Tripeptide adds volume to gluten-free rice bread
June 2, 2010
by Jeff Gelski
IBARAKA, JAPAN — Results of a scientific study suggest adding glutathione, a tripeptide, to rice batter may improve the elasticity and volume of gluten-free bread. The addition also may reduce the amount of salt in bread. The study involved researchers from the National Food Research Institute in Japan and appeared on-line June 2 in the Journal of Agricultural and Food Chemistry.
Rice flour does not contain gluten, but it is unsuitable for the production of yeast-leavened products because rice proteins do not have the viscoelastic properties typically found in gluten, according to the researchers.
The added glutathione improved the gas-retaining properties of rice batter and appeared to gelatinize rice starch at lower temperatures.
“As the temperature of the bread pan rose, the glutathione-added rice batter swelled,” the researchers wrote. “In contrast, the control batter did not rise and was bubbling because it could not hold the fermentation gas.”
The rate of swelling increased as the amount of added glutathione increased, up to 0.75 grams of glutathione per 280 grams of rice powder. The addition of more glutathione gradually decreased the volume of the bread.
Salt had a negative effect. Bread volume fell when 0.1 grams, 0.25 grams or 0.5 grams of sodium chloride were added. The addition of salt also cancelled glutathione’s ability to gelatinize rice starch at lower temperatures.
“Rice breads, which do not require any additional salt, may be beneficial to public health by lowering the intake of salt from bread,” the researchers wrote.
They added, “We have conducted a tasting experiment of the glutathione bread and confirmed that addition of glutathione and absence of salt did not affect the taste negatively.”