The volume and texture of rice bread may be enhanced by simply adding glutathione, a protein and safe food additive, and offer better gluten-free products to a growing market, says new research.
The ability of rice batter to retain gas, and therefore enhance volume, was enhance when glutathione was used, according to findings published in the Journal of Agricultural and Food Chemistry.
Hiroyuki Yano from the National Food Research Institute at Japan’s National Agriculture and Food Research Organization reports that glutathione was found to inhibit the formation of linkages in the batter called disulfide bonds, previously reported to produce a strong network and resist expansion on baking.
“Microstructure analyses of glutathione-added rice bread revealed it to have a perforated structure like wheat bread but with a smoother-looking surface,” wrote Yano. “These data collectively suggest that glutathione facilitates the deformation of rice batter, thus increasing its elasticity in the early stages of bread baking and the volume of the resulting bread.”
Implications for allergy
There is evidence that glutathione may play a role in reducing the allergenicity of other foods, stated Yano. This is again related to its ability to break the disulfide bonds in proteins, as this is said to increase a protein’s stability and increase the likelihood of a protein fragment reacting with the gut immune system and producing an allergic response.
“If glutathione cleaves the disulfide bonds of the macromolecular network, it may also be used industrially to cleave the disulfide bonds of cereal allergens in food processing, thus eventually making it possible to produce less allergenic foods. As glutathione is a ubiquitous thiol-containing tripeptide, there is a lesser possibility for it to function as an allergen,” stated Yano.
Yano produced rice batters for bread by using rice flour, water and glutathione (Sigma-Aldrich) and left overnight before adding sugar and bakery yeast.
After baking at 140 Celsius for 35 minutes the Japanese researcher reported: “The rate of swelling of the bread increased to 2.4 as the amount of added glutathione increased to 0.75 g against 280 g of rice powder.
“The addition of more glutathione gradually decreased the volume of bread,” added Yano.
Possibilities for a growing market
The gluten-free food market is blossoming and was worth almost $1.6bn last year, according to Packaged Facts. The market is experiencing a compound annual growth rate of 28 per cent over four years.
Sufferers of coeliac disease have to avoid all gluten in their diet, but diagnosis is not the only factor. Other sectors of the population, such as those who have self-diagnosed wheat or gluten intolerance or who believe gluten-free to be a healthier way of eating, are also strong drivers.
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, ASAP Article, doi: 10.1021/jf1003946
“Improvements in the Bread-Making Quality of Gluten-Free Rice Batter by Glutathione”
Author: H. Yano