Modelling the browning of bread during baking

Molecular changes and interactions of wheat flour biopolymers during bread-making: Implications to upcycle bread waste into bioplastics

This study aims to understand the molecular and supramolecular transformations of wheat endosperm biopolymers during bread-making, and their implications to fabricate self-standing films from stale white bread. A reduction in the Mw of amylopectin (51.8 × 106 vs 425.1 × 106 g/mol) and water extractable arabinoxylans WEAX (1.79 × 105 vs 7.63 × 105 g/mol), and a decrease in amylose length (245 vs 748 glucose units) was observed after bread-baking. The chain length distribution of amylopectin and the arabinose-to-xylose (A/X) ratio of WEAX remained unaffected during bread-making, suggesting that heat- or/and shear-induced chain scission is the mechanism responsible for molecular fragmentation. Bread-making also resulted in more insoluble cell wall residue, featured by water unextractable arabinoxylan of lower A/X and Mw, along with the formation of a gluten network. Flexible and transparent films with good light-blocking performance (<30 % transmittance) and DPPH-radical scavenging capacity (~8.5 %) were successfully developed from bread and flour. Bread films exhibited lower hygroscopicity, tensile strength (2.7 vs 8.5 MPa) and elastic modulus (67 vs 501 MPa) than flour films, while having a 6-fold higher elongation at break (10.0 vs 61.2 %). This study provides insights into the changes in wheat biopolymers during bread-making and sets a precedent for using stale bread as composite polymeric materials.

Plant-based egg washes for use in baked goods: Machine learning and visual parameter analysis

Pea protein is one potential environmentally sustainable way of recreating the functionality of eggs in coatings for baked goods. These coatings are commonly applied to enhance visual properties of baked goods that consumers desire, especially color and gloss. This project used a simplified pie crust formulation (flour, shortening, and water) as a model baked good system to investigate color and gloss properties of pea protein coatings comprising three pea protein glycerol ratios, prepared at 2 pH values, and applied at three different weights, baked for either 15 or 30 min. Pictures were also taken and used to estimate L*, a*, and b* colorimeter values from images using random forest and artificial neural network models developed using SciKit-Learn. Image acquisition was also conducted at different lighting conditions and the results are corrected utilizing a principal component analysis (PCA) weighting approach. Results show that pea protein glycerol solutions are all glossier than egg washes, and the 80%/20% ratio gives the highest glossiness. Furthermore, there are not significant differences in any of the colorimeter values at any concentration when applying 1 g of protein. The artificial neural network model coupled with PCA weighting led to reasonable estimates of color at different lighting conditions. Together, these results offer an alternative for the use of pea protein/glycerol in lieu of egg washes.

Morphological changes and color development during cookie baking-Kinetic, heat, and mass transfer considerations

Color and shape are important quality attributes in baked goods, particularly cookies. Composition and processing conditions determine and influence color development and morphological changes in these baked goods. The objective of this study was to systematically evaluate the evolution of color and shape during baking to determine useful correlations that can be implemented during the assessment and modeling of the baking process. Cookies (AACC-I standard protocol 10-53.01) were baked at 185, 205, and 225°C. Moisture content, water activity, surface temperature, characteristic dimensions (radius and thickness), and color indexes (lightness, redness, blueness, and browning index [BI]) were monitored at different locations on the cookie surface and baking times. Relationships among the tested conditions were explored using correlation analysis. The cookies' dimensions and color indexes were strongly correlated with changes in moisture content over time, and those relationships were characterized using empirical models. The temperature dependence of the kinetic parameters of the changes in lightness and BI was also described and deemed independent of the location on the cookie surface. This study provides insights into the influence of heat and mass transfer on the physical and physicochemical changes of cookies during baking. The kinetic and secondary models developed in this study can serve as important components for establishing a comprehensive approach for coupling heat transfer, mass transfer, and reaction kinetics to estimate and optimize cookie-baking processes. PRACTICAL APPLICATION: The findings from this study provide valuable information for better understanding the morphological changes and color developments during the cookie-baking process. The quantitative data and models generated in this study will allow identifying baking conditions for better quality development.

