Interactions of different carrageenan isoforms and flour components in breadmaking.

The aim of this study was to compare the effects of carrageenans with different sulfate contents on bread volume and dough rheological properties. Results showed that only lambda carrageenan, the most sulfated isoform, produced a significant increase in bread volume. In contrast, the different carrageenans induced a negative effect on the cookie factor. Alveographic and farinographic analyses indicated that dough rheological properties were differentially modified depending on whether lambda carrageenan was added to flour and then hydrated or vice versa. Analysis of the interaction between lambda carrageenan and flour components by infrared spectroscopy and SDS-PAGE indicated that a pool of low molecular weight hydrophobic gluten proteins interact with carrageenan. This interaction drastically changes their physicochemical properties since carrageenan-gluten protein complexes show a hydrophilic behavior. In addition, the results indicate that carrageenan sulfate groups and probably the amino groups of glutamines present in the primary structure of gluten proteins are involved in the interaction.