Comparison of the volatile profiles of the crumb of gluten-free breads by DHE-GC/MS

The aroma of gluten-free bread has been considered of lower quality than that of the common wheat bread. With the aim of improving the aroma of gluten-free bread, the volatile profiles of the crumb of gluten-free breads made from rice, teff, buckwheat, amaranth and quinoa flours as well as corn starch, respectively, were evaluated. Wheat bread was used as a reference and dynamic headspace extraction together with GC/MS was employed. It was found that the whole grain breads, made with teff, quinoa and amaranth flours, presented a stronger aroma with higher number of important aroma contributors. Rice bread was characterised by the highest levels in nonanal and 2,4-decadienal and corn starch bread by 2,3-pentanedione and 2-furaldehyde. Teff presented the highest abundance of ethyl hexanoate and ethyl nonanoate, but also of alcohols and aldehydes from lipid oxidation. Quinoa and amaranth were classified by the highest content in Strecker and Ehrlich aldehydes as well as 1-propanol, 2-methyl-1-propanol, 3-methyl-1-butanol or 3-hydroxy-2-butanone from fermentation. Corn starch bread was the closest to wheat bread in the PCA due to the highest content mainly in 2,3-butanedione and furfural as well as the lowest contents in 1-propanol, 1-hexanol and pentanal.