Arnaud Dubat

Arnaud holds a Master's Degree in Sciences and Techniques for the agro-food industry and a Master's in International Marketing and Strategy. His original background is in Biochemistry, and he also holds a Miller’s Degree from the French Milling School (ENSMIC). He started working for CHOPIN Technologies, a KPM Analytics product brand, in 1989. His various occupations in the company (he started as an after-sales technician) and his current role put him in constant contact with bakery manufacturers and bakery quality control teams. Arnaud is a standardization expert for AFNOR, ISO and CEN. He is active with the BIPEA, corporate member representative for ICC and is also actively involved in Cereals and Grains standardization working groups.

Arnaud Dubat

External Publications

The Mixolab: a New approach to rheology

Publishing high-quality food production applications handbooks is a hallmark of AACCI PRESS and Mixolab: A New Approach to Rheology is no exception. Increasing consumer demand for quality foods with superior nutritional value makes innovative tools like the Mixolab of increasing interest to food developers and producers. Operators, breeders, millers, researchers, product developers, formulators, and bakers will find answers to their questions, along with guidelines for maximizing the use of the Mixolab for a wide range of applications. Gaining a better understanding of the instrument's capabilities will assist in discovery of novel uses by both research and production professionals.

Thermomechanically Induced Protein Aggregation and Starch Structural Changes in Wheat Flour Dough

Various studies have been carried out on wheat flour to understand protein and starch changes when subjected to mixing and temperature constraints, but structural changes of proteins and starch at the typical moisture levels of a dough system are not fully understood. The aim of this research was to improve our understanding of (micro) structural changes at the mesoscopic level, using: empirical rheology, microscopy (light and scanning electron microscopy), sequential protein extractions and glutenin macropolymer (GMP) wet weight, along mixing-heating-cooling stages of the Mixolab® assay. Studies were performed in three wheat flours with different protein content. The rheological analysis allowed identifying the role of the proteins and the relationship between the protein content and different primary and secondary parameters obtained from the recorded curves. The progressive heating-mixing stages during the Mixolab assay result in a dynamic re- and de-structuring of proteins involving interactions between the flour proteins from water-soluble to SDS soluble to SDS insoluble and vice-versa. The microstructure analysis using light, polarized and scanning electron microscopy revealed the changes that proteins and starch molecules undergo during mixing, heating and cooling. Qualitatively, the starch structural changes, swelling and gelatinization observed by microscopic techniques show some parallels with protein (and glutenin) content of the respective flour. Nevertheless, this tentative finding needs further confirmation by studying flour samples with a large difference in glutenin content.

Bread wheat milling behavior: effects of genetic and environmental factors, and modeling using grain mechanical resistance traits

Near-isogenic lines of bread wheat that differ in hardness, due to distinct puroindoline-b alleles (the wild type, Pinb-D1a, or the mutated forms, Pinb-D1b or PinbD1d), were grown in different environments and under two nitrogen fertilization levels, to study genetic and environmental effects on milling behavior. Milling tests used a prototype mill, equipped with two break steps, one sizing step, and two reduction steps, and this enabled 21 individual or aggregated milling fractions to be collected. Four current grain characters, thousand grain weight, test weight, grain diameter, and protein content, were measured, and three characters known to influence grain mechanical resistance, NIRS hardness, SKCS hardness index, and grain vitreousness (a character affecting the grain mechanical behavior but generally not studied)

Collaborative study Concerned with damaged starch measurement using an amperometric method

Damaged starch initially has a positive impact (increased water absorption capacity of the flour), but can later become a negative (dough sticking, slackening, intense coloring of the baking products). An optimum solution can be defined on the basis of the protein content of the flour, the α-amylase content, and the type of bread-making process. The miller can modify the damaged starch content of his flour. The choice of wheat, its preparation, and the mill settings condition the quantity of damaged starch in the flour. During the milling process, some of the starch granules invariably suffer mechanical damage. According to Dubois (2), the biggest grains suffer the most damage. He also showed that the granule has certain elastic properties that can result in several types of damage. The damage may then take the form of cracks or granule “breaking.” Claude Willm (8) provided more details with regard to milling factors favoring the production of damaged starch. The two authors both underlined the

Effect of green tea powder on the quality attributes and antioxidant activity of whole-wheat flour pan bread

The effects of green tea powder (GTP) on the quality attributes and antioxidant activity of whole-wheat flour (WWF) pan bread were studied. Crumb hardness, cell diameter, and chewiness of WWF pan bread increased at higher GTP levels, whereas specific volume and brightness showed a reverse trend. At the 1.00 g GTP/100 g flour addition level, hardness, resilience and specific volume of WWF pan bread were not significantly affected, but antioxidant activity increased by 1.00 mM TE/g sample. In the storage test, GTP greatly inhibited the production of peroxide, as determined by peroxide value (PV), in WWF pan bread. After 8 days of storage at room temperature, the PV of the lipid fraction of WWF pan bread without GTP (control) increased by 0.35 mg/100 g, while the PV of bread with the addition of 1.00 g GTP/ 100 g flour increased by 0.14 mg/100 g. These results suggest that the addition of GTP at the 1.00 g/100 g flour level effectively increases the antioxidant activity, and significantly reduces the production of peroxide during storage, while at the same time maintaining the baking quality of WWF pan bread.

