The insight into the production process, from Hiroshima University, could help address hunger in many regions of the world, especially where rice dominates grain crops. The university researchers have provided a scientific breakdown of a method of making rice-bread, developed by Japan’s National Agriculture and Food Research Organization.
Breads made from rice-flour breads are not new. However, the end products have only loosely resembled ‘bread’ in terms of using wheat or rye. To an extent a better structure can be overcome by additives, to give more of the expected ‘bubble structure’ and volume, but additives are not always practical in some regions of the world and there is also a drive with some people for more ‘natural’ foods.
In Japanese, rice flour is called komeko and is available two forms: glutinous and non-glutinous. Glutinous rice (or sweet rice) it is neither sweet nor does it contain gluten; ‘glutinous’ is used to describe the stickiness of the rice when it is cooked.
By understanding the science of bread making, researchers have developed a rice-bread that resembles a white loaf of wheat bread. With wheat bread the texture is the result of gluten forming a flexible matrix, locked between molecules of carbon dioxide (with the gas formed by bubbles released by fermenting yeast). This chemical reaction allows the bread to “rise”, with the degree of rising proportionate to the carbon dioxide levels.
Given that rice flour does not contain gluten, the innovative part is in achieving the ‘rising’ of the food structure to create a loaf resembling wheat based bread. This is achieved through processing the flour using a wet milling process. This process leads to a different microstructure of the fermenting batter (rice flour creates ‘batter’ instead of ‘dough’). The arrangement of the bubbles in the structure is key to the rice flour forming an end-product that resembles a loaf of wheat-based bread. The researchers have developed the wet milling process to create loafs of rice flour bread with good consistency. This is due to uniform hydrophobicity due to the formation of similar sized molecules which maintain a barrier between damp gaseous air pockets and the liquid batter.
The research has been published in the journal LWT – Food Science and Technology, in a research paper titled “Development of gluten-free rice bread: Pickering stabilization as a possible batter-swelling mechanism.”