Comparison of the effect of hydroxyl propyl methyl cellulose, pectin, and concentrated raisin juice on gluten-free bread based on rice and foxtail millet flour

The nutritional and technological challenges of gluten-free (GF) bread have increased the need for its modification due to the growing demand for this product, especially from celiac patients. Therefore, the present study aims at evaluating the influence of hydroxyl propyl methyl cellulose (HPMC) at 1% and 2% levels, pectin at 1.5% and 2.5% levels, and concentrated raisin juice (CRJ) at 3% and 4% levels on the dough rheological properties and quality of GF bread based on rice and millet flour. The GF bread prepared with HPMC and incorporating CRJ had higher water absorption, dough development time, and dough stability. In addition, the firmness of GF bread during 24-72 h after baking in the presence of 1% HPMC with 3% and 4% CRJ followed by 2.5% pectin incorporating 3% and 4% CRJ showed a significant decrease compared to the control sample. Further, the color index of GF bread was improved with the addition of HPMC and pectin and the L* index decreased in all GF breads with CRJ. The highest volume was occupied by bread containing 1% HPMC. The results demonstrated that GF bread could be produced from a mixture of rice and millet flour and its technological quality was improved by using 1% HPMC and 3% CRJ. Therefore, it has the necessary potential for high-scale production and consumption among members of the society.

Study on the optimization of temperature uniformity in the oven under the forced convection mode

In order to study the temperature distribution in a multi-functional oven and optimize the structural parameters of the oven, the internal temperature uniformity was improved. The test was conducted and the numerical simulation was conducted in two ways. The distribution of temperature field in each layer of ovens was measured in real time using a 13-point distributed thermocouple, and the oven temperature uniformity index was measured and analyzed. The temperature field inside the oven was numerically simulated using computational fluid dynamics. Investigated the heat conduction, convection and radiation effects respectively, and found out the main heat transfer mode of the oven. Further through the test of temperature measurement, verify the accuracy of the numerical simulation method. According to the results of the experiment and simulation, the reason of the uneven temperature field in the original structure of the oven was revealed and analyzed. By changing the structure of the oven tailgate, adjusting the air volume distribution, changing the distribution of the air outlet and other measures, greatly improving the uniformity of the temperature field inside the oven.

Improving the Leavening Effect of Ice like CO2 Gas Hydrates by Addition of Gelling Agents in Wheat Bread

This article brings together the application of ice-like CO2 gas hydrates (GH) as a leavening agent in wheat bread along with the incorporation of some natural gelling agents or flour improvers into the bread to enhance the textural properties of the wheat bread. The gelling agents used for the study were ascorbic acid (AC), egg white (EW), and rice flour (RF). These gelling agents were added to the GH bread containing different amounts of GH (40, 60, and 70% GH). Moreover, a combination of these gelling agents in a wheat GH bread recipe was studied for each respective percentage of GH. The combinations of gelling agents used in the GH bread were as follows: (1) AC, (2) RF + EW, and (3) RF + EW + AC. The best combination of GH wheat bread was 70% GH + AC + EW + RF combination. The primary goal of this research is to gain a better understanding of the complex bread dough created by CO2 GH and its influence on product quality when certain gelling agents are added to the dough. Moreover, the prospect of managing and modifying wheat bread attributes by the use of CO2 GH with the addition of natural gelling agents has not yet been researched and is a fresh idea in the food industry.

An Innovative Approach in the Baking of Bread with CO2 Gas Hydrates as Leavening Agents

Gas (guest) molecules are trapped in hydrogen-bonded water molecules to form gas hydrates (GH), non-stoichiometric solids that resemble ice. High pressure and low temperature are typical conditions for their development, with van der Waals forces joining the host and guest molecules. This article study investigates the application of CO2 gas hydrates (CO2 GH) as a leavening agent in baking, with particular reference to the production of wheat bread. The main intention of this study is to better understand the complex bread dough formed by CO2 GH and its impact on product quality. This may enable the adaptation of CO2 GH in baking applications, such as those that can specifically influence wheat bread properties, and so the final bread quality. The present research further examines the comparative evaluation of yeast bread with the GH bread's impact on bread quality parameters. The amount of GH was varied from 10 to 60%/amount of flour for the GH breads. The GH breads were compared with the standard yeast bread for different quality parameters such as volume, texture, and pore analysis. The results show that the bread with 20% and 40% GH obtained the best results in terms of volume and pore size. Moreover, this article also sheds some light on the future applications of the use of CO2 GH as leavening agents in foods. This knowledge could help to create new procedures and criteria for improved GH selection for applications in bread making and other bakery or food products.