Effects of particle size on the quality attributes of reconstituted wholewheat flour and tortillas made from it

The objective of this study was to examine the effects of whole-wheat flour (WWF) particle size on the quality attributes of WWF tortillas. WWF samples of different particle size distributions from commercial U.S. hard white (median diameters: 175.7, 128.6, 120.0, 108.5 and 102.4 mm), hard red winter (median diameters: 173.7, 133.6, 124.3, 110.8 and 104.2 mm) and hard red spring (median diameters: 173.7, 132.1, 124.7, 112.9, 106.3 mm) wheat classes were obtained by fine grinding of bran and shorts and re-combining with the rest of fractions. For all three wheat classes, as WWF median particle size decreased, the L* (lightness) value decreased but the adjusted damaged starch, polyphenol oxidase activity, and a* and b* values increased. Mixolab data showed that development time decreased as WWF particle size was reduced, while stability time and starch retrogradation increased. As for WWF tortilla quality, the breaking force and extensibility increased with decreasing particle size from ~175 to 129e134 mm, but diameter and thickness were not significantly affected. The results indicated that reducing the median particle sizes of WWFs from ~175 mm to ~130 mm would significantly improve the WWF tortilla quality.

Gluten Composition, Gluten Quality, and Dough Mixing Properties

Triticum dicoccum and Aegilops tauschii carry genes/alleles influencing favorably yield, resistance to diseases, and tolerance to abiotic stresses. Hybrids made by crossing these two species, are referred to as synthetic wheats. Synthetic wheat has been crossed to modern wheat genotypes to combine desirable traits from the first into agronomically-acceptable wheat hybrids. A set of 14 synthetic-derived, agronomically-acceptable, wheat lines and 8 common wheat cultivars, were examined in relation to Glu-1/Glu-3 glutenin subunit composition, gluten quality-related parameters (protein and SDS-Sedimentation), and dough viscoelastic properties (using the National-Mixograph and the Chopin-Mixolab dough mixers and the Alveograph). Nine lines possessed the Glu-1/Glu-3 glutenin composition of the common wheat parent (Cv. Pastor, Glu-1: 1, 17+18, 5+10, Glu-3Ac, and Glu-3Ag); other two showed the Glu-D1t subunit, 1.5+T2, from Ae. tauschii, and other five genotypes possessed the Glu-A3b’ allele, from T. dicoccum. The wide differences in the gluten quality-related parameters observed among the synthetic-derived lines could not be clearly associated to their differences in Glu-1/Glu-3 allelic composition. However, the Glu-D1t subunit 1.5+T2 was present in the lines showing the best gluten extensibility but the weakest gluten type. The Chopin-Mixolab proved to be a potential instrument to screen breeder’s lines for gluten quality; when testing whole grain flour, the dough development time stability, and breakdown parameters of the Mixolab showed high correlation with the dough strength parameter W of the Alveograph.

Measurement of water absorption rate in flours and rheological characteristics of dough during kneading

Levels of performance for the measurement of water absorption rate in flours and rheological characteristics of dough during kneading have been studied in this paper. The Mixolab is a recent laboratory device designed for monitoring the quality of cereals and derivatives. The principle of the device is based on that of an older instrument: the Pétrinex. Updated by the Belgian company Rhéotec, the device was renamed the Multigraphe.

Potential utilization of Mixolab for quality evaluation of bread wheat genotypes

The aim of this study was to determine the possibility of using Mixolab to assess the quality of different wheat genotypes. Mixolab data were compared with various flour quality characteristics and bread volume. The samples were chosen to represent a wide range in terms of grain and rheological properties and baking quality. There are eight paramaters used to evaluate a Mixolab curve. C1 and C2 are related to protein quality, whereas C3, C4 and C5 are related to the starch characteristics. Slopes α, β, γ are the indicators of protein weakening, starching speed, and enzymatic degradation. There were significant correlations between two Mixolab parameters (Stability and C2) and Zeleny sedimentation and Alveograph W values (P < 0.01). Some of the Mixolab parameters (C3, C4, C5) were correlated with Alveograph G and P/L value (P < 0.01). Mixolab values are generally in agreement with Farinograph values. There were significant negative correlations between most of the Mixolab parameters (Stability, C2, C3, C4) and Farinograph softening degree. Stability and C2 parameters of Mixolab were also significantly correlated with Farinograph stability values (P < 0.01). The correlation between Mixolab stability and Farinograph stability was considerably high (r = 0.907, P < 0.001). The Mixolab parameters C3, C4, and C5 were significantly correlated with bread volume. Significant correlations were observed between slope α and Zeleny sedimentation (P < 0.05), Alveograph W (P < 0.01), Farinograph softening degree (P < 0.001), and stability (P < 0.001) values.

