The effects of sodium reduction on the gas phase of bread doughs using synchrotron X-ray microtomography

Rheo-fermentation properties of bread dough with different gluten contents processed by 3D printing

The rheological properties of dough closely correlate to a dough's ability to be three-dimensionally (3D) printed, but only weakly characterize its fermentation and baking process. This study aimed to use rheo-fermentation properties to predict rheological properties of dough, thereby obtaining indirect information on both 3D printing properties and post-processing characteristics. The 3D printing behavior and baking quality of the dough were measured. A gluten content of 13% was found to be the most suitable for 3D printing and exhibited desirable performance during fermentation and baking. Pearson correlation analysis revealed a strong correlation between rheological properties and rheo-fermentation properties. Using partial least squares regression-based models, the coefficients of determination of the prediction for rheological parameters (G', G″, η*) were 0.920, 0.854 and 0.863, respectively, with corresponding residual prediction deviation values of 3.063, 3.774, and 4.773. These findings suggest that 3D printing of bread dough products can be easily and successfully accomplished.

Structural formation during bread baking in a combined microwave-convective oven determined by sub-second in-situ synchrotron X-ray microtomography

A new concept has been developed for characterizing the real-time evolution of the three-dimensional pore and lamella microstructure of bread during baking using synchrotron X-ray microtomography (SRµCT). A commercial, combined microwave-convective oven was modified and installed at the TOMCAT synchrotron tomography beamline at the Swiss Light Source (SLS), to capture the 3D dough-to-bread structural development in-situ at the micrometer scale with an acquisition time of 400 ms. This allowed characterization and quantitative comparison of three baking technologies: (1) convective heating, (2) microwave heating, and (3) a combination of convective and microwave heating. A workflow for automatic batchwise image processing and analysis of 3D bread structures (1530 analyzed volumes in total) was established for porosity, individual pore volume, elongation, coordination number and local wall thickness, which allowed for evaluation of the impact of baking technology on the bread structure evolution. The results showed that the porosity, mean pore volume and mean coordination number increase with time and that the mean local cell wall thickness decreases with time. Small and more isolated pores are connecting with larger and already more connected pores as function of time. Clear dependencies are established during the whole baking process between the mean pore volume and porosity, and between the mean local wall thickness and the mean coordination number. This technique opens new opportunities for understanding the mechanisms governing the structural changes during baking and discern the parameters controlling the final bread quality.

Effect of Salt Content Reduction on Food Processing Technology

Higher salt intake is associated with the risk of cardiovascular and kidney diseases, hypertension and gastric cancer. Salt intake reduction represents an effective way to improve people’s health, either by the right choice of food or by a reduction of added salt. Salt substitutes are often used and also herb homogenates are treated by high pressure technology. Salt reduction significantly influences the shelf life, texture, pH, taste, and aroma of cheese. The composition of emulsifying salts or starter cultures must be modified to enact changes in microbial diversity, protease activity and the ripening process. The texture becomes softer and aroma atypical. In bakery products, a salt reduction of only 20–30% is acceptable. Water absorption, dough development, length and intensity of kneading and stability of dough are changed. Gluten development and its viscoelastic properties are affected. The salt reduction promotes yeast growth and CO₂ production. Specific volume and crust colour intensity decreased, and the crumb porosity changed. In meat products, salt provides flavour, texture, and shelf life, and water activity increases. In this case, myofibrillar proteins’ solubility, water binding activity and colour intensity changes were found. The composition of curing nitrite salt mixtures and starter cultures must be modified.

Salt reduction in bread via enrichment of dietary fiber containing sodium and calcium

The high intake of sodium and low intake of dietary fiber are two major dietary risk factors for preventable deaths worldwide, highlighting the need and implementations for developing health foods with low-salt/high-dietary fibers. Bread as a staple food contributes about 25% to the daily intake of sodium in many countries, and salt reduction in bread still remains a great technical challenge. In this study, we developed a simple method to reformulate the white bread in terms of reducing salt contents via dietary fiber fortification, while maintaining the taste and texture qualities. Low molecular weight water-extractable arabinoxylans (LMW-WEAX) as a soluble dietary fiber was first hydrated in salt water before dough mixing, leading to an inhomogeneous spatial distribution of sodium in bread and accelerating the release of sodium ions from crumbs, allowing 20% salt reduction in bread without impacting the salt perception. Data from the moisture content, crumb structure, water distribution, dough rheology and bread texture properties suggest that the pre-hydrated incorporation of LMW-WEAX mitigates the detrimental effect of dietary fiber on the dough and bread quality. The modulation of Ca²⁺ on the permeability of Na⁺ through the mucus layer and implication in salt enhancement of the bread were investigated. Results show that the pre-hydrated incorporation of WEAX containing Na⁺ and Ca²⁺ (1.0%) makes it possible to reduce 30% salt content in breads, which have implications in the large-scale production of low-salt/high-dietary fiber bread.