Effect of packaging material and oxygen concentration on quality of Ghavoot during the storage

Ghavoot is an Iranian traditional food product that prepared by a combination of several types of plant seeds mixed with sugar. The lack of appropriate packaging caused Ghavoot exposed to environment conditions, which leads to oxidation of this product and reduce its nutritional value and marketability. In this study, different types of packaging materials including nylon, the Polyester/ Aluminum/ polyethylene (PET/AL/PE) and the Polyester /Aluminum / Low-Density Polyethylene (PET/AL/LDPE) with different concentrations of oxygen inside the packaging (zero, 5 and 21%) were used to maintain quality properties of Ghavoot. The results showed that samples stored in the PET/Al/LDPE packaging under vacuum, had fewer moisture changes during storage compared with other treatments, as a result, the least changes in the color parameters of Ghavoot occurred. Increasing the concentration of oxygen inside the packaging resulted in higher peroxide, anisidine and totox values as well as the higher total acidity of the Ghavoot's oil. Keeping Ghavoot in the three-layer PET/Al/LDPE pouches under vacuum condition, caused the lipid oxidation to be delayed during the storage. Results of sensory properties showed that increasing the oxygen concentration inside the packaging caused the average score for product flavor to decrease as a result of rancidity development.

Pre-Gelatinisation of Rice Flour and Its Effect on the Properties of Gluten Free Rice Bread and Its Batter

In order to improve the quality of the gluten free rice bread (GFRB), pre-gelatinised rice flour (PGRF) was made and used to partially replace natural rice flour in the production of GFRB. The pre-gelatinisation parameters were optimised and the effects of PGRF on the quality of the GFRB and its batter were studied. The results showed that optimal PGRF was obtained when 50% total water was mixed with 1.0% rice flour and the mixture heated at 80 °C for 2 min. Supplementation with PGRF significantly improved the properties of GFRB by affecting its baking properties, textural properties, colour, and crumb grain features. Effects of PGRF on GFRB were mainly caused by the more closely packed gel structure of rice starch in the bread batter, the higher onset temperature during gelatinisation and the complex effect of PGRF on water-binding capacity in bread batter during the baking process. As the pre-gelatinisation parameters of flours and their effect on gluten-free baked products varied with grain variety, processing properties should be studied before using them, and emphasis should be placed on new techniques such as flour pre-gelatinisation to obtain gluten-free foods with improved quality.

Establish intelligent detection system to evaluate the sugar smoking of chicken thighs

The objective of this study was to establish a standardized color detection method to achieve low-cost, rapid, nonintrusive and accurate characterization of the color change of smoked chicken thighs during the smoking process. This study was based on machine vision technology using the Mean algorithm, K-means algorithm and K-means algorithm + image noise reduction algorithm to establish 3 colorimetric cards for the color of sugar-smoked chicken thighs. The accuracy of the 3 colorimetric cards was verified by the K-medoids algorithm and sensory analysis, respectively. Results showed that all 3 colorimetric cards had significant color gradient changes. From the K-medoids algorithm, the accuracy of the colorimetric card produced by the Mean algorithm, K-means algorithm and K-means algorithm + image noise reduction algorithm was 87.2, 95.1, and 96.7%, respectively. Meanwhile, the verification results of the sensory analysis showed that the accuracy of the Mean algorithm, K-means algorithm and K-means algorithm + image noise reduction algorithm colorimetric card was 69.4, 80.9, and 79.2%, respectively. A comparative analysis found that the colorimetric cards produced by the K-means algorithm and K-means algorithm + image noise reduction have excellent accuracy. These 2 colorimetric cards could become a suitable method for rapid, low-cost, and accurate online color monitoring of smoked chicken.

Nutritional Value and Biological Activity of Gluten-Free Bread Enriched with Cricket Powder

Cricket powder, described in the literature as a source of nutrients, can be a valuable ingredient to supplement deficiencies in various food products. Work continues on the implementation of cricket powder in products that are widely consumed. The aim of this study was to obtain gluten-free bread with a superior nutritional profile by means of insect powder addition. Gluten-free breads enriched with 2%, 6%, and 10% of cricket (Acheta domesticus) powder were formulated and extensively characterized. The nutritional value, as well as antioxidant and β-glucuronidase activities, were assessed after simulated in vitro digestion. Addition of cricket powder significantly increased the nutritional value, both in terms of the protein content (exceeding two-, four-, and seven-fold the reference bread (RB), respectively) and above all mineral compounds. The most significant changes were observed for Cu, P, and Zn. A significant increase in the content of polyphenolic compounds and antioxidant activity in the enriched bread was also demonstrated; moreover, both values additionally increased after the digestion process. The total polyphenolic compounds content increased about five-fold from RB to bread with 10% CP (BCP10), and respectively about three-fold after digestion. Similarly, the total antioxidant capacity before digestion increased about four-fold, and after digestion about six-fold. The use of CP also reduced the undesirable activity of β-glucuronidase by 65.9% (RB vs. BCP10) in the small intestine, down to 78.9% in the large intestine. The influence of bread on the intestinal microflora was also evaluated, and no inhibitory effect on the growth of microflora was demonstrated, both beneficial (Bifidobacterium and Lactobacillus) and pathogenic (Enterococcus and Escherichia coli). Our results underscore the benefits of using cricket powder to increase the nutritional value and biological activity of gluten-free food products.

