Conventional Baking Research Articles

Ohmic baking of gluten free sponge cake: Analysis of technological and quality characteristics

The demand of gluten-free bakery products is worldwide increasing. Simultaneously, ohmic heating is an alternative heating technology that still deserves further research and development. Therefore, the aim of this work was assessing different technological and quality characteristics of gluten free sponge cake baked by ohmic heating. A custom ohmic system was designed and built and different electric field strengths (1500, 2000 and 2500 V/m) were tested. Conventional baking was performed for comparison purposes. The conventional baking time was 24 min, whilst the ohmic heating time ranged from 3.51 min at 2500 V/m to 7.93 min at 1500 V/m. The ohmic system achieved significantly higher energy efficiencies, reaching nearly 60%, compared to only 4.1% for conventional baking. Additionally, specific energy consumption was significantly lower for ohmic heating. Weight loss was higher for ohmically processed samples, showing larger number of pores in their inner spongy structure. Ohmic heating resulted in a larger volume expansion and a cake with lower density. The remaining quality characteristics, such as color, hardness, cohesiveness, and elasticity, were not significantly different. Results demonstrated that ohmic heating is a suitable technology for baking gluten-free sponge cakes and that it is a promising technology for fast industrial baking of such products.

Pengembangan roti berbahan pati jagung dengan modifikasi enzimatis & pemanas ohmik (Kajian: pengaruh variasi tegangan dan transglutaminase terhadap karakteristik produk) [Development of corn starch-based bread with enzymatic modification & ohmic heating: study effect of voltage and transglutaminase variations on product characteristics

The main challenges in producing gluten-free bread are closely related to its development, texture, and nutrition. This research consisted of 2 stages. Stage 1 was aimed to determine the effect of voltage variations (70 V, 80 V, 90 V, 100 V, 110 V, 120 V, and conventional baking as a control) on bread characteristics and process parameters. The experiment was arranged as non-factorial in a completely randomized design with 3 replications. The best results of the first stage were applied in stage 2, aimed to determine the effect of various concentrations of TGase (0, 0.5, 1, 1.5, 2, and 2.5%). The data were processed using analysis of variance, then further tested using Tukey's at the 5% level. The 120 V voltage gradient treatment was found to be the best treatment. It shows specific volume 3.17±0.17 cm3/g, baking loss 14.58±1.50%, brightness 50.97±3.27, hardness 3.76±0.11, cohesive 0.34±0.03, pore density 84±2.52. In addition, baking at a higher voltage level increased the temperature rate and electrical conductivity. The 120 V voltage treatment shows the time required to reach a maximum temperature of 97°C was 3 minutes 5 seconds, and an electrical conductivity value of 0.26-0.51 S/m. Based on the TGase treatment, it was found that when bread dough was applied with a higher TGase concentration, the specific volume, hardness, chewiness, resilience, cohesiveness and springiness, average pore size, and pore porosity of the bread increased.

The effect of a microwave susceptor on the textural properties of cupcakes during baking – A comparison with microwave and conventional baking methods [pdf

The effect of a microwave susceptor on the textural properties of cupcakes during baking – A comparison with microwave and conventional baking methods [pdf

Vacuum modification of wheat bread with encapsulated rosehip extract: Evaluation of physicochemical and microstructural properties

In this study, effect of vacuum modification (VM) on wheat bread containing rosehip extract (RE) and encapsulated rosehip extract (EnRE) was investigated in terms of the color parameters, textural properties, total phenolic content and antioxidant activity of breads. Analyzing starch crystalline structure and microstructure of breads were performed by X-ray diffraction and scanning electron microscopy. Rosehip extract was encapsulated using sodium alginate by ionic gelation method. Baking was conducted by conventional baking (CB, 220°C-17 min) and VM (220°C-12 min at atmospheric pressure and modification until −90 kPa vacuum pressure by 60 s time intervals at −30, −50, −70, and −90 kPa). PCA results showed that textural properties were the main distinctive feature with even harder texture of EnRE breads. VM led to have lower hardness for EnRE breads with the average hardness value of 781.51 ± 119.62 g than that of 1232.2 ± 83.83 g for conventional counterparts. Total phenolic content and antioxidant activity of EnRE breads were the highest after CB and VM. EnRE breads had more crystalline structure and less gluten aggregation after CB and VM processes. Results showed that vacuum modification is prominent technique to obtain softer texture of capsule containing breads with a high bioactivity.

