Flour Constituents Research Articles

Understanding the impact of water-extractable cereal flour constituents on network formation in gluten-starch dough

Water-extractable cereal flour constituents influence bread loaf specific volume, suggesting a contribution to gas cell (de)stabilization in dough. However, the underlying mechanism remains largely unexplored. We studied the impact of incorporating five cereal flour aqueous extracts in model gluten-starch bread (doughs) on specific volume, dough extensional rheology, and protein extractability changes during bread making. Incorporating wheat, rye, or triticale flour aqueous extracts in gluten-starch doughs increased bread specific volume by 12–17%. There were no changes in dough rheology that could explain this specific volume increase, suggesting that other mechanisms relating to gas cell stabilization might be at play. Incorporating oat flour aqueous extracts decreased bread specific volume by 50%. This negative impact was related to poor dough strain hardening behavior, in turn probably explained by disruption of intermolecular glutenin disulfide bonds, as revealed by chromatography. While this study has provided a novel perspective on the mechanisms by which water-extractable cereal flour constituents influence bread volume, it also demonstrates that the compositional heterogeneity of the flour aqueous extracts needs to be addressed to allow an even better understanding of the role of water-extractable cereal flour constituents in stabilizing gas cells in bread dough.

Effects of Sucrose Replacement by Polyols on the Dough-Biscuit Transition: Understanding by Model Systems.

This study investigated the impacts of the complete substitution of sucrose by maltitol and/or sorbitol on the dough-crumb transition in biscuits. To this end, the phenomena of starch gelatinization/melting were studied at different moisture contents, both in the biscuit dough and model systems, by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and by environmental scanning electron microscopy (ESEM). Observation of doughs in ESEM revealed sorbitol had a structure very different from sucrose and maltitol crystals. After forming the dough pieces, it could be seen that at least some sugar and maltitol crystals were still present while sorbitol flakes were solubilized. At a limiting real water content (~20% dry basis), adding sweeteners to the mixture increased the gelatinization temperature, more markedly for sucrose and maltitol, as well as increasing the enthalpy. These results were confirmed by the model systems analyses. The calorimetric study with mixing batch cells revealed that sorbitol dissolved completely while maltitol and sucrose competed with the flour constituents to capture water. The proportion of water available for the sorption of the starch grain and its gelatinization was therefore different according to the affinity of the sweetener for water, and might influence the degree and temperature of starch gelatinization/melting.

Effect of fermentation conditions on nutritional and phytochemical constituents of pearl millet flour (Pennisetum glaucum) using response surface methodology

In the current study, fermentation conditions for pearl millet flour were optimized using baker's yeast. A central composite experimental design with three independent variables, temperature (30°C-45°C), yeast concentration (2%–4%) and time (18–24h) was used to study the dependent variables (total protein, total sugar, total phenolics, total flavonoids, total Titratable acidity, total soluble solids and pH). Based on response surface methodology, twenty run were processed. Regression model interpretation revealed the significant relationship between considered dependent and independent variables. Also all linear terms, two quadratic terms (fermentation temperature and time) and all interactive terms had significant (p<0.05) effect on the response variables. The optimum fermentation condition for pearl millet flour was achieved with 2% baker's yeast at 30°C for 18h. Fermentation at this condition significantly improved the phytochemical constituents of pearl millet flour. Thus, this pearl millet flour with improved phytochemical constituents can be used to develop healthy functional food products by food industries.

