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Flat breads qualities and attributes — ovens design, energy consumption, and environmental conservation: A review
Abstract
Flat bread is considered a staple food worldwide and especially balady bread in Egypt and the Middle East region. The most common flat bread types produced all over the world, contents, used leavening agents, properties, and countries were reviewed. Also, balady bread ingredients, formula, preparation, dough rheology, baking conditions, as well as physical characteristics, color attributes, sensory evaluation, and freshness or staling retardation of loaves were presented. Flat bread (balady bread) is processed from attened dough of wheat our, sodium chloride, water, and yeast and is often served freshly baked and produced in both bakeries and homes. The main features of a balady bread oven, such as composition, construction, dimensions, fuels, emissions, and its effect on the environment and energy consumption, were also mentioned. The common specifications and general design of a balady bread industry oven in Egypt on a commercial scale were presented as follows: Oven length could be more or less than 600 cm depending on available space in the baking building. Also, oven width could be more or less than 90 cm, depending on the needed productivity of bread per hour. To “keep the environment, minimize heat losses, maximize quantity and quality of production, and assure economic visibility,” the determination of oven dimensions, selecting construction materials and transmission systems must be done by oven designers using the oven general model.
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The supply and control of heat within an oven with minimal loss is an integral process in optimizing the bread-baking process. Research over the years reports on measures to control heat, however, there is limited data on optimizing burner designs for efficient heat supply. Challenged with enhancing the functionality of a bread baking oven made locally, three different burner concepts (i.e., U, H and Rectangular shaped) were designed, fabricated and evaluated in a locally manufactured bread baking oven. The study investigated the three burner configurations to enhance the locally manufactured ovens' environmental sustainability, cost-effectiveness, and efficiency. The study also assessed each burner design concept's performance in relation to heat distribution, fuel consumption, and emissions through thorough experimentation and analysis. Thermocouples were used to determine the temperature differences within the oven and outside the oven walls to verify heat losses. The results showed that the concept burner design can be used to bake bread with good quality parameters like colour, texture and taste within efficient baking time. Computational Fluid Dynamic (CFD) analysis performed on the proposed burner design concepts in relation to heat flow show that continuous flow of heat was assured during baking. Also, simulation performed on the baking trays show an acceptable stress and strain levels as well as favorable factor of safety, indicating that the designs proposed is suitable for the purpose. Data analysis performed on the heat generated within the oven chamber considering the lower and upper trays for all the burners evaluated can be ranked in terms of percentage as RB > HB > UB (41.39% > 30.72% > 27.89%). Based on the study conducted, the authors can suggest the best design concept for heat generation in locally manufactured ovens should be rectangular-shaped.
Despite three decades of policies discouraging biomass-based cooking in Africa, demand for fuelwood continues to rise. Several studies focus on household energy use, but few consider the role of commercial premises such as bakeries in deforestation, despite growing demand for bread. This study examines bread production by commercial bakeries in forest communities in Nigeria, investigating (a) the energy sources used, (b) the changes to forests and (c) the factors that could enable bakeries to transition towards clean energy. Mixed methods were used including questionnaire surveys, land use change mapping and assessments of forest plots. Questionnaires with 21 bakeries in two northern Nigerian states (Kaduna, Nasarawa) and Abuja Federal Capital Territory suggest that they depend heavily on fuelwood, collected directly from the forest, or purchased from (largely female) suppliers, retailers or wholesalers. Bakeries most commonly use Anogeissus leiocarpa mainly due to its burning quality and availability. Remote sensing data show declines in forest cover from 71% (56,157 km²) in 2000 to 49% (38,756 km²) in 2020. While all bakeries were willing to transition to more sustainable energy sources, training on alternative fuels and more energy efficient ovens is required. Policies supporting energy transition must consider all value chain actors, not just fuelwood consumers, recognising that women play a key role in fuelwood sales at the community level. Transition efforts need to be underpinned by detailed analyses of trade-offs so that measures to reduce undesirable livelihood impacts can be established, and should consider more efficient ovens as well as stoves.
This research aimed to enhance the nutritional and sensory qualities of Balady bread by adding locally Egyptian buckwheat flours, Fagopyrum esculentum (FE) and Fagopyrum tataricum (FT),
to Hard Wheat Flour (HWF) 82% extraction at three levels (10%, 20%, and 30%). The chemical composition, rheological properties, color, sensory evaluation and stalling of the balady bread were determined. The chemical composition of raw materials revealed that FE was significantly (P ≤ 0.05) higher in protein and fat contents compared to HWF and FT. While FT was higher in fiber and ash contents. The findings show that a 30% replacement with FE or FT significantly enhances the bread’s nutritional profile, notably increasing protein, fiber, ash, and moisture content. Rheological analysis revealed that FE and FT alter dough handling, with a notable improvement in dough stability
and mixing tolerance at 30% FT. Sensory evaluation indicated acceptable qualities even at higher substitution levels, although 30% FE showed slight declines in certain attributes. Furthermore, bread supplemented with 30% FT demonstrated slower staling and potentially extended shelf life. These results highlight the potential of FE and FT as nutritional enhancers in bread formulations, with
30% FT emerging as the optimal replacement level for balancing nutritional benefits and sensory acceptance.