Rheological and quality properties of tiger nut containing biscuit dough baked in IR-MW combination oven.

The effects of replacing part of the rice flour (RF) with tiger nut flour (TNF) were studied in gluten-free biscuits. A control biscuit dough containing RF only and 5 formulations containing 10, 20, 30, 40, and 50 % tiger nut flour on a flour basis (10TNF, 20TNF, 30TNF, 40TNF, and 50TNF) were prepared. The rheological and quality properties of biscuits baked both in conventional and infrared-microwave combination (IR-MW) ovens were determined. The rheological results showed that as the TNF ratio increased, G', G" and ƞ* decreased due to the high oil and dietary fiber content of the TNF. Texture analysis results showed that control dough and biscuits showed harder texture because of the damaged starch content of RF. Damaged starch also affected the spread ratio of the biscuits adversely. Weight loss of the biscuits baked in the IR-MW oven was higher than the ones baked in the conventional oven since higher inside pressure occurred in the dough. The color of the conventional baked biscuits was darker than IR-MW baked ones due to the greater extent of Maillard Browning. As the TNF ratio increased, darker biscuits were obtained since TNF has a high amount of sugar, and also its natural color is brown. Given the excellent nutritional and product quality impacts of TNF, it would be appropriate to use it as a raw material substitute in gluten-free biscuits. Furthermore, IR-MW baking was shown to be an appropriate method for biscuit quality when compared to conventional baking. This article is protected by copyright. All rights reserved.

Comparative study of different bread baking methods: Combined ohmic – infrared, ohmic – conventional, infrared – conventional, infrared, and conventional heating

Developing bakery techniques is essential to improve the qualitative and quantitative parameters of the bread baking process. In this study, the influence of different baking methods was evaluated on baking kinetics, energy consumption, mechanical properties, volume expansion, and sensory parameters of the bread. The results showed that ohmic-conventional method increased the baking time compared with conventional baking. The baking time of the combined infrared–conventional was 63.0–73.7% lower than the conventional method. The maximum values of specific energy consumption and volume expansion were found in the combined ohmic-conventional method. The specific volume expansion, firmness, and shearing force of the baked samples under infrared-conventional conditions were higher than the infrared and infrared-ohmic conditions. The maximum energy efficiency was obtained using the oven-infrared method. The sensory evaluation indicated that the baked samples in the infrared-conventional method had higher scores of taste and flavor than the other baking methods (p < 0.05). Future studies to optimize the baking parameters on bread quality are recommended for improved results.

Mineral, Nutritional, and Phytochemical Composition and Baking Properties of Teff and Watermelon Seed Flours.

Demonstrated limitations in the mineral and nutritional composition of refined flours have led to calls for the possibility of enriching them with health-promoting supplements, such as high-value non-cereal seeds. Teff and watermelon seeds have been found suitable for the production of gluten-free flour, but so far, their potential to enrich conventional baking flours has not been comprehensively studied. Hence, the present study aimed at farinographic evaluation of dough based on refined wheat flour with additions of whole white teff (TF) and watermelon seed (WSF) and pomace (DWSF) flours (tested levels 10%, 20%, and 30%), as well as possibly extensive chemical characterization of the plant material tested, including LC-MS/MS, GC-MS, total phenolics, flavonoids, melatonin, and antioxidant potential. Most of the rheological traits were improved in the flour mixtures compared to the base white flour: development time and quality number (above 1.6-fold increase), softening and stability time (up to 1.3-fold change), and water absorption (up to 6%). Overall, the best results were achieved after the addition of watermelon seed pomace. The DWSF material was characterized by the highest levels of P, Mg, Na (7.5, 1.7, 0.4 g/kg, respectively), and Fe and Zn (124 and 27 mg/kg), while TF was the richest in Ca (0.9 g/kg) and Mn (43 mg/kg). Protein and fat levels were significantly higher in watermelon seeds compared to teff (about double and up to 10-fold, respectively). Phytochemical analyses highlighted the abundance of phenolics, especially flavones, in TF, WSF and DWSF flours (244, 93, and 721 mg/kg, respectively). However, the value of total polyphenols was low in all materials (<2 mg GAE/g), which also correlates with the low antioxidant potential of the samples. Watermelon seed pomace was characterized by significantly higher melatonin concentration (60 µg/kg) than teff (3.5 µg/kg). This study provides new information on the chemical composition and application opportunities of teff and watermelon seeds.