Data fusion of near-infrared diffuse reflectance spectra and transmittance spectra for the accurate determination of rice flour constituents

The data fusion method effectively fuses multiple complementary inputs for highly accurate analysis. The spectral signals collected by near-infrared diffuse reflectance (NIRr) and diffuse transmission (NIRt) contain various information on the physical structure and chemical composition of the sample. Thus, the data fusion method (for NIRr and NIRt) can be used to further improve the accuracy of the NIR quantitative analysis method. The NIR spectroscopic analysis of protein content (PC), amylose content (AC), and fat content (FC) of rice can be used to select high-quality rice varieties. The data obtained using the NIR spectroscopic analysis method for rice flour were used to optimize NIRr and NIRt data fusion and verify the feasibility of this method to achieve more accurate quantitative analysis. Two types of rice flour spectra, NIRr spectra and NIRt spectra, were processed by different pretreatment methods to obtain high-quality fused spectra. The combinations of different pretreatment methods and spectral ranges were subsequently used for the optimization and calibration of partial least square models. The results reveal that the models of the fused spectra processed by the first derivative [NIRr–NIRt (1 der)] exhibit optimal prediction accuracy. The root mean square errors of prediction (RMSEPs) of the optimal NIRr–NIRt (1 der) PC, AC, and FC models were 0.280, 1.240, and 0.165, respectively, which were lower than those of the NIRr and NIRt models. The results show that the fusion of NIRr and NIRt data can achieve accurate detection of rice flour constituents, indicating the method has potential for further development and application.

Potential of Chickpea Flours with Different Microstructures as Multifunctional Ingredient in an Instant Soup Application.

Chickpea flours are an interesting multifunctional ingredient for different food products. This study investigated the potential of differently processed chickpea flours as alternative thickening agents in an instant soup recipe, replacing potato starch. Dry instant soup powders were compared on bulk density and powder flowability, whereas prepared liquid instant soups were studied in terms of rheological behaviour (as influenced by microstructure) and volatile composition. The chickpea-flour-containing soup powders possessed similar powder flowability to a reference powder but were easier to mix and will potentially result in reduced blockages during filling. For prepared liquid instant soups, similar viscosities were reached compared to the potato starch reference soup. Nevertheless, the chickpea-flour-containing soups showed higher shear thinning behaviour due to the presence of larger particles and the shear induced breakdown of particle clusters. Flavour compounds from the soup mix interacted with chickpea flour constituents, changing their headspace concentrations. Additionally, chickpea flours introduced new volatile compounds to the soups, such as ketones, aldehydes, alcohols, and sulphur compounds, which can possibly alter the aroma and flavour. It was concluded that chickpea flours showed excellent potential as alternative thickening ingredient in instant soups, improving the protein, mineral and vitamin content, and the powder flowability of the soups, although the flavour of the soups might be affected by the changes in volatile profiles between the soups.

Pasting properties and the baking functionality of whole‐grain wheat flour with different amylose and dietary fibers content

Twenty-five varieties of wheat were used in this study in order to determine the effect of amylose and amylopectin, as well as dietary fibers on the pasting properties and baking functionality of the whole-grain flour. The results were compared to the properties of refined wheat flour. The analyzed samples were divided into six groups based on the amylose content: (1) 11%–14%, (2) 15%–17%, (3) 18%–19%, (4) high amylose (36.5% and 41%), (5) waxy (0%), and 6) refined flour (22%). Amylose influenced viscosity by large, however, variations in pasting properties can as well be attributed to the differences in the non-starch structural components. Variations in solvent retention capacities (SRC) of flours depended primarily on the content of different fiber fractions and proteins. The starch and amylose content had a positive effect on SRC for lactic acid and sucrose, respectively. Furthermore, pasting and functionality are complex properties conditioned by different flour constituents. Novelty impact statement Whole-grain wheat flour, predominantly used in the bakery and confectionery industry, is an important food ingredient that provides a large portion of calories and protein to the everyday diet of many consumers worldwide. Wheat starches with different amylose contents, especially high amylose starches, have the potential to modify the texture and quality of end-use products by enhancing their nutritional functionality. The data on variations in pasting properties of whole-grain wheat flours, as well as their respective solvent retention capacities, can provide guidelines regarding the manufacturing of the most suitable food products from these flours.

Influence of composite flour constituents and extrusion temperature in the production of analog rice.

