Dr. Reihaneh Abdi, Researcher in Food Science and Technology – University of Guelph

Reihaneh Abdi is a Ph.D. candidate at the Department of Food Science, University of Guelph, Canada. She is working in the Cereal Science and Technology Lab (under the supervision of Dr. Iris Joye) on a project focusing on wheat sprouting. Reihaneh is concentrating on changes in the activity of specific enzymes involved in the synthesis and conversion of a number of health-improving molecules found in wheat. As such, she is working to shed light on the effect of sprouting on wheat functionality and health benefits. Reihaneh has been the (co-) author of several peer reviewed publications and has presented her findings at several conferences to date. She was the recipient of a highly competitive Ontario Graduate Scholarship (OGS) in 2021. Also, the best student paper award 2021 of the Protein Division at the Cereals & Grains annual meeting was given to Reihaneh. She is closely involved with the outreach activities within the Department of Food Science tailored towards fueling passion for STEM studies in high school students.

PRESENTATION:

Physicochemical Wheat Kernel Characteristics and their Correlation to Water Absorption Behavior of Wheat Kernels

Reihaneh Abdi¹, Jarvis Stobbs^1,2, Maria G. Corradini^1,3, Wei Cao¹, Nick Wilker⁴, and Iris J. Joye¹

¹ Department of Food Science, University of Guelph, Canada

² Canadian Light Source Synchrotron, Saskatoon, Canada

³ Arrell Food Institute, University of Guelph, Canada

⁴ Department of Plant Agriculture, University of Guelph, Canada

Knowledge on the relation between wheat kernel characteristics and its water absorption behavior is crucial to optimize soaking parameters for specific wheat samples. Indeed, these insights can inform the soaking practices of the wheat processing sector, allowing producers, for example, to determine the appropriate soaking time to achieve a targeted moisture content favorable for sprouting, or to optimize the tempering time prior to milling of a particular wheat variety. From a processing and engineering point of view, it is important to know how fast water absorption in wheat kernels proceeds; and the role that physicochemical kernel characteristics such as hardness, dimensions and composition play in this process. In this project, 30 wheat varieties, varying in hardness from super soft to hard, were immersed in water for 8 h. Kernel mass as function of soaking time was monitored and the kinetics of water uptake was characterized using a non-linear model (Mathematica 12.0.0) in which hydration rate and maximum hydration level were parameters. In order to gain a better understanding and visualization of water absorption in wheat kernels, X-ray micro computed tomography (µCT) was used. Wheat kernel scans were collected at specific time intervals over 8 h of soaking and combined into a 3D kernel model using the EZ-ufo toolkit and analyzed with Avizo. The relevance of wheat kernel features on hydration kinetics was evaluated using hierarchical cluster analysis (HCA), as a classification tool to segregate the samples with common characteristics (e.g., desirable water absorption parameters) into groups. Lastly, response surface methodology (RSM) was applied to map hydration rate/maximum hydration of wheat samples as a function of basic and easy-to-determine kernel characteristics. The preliminary analysis of the data indicates that X-ray imaging provides valuable information on kernel coat thickness, kernel coat and endosperm porosity, protein matrix density, starch granule size and distribution, kernel volume, architecture of the crease and germ, and vascular systems in the kernel, all of which affect water absorption. Extent of the increase in kernel volume and decrease of its density as consequence of water absorption are currently under analysis. These data will help identify if other relevant characteristics should be incorporated into an absorption model. In conclusion, this study presents a highly innovative approach to correlate and explain how the physicochemical kernel properties affect water absorption in wheat kernels. This information will provide new opportunities for the cereal processing industry to improve process efficiency and consistency.

Dr. Reine-Marie Guillermic, Research Associate – University of Manitoba

Reine-Marie Guillermic is a research associate at the University of Manitoba, in the Department of Food and Human Nutritional Sciences, and more specifically in the team of Dr. Filiz Koksel. Reine-Marie got a Ph.D. in soft matter physics from the Université Rennes 1 in France in 2011. She works on various projects involving ultrasounds, mechanical properties of soft and bubbly materials, and X-ray microtomography. She is currently developing methods using ultrasounds to assess the textural properties of meat analogues.