Design of an Improved Traditional Baking Oven and evaluation of Baking Performance

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 101.58 to 158.69°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 cm3 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.

Influence of different heat treatments on the lipid quality of African Catfish (Clarias gariepinus)

ABSTRACT The influence of the most important heat treatments: cooking, microwave heating, baking, and frying (with comparison of deep-frying with pan-frying and convection baking with conventional) on the level of oxidation and fatty acids composition in lipids of African catfish was studied. After any heat treatment, the peroxide value did not exceed 5 mEq O2 kg−1 lipids and the anisidine value did not exceed 6.5, which can be considered as good lipid quality. It was found that the fillets subjected to convection baking and pan frying were characterized by lower oxidation levels and higher nutritional quality of lipids than those subjected to conventional baking and deep frying. When converted to wet weight, EPA and DHA losses after heating did not exceed 33%. However, when converted to dry mass, the losses of these acids, depending on the treatment applied, were between 3.8 and 51.8%. Better quality of lipids was found in heated fillets in which heat transfer took place by convection (cooking, baking) than by conduction (frying). It was found that depending on the applied heat treatment, 200 g portion provides about 190 (fried fillets) to 350 (convection-baked fillets) mg EPA and DHA.

INTERSPECIFIC HYBRID BETWEEN Saccharomyces mikatae AND Saccharomyces cerevisiae AS AN ALTERNATIVE STRAIN FOR BREAD MAKING

Hybrids of the homothallic diploid Saccharomyces mikatae and heterothallic haploid Saccharomyces cerevisiae isolated from local fruits in Hokkaido and a baking strain, respectively, were constructed by the spore to cell mating method. Interspecific hybridization of the selected strain was confirmed by polymerase chain reaction using species-specific primers, fermentation profiles, and spore formation. The leavening ability of the dough and enzyme activities of the hybrid exhibited intermediate traits of their parental strains. A baking test by the sponge-dough method with a standard formulation of white bread showed that breads produced using the hybrid differed in aroma and taste from those made using a conventional baking strain. Thus, the hybrid may be used to produce baked goods with diverse quality, which may be more acceptable to specific consumers.

Multivariate analysis of staling properties in vacuum-combined baking gluten-free cake during storage

In this study, the staling properties of vacuum-combined baking (VCB) gluten-free cake samples were investigated and compared with the conventional baking method. Textural, water-loss and moisture-content changes were determined during 5-day storage. Principal component analysis (PCA) was carried out to provide an understanding of the importance of the physicochemical variables during the storage period. X-ray diffraction and atomic-force microscopy analyses were performed in order to study the VCB effect on the cake samples at the microstructural level. The springiness and firmness values of the VCB cake samples were lower than control at the end of the storage period (p < 0.05). As a result of the PCA analysis, the dominant distinctive factor for the VCB and conventional baking was found to be springiness, and it was the moisture content of the crumb that caused staling during storage for both methods. The crystal type and morphological structure of the vacuum-baked samples were different than for the control. The main crystalline structure was found to be dominantly of the A-type in the VCB cake and V-type in the control. Overall, the vacuum combined baking method increased the storage time of gluten-free cake without significantly changing its physicochemical properties.

Changes in 3-, 2-Monochloropropandiol and Glycidyl Esters during a Conventional Baking System with Addition of Antioxidants.

Shortening derived from palm oil is widely used in baking applications. However, palm oil and the related products are reported to contain high levels of monochloropropandiol (MCPD) ester and glycidyl ester (GE). MCPD and glycidol are known as process contaminants, which are carcinogenic and genotoxic compounds, respectively. The objective was to evaluate the effects of antioxidant addition in palm olein and stearin to the content of MCPD esters and GE in baked cake. Butylated hydroxyanisole (BHA), rosemary extract and tocopherol were used to fortify the samples at 200 mg/kg and in combinations (400, 600 and 800 mg/kg rosemary or tocopherol combined with 200 mg/kg BHA). The MCPD esters and GE content, radical formation and the quality of the fats portion were analyzed. The results showed that palm olein fortified with rosemary extract yielded less 2-MCPD ester. The GE content was lower when soft stearin was fortified with rosemary. ESR spectrometry measurements showed that the antioxidants were effective to reduce radical formation. The synergistic effects of combining antioxidants controlled the contaminants formation. In conclusion, oxidation stability was comparable either in the single or combined antioxidants. Tocopherol in combination with BHA was more effective in controlling the MCPD esters and GE formation.