This study was conducted to determine the effect of composite flour (CF) constituents and different extrusion temperatures on the production of analog rice and community perceptions about the produced rice. CF was produced by mixing modified cassava flour (Mocaf) and snakehead fish flour (SF) in the following ratios: 100:0; 97:3; 94:6; 91:9; and 88:12. Analog rice was then extruded from CF at the following temperatures: 50, 70, and 90°C. The analog rice was tested for physical properties (bulk density and cooking time), chemical properties (nutrient content), and organoleptic properties. The results showed that CF and extrusion temperature affect the nutrient content of analog rice. The best analog rice formulation constituted of CF with Mocaf:SF ratio of 91:9 and extrusion temperature of 70°C, and contained 14.34% water, 0.85% ash, 71.83% carbohydrate, 11.24% protein, 1.12%, calcium 1,113 ppm, and 2.43% dietary fiber. This study included 42 respondents aged 20–23 years, including 20 males and 22 females. All the respondents showed acceptance for the analog rice, suggesting that it could substitute ordinary rice as a staple food.

Impact of water and flour components in dough investigated through low-field nuclear magnetic resonance

Bound and free water within dough strongly affect its rheological behavior and processability, as well as its gluten network. Depending on its total content and on the characteristics of flour constituents, water can be both bound to components and free in the dough. The equilibrium between bound and free water directly impacts the elasticity and extensibility of dough and therefore controls the texture of final products. In this study, Nuclear Magnetic Resonance (NMR) was used to assess the relaxation behavior with the focus on water. The proton spin-spin relaxation measurements were carried out at 20 MHz with a Bruker Minispec mq20 NMR spectrometer (Bruker, Rheinstetten, Germany). The transverse relaxation time in a spin locking field (T1?) was determined at 25°C following the Carr–Purcell–Meiboom–Gill (CPMG) sequence. The data were analyzed by the continuous distribution model. The dough was prepared with commercial semolina, which was mixed with water in a Brabender Mixer 350 (Brabender® GmbH, Duisburg, Germany) to reach three different levels of water content (30, 50, and 70%, based on semolina weight) and to study the water distribution as a function of the water total content. The dough characterization was carried out also comparing the T1? distribution of semolina dough with that of starch-water and gluten-water mixtures and also of pure starch and gluten to assess the role of each flour component. Additionally, the semolina dough sample was compared with a sample prepared with pastry flour, with a lower content of proteins, to investigate the different behavior as a function of the gluten amount. It was found that the dough presents three relaxation processes: one, very fast, is related to crystalline starch, while the other two are characteristic of two water populations, water in intragranular and in extragranular regions of starch, respectively. The comparison with pastry flour showed that the dough prepared with the latter one was less homogenous than the semolina one, with a clear distinction between free and bound water, while the semolina dough seemed to contain several water populations differently bounded, that were responsible for a broader peak at medium water content (around 50%).

A review on mechanistic aspects of individual versus combined uses of enzymes as clean label-friendly dough conditioners in breads.

Numerous dough improvers are used alone or in combination to enhance the quality of baked goods such as breads. While modern consumers demand consistent quality, the expectations for ingredients have changed over the past few years, and reformulations have taken place to provide "clean label" options. However, the effects and mechanisms of blended dough conditioners suitable for such baked products have not been systematically summarized. In this review, dough and bread properties as affected by different improver combinations are examined, with a focus on additive or synergistic interactions between enzymes or between enzymes and ascorbic acid. The combination of enzymes that hydrolyze starch and cell wall polysaccharides has been shown to reduce textural hardness in fresh and stored bakes goods such as breads. Enzymes that hydrolyze arabinoxylans, the main nonstarch polysaccharide in wheat, have synergistic effects with enzymes that result in cross-linking of wheat flour biopolymers. In some studies, the effects of bread improvers varied for wheat flours of different strength. Overall, bread products in which wheat is used in whole grain form or in a blend with other flours especially benefit from multiple improvers that target different flour constituents in doughs.