PRESENTATION:

X-Ray microtomography and ultrasonics to study the microstructure and mechanical properties of wheat food products

Reine-Marie Guillermic^1*, Anatoliy Strybulevych², Serdar Aritan³, John H. Page², M. G. Scanlon¹, Filiz Koksel¹

¹Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Canada

²Department of Physics and Astronomy, University of Manitoba, Winnipeg, Canada

³Biomechanics Laboratory, Hacettepe University, Ankara, Turkey

Bubbles are present in a large number of food products and play a major role in the product texture and quality. In the case of bread dough, for example, not only they provide an appreciated aerated texture, but bubbles entrapped at the mixing stage are also important to ensure that the gas produced by yeast has a place to diffuse into and therefore to enable a high-volume loaf of bread to be produced. Sheeted wheat products, such as noodle dough, also capture bubbles at the manufacturing stage, which are an important ingredient affecting the evolution of the mechanical properties in time. Therefore, it is crucial to improve knowledge of the bubble size distribution and its evolution in time to get a better insight on the link between processing, ingredients and final texture of the bubble food products.

X-ray microtomography was used to investigate the bubble size distribution in bread dough, and its evolution in time.  Ultrasonic contact experiments have been carried out over a wide range of frequencies (100 kHz – 10 MHz) to extract the phase velocity and attenuation of the sound wave propagating through non-yeasted bread samples at different aging times. Using a wave scattering model, and the bubble-size distribution obtained with X-ray experiments, we calculated theoretically the phase velocity and attenuation. We found that the agreement between the theoretical calculation and experiments was good over a wide frequency range, showing that ultrasound is a very promising tool that can provide information on the bubble-size distribution. A similar study on Asian noodle dough showed a similar agreement between the theoretical calculations and ultrasonic experimental data, and also indicated the important effect of water content on the evolution of bubbles in time. We also used this ultrasonic technique to investigate the effect of Fusarium damage in noodle dough properties.   

Dr. Iris J. Joye, Associate Professor – University of Guelph

Iris Joye obtained her Ph. D. degree at the University of Leuven (Belgium) in 2010. Her doctoral research encompassed an in-depth study of enzyme systems in wheat that affect the redox state of bread dough and the quality of the final bread loaf. After her Ph.D., she focused on chemical redox agents which are commonly used to improve dough and bread quality, on fortification of breakfast cereals and encapsulation technology with special emphasis on biopolymer-based systems. Iris Joye is currently working as associate professor Cereal Science and Technology at the University of Guelph. She combines her research expertise in cereal science with her knowledge on colloidal chemistry. The research line she and the students in her team are working on combines the different aspects of cereal science and colloidal chemistry by focusing on cereal proteins as intriguing and highly functional food components. Iris Joye is the (co-)author of 43 peer reviewed publications, 3 book chapters and contributed to 50 presentations on scientific meetings.

PRESENTATION:

Impact of inclusion of soluble dietary fibre from flaxseed hull on quality of bread made from frozen dough