Effects of shortening and baking temperature on quality, MCPD ester and glycidyl ester content of conventional baked cake

The quality of a baked product can be greatly affected by the choice of shortening. However, a palm-based shortening can be contaminated by monochlropropanol (MCPD) ester and glycidyl ester (GE) as it is a product derived from a refined palm oil. MCPD esters and GE can be transferred into a baked product through further processing. Therefore, this study aimed to evaluate the effects of different palm-based shortening on the qualities of cake, MCPD esters and GE content during a conventional baking system. Commercial margarine, palm olein, palm mid-fraction, and soft and hard stearin were used in a cake recipe, baked at different baking temperatures (160, 180 and 200 °C) for 20 min. First, the quality characteristics of baked cake (moisture content, texture profile and surface color) was analysed. Second, the MCPD esters and GE content, acylglycerol composition and oxidation status of the fats portion from baked cake were investigated. The results showed soft stearin, palm olein and margarine delivered a similar volume, surface color, and texture to the finished product. An elevated baking temperature was detrimental to the quality characteristics of all the studied samples and delivered a finished product with extra hardness and low moisture. The free fatty acid content and specific extinction value showed that the fat portions were significantly oxidized at high baking temperatures. In addition, 2- and 3-MCPD esters were stable during baking, but GE showed that it was vulnerable to the heating process and constantly degrades when the baking temperature increased. In short, the finished products were in better quality (physical and texture properties) when lower baking temperature (160 °C) was used, especially when margarine, soft stearin and palm olein were used as the shortening. Hard stearin naturally contains lower MCPD esters and GE, but it was not able to provide similar qualities as compared to margarine sample.

Ohmic Heating\u2014a Novel Approach for Gluten-Free Bread Baking

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.

Ohmic versus conventional heating for studying molecular changes during pound cake baking

Ohmic or electrical resistance (ER) heating of pound cake batter results in a crumb only cake that corresponds to the center of conventionally baked cake. ER heating in an ER oven (ERO) excludes significant temperature and moisture gradients during pound cake baking and was here combined with a proportional integral derivative (PID) controller imposing a predefined temperature-time profile corresponding to that in the center of a batter/cake during conventional (CONV) baking. As a result of this homogenous baking, in contrast to what is the case in CONV baking, there is no cold front in the batter where water condenses. Therefore, the sucrose concentration in ERO batter can be lower than in CONV batter while still obtaining similar extents of both starch gelatinization and protein network formation. This study also provides the insights that during the metamorphosis of batter into cake a primary role is to be attributed to protein network formation and that starch gelatinization only contributes in a later phase. Ohmic heating is thus an interesting method to study the mechanisms involved in cake baking.

Thermally transferred emitting layer at low pressure for residual solvent-free organic light-emitting diodes

We utilize thermal transfer technology to suggest a novel baking process for the emitting layer (EML) of residual-solvent-free organic light-emitting diodes (OLEDs). We deposited the EML onto an intermediate substrate using a conventional spin-coating process, after which the EML was transferred to the device by evaporating the EML through heating of the intermediate substrate. The EML films were fully transferred from an intermediate substrate to the target substrate at a temperature exceeding 350 °C under both a low vacuum of ∼10−3 Torr and a high vacuum of ∼10−6 Torr. The quantity of residual solvent was carefully investigated using gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) analysis methods. While residual solvent peaks were found to exist 1.69 min after the beginning of the measurement process in the conventional spin-coating EML films despite the baking condition of 150 °C, solvent peaks were not observed in the EML films created with the novel baking process under conditions identical to those used in the GC-MS measurement. Moreover, according to the NMR analysis, the solvent peak of toluene at 2.3 ppm was not found in the thermally transferred EML films. Furthermore, we investigated the device performance capabilities between samples fabricated using the conventional baking process and those created with the novel thermal transfer process. In spite of low pressure of ∼10−3 Torr, the current efficiency and the lifetime of the OLED device created via the thermal transfer process were enhanced owing to the elimination of the residual solvent.

