Water mobility and association by 1H NMR and diffusion experiments in simple model bread dough systems containing organic acids

Effects of chia seed gum on the physicochemical properties of frozen dough and the quality of dumplings

This study was designed to investigate the properties of chia seed gum (CSG) and its use in frozen dough. The CSG prepared by vacuum freeze-drying had the lowest water separation (4.22 ± 0.11 %) after three freeze-thaw cycles and the best color among the samples. The addition of 0.4 % to 1.0 % CSG significantly increased the peak, trough and final viscosity and decreased the breakdown and setback of the flour. The water absorption and cooking stability of the dough increased with increasing CSG content. The addition of 0.8 %-1.0 % CSG significantly increased the content of strongly bound water in dough during frozen storage. The CSG improved the texture of dough, and there were no significant differences in hardness, springiness, cohesiveness or chewiness of dough with 0.8 %-1.0 % CSG during frozen storage for 30 days. The cooking loss rate and the cracking rate of the dumpling wrappers with 0.8 % CSG were reduced by 2.31 % and 21.34 %, respectively. In conclusion, CSG can be used to improve the quality of wheat dough and its products and has promising applications in flour products.

The use of time domain 1 H NMR to study proton dynamics in starch-rich foods: A review

Starch is a major contributor to the carbohydrate portion of our diet. When it is present with water, it undergoes several transformations during heating and/or cooling making it an essential structure-forming component in starch-rich food systems (e.g., bread and cake). Time domain proton nuclear magnetic resonance (TD ¹ H NMR) is a useful technique to study starch-water interactions by evaluation of molecular mobility and water distribution. The data obtained correspond to changes in starch structure and the state of water during or resulting from processing. When this technique was first applied to starch(-rich) foods, significant challenges were encountered during data interpretation of complex food systems (e.g., cake or biscuit) due to the presence of multiple constituents (proteins, carbohydrates, lipids, etc.). This article discusses the principles of TD ¹ H NMR and the tools applied that improved characterization and interpretation of TD NMR data. More in particular, the major differences in proton distribution of various dough and cooked/baked food systems are examined. The application of variable-temperature TD ¹ H NMR is also discussed as it demonstrates exceptional ability to elucidate the molecular dynamics of starch transitions (e.g., gelatinization, gelation) in dough/batter systems during heating/cooling. In conclusion, TD NMR is considered a valuable tool to understand the behavior of starch and water that relate to the characteristics and/or quality of starchy food products. Such insights are crucial for food product optimization and development in response to the needs of the food industry.

Effects of vacuum degree, mixing speed, and water amount on the moisture distribution and rheological properties of wheat flour dough

Effects of vacuum degrees (0.00, 0.02, 0.04, 0.06, 0.08 MPa) on water distribution state, tensile properties, stress relaxation properties, and viscoelasticity of dough, as well as the effects of mixing speed (50, 70, 90 rpm/min) and water content (40%, 45%, 50%) under optimum vacuum degree were studied. The results showed that the proper vacuum degree (0.06 MPa) could promote the full contact between flour and water and improved the water-holding capacity of the dough. Meanwhile, the dough had stronger tensile strength, the best viscoelasticity and the ability to recover from external deformation more quickly. Under the vacuum of 0.06 MPa, with the increasing of mixing speed, the response to the external force of dough increased first and then decreased. Adding more water reduced the strength of dough, weakened the response to external forces, and led to a significant decrease in tensile resistance and tensile area of the dough, as well as a decrease in viscoelasticity (p < 0.05). The proper vacuum mixing allowed the preparation of dough to require more water and less energy. PRACTICAL APPLICATION: In the processing of wheat flour products, vacuum mixing is considered to be beneficial to the quality of noodles and breads. As the intermediate of these products, the dough is of great significance for the monitoring of its rheological characteristics. In this study, a moderate vacuum degree led to a significant improvement in the rheological properties of the dough, and the processing performance was the best. Under the optimal vacuum degree, the influence of mixing speed and water amount cannot be ignored. Vacuum mixing is an efficient dough preparation method, which can produce certain economic benefits.

Use of the 1H NMR technique to describe the kneading step of wholewheat dough: The effect of kneading time and total water content

The kneading step of wholewheat flour (WWF) dough was monitored using low-resolution ¹H nuclear magnetic resonance (NMR). The tested variables were kneading time and total water content. Two ¹H Free induction decay (FID) (A and B) and four ¹H T₂ Car-Purcell-Meiboom-Gill (CPMG) (C, D, E and F) proton populations were observed and the attribution to the different proton domains was made based on the literature and data acquisition. Kneading time significantly increased the mobility and the relative abundance of popA, the relative abundance and strength of protons of popC, D and E, while significantly reducing the relative amount of popF and increasing its mobility. This evolution of the proton populations during kneading was interpreted as chemical/physical transformations of the flour constituents. The use of WWF may reveal the changes in molecular dynamics underlying the higher water requirements of unrefined doughs, often associated with improved bread quality.