Optimization of nutrient retention in whole flours extruded from cowpea biofortified grain

Abstract Whole flour of cowpea grains of the cultivar BRS Tumucumaque biofortified in iron and zinc were processed in a co-rotating twin-screw extruder Clextral HT 25. A central rotational composite design 23, combining temperature (from 86.4 to 153.6 °C), screw rotation speed (from 163.6 to 836.4 rpm) and moisture content (from 16.6% to 23.4%), was used to assess the effects on flour constituents. The three variables significantly affected (p &lt; 0.05) the levels of protein and copper in the extrudates. The reactions of the extrusion process caused a decrease in the levels of proteins and an increase in the levels of copper, zinc and potassium, and these amounts were accentuated as the values of the process variables approached those of the central point region. Extreme conditions at high rotational screw speeds combined with low moisture content reduced the magnesium content, at the opposite end of the values for these two variables, the intensity of the reduction was lower. In the analysis of global desirability, it was found that the extrusion condition at 112.6 °C, 587.4 rpm and 23.4% moisture provided the highest nutrient retention. The levels of iron and zinc remained above 60 and 40 mg kg-1, respectively, in extruded products.

Effect of low pressures homogenization on the physico-chemical and functional properties of rice flour

Research was conducted to explore the use of low pressure homogenization for extending functionality of rice flours. The impact of low pressure homogenization (0, 30, 50 MPa and 0, 1, 2, 3 passes) on the particle size distribution of long (LRF) and medium (MRF) rice grain flour was evaluated. The pressure level and the number of passes resulted in a lower particle size in both rice flours. Higher pressures and 3 passes led to an increase in the particle size due to aggregation of smaller particles. The effect of low pressure homogenization (0, 30 or 50 MPa - 3 passes) on the physicochemical (composition, bulk density, thiol groups, hydration, emulsifying properties, hydrophobicity, crystallinity) thermal and pasting properties was analyzed. Homogenization increased swelling, oil absorption capacity and surface hydrophobicity of LRF and MRF samples even at 30 MPa. The bulk density and the emulsion stability of samples decreased by pressure. However, the emulsifying activity and thiol groups did not change in LRF, while increased in MRF particularly at 30 MPa. SEM micrographs revealed the microstructure changes, but no significant differences were observed in starch crystallinity. FTIR spectra suggested the modification of the flour constituents, particularly in MRF, reaching higher intensities. The disintegration and modification of the large molecules, increasing availability of binding sites, and partial gelatinization of starch granules, led to flours with different pasting performances. Correlation analysis confirmed that the particle size reduction played a determinant role in the structural and physicochemical changes of both rice flour varieties used.

Use of the 1H NMR technique to describe the kneading step of wholewheat dough: The effect of kneading time and total water content

The kneading step of wholewheat flour (WWF) dough was monitored using low-resolution 1H nuclear magnetic resonance (NMR). The tested variables were kneading time and total water content. Two 1H Free induction decay (FID) (A and B) and four 1H T2 Car-Purcell-Meiboom-Gill (CPMG) (C, D, E and F) proton populations were observed and the attribution to the different proton domains was made based on the literature and data acquisition. Kneading time significantly increased the mobility and the relative abundance of popA, the relative abundance and strength of protons of popC, D and E, while significantly reducing the relative amount of popF and increasing its mobility. This evolution of the proton populations during kneading was interpreted as chemical/physical transformations of the flour constituents. The use of WWF may reveal the changes in molecular dynamics underlying the higher water requirements of unrefined doughs, often associated with improved bread quality.