Impact of inclusion of soluble dietary fibre from flaxseed hull on quality of bread made from frozen dough Nirmala Prasadi VP*, Iris J Joye Department of Food Science, University of Guelph, Canada The frozen dough product market is a growing market segment. Frozen dough products often suffer from quality deterioration during frozen storage due to the formation of ice crystals that cause physical damage to the gluten network and overall dough structure. However, dietary fibre may play a positive role in quality retention of frozen dough products. In 3 of 3 addition, dietary fibre may also play a role in reducing starch retrogradation and, hence, slowing down bread staling. Flaxseed mucilage (soluble flaxseed gum, SFG) is easily extracted using water from the outermost layers of flaxseed hull. SFG can be effectively used to increase the dietary fibre content of food and could potentially improve frozen dough bread quality. Therefore, this research was focused on unraveling the effect of SFG on quality of fresh bread made from frozen dough stored at −18°C for 8 weeks. In addition, changes occurring during storage of these breads in terms of textural properties and thermal properties were also studied. Dough samples were prepared according to AACC-I Approved Method (10-10.03). Wheat flour was substituted with the extracted SFG in two levels, i.e. 4.0 (SFG4) and 8.0 (SFG8) w/w%. Dough samples were frozen at -35°C for 3 hr at the end of the fermentation period and then subsequently stored at -18°C for 8 weeks. The quality of the bread loaves produced from fresh and frozen dough was evaluated in terms of crumb texture and structure, moisture content and specific loaf volume. The starch retrogradation enthalpy of bread samples stored at room temperature after baking was also evaluated. Dough liquor was isolated from fermented dough by ultracentrifugation. The monosaccharide composition, protein content and bulk rheological properties of dough liquor samples were evaluated. Interfacial properties of dough liquor were evaluated using tensiometer. A significant reduction in loaf volume after frozen dough storage was observed for all the formulations. SFG8 recipes showed the highest specific loaf volume after 8 week of frozen storage. Bread moisture content did not change in function of frozen storage time, while bread hardness substantially increased. SFG8 bread loaves showed the lowest crumb hardness after 8 week frozen storage. Bread crumb hardness progressively increased in function of loaf storage at room temperature for up to 5 days. Among the bread loaf samples made from 8 week frozen stored dough, the least hardness increase after 5 days was observed for the SFG8 loaves. Bread loaves made with the SFG8 recipe were also capable of maintaining their moisture content throughout the storage period of 7 days. Both SFG4 and SFG8 recipes had significantly lower starch retrogradation enthalpy after storage of breads for 7 days compared to the control recipe, signifying less pronounced bread staling in these samples. Dough liquor obtained from dough substituted with SFG showed higher bulk viscosity (shear rate of 50 s-1) than what was measured for the control dough liquor samples. According to power law analysis SFG8 showed more pronounced shear thinning behavior. SFG4 showed the lowest surface tension from all samples 900 s after forming an air-water interface. There are also noticeable differences in the interfacial elastic (E’) and viscous moduli (E”) among samples substituted with SFG. The highest values for E’ and E” were obtained for dough liquor isolated from dough prepared with SFG8, implying more and/or stronger interactions at the interface, possibly increasing the stability of gas cells in bread dough. The results indicate that SFG8 would be suitable to increase the dietary fibre content of bread as well as to mitigate the undesirable changes that occur during dough freezing and bread storage. Higher viscosity of the SFG dough liquor samples and higher interfacial viscoelastic moduli correlate positively with specific bread loaf volume. These dough liquor parameters, combined with a lower surface tension observed for SFG dough liquor are factors that will improve the stability of air cells present in the dough, increasing the cell density of bread crumb and decreasing bread firmness. All these data show that dietary fibre from flaxseed hull can be used to improve the frozen bread quality. SFG8 is most efficient in ensuring a high specific bread loaf volume, soft bread texture, fine bread structure and reduce the rate of starch retrogradation in breads prepared from frozen dough.

Prasadi Pathirannehelage, Ph.D. Candidate – University of Guelph

Nirmala Prasadi obtained her B’Sc. and M.Sc. in Food Science from the University of Peradeniya, Sri Lanka. Her M.Sc. research focused on the effect of hermetic storage conditions on the physicochemical and functional properties of grain legumes. After her M.Sc., she joined Wayamba University of Sri Lanka as a lecturer. During this time, she was involved in multidisciplinary research projects in the wider framework of Food Science. Her research interests focus mainly on cereals and their dietary fibre components to improve the dietary fibre content in cereal based products. To rationalize fibre addition to a cereal product matrix, she is investigating how added dietary fibre affects the intermolecular interactions between cereal biopolymers in dough products

PRESENTATION

Impact of inclusion of soluble dietary fibre from flaxseed hull on quality of bread made from frozen dough

