I've just read the following papers. They contain cooked starch granules.
- Heiss, A. G., Pouget, N., Wiethold, J., Delor-Ahü, A., Goff, I. L. 2015. Tissue-based analysis of a charred flat bread (galette) from a Roman cemetery at Saint-Memmie (Dep. Marne, Champagne-Ardenne, north-eastern France). Journal of Archaeological Science 55: 71-82.
- Lantos, I., Spangenberg, J. E., Giovannetti, M. A., Ratto, N., Maier, M. S. 2015. Maize consumption in pre-Hispanic south-central Andes: chemical and microscopic evidence from organic residues in archaeological pottery from western Tinogasta (Catamarca, Argentina). Journal of Archaeological Science 55: 83-99.