Small-scale baking ovens are built by the local workers and usually no scientific principles are followed to design and build of it. Modern scientific principles and procedures are followed to design and fabricate the baking ovens using low-cost materials. The major drawbacks of this type of traditional oven are: improper control of baking temperature; contamination of products with ashes during heating and excess cost for heating. This study aimed at modeling heat and mass transfer during baking, and evaluating the quality characteristics of bread and cake. The problems were identified by conducting a one-time cross-sectional survey, and the heat and mass transfer were modeled by designing and fabricating an improved oven. This model predicted the bread temperature and moisture content at 160, 170, 180, 190 and 200°C oven temperatures. The result indicated that increasing the oven temperature from 160 to 200°C increased the bread crust temperature from 101.6 to 158.7°C. However, the temperature and weight of bread increased gradually with increasing baking time up to 18-20 min and then started declining until it reached equilibrium after 30 min. The weight loss of bread increased with increasing bread temperature. The model predicted fairly accurate bread temperature and weight loss. It predicted 20 to 132°C against the observed 22 to 115°C during baking at 200°C oven temperature, 0 to 40% weight loss against 0 to 49% observed weight loss. The developed improved oven required 25% less time for baking bread and cake compared to the traditional one. Loaves of bread baked in the improved oven had 27.4% lower moisture content, 660 cm 3 higher volume, and 408 g lower crumb firmness value compared to the conventional baking process. The improved baking oven is, therefore, more efficient than traditional baking ovens in terms of heat and mass transfer, baking time and product quality.
The current study investigates the feasibility of preparing Arabic bread from wheat flour,
sweet potato flour, or peeled sweet potatoes based on the nutritional values, technological characteristics,
and sensory properties of the final products. First, we analyzed the proximate, elemental,
total and individual phytochemical compositions of the raw materials and bread samples. The
analysis showed that potassium, calcium, and phosphorus were higher in peels than pulp, in the
same manner to the total phenolics, flavonoids, and anti-radical scavenging activities. Phenolic acids
and flavonols were quantified, where p-coumaric, feruloyl-D-glucose, eucomic, gallic, and ferulic
acids were measured as major phenolic acids in either peels or pulp flours, and their quantities were
higher in the peels. Furthermore, we evaluated the effects of wheat substitution on the properties of
the dough blends and their final bakery. The results indicated that the fortified samples’ nutritional
and rheological properties were significantly improved, while their sensory qualities were comparable
to those of the control. Thereby, the fortified dough blends presented higher dough stabilities,
indicating a wider range of applications. Additionally, after the heat treatment, the fortified breads
maintained significantly higher total phenolic, flavonoid, anthocyanin, and carotenoid contents, and
total antioxidant activities, implying their accessibility for humans upon consumption.
An in-depth survey was conducted by collecting information from web sources, supplemented by interviews with experts and/or bakers, to identify all the flat breads (FBs) produced in the nine Mediterranean countries involved in the FlatBreadMine Project (Croatia, Egypt, France, Greece, Italy, Jordan, Lebanon, Malta and Spain), and to have an insight into their technical and cultural features. A database with information on 143 FB types (51 single-layered, 15 double-layered, 66 garnished, 11 fried) was established. Flours were from soft wheat (67.4%), durum wheat (13.7%), corn (8.6%), rye, sorghum, chickpea, and chestnut (together 5.2%). The raising agents were compressed yeast (55.8%), sourdough (16.7%), baking powder (9.0%), but 18.6% of FBs were unleavened. Sixteen old-style baking systems were recorded, classified into baking plates and vertical ovens (tannur and tabun). Artisanal FBs accounted for 82%, while the industrial ones for 7%. Quality schemes (national, European or global) applied to 91 FBs. Fifteen FBs were rare, prepared only for family consumption: changes in lifestyle and increasing urbanization may cause their disappearance. Actions are needed to prevent the reduction of biodiversity related to FBs. Information in the database will be useful for the selection of FBs suitable to promotional activities and technical or nutritional improvement.
The aim of the study was to evaluate the physical and microstructural characteristics of crackers baked in four different industrial baking ovens (indirect radiation‐cyclotherm, indirect convection, hybrid and industrial tunnel‐ITO). Indirect convection and cyclotherm ovens provide the highest (5685.43 ± 51 W m⁻²) and the lowest (4860 ± 38.87 W m⁻²) amount of heat flux, respectively. Despite the amount of heat flux, indirect convection led to crackers with the highest moisture (7.86% vs. 4.82% in clyclotherm) and specific volume, but the lowest hardness. Cyclotherm resulted in crackers with lower specific volume, surface area, porosity, smooth and regular surface. Conversely, the hybrid and ITO ovens showed closer heat flux, leading to crackers with similar moisture content, texture parameters, specific volume, browning and inner porosity. Overall results show the potential of baking using different ovens for modifying the quality parameters of the crackers.
