The study, published in Food Chemistry, found that germination for 48 hours provided gluten-free breads of “superior quality”.
When comparing different germination times (0h, 12h, 24h and 48h), germination for 48 hours provided bread nutritionally superior because of its higher protein, lipids and bioactive compounds content and increased antioxidant activity.
In addition, inclusion of 48h germinated flour reduced phytic acid content and glycemic index.
“Overall, germination seems to be a natural and sustainable way to improve the nutritional quality of gluten-free rice breads,” the researchers wrote.
Using germinated brown rice flour created nutritional changes in the gluten-free bread product, but did little to change its chemical composition, with the exception of ash content which was lower in bread from soaked flour “likely due to the loss of minerals during washing”, the researchers said.
Protein increased when using germinated flour and carbohydrate content decreased. Fat content also progressively decreased, but only with up to 24 hours germination – after that time “a significant increase was observed”.
Starch digestibility was also decreased by soaking and germination of the rice flour. “Presumably, germination gives some resistance to starch granules, likely due to the annealing that could undergo during soaking and drying,” the researchers explained.
Glycemic Index (GI) was lower in breads using germinated flour – a favorable factor, the researchers said, particularly for rice breads often associated with higher GI levels. “The significant reduction of glycemic index induced by the rice germination might be associated to the internal changes in the starch granules during germination.”
In terms of bioactive compounds, gamma-Aminobutyric acid (GABA) and polyphenols were increased with germinated flour. Breads that incorporated 48h germinated brown rice showed six times higher GABA content than control bread, for example. “GABA accumulation is initiated in the soaking process and continues during germination,” the researchers explained.
Overall antioxidant content of breads increased when using flours that had been germinated for longer: 12 – 48 hours, findings showed.
Source: Food Chemistry
Published online ahead of print, doi: 10.1016/j.foodchem.2014.10.037. Print: April 2015, Volume 173, Pages 298-304
“Effects of germination on the nutritive value and bioactive compounds of brown rice breads”
Authors: F. Cornejo, PJ. Caceres, C. Martinez-Villaluenga, CM. Rosell and J. Frias