Impact of long-term frozen storage on the dynamics of water and ice in wheat bread

The impact of magnetic field-assisted freeze-thaw treatment on the quality of foxtail millet sourdough and steamed bread

Foxtail millet and sourdough are used to make foxtail millet sourdough steamed bread to improve the flavor and taste. Compared with the conventional freeze-thaw treatment (CFT), the effect of magnetic field-assisted freeze-thaw treatment (MFT) on the storage quality of foxtail millet sourdough and steamed bread is explored. The results showed that compared with CFT, MFT shortened the phase transition time of dough; decreased the water loss rate, the water mobility, and the freezable water content; increased the fermentation volume; stabilized the rheological properties; and minimized the damage of freezing and thawing to the secondary structure and microstructure of the gluten. In addition, an analysis of the specific volume, texture, surface color, and texture structure showed that MFT was beneficial to slowing the deterioration of the steamed bread texture. Finally, MFT effectively inhibited the growth and recrystallization of ice crystals during freezing and thawing, improving the quality of millet dough and steamed bread.

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.