Effects of different cooking methods on the lipids and volatile components of farmed and wild European sea bass (Dicentrarchus labrax)

European sea bass is very popular in the Mediterranean area, although very little is known about the possible different behaviours of farmed and wild samples during cooking. This study addresses the effect of microwave cooking, salt-crusted and conventional oven baking on the lipids and volatile profile of farmed and wild sea bass. Proton Nuclear Magnetic Resonance did not detect that hydrolysis or oxidation of lipidic components had taken place. However, Solid Phase Microextraction-Gas Chromatography/Mass Spectrometry evidenced that polyunsaturated acyl group oxidation and Maillard-type reactions occurred to a very slight extent, yielding a wide variety of volatile odour-active compounds. Conventional baking enriched fish volatile profile to a higher extent than the other two techniques assayed. In fact, 15 Maillard reaction-derived compounds (pyrroles, alkylpyrazines, alkylthiophenes and 2-ethylpyridine) were only detected in oven-baked samples. Regardless of the cooking method applied, farmed sea bass showed a much richer aromatic profile than did wild samples, having 6-fold higher lipid content than the latter.

Effect of Processing on Pesticide Residues in Some Edible Fresh Water Fishes

The present study was undertaken to ascertain the effect of processing on pesticide residues in edible fresh water fishes. The fish samples were collected from two different fish markets located in Ludhiana city. Pesticide residues were detected in five different fish species by employing Gas Liquid Chromatography. Major pesticides detected include β-HCH, γ-HCH and chlorpyriphos with levels 0.30 mg kg−1, 0.1–0.35 mg kg−1 and 0.14–0.58 mg kg−1, respectively. Catla catla, Labeo rohita and Cirrhinus mrigala were found to have higher levels of pesticide residues. These fish samples were then processed by four different processing methods viz. deep frying, steaming by pressure cooker, conventional oven baking and microwave oven baking to check the reduction in residue levels. Deep frying caused maximum reduction i.e. 40–45% as compared to other processing methods. Steaming reduced pesticide residues by 14–16%, microwave oven baking resulted in 17–20% and conventional oven baking resulted in 20–21% reduction.

Investigation of the Effect of Dielectric Properties of the Biscuit on RF Power Uniformity using a Finite Element Computer Model

Background: Biscuit baking process is a major energy consuming and quality deciding process. In conventional biscuit baking process which rely on conduction, convection, radiation mode of heat transfer a condition called checking arises. Checking arises due to the build-up of stresses in the product being heated. The cause for the stresses is the differential moisture content between the outer surface and the centre bone of the biscuit and causes cracking of biscuit. Radio Frequency (RF) Post Baking is a proven solution to this problem. But the wide scale industrial use of RF post baking of biscuits is limited by energy efficiency and cost of the RF heating system. Energy efficiency can be improved by having better RF power uniformity/heating uniformity in the sample (biscuit) being RF heated. The uniformity of radio frequency power distribution defined by a metric called Power Uniformity Index (PUI) is used to evaluate the efficiency of the radio frequency heating. Methods: A finite element computer model of the RF heating system for post baking biscuits with staggered electrode configuration was developed using comsol multiphysics software. The dielectric properties of biscuit were varied from a scale of 0 till 80 and its effect on the RF power distribution and hence the heating uniformity in radio frequency post baking of was observed. Findings: The simulation results obtained indicate that the dielectric properties of the sample (biscuit) do have significant effect on RF power distribution and hence the heating uniformity when the values of dielectric constant and loss factor are lower than 10. Application: The results obtained give an insight into the effect of dielectric properties of biscuit on the RF power distribution in RF dielectric heating of biscuits.

Experimental investigation of French bread baking under conventional conditions or short infrared emitters

The objective of this study is to improve energy efficiency of an oven used for the conventional baking of French bread. Experiments performed to validate a numerical model and test different infrared emitters are presented. In order to provide a relevant experimental database, we first instrumented an industrial electrical static oven. The modifications made to the oven and instrumentation installed allows monitoring baking kinetics. The quantities measured are bread mass, temperature field, volume expansion and pressure. An energy balance is calculated to define the energy necessary to cook one “baguette”. Heat is provided by natural convection, direct conduction and mainly by infrared radiation to the dough. To improve energy efficiency, short infrared emitters are arranged on the vault instead of traditional electrical resistances made of reinforced metal alloy. These emitters allow increasing radiation heat transfer. Then, baking under short infrared emitters is carried out at lower air temperature, for the same total baking time. Energy consumption is analyzed and compared in both cases.