Developing an efficient rotary oven that is capable of addressing the issue of long baking duration and uneven heating distribution during baking could aid in encouraging indigenous use of the oven by small and medium scale bakeries in developing countries. This study aimed to develop and evaluate the performance of a rotary oven. Taguchi experimental design was used to investigate the influence of oven temperature (160, 180, 200°C) and oven rack speed (0, 10, 20 rpm) on the physical properties (baking time, mass, surface area, specific volume and density) of bread produced from the rotary oven. The baking capacity and efficiency of the rotary oven were 16 kg h-1 and 94%, respectively. Investigation showed that baking time ranges from 20 to 82 min, bread mass (884 to 925.7 g), surface area (1050 to 1370 cm2 ), specific volume (2.36 to 3.70 cm3 g -1 ) and density (0.25 to 0.39 g cm-3 ), respectively. The optimum baking time (20 min) was achieved at 200°C oven temperature and 10 rpm oven rack speed. The oven could be adopted for both domestic and industrial production of bread and other bakery products. Keywords: Bread, oven temperature, oven rack speed, taguchi, rotary oven.
In this work, we propose a mathematical model describing thermal behavior and heating process optimization of solid fuel bread ovens. Numerical simulation leads to temperature profiles of the oven. The design and implementation of an operating prototype permits us to obtain, with type K thermocouples, experimental temperature profiles in some points of the oven. There is a good agreement between the experimental results and those obtained from the numerical simulation of the proposed model. A permanent temperature value of 220 °C is reached in the baking chamber. It is obtained that the energy efficiency of the oven is 49%. Making use of the objective gain function, it is found that the optimal parameters of the oven are the following: 50 W as optimum operating value of the electric power of the blower, 3 m² as the optimum operating value of the total surface of the baking chamber; and 0.67 as the optimum operating value of the filling factor between the heating chamber and the baking chamber. The developed model serves to better understand the operation, the optimization and to rationally manage energy expenditure related to solid fuel bread ovens in developing countries.
Electric resistance baking (ER baking) was featured as an object of a large number of studies devoted to dough and bread. This paper provides a brief overview of the known and most prominent studies of this process. Almost all studies consider this method of baking only as a convenient scientific tool. However, there are almost no papers in which the electric resistance baking method would be used in the production of a particular type of bread. In this paper we examine the theory of the use of the ER baking for the production of toast bread. The best indicators belong to the samples, which were baked in the following conditions: use of the formula and technology of American toast bread; use of a specific way of bread dough shaping, characteristic of toast bread; division of the dough pieces by weight based on 225 g of dough per liter of mould volume; use of an electric resistance design of the oven, equipped with a clamp cap; greasing of the lower edges of the clamp cap; baking dough at 220 V, 50 Hz until the dough reaches a temperature of 98 … 100 ° C.
Losses of volatile compounds during baking are expected due to their evaporation at the high temperatures of the oven, which can lead to a decrease in the aroma intensity of the final product, which is crucial for gluten-free breads that are known for their weak aroma. Volatiles from fermentation and lipids oxidation are transferred from crumb to crust, and they flow out to the air together with Maillard and caramelisation compounds from the crust. In this study, the release to the oven of volatile compounds from five gluten-free breads (quinoa, teff and rice flours, and corn and wheat starches) and wheat bread during baking and toasting was measured in real-time using proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS). Baking showed different volatile release patterns that are described by bell-shaped curves, plateaus and exponential growths. Flour-based breads had the higher overall volatile release during baking, but also high ratios in the final bread, while starch-based breads showed high pyrazine releases due to moisture losses. Meanwhile, toasting promoted the release of volatile compounds from the bread matrix, but also the additional generation of volatiles from Maillard reaction and caramelisation. Interestingly, gluten-free breads presented higher losses of volatiles during baking than wheat bread, which could partially explain their weaker aroma.
Gluten-free (GF) batters usually present several technological challenges that limit the performance during conventional baking and the resulting product quality. Due to the volumetric heating principle and faster heating rates, ohmic heating (OH) may be advantageous compared with conventional baking. Therefore, the potential of using ohmic heating as a novel approach for gluten-free bread baking was explored. In detail, the effect of different OH process parameters (power input, holding time) on the chemical and functional properties (specific volume, crumb firmness and relative elasticity, pore properties, color, starch gelatinization) and digestibility of breads was investigated. Results showed that GF breads could benefit from the uniform rapid heating during processing, as these breads showed superior functional properties (specific volume, 2.86–3.44 cm3/g; relative elasticity, 45.05–56.83%; porosity, 35.17–40.92%) compared with conventional oven-baked GF bread (specific volume, 2.60 cm3/g; relative elasticity, 44.23%; porosity, 37.63%). In order to maximize bread expansion and the OH performance, it was found that the OH process could be improved by applying the electrical energy in three descending power steps: first step with high power input (in this study, 2–6 kW for 15 s), followed by 1 kW for 10 s, and 0.3 kW for 1–30 min. In total, ohmic baking only needed a few minutes to obtain a fully expanded GF bread. The determination of pasting properties and starch digestibility demonstrated that these breads were comparable or even superior to GF breads baked in a conventional baking oven.