Assessing the impact of xylanase activity on the water distribution in wheat dough: A 1H NMR study

The molecular mobility of water and biopolymers in wheat dough and the influence of xylanases thereon was investigated with time domain proton nuclear magnetic resonance relaxometry. To reduce the complexity, model systems containing starch, gluten and/or water-unextractable arabinoxylan (WU-AX) were used. In the starch-WU-AX-water model, starch binds water fast but less strong compared to WU-AX, resulting in water withdrawal from starch during resting. In contrary, WU-AX did not affect the water distribution in a gluten-WU-AX-water system, despite the higher water retention capacity (WRC) of WU-AX compared to gluten. In a starch-gluten-WU-AX-water model and in wheat flour, water was distributed over the different constituents including WU-AX. Addition of xylanase reduced the WRC of WU-AX, resulting in a release of water. Therefore, the beneficial effect of xylanase on dough and bread quality can, in part, be attributed to the redistribution of water, initially bound by WU-AX, between the other flour constituents.

Shift of Volatile Organic Compounds (VOCs) in Gluten-Free Hemp-Enriched Sourdough Bread: A Metabolomic Approach.

Hemp seed flour represents a potential ingredient for protein enrichment of gluten-free bakery products, the nutritional value of which could be further increased by fermentation with sourdough or with beneficial lactic acid bacteria strains. In this study, a metabolomic approach was used to evaluate the effect of hemp seed flour addition and sourdough fermentation on the production of flavoring and health-related volatile organic compounds (VOCs) in a gluten-free bread. Multivariate analysis of VOCs provided an in-depth description of the effects of hemp seed flour addition and sourdough fermentation on flavoring and bioactive compounds. In particular, an increased concentration of antimicrobial compounds, a larger spectrum of bioactive VOCs and a typical flavoring profile was evidenced in comparison to standard products. Furthermore, an increase of fermentation metabolites was observed in comparison to a standard dough, relating to abundances of 2-butanone-3-hydroxy, acetic acid, ethanol, and 1,4-butanediol. This study provides new insights on the evolution of flavoring and bioactive hemp seed flour constituents during sourdough fermentation, evidencing their retention in baked goods, and describes a new approach that could guide the formulation of innovative, fermented food with enhanced nutritional value.

FT-IR spectroscopy with chemometrics for rapid detection of wheat flour adulteration with barley flour

The quality of wheat flour (WF) is among the highest of cereal flours and therefore, it is one of the most expensive flours for manufacturing food products. In developing countries, adulteration of WF by mixing up with lower price cereal flours is often seen. Hence, the classification and determination of the adulteration quantity in WF is of great interest. The aim of this research was to evaluate the feasibility of FT-IR spectroscopy and multivariate data analysis methods for the detection of adulteration of WF with the most likely adulterant barley flour (BF). For this purpose, 20 pure cereal flours and 120 flour blends were analyzed using FT-IR spectroscopy with chemometrics. The spectra were collected in the region of 4000–450 cm−1 and up to 15 wavenumber regions corresponding to peaks of flour constituents were selected. The classification limit value of soft independent modeling of class analogies for detection of BF added to WF was better than 1%. Additionally, 98.25% of the flours were correctly classified by linear discriminant analysis. Partial least squares regression was adopted to construct a model to quantify the adulteration level. The root mean square error of calibration for sample calibration associated forecast parameters was 0.34–1.34% and the root mean square error of cross validation was 0.36–1.50%. Thus, the BF adulterant could be detected down to approximately 0.30%.

Influence of Peanut Flour Addition on Rasi Process Production

Rasi is a cassava flour made from grains resembling rice granules. In general, rasi is processed by using cassava flour took tapioca and manual granulation after that dried. One of the disadvantages of rasi traditional process production is the form of granules that are not uniform and easily destroyed also has low protein and fat levels. Increasing the levels of fat and protein of rasi should be done the addition peanut flour. This study aimed to characterize the effect of adding peanut flour and improvement of granular formation method by using extrusion technology to physic chemical properties of the rasi product. There were three treatments of peanut flour addition, i.e 5, 10 and 15% that compared with control. The study was designed using a complete randomized design and the data obtained was analyzed using SPSS 2.1 software. Based on the result of the research, there was an increase of fat and protein content of rasi sample which added peanut flour. Peanut flour added constants have higher lightness and WI (Whiteness Index) values than controls. The amorphous phase of the constituents added with peanut flour was higher than the control, while the crystalline phase shows the opposite value. This was evident from the microstructural profile, where the constituents of peanut flour have starch granules that have started to break apart from the controls.