Quality attributes of whole wheat flour tortillas with sprouted whole wheat flour substitution

Sprouted whole-grain foods are an emerging trend in the food market due to consumers' desire for health-promoting foods. The objectives of this study were to examine the rheological properties of whole-wheat flour (WWF) with sprouted WWF substitution (0, 25, 50, 75 and 100 g/100 g) and tortilla products made from it. Flour samples were analyzed for gluten index, color, solvent retention capacity, and Mixolab parameters, while tortillas were analyzed for weight, diameter, color, opacity, texture, rollability, and sensory attributes. Mixolab data showed that water absorption, dough development, and stability times decreased with an increase of sprouted WWF substitution. In terms of tortilla baking performance, tortillas made with higher amounts of sprouted WWF were larger in diameter and specific volume, brighter, and more opaque, and received higher sensory scores in color, flavor, and overall acceptability. For texture parameters, tortillas made with a higher percent of sprouted WWF required less force to break, which indicated that tortillas were less firm. After 16 d of storage, tortillas made with higher amounts of sprouted WWF were more rollable and shelf-stable. The results demonstrated that sprouted WWF could bring benefits to WWF tortilla's baking performance, i.e. better appearance, higher consumer acceptability, and longer shelf life.

Significance of starch damage and changes in measurement methods

amidon représente 67 à 68 olodu grain de bl"é et 78 à 82 % de[a farine qui en est issue.Composé d'amytose (26-28 %) etd'amylopectine (72-74 %), famidonconstitue [e principal polyoside deréserve des végétaux supérieurs(FEILLEI 2000). Ses longues chaînesde glucose s'enchevêtrent pourformer des granutes sphériques d'unetaille comprise entre 20 et 25 pm(amidons A) ou 2 et 10 prm(amidons B)

The Alveoconsistograph Handbook

New Handbook Explains the Value of the AlveoConsistograph to Optimize Processing and Quality of Wheat-based Products

Utilization of Mixolab to predict the suitability of flours in terms of cake quality

The objective of this study was to determine the possibility of using Mixolab1 to predict the cake baking quality of different wheat flours. Mixolab1 data were also compared with various flour quality characteristics. The correlations between Alveoconsistograph data and the cake quality characteristics were not significant. Therefore, Alveoconsistograph test does not seem to be useful to predict the cake quality of the flour samples. Mixolab1 characteristics C2, C3, C4 and C5 were found to be significantly correlated with volume index while C5 was correlated with hardness of cakes. The parameters C2 to C5 represent the end point of the corresponding mixing stages. The flour samples which gave higher cake hardness values had higher C5 values and the samples with lower cake volumes had higher C2, C3, C4 and C5 values. It seems to be possible to estimate the texture and volume of cakes by these values. Therefore, Mixolab1 seems to be a useful tool to predict the cake making quality of flour samples.

Arnaud Dubat

Arnaud Dubat

Posts

Crispness: A Defining Sensory Signature

Protein: The Foundation of Dough Strength and Baking Performance

Flat Bread: Balancing Flexibility and Texture

Baked Products: Understanding Surface Diversity

Crumb Texture: The Signature of Quality

Sponge Cake: The Science of Lightness

Volume & Rise Through Flour Components

From Soft Crumbs to Crisp Bites: Inner Moisture in Focus

Understanding Staling Through Flour Components

From Flour to Loaf: Ensuring Pan Bread Quality

Key Flour Factors That Define the Size & Shape of Baked Products

Understanding What Impacts 100% of Baked Product Color

Damaged Starch

Understanding Croissant Quality Starts with Flour

Introducing the Back to Flour Series

Evolution of the Grain, Flour, and Bread World - a Personal View

The Flour Milling Steps

Commercial Bakers - Analyze Your Flour to Predict Bread Height

What Is a Good Flour?

Addressing Production Pain Points of High-Protein Products with Instrumentation

Simplifying White Wheat Flour Quality Control for Bakers

Water Absorption Capacity of Flour

Preparing Wheat for Milling

What is Baking Strength

SDmatic 2 - Measurement of Starch Damage

Arnaud Dubat

External Publications

The Mixolab: a New approach to rheology

Thermomechanically Induced Protein Aggregation and Starch Structural Changes in Wheat Flour Dough

Bread wheat milling behavior: effects of genetic and environmental factors, and modeling using grain mechanical resistance traits

Collaborative study Concerned with damaged starch measurement using an amperometric method

Effect of green tea powder on the quality attributes and antioxidant activity of whole-wheat flour pan bread

Effects of particle size on the quality attributes of reconstituted wholewheat flour and tortillas made from it

Gluten Composition, Gluten Quality, and Dough Mixing Properties

Measurement of water absorption rate in flours and rheological characteristics of dough during kneading

Potential utilization of Mixolab for quality evaluation of bread wheat genotypes

Quality attributes of whole wheat flour tortillas with sprouted whole wheat flour substitution

Significance of starch damage and changes in measurement methods

The Alveoconsistograph Handbook

Utilization of Mixolab to predict the suitability of flours in terms of cake quality

Affiliations & Partnerships