There is increasing demand for energy in South Africa. With all the developments in townships, more people are getting water, sanitation and electricity services. This is good for the country because the quality of life is being improved daily even in the poorest of communities. However, the high demand needs to be met with high production capacity. This strains the South African power utility, Eskom. This high and increasing demand has led to very high electricity bills, power shortages, more frequent load shading, and power cuts. This negatively affects businesses. Bakeries are some of the most affected businesses. The whole production line depends on electricity. Baking requires air temperatures of 200oC - 250oC. Such temperatures can be achieved using renewable energy sources such as solar, which is abundant in South Africa. Solar irradiance in Johannesburg can be as high as 1 kW per square meter. The aim of this work was, therefore, to research, develop and design a solar powered oven for baking bread. Baking bread requires air at 200⁰C and oven inlet speed of 1.8m/s. Using these basic requirements, the collector size was determined and the fan parameters. The performance of the oven is evaluated by numerical modelling and shows good performance for the required airflow rates. The evacuated tube solar collectors were integrated with a domestic oven of dimensions 400×26×280mm. The system was found to require 2.182kW and with the average Johannesburg solar intensity(0.76), the required number of evacuated tubes was found to be 28. A fan is also placed at the system inlet to give good baking airflow rates, air circulation and to balance for frictional losses in the system.
Textural deterioration of pita bread, PB, due to staling is an important quality parameter during storage. Loss of freshness due to PB staling results in significant quality and economic loss. PB staling was studied using both MR-FTIR spectroscopy and textural profile including time to rupture and tensile and compressive forces. The study was conducted at room temperature (23°C) and freezing temperature (−18°C) over 96 h of storage time after baking. Some physical properties of PB such as loaf weight, dimensions, water activity, and density were measured. MR-FTIR measurement spectra in the wavelength 900–1150 cm ⁻¹ corresponding to the “saccharides” regions and the range 3000–3600 cm ⁻¹ corresponding to O-H bond stretching vibration were able to clearly detect the PB deterioration at different storage times as shown by statistical significance test. Mechanical measurements of tearing force, time to rupture, and 25% compression force were also found to be good indicators of PB quality deterioration. Time to rupture, however, was found to be the best PB deterioration indicator. In addition, PB stored at room temperature showed a significant deterioration (toughening) compared to that stored at freezing temperature which showed little or nonsignificant deterioration during storage. High negative correlation, r = - 0.97, was observed between the 25% compression force and the wavenumber 960 cm ⁻¹ at room temperature.
Volumetric ceramic (porous) burner technology is based on combustion of premixed, gaseous air/fuel mixture inside the cavities of inert, porous materials. This alternative combustion technology offers a number of advantages in comparison to free flame combustion, i.e. homogenous surface temperature distribution, low NOx- and CO-emissions, stable operation over a wide range of power loads and air ratios, compact design and high thermal radiation output.
Although this technology has proven its advantages in many different areas, its application within the food industry is still not well established. Successful baking process dependents strongly on the temperature level at the surface of the target object and within the oven. Thus, in order to integrate this combustion technology into a baking oven, it is crucial to evaluate the radiation heat exchange between the burner and the target object.
Literature indicates that the baking process can profit from near infrared radiation (NIR), due to its high penetration depth. Previous investigation of the spectra of the volumetric ceramic (porous) burner in the spectral range of 1100 – 2100 nm showed that the global maximum of the emission spectra is always positioned in the range of 1550 – 1560 nm (Jovicic et al., 2014).
Contribution of thermal radiation to the total exchanged thermal energy between a target object and a volumetric ceramic (porous) burner was determined within a model backing oven. Temperature distribution within the stone HIPOR, which behaves as a food product, was conducted for a range of burner thermal loads and two burner-to-object distances. The surface temperature on- and the temperature distribution within the target object, and the amount of absorbed radiation were determined. Measurements showed that the amount of absorbed radiation can reach ca. 60% of the total exchanged thermal energy.
Keywords: volumetric ceramic (porous) burner; infrared baking; radiation ratio; baking systems
Effect of superheated steam baking on quality attributes of bread was studied. Superheated steam and conventional ovens were used for baking bread at 180, 200 and 220° C for 20, 25 and 30 minutes. The moisture content, color (L*, a* and b*) and texture properties of bread were evaluated using two different heating model with various temperature and time. Moisture content of bread baked in superheated steam was almost similar to the one baked in conventional oven. Increased baking temperature at constant baking time retained higher moisture content in bread whereas increasing baking time caused reduction in moisture content of bread crumb in both heating baking models. Baking temperature and time significantly affected the color values of bread. Superheated steam baking resulted in lighter color as determined by L*, a* and b* values as compared to conventional baking. Bread hardness values increased by increasing baking temperature and time in most bread baked using superheated steam oven. Bread hardness values are similar for superheated steam baked bread at 200°C for 20 minutes and conventional baked bread at 200°C for 25 minutes (14.27 N and 14.26 N respectively) as well as superheated steam baked bread at 200°C for 25 minutes and conventional baked bread at 200°C for 30 minutes (14.32 N). Springiness of bread for most heat treatments was almost the same for both superheated steam and conventional ovens
Fagopyrum esculentum contained alkaloids, amino acids, anthraquinones, carbohydrates, flavonoids, phlobatannins and tannins. The nutritional analysis of Fagopyrum esculentum flour and bran revealed that they contained starch: 55, 75 and 18%; proteins: 12, 6 and 36%; lipids: 4, 1 and 11%; soluble carbohydrates: 2, 1 and 6%; total dietary fibers: 7, 3 and 15%; and ash: 2, 1 and 7% respectively. The pharmacological studies showed that Fagopyrum esculentum possessed antioxidant, antiinflammatory, cardiovascular, hypolipidemic, antigenotoxic, antidiabetic, reno-protective, anticancer, antimicrobial, wound healing, antistress, protected memory impairment and photoprotective effects. This review will highligh the chemical constituents and pharmacological effects of Fagopyrum esculentum.