Impact of inclusion of soluble dietary fibre from flaxseed hull on quality of bread made from frozen dough Nirmala Prasadi VP*, Iris J Joye Department of Food Science, University of Guelph, Canada The frozen dough product market is a growing market segment. Frozen dough products often suffer from quality deterioration during frozen storage due to the formation of ice crystals that cause physical damage to the gluten network and overall dough structure. However, dietary fibre may play a positive role in quality retention of frozen dough products. In 3 of 3 addition, dietary fibre may also play a role in reducing starch retrogradation and, hence, slowing down bread staling. Flaxseed mucilage (soluble flaxseed gum, SFG) is easily extracted using water from the outermost layers of flaxseed hull. SFG can be effectively used to increase the dietary fibre content of food and could potentially improve frozen dough bread quality. Therefore, this research was focused on unraveling the effect of SFG on quality of fresh bread made from frozen dough stored at −18°C for 8 weeks. In addition, changes occurring during storage of these breads in terms of textural properties and thermal properties were also studied. Dough samples were prepared according to AACC-I Approved Method (10-10.03). Wheat flour was substituted with the extracted SFG in two levels, i.e. 4.0 (SFG4) and 8.0 (SFG8) w/w%. Dough samples were frozen at -35°C for 3 hr at the end of the fermentation period and then subsequently stored at -18°C for 8 weeks. The quality of the bread loaves produced from fresh and frozen dough was evaluated in terms of crumb texture and structure, moisture content and specific loaf volume. The starch retrogradation enthalpy of bread samples stored at room temperature after baking was also evaluated. Dough liquor was isolated from fermented dough by ultracentrifugation. The monosaccharide composition, protein content and bulk rheological properties of dough liquor samples were evaluated. Interfacial properties of dough liquor were evaluated using tensiometer. A significant reduction in loaf volume after frozen dough storage was observed for all the formulations. SFG8 recipes showed the highest specific loaf volume after 8 week of frozen storage. Bread moisture content did not change in function of frozen storage time, while bread hardness substantially increased. SFG8 bread loaves showed the lowest crumb hardness after 8 week frozen storage. Bread crumb hardness progressively increased in function of loaf storage at room temperature for up to 5 days. Among the bread loaf samples made from 8 week frozen stored dough, the least hardness increase after 5 days was observed for the SFG8 loaves. Bread loaves made with the SFG8 recipe were also capable of maintaining their moisture content throughout the storage period of 7 days. Both SFG4 and SFG8 recipes had significantly lower starch retrogradation enthalpy after storage of breads for 7 days compared to the control recipe, signifying less pronounced bread staling in these samples. Dough liquor obtained from dough substituted with SFG showed higher bulk viscosity (shear rate of 50 s-1) than what was measured for the control dough liquor samples. According to power law analysis SFG8 showed more pronounced shear thinning behavior. SFG4 showed the lowest surface tension from all samples 900 s after forming an air-water interface. There are also noticeable differences in the interfacial elastic (E’) and viscous moduli (E”) among samples substituted with SFG. The highest values for E’ and E” were obtained for dough liquor isolated from dough prepared with SFG8, implying more and/or stronger interactions at the interface, possibly increasing the stability of gas cells in bread dough. The results indicate that SFG8 would be suitable to increase the dietary fibre content of bread as well as to mitigate the undesirable changes that occur during dough freezing and bread storage. Higher viscosity of the SFG dough liquor samples and higher interfacial viscoelastic moduli correlate positively with specific bread loaf volume. These dough liquor parameters, combined with a lower surface tension observed for SFG dough liquor are factors that will improve the stability of air cells present in the dough, increasing the cell density of bread crumb and decreasing bread firmness. All these data show that dietary fibre from flaxseed hull can be used to improve the frozen bread quality. SFG8 is most efficient in ensuring a high specific bread loaf volume, soft bread texture, fine bread structure and reduce the rate of starch retrogradation in breads prepared from frozen dough.