New bioprocesses to prepare high energy density (HED) gruels for complementary young child feeding are being developed based on the ability of amylolytic lactic acid bacteria (ALAB) to modify the rheological characteristics of cereal-based slurries, provided appropriate pretreatment are applied. Gelatinisation is a common pre-treatment which could be implemented to enhance the action of amylases, and has been successfully used in a former study (Nguyen, T. T. T., Loiseau, G., Icard-Vernière, C., Rochette, I., Trèche, S., & Guyot, J.-P. (2007). Effect of fermentation by amylolytic lactic acid bacteria in process combinations on characteristics of rice/