Configuring ovens for baking bread is a complex scientific and industrial problems. Find the best modes of operation allows computer simulation of aerodynamic and thermal processes in the heating ducts and the baking chamber. Shows an example of a motion study of heating gases in areas of attention, shows the typical problems and methods their solutions.
Four gluten-free (GF) breads produced using commercial GF mixes with different formulations were characterized during 1 week of storage and compared to wheat-flour-based bread (STD), in terms of texture (texture profile analysis), amylopectin retrogradation (differential scanning calorimetry) and water status (moisture content, frozen water content by differential scanning calorimetry and 1H nuclear magnetic resonance—NMR mobility by a low-field spectrometer). GF fresh breads were significantly harder, less cohesive and less springy than STD. Water status indicated higher water availability in GF breads, depending on formulation, with higher moisture and frozen water content that was also reflected in a higher molecular mobility (1H spin–spin NMR relaxation time). Furthermore, limited changes in moisture and frozen water contents were observed in GF bread, and therefore, textural changes in these GF products were mostly related to retrograded amylopectin. Statistical analysis with PCA (principal component analysis) allowed to identify the most important factors in the GF bread staling process. The effect of formulation (GFs vs STD) was related to water status descriptors and the effect of storage to textural properties, retrograded amylopectin parameters, as well as the mobility of the more rigid protons.
The aim of this study was to evaluate the effect of two different concentrations of banana peels BP (5% and 10%) as a partial replacement for wheat flour on physicochemical and sensory properties of Egyptian balady flat bread. The peel powder (0.50 mm size) from banana was prepared from their dried peel. The bread was prepared by replacing 5% and 10% of wheat flour with a banana peel. The bread prepared was designated as B1 and B2 respectively. They were tested for moisture, ash, protein, fat, crude fiber as per the standard methods. The physicochemical and sensory parameters of these two test bread were compared with a control bread 100% wheat flour designated as B0. Results showed that BP flour was owing 11.20% crude fiber which is higher than the wheat flour 1.21%. Also, BP flour has high potassium, calcium, sodium, iron and manganese compared with wheat flour. The protein and fiber content of B2 and B1 bread were higher (12.52% and 11.79% protein and 2.18% and 1.97% fiber) as compared to the control bread (10.79 protein and 1.42% fiber). B1 and B2 had the highest K, Na, Ca, Fe, Mg and Zn content compared with control bread. The water holding capacity (WHC) and oil holding capacity (OHC) of bread with BP flour were higher as compared to the bread control. The bread prepared by replacing 5% and 10% of BP (B2) is found to be sensorially acceptable. Our results showed that the nutritionally and sensory accepted bread can be prepared by replacing at most 10% of flour.
The main aim of the present work is to study and evaluate baking process energy requirements which considered the most consumable energy of bread baking stages. This was achieved by determining the moisture content, baking time, productivity and three types of energy (electrical, human and thermal) at four different belt speeds for two different types of baladi-breads, namely Magr and Mawi. Those four speedswere1.18, 1.97, 2.40 and3.55 ms-1. The results show that initial moisture content of dough was 42.12% for Magr but 62.02% for Mawi, while after baking it were 24.32, 24.61, 26.09 and 29.25% for Magr and 34.25, 39.50, 40.98 and 41.66% for Mawi at each speed, respectively. The results also indicated that the average baking time were 1.65, 1.10, 0.86 and 0.81minkg-1 andproductivity were 36.54, 54.63, 70.11and73.80 kghr-1 for Magr Baladi bread while the average baking time were 1.87, 1.13, 0.89and 0.84minkg-1 andproductivity were 32.62, 53.10, 67.48and 71.33 kghr-1 for Mawi baladi-bread at each speed, respectively. The specific energy requirements consumed were3.57, 2.92, 2.54 and 1.93 kWhkg-1 for Magr, while it were 4.35, 3.54, 3.11 and 2.53 kWhkg-1 for Mawi bread at speeds 1.18,1.97, 2.40 and 3.55 ms-1 , respectively. The results also indicated that the total costs of baking stage per 1kg of bread baking stage were 1.14, 0.86, 0.71 and 0.59 LE kg-1 for Magr while it were 1.34, 0.98, 0.82and 0.71LE kg-1 for Mawi bread, respectively at the same speeds.