5-Hydroxymethylfurfural Formation in Bread as a Function of Heat Treatment Intensity: Correlations with Browning Indices

5-hydroxymethylfurfural (HMF) is formed during bread baking as a Maillard reaction product (MRP); it can exert toxicity and it is regarded as a potential health risk because of its high consumption levels in western diets. The aim of this study was to evaluate HMF formation in bread as a function of heat treatment intensity (HTI) and to investigate correlations between HMF and easily detectable browning indices. White breads were baked at 200 °C and 225 °C for different baking times for a total of 24 baking trials. Browning development was evaluated by reflectance colorimetric and computer vision colour analysis; MRP were quantified spectrophotometrically at 280, 360 and 420 nm and HMF was determined by HPLC. HMF concentrations varied from 4 to 300 mg/kg dw. Colour indices (100-L*) and Intensity mean resulted significantly correlated between each other (r = -0.961) and with MRP (r ≥ 0.819). The effects of the different HTI were visualized by principal component analysis and the data were used to evaluate the best fitting regression models between HMF concentration and other browning indices, obtaining models with high correlation coefficients (r > 0.90).

Effect of Hydration on Gluten-Free Breads Made with Hydroxypropyl Methylcellulose in Comparison with Psyllium and Xanthan Gum

The use of hydrocolloids in gluten-free breads is a strategy to improve their quality and obtain products with acceptable structural and textural properties. Hydration level (HL) optimization is important to maximize the hydrocolloids effects on dough and bread quality. This study evaluated the optimum hydration level (OHL) for gluten-free breads prepared with different starch sources (rice flour or maize starch) and hydroxypropyl methylcellulose (HPMC) in comparison with psyllium husk fibre and xanthan gum. Breads with the same final volume and the corrected hydration (CH) were evaluated. The hydration is a key factor that influences the final characteristics of gluten-free breads. Breads made with HPMC had greater dependence on the HL, especially for preparations with maize starch. Psyllium had similar behaviour to xanthan with respect to specific volume and weight loss. Breads manufactured with maize starch and HPMC had low hardness due to their great specific volume. However, in breads made with rice flour, the combined decreased hydration and similar specific volume generated a harder bread with HPMC than the use of psyllium or xanthan. Breads made with HPMC presented higher specific volume than the other hydrocolloids, however combinations among these hydrocolloids could be evaluated to improve gluten-free breads quality.

Karl Fischer Water Titration—Principal Component Analysis Approach on Bread Products

(1) Background: The water content and the way of bonding in the food matrices, including bread, can be easily and simply evaluated by Karl Fischer titration (KFT). The goal was to identify the main KFT parameters that influence the similarity/dissimilarity of commercial bread products, using multivariate statistical analysis. (2) Methods: Various commercial bread samples were analyzed by volumetric KFT and the water content, parameters from titration process and KFT kinetics were used as input for principal component analysis (PCA). (3) Results: The KFT water content was in the range of 35.1–44.2% for core samples and 19.4–22.9% for shell samples. The storage and transportation conditions consistently influence the water content of bread. The type of water molecules can be evaluated by means of KFT water reaction rates. The mean water reaction rates up to 2 min are consistently higher for bread core samples, which indicates a high fraction of “surface” water. PCA reveals the similarity of core samples and various bread types, as well as dissimilarity between bread parts, mainly based on KFT kinetic parameters. (4) Conclusions: KFT kinetics can be a useful tool for a rapid and simple differentiations between various types of bread products.

The effect of the ultrasound process and pre-gelatinization of the corn flour on the textural, visual, and sensory properties in gluten-free pan bread

The present study used ultrasound waves with the intensity of zero, 30, and 70%, as well as the microwave-induced pre-gelatinization of corn flour and natural ones to produce gluten-free pan bread. To this end, the microstructure of pre-gelatinized corn flour was compared to the natural one. The result of the electron microscope image indicated the extension of structure and further swelling of the pre-gelatinized corn flour as compared to the natural one. In addition, the result represented that samples containing pre-gelatinized corn flour had a firmer dough, more moisture, porosity, specific volume, the L* component of the crust and crumb texture, the a* component of crumb texture and the sensory properties when compared to those which contained the native corn flour. Based on the results, pre-gelatinized corn flour caused a decrease in the b* component in the crust and crumb texture, along with firmness during 2 and 72 h after baking. On the other hand, the ultrasound waves resulted in a reduction in the dough and bread firmness and b* colorful component while those with 30% intensity increased the L* colorful component, specific volume, porosity, and the overall acceptability score in sensory assessment. In general, the sample containing pre-gelatinized corn flour, treated with 30% intensity of ultrasound waves demonstrated better technological, visual, and sensory properties and was considered as a superior sample in the present study.

