dried flour-water doughs. The extracted flour doughs also showed a linear relationship between G′ and farinogram peak height with slope = 1.07.