Flat breads are popular all over the world. There are several forms of flat bread, which differ in their methods of preparation. In comparison to pan breads, the leavened flat breads have shorter fermentation period. Nowadays, the use of additives has become a common practice in the baking industry. In this paper, supplementation of several hydrocolloids having different chemical structure and diverse origin to the flatbread making process is presented. Hydrocolloids comprise a number of water-soluble polysaccharides providing a range of functional properties that make them suitable to this application. They provide proper texture, control moisture, improve overall product quality and stability, reduce cost, and facilitate processing in the flat breads. Various gluten-free formulations have applied hydrocolloids to mimic the viscoelastic properties of gluten. Hydrocolloids have been used for retarding the staling and for improving the quality of the fresh products. In addition to this, good sensory properties for visual appearance, aroma, flavor, crunchiness, and overall acceptability were obtained.
This research, concerns the design and construction
of a charcoal baking oven using locally available materials as
a case study for entrepreneurial development in Nigeria. The
baking oven in this work has a rectangular box like shape with
a total baking area of 315000mm2
. The oven is used for
baking, drying and warming of food e.g cakes, bread, fish,
meat etc. It is constructed with mild steel and angle bars. It
comprises baking tray, housing frame, charcoal heating tray
and baking chamber door. The oven is capable of generating
1488KJ of heat energy. The maximum temperature attainable
with the oven is about 500 degree Celsius. The cost of
producing one unit of this charcoal baking oven is about fifty
five thousand naira only.
The main objective of this research was to develop a mathematical model of heat and mass balance of the bread baking process to predict the temperature and water content of bread at different heating temperatures and times. The model was able to predict the bread temperature and water content at different oven temperatures (180, 190, 200, 210 and 220°C). The results showed that the bread temperature and weight loss of bread increase with increasing oven temperature, when, the oven temperature increased from 180 to 220°C, the temperature of bread increased from 112.73 to 168.49°C and the weight loss of bread increased from 22.40 to 52.46%. The results also showed that the bread temperature and weight loss of bread increase with increasing time, this increment starts to decline after 18-20 min, until it reach equilibrium after 30 min. The weight loss of bread increases with increasing bread temperature. It indicates that when the bread temperature increased from 20.00 to 131.69°C, the weight loss of bread increased from 0.00 to 40.79% at 200°C oven temperature. The model was validated with an experimental data and showed a reasonable agreement with those measured, where; it ranged 20.00 to 131.69°C theoretically while it was from 25.00 to 119.00°C experimentally during the baking at 200°C oven temperature. The weight loss data was in a reasonable agreement with those measured, where; it ranged 0.00 to 40.79% theoretically while it was from 0.00 to 48.69% experimentally during the baking at 200°C oven temperature.
Humidified baking was investigated in the light of producing breads envisaged to have better quality and freshness. Open bread loaves were prepared using the straight dough method where baking was performed with or without humidity at three levels of temperatures of 185, 195 and 205°C, and baking times of 25, 30 and 35 min. Baked breads were evaluated by measuring its crust color and thickness, and bread crumb moisture content and firmness. Humidified baking has no significant effect in enlightening bread crust color (P > 0.05) but significantly reduced the crust thickness (P < 0.001) and increased the initial moisture content (IMC) of bread crumb. The higher IMC of bread crumb led to a higher final moisture content (FMC) of bread during storage and these helped to reduce the firming rate of bread during a 96 h storage especially for the lower baking temperatures and times. Significant differences (P < 0.001) were observed on crust color and thickness, and bread crumb moisture content and firmness as effect of baking temperature and time.
The quality of flat breads depends in part on the textural properties of breads during storage. These properties are largely affected by flour protein quality and quantity. The present study aimed to examine differences between sensory properties, textural and staling of Tandoori breads made from flours of different quality and different quantities of protein. This was implemented by using three flours with 9.4, 11.5 and 13.5% protein contents and different protein qualities shown by Zeleney sedimentation volume 16.25, 22.75 and 23.25 mL respectively. Bread strips were submitted to uniaxial compression between two parallel plates on an Instron Universal Testing machine, and firmness of the breads was determined. Results indicated the differences in the sensory attributes of breads produced by flours of different protein content and quality, demonstrating that high protein high quality flours are not able to sheet and expand under the high temperature - short time conditions employed in Taftoon bread production and are therefore not suitable for this kind of bread. Results showed that flour with 11.5% protein content, produced bread with better sensory characteristics and acceptable storage time.
The effect of crust temperature and water content on acrylamide formation was studied during the baking of white bread. To assess the effect of over-baking, we used a full factorial experimental design in which the baking time was increased by 5 and 10 min at each baking temperature. Additional experiments were performed with steam baking and falling temperature baking. Immediately after baking, the crust was divided into the outer and inner crust fractions, and the water content and acrylamide concentration of each fraction was measured. The outer crust had a significantly lower water content and higher acrylamide concentration than the inner crust did. Crust temperature in combination with water content had a significant effect on acrylamide formation, higher temperatures resulting in higher acrylamide concentrations. However, at very high temperatures and lower water contents, acrylamide concentration was observed to decrease, though the bread colour was then unacceptable for consumption. Steam and falling temperature baking, on the other hand, decreased the acrylamide content while producing bread crust with an acceptable colour. The lowest acrylamide values and an acceptable crust colour were produced by steam baking.