Insights into melanoidin conversion into fluorescent nanoparticles in the Maillard reaction

Melanoidins are not the final product of the Maillard reaction, and they can be further converted to fluorescent nanoparticles after hydrothermal treatment.

Water transport during bread baking: Impact of the baking temperature and the baking time

The impact of the baking temperature on the moisture profile (in terms of water content), during bread baking was analyzed using a convection oven (three oven temperatures and different baking times). During baking, local water content and temperature were measured at different regions of the crust and crumb. There was found an increase in water content at the core. Water content reached a maximum level (at about 2.5%), with no effect of the baking temperature, and decreased slowly at advanced baking times. Regarding the crust, a theoretical model relating water flux to the driven force (temperature difference between the oven environment and the vaporization front) and the crust thermal resistance was validated with experimental values. Water losses were also reported. The water lost by bread contributes significantly to the energy consumption by this process and its reduction is of concern for conducting the process in a more sustainable manner. A better optimization of heat transfer between the surface (for coloration purposes) and the core (for inflation purposes) could help in this way, together with shorter baking duration and hence higher yield.

Performances of Different Metabolic Lactobacillus Groups During the Fermentation of Pizza Doughs Processed from Semolina

The main hypothesis of this work is that facultative and obligate heterofermentative Lactobacillus species can differently impact the final characteristics of pizza. The objective was to evaluate separately the behaviors of the obligate heterofermentative species (OHS), such as Lactobacillus sanfranciscensis, Lactobacillus brevis, and Lactobacillus rossiae, and the facultative heterofermentative species (FHS), including Lactobacillus plantarum, and Lactobacillus curvatus, in the sourdoughs to be used for pizza production. The production of the experimental pizzas was carried out with semolina (Triticum turgidum L. ssp. durum). The acidification process—which was followed by pH, total titratable acidity (TTA), and lactic acid bacteria (LAB) development—indicated for all of the experimental trials that the kinetics is comparable to those of the controls. The fermentation quotient of the FHS trial was particularly higher than that of the other trials, including the control production performed with a sourdough inoculum used in an artisanal bakery. The dominance of the added strains indicated the clear persistence of L. sanfranciscensis PON100336, L. brevis 200571, and L. plantarum PON100148 in the obligate–facultative heterofermentative species (OFHS) trial. The pizzas were baked without seasoning in order to investigate weight loss, color, morphology, and a generation of volatile organic compounds (VOCs). The data showed the differences among trials regarding the inocula. Eight classes of VOCs were detected in the pizza samples with aldehydes, esters, alcohols, and acids as major compounds. The sensory attributes were significantly different for the judges and the pizzas. The multivariate statistical approach found marked differences among the trials. The results indicated that the application of mixed cultures of the facultative heterofermentative species of Lactobacillus determined high quality pizzas.

Production of Barbari Bread (Traditional Iranian Bread) Using Different Levels of Distillers Dried Grains with Solubles (DDGS) and Sodium Stearoyl Lactate (SSL)

Bread is one of the oldest foods known throughout history and even though it is one of the principal types of staple around the world, it usually lacks enough nutrients, including protein and fiber. As such, fortification is one of the best solutions to overcome this problem. Thus, the objective this study was to examine the effect of three levels of distillers dried grains with solubles (DDGS) (0%, 10% and 20%) in conjunction with three levels of SSL (sodium stearoyl lactate) (0%, 2% and 5%) on physical and chemical properties of Barbari bread (traditional Iranian bread). To the best of our knowledge, this is the first study to evaluate DDGS and Sodium Stearoyl-2-Lactilate (SSL), as sources of fortification in Barbari bread. The results showed that incorporation of 20% of DDGS and 0% SSL caused a significant increase in the amount of fiber and protein. As for the physical attributes, using higher amount of DDGS caused a darker color, and as for the texture parameters, the highest firmness was measured when 10% DDGS and 5% of SSL were used. Different Mixolab and Rapid Visco Analyzer (RVA) parameters also were measured with varying results. The findings of this study show that DDGS can be a valuable source of fiber and protein, which can be used as a cost effective source to fortify cereal-based products.