Comparison of inter-varietal differences in chemical composition and nutritional properties of coconut testa flour

Coconut testa is the brown colour thin outer covering of the coconut endosperm. An attempt was made to convert coconut testa into flour for bakery products. In this study, chemical composition and nutritional properties of coconut testa flour of four local cultivars, namely, San Raman, Gon Thambili, Ran Thambili and Tall × Tall were compared against those of a commercial hybrid grown in Sri Lanka. Partially defatted coconut parings of each cultivar were oven-dried and ground into coconut testa flour. Moisture, crude fat, ash and crude protein contents of coconut testa flour were determined according to AOAC methods. The carbohydrate content was calculated by the difference. Inter-varietal differences of fatty acids and micro-mineral distributions were also determined. The main constituent of coconut testa flour regardless of cultivar was carbohydrate (42.55–59.24 %) followed by protein (23.82–32.22 %) and fat (7.93–23.49 %). Commercial hybrid had the highest carbohydrate content (59.24 %) while the minimum carbohydrate content was recorded for San Raman variety (42.55 %). Highest protein content was observed in Gon Thambili (32.22 %) variety while the least was observed in commercial hybrid (23.82 %). The highest fat content was noted in San Raman variety (23.49 %). Tall × Tall variety contained the least fat content (7.93 %). Maximum ash content was observed in Ran Thambili variety (5.30 %) while the least ash content was for Gon Thambili variety (3.70 %). Highest moisture content was prevalent in San Raman variety (4.27 %) while the least was observed in commercial hybrid (2.27 %). These results suggested that coconut testa flour is a nutritious substance, which provides value addition to the under-utilised by-product of coconut processing industry.

Lipases in wheat flour bread making: Importance of an appropriate balance between wheat endogenous lipids and their enzymatically released hydrolysis products

Lipids are only minor wheat flour constituents but play major roles in bread making (BM). Here, the importance of a well-balanced lipid population in BM was studied by applying a lipase from Fusarium oxysporum in the process. Monogalactosyldiacylglycerols and N-acyl phosphatidylethanolamines were the most accessible lipase substrates. Hydrolysis thereof into their corresponding lysolipids was largely if not entirely responsible for loaf volume increases upon lipase application. Degradation of endogenously present lipids and enzymatically released lysolipids caused loaf volume to decrease, confirming that an appropriate balance between different types of lipids is crucial in BM. For optimal dough gas cell stability, the level of lipids promoting lamellar mesophases and, thus, liquid condensed monolayers needs to be maximal while maintaining an appropriate balance between lipids promoting hexagonal I phases, non-polar lipids and lipids promoting hexagonal II or cubic phases.

Capability of solvent retention capacity to quality of flat bread in three wheat cultivars.

Variations in levels and properties of flour constituents have an impact on the quality of its end products and a given application. While the solvent retention capacity test has been used to assess flour quality of pan breads and cookies, to date, this test for determination the suitability of flour for flat breads, where extensibility is the most desirable, has not been evaluated. In this study, three bread wheat cultivars were investigated for their major polymeric constituents, the number of disulfide bonds and SRC test values. The attained results revealed that in the gluten network, WRC and SuRC were affected by the gliadin, whereas SCRC and LaRC by gluten as a whole and glutenin content. These observed relationships are respectively owed to the solubility of gliadin in alcoholic solutions, and the solubility of glutenin in either acid or basic solutions. Also, consumers acceptability of flat-bread was observed at higher ratio of arabinose/xylose, which related to structural characteristics of arabinoxylan.

Phytochemical Constituents of Flour and Composite Bread from African Palmyra (Borassus aethiopum) Fruit from Ghana

Phytochemical Constituents of Flour and Composite Bread from African Palmyra (Borassus aethiopum) Fruit from Ghana