Crumb color quality characteristics of bread of different compositions (whole grain, rye, barley and diet bread) at 24 hours intervals during three days after bread preparation were investigated by means of a MOM-color 100 tristimulus photo colorimeter, in CIE, CIELab, ANLAB and Hunter systems. The highest value of average reflectance y (%) was found for barley bread (immediately after preparation), so that can be said that this sample was "conditionally" the lightest. The lowest values of y (%) were found for diet bread, so that it can be considered as the "conditionally" the darkest product. Colors of all investigated bread samples were lighter after three days of keeping compared to day 0. Changes of average reflectance of bread samples packed in polyethylene packaging with keeping time can be described by linear equation (correlation coefficient 0.99). The dominant wavelength of barley and diet bread confirm the presence of yellow pigment. Color qualities of the mentioned kinds of bread depend on processes during bread staling and raw material composition of bread (flour). Color quality measurements can be used as easy auxiliary method for screening in the development of slower staling bread.
Bread dough baking was investigated using ohmic heating technology. An experimental system was set up for the measurement of the electrical conductivity of bread dough during heating. The influence of temperature, salt content and degree of fermentation (porosity) on the electrical conductivity of dough was investigated. It was observed that it increased linearly with temperature, until starch gelatinisation during which the dough conductivity remained constant or slightly decreased. The conductivity increased linearly again after starch gelatinisation, but at a lower rate. The electrical conductivity of dough had a linear positive dependence on salt content, but decreased with increasing dough porosity. Numerical simulations of temperature increase were carried out and compared with experimental data. For a good correlation between numerical and experimental data, a corrective coefficient was numerically estimated and validated, taking into account mainly the conversion of electrical energy to heat, and geometric uncertainties. Numerical results showed that the linear evolution of temperature with heating time was mainly caused by heat losses.
Samples from different radial positions of flat Arabic bread were analysed by differential scanning calorimetry (DSC) immediately after baking and after up to 3 days storage. This showed that whilst almost complete gelatinisation initially occurs, higher levels of subsequent retrogradation (typically 1.5 to 3 times) occurred in an area intermediate between the centre and outside of the pita bread (viewed from above). This coincided with the region with the highest moisture content (30% w.b.) immediately after processing, and which is likely to have heated at the slowest rate. A parallel study using DSC which subjected dough samples to a temperature profile similar to that found in baking also found that relatively low heating rates of 20 °C min-1 produced slightly higher amounts of retrogradation (typically 5-25%) than higher heating rates of 200 °C min-1. In each case moisture contents during storage were comparable between samples, thus suggesting that the local heating rate experienced during baking is a key parameter that can explain differences in subsequent retrogradation in different regions of the pita bread.
Understanding "what" consumers want and "why" are two of the most significant hurdles faced by any business creating products for consumers. Properly conducted sensory research experiments can provide answers to these questions and more. Sensory evaluation provides strategic information at various stages in the product lifecycle including the front end of innovation, new product development, product optimization, marketplace audits, and quality control among others. Sensory research can help identify issues that contribute to a product's success (or failure). This fourth edition draws on the author's practical experience in partnering with business associates in marketing and development teams to bring creativity and innovation to consumer driven product development in today's global business environment. The field of sensory science continues to grow and is now recognized as a strategic source of information for many Fortune 500 companies. Many scientists working in this field depend on the core textbooks such as this one to enhance their working knowledge base with practical business applications. * Appeals to sensory professionals in both in academia and business * Methods to integrate sensory descriptive information and consumer assessment * Coordinate marketing messages and imagery with the product's sensory experience.
Three gluten enriched breads were produced (5% and 15% gluten samples where water was adjusted with farinograph determination, and a 15% sample with the same water amount of the control). The effect of gluten on bread staling (7 days) was evaluated, focussing on texture, amylopectin retrogradation, water status and H-1 molecular mobility. The addition of gluten at higher levels (15%) resulted in breads, that retained higher softness, springiness and cohesiveness upon storage. Crumb moisture content was not affected by gluten but at a macromolecular level (DSC) 15% samples showed higher frozen water content. NMR measurements showed a significant effect of gluten on proton T-2 relaxation time distributions, revealing a larger presence of protons strongly interacting with water and a more pronounced proton exchange with increasing storage time. The results suggested that, in the presence of gluten, a larger amount of water might be available to plasticize the crumb structure, resulting in a softer product.
In response to increasing energy costs and legislative requirements energy efficient high-speed air impingement jet baking systems are now being developed. In this paper, a multi-objective optimisation framework for oven designs is presented which uses experimentally verified heat transfer correlations and high fidelity Computational Fluid Dynamics (CFD) analyses to identify optimal combinations of design features which maximise desirable characteristics such as temperature uniformity in the oven and overall energy efficiency of baking. A surrogate-assisted multi-objective optimisation framework is proposed and used to explore a range of practical oven designs, providing information on overall temperature uniformity within the oven together with ensuing energy usage and potential savings.
