Electric shocks are used to heat gluten-free bread from the inside, saving energy and time compared to conventional baking applying heat from the outside. A new study in Ohmic heating (OH) has been published by the Institute of Food Technology of the University of Natural Resources and Life Sciences (BOKU), Vienna, in Food and Bioprocess Technology.
The first results show the superior quality of the Ohmic bread while saving energy and time during the manufacturing process. The ohmic heating treatment chamber used for the experiment was designed to resemble the baking tin used in conventional baking.
OH is an emerging technology that has shown many advantages over other heating methods. Heat is distributed in a very rapid and uniform manner, as heating occurs volumetrically and does not rely on conventional heat transfer based on conduction, convection or radiation, the researchers say.
This study demonstrated that OH was a suitable and promising technology for the production of GF crustless bread. It showed the need to implement a heating profile with variable power in different heating steps in order to achieve optimum product quality, such as specific volume, elasticity, and porosity.
Compared with conventional baking, OH has shown many advantages in terms of improved bread quality and reduced baking time, the researchers underline. Starch digestibility of the bread baked with OH was slightly reduced, compared with conventional baking; this resulted in bread with higher RS content, which has been associated to several health-related benefits.
Regarding the costs, OH might even reduce processing costs, as baking is known to consume most of the energy (around 40%) during bread making. Although energy expenditure of OH in industrial scale cannot be transferred directly from the pilot scale equipment and remains currently unknown, it might provide economical advantage over conventional baking methods. Moreover, due to the use of high frequencies (kHz range in this study), the electrochemical reactions at the electrode interface may be reduced, minimizing corrosion and leakage of metals to the heating medium.
Overall, this process is still in need of optimization and further fundamental research should be carried out in order to understand the behavior of the batter and its components (e.g., starch, protein) during OH and to further optimize the process variables for a tailored and targeted processing. The complete study can be found here: https://link.springer.com/article/10.1007%2Fs11947-019-02324-9