Staling of bread is cause of significant product waste in the world. We reviewed the literature of the last 10 y with the aim to give an up-to-date overview on processing/storage parameters, antistaling ingredients, sourdough technology, and measurement methods of the staling phenomenon. Many researchers have been focusing their interest on the selection of ingredients able to retard staling, mainly hydrocolloids, waxy wheat flours (WWF), and enzymes, but different efforts have been made to understand the molecular basis of bread staling with the help of various measurement methods. Results obtained confirm the central role of amylopectin retrogradation and water redistribution within the different polymers in determining bread staling, but highlighted also the importance of other flour constituents, such as proteins and nonstarch polysaccharides. Data obtained with thermal, spectroscopy, nuclear magnetic resonance, X-ray crystallography, and colorimetry analysis have pointed out the need to encourage the use of one or more of these techniques in order to better understand the mechanisms of staling. Results so far obtained have provided new insight on bread staling, but the phenomenon has not been fully elucidated so far.
Combustion of biomass in small-scale furnaces is used widely in different applications. The technology used is often “fixed grate” combustion in small batch furnaces. The efficiency of such a furnace is often low, which results in a high environmental impact. The aim of this work was to analyse the performance of the existing wood-fired bakery ovens that can be used to improve the efficiency. The data collected from 15 semi-direct and 3 indirect bakeries consisted of: the dimensions of the oven, the temperature profiles of the combustion chamber and the baking oven, the baking time and the bread quality. It was found that as much as 60 tons/day of green wood are consumed in the bread baking process in the area investigated. Two types of bakery ovens are used most commonly: indirect and semi-direct. The specific consumption was found to be 0.55 and 0.90 kg of wood per kg of wheat flour baked for the indirect and the semi-direct respectively. The analyses of the bread baked show that the variation of the temperature profile during the baking process influences the quality of the bread produced.
Staling of bread is a highly complex phenomenon that is not yet fully understood. This study examined the effect of staling on thermal (DSC) and thermo-physical (DMA) properties of bread. The staling process increased water migration from the crumb to the crust and increased unfreezable water (UFW) fraction. Amylopectin retrogradation incremented during bread staling, and it was showed that the loss in freezable water (FW) was caused from water incorporation into the starch crystalline structure and water migration from the crumb to the crust. DMA was able to follow the shrinking behavior of bread crumb during freezing. Crumb shrank through the entire cooling and freezing process. The matrix shifts through their freezing process incremented the rate of their contraction, probably due to the matrix dehydration as consequence of ice formation. The ageing process changes the thermo-mechanical profile of the crumb, and it was showed that a greater amount of retrogradated starch, affected significantly the contraction capacity of bread crumb.
The development of browning at bread surface during baking is an important quality index. In this paper, the colour (CIE L∗a∗b∗ parameters) of bread surface was measured by computer vision. Also, the weight loss variation was determined during the process. Baking experiences were performed at 180, 200 and 220°C under natural and forced convection. Linear trend was found between total colour change and weight loss of breads. A simple mathematical model was proposed to predict the development of browning during baking. The independent variables were the weight loss of breads and the baking temperature. For values of weight loss greater than 7%, the mean absolute estimation error of the proposed model was 6.23%.
Bread staling is a complex phenomenon that originates from multiple physico-chemical events (amylopectin retrogradation, water loss and redistribution) that are not yet completely elucidated. Molecular properties of white bread loaves were characterized by multiple proton Nuclear Magnetic Resonance (NMR) techniques (proton FID, T2 and T1 relaxation time) over 14 days of storage. Changes at a molecular level (faster decay of proton FIDs and shifting of proton T2 relaxation times distributions towards shorter times), indicating a proton mobility reduction of the bread matrix, were observed during storage. Multiple 1H T2 populations were observed and tentatively associated to water-gluten and water-starch domains. Proton T1 of bread was for the first time measured at variable frequencies (Fast Field Cycling NMR) and found to be strongly dependent upon frequency and to decrease in bread during storage, especially at frequencies ≤ 0.2 MHz. An additional proton T1 population, relaxing at 2 ms, was detected at 0.52 MHz only at early storage times and tentatively attributed to a water-gluten domain that lost mobility during storage.
Bread crumb X-ray patterns were analysed by different methods, the objective being to provide more in-depth knowledge of the relationships among starch crystallinity, amylopectin retrogradation and bread firming. Both crumb-firming and amylopectin retrogradation increased with storage time. However, total mass crystallinity grade and relative crystallinity increased only in the first 24h. The determination of starch crystallinity requires the separation of the crystalline and amorphous intensities, which is sometimes arbitrary, so it would be useful to improve this methodology. Different methods used to determine total crystallinity grade only show the differences existing between fresh and stored bread. B-type crystal structure—corresponding to the amylopectin retrogradation—increased during bread storage, showing a high correlation with bread-firming and storage time. This fact emphasized the above results and suggested that amylopectin retrogradation is an important component to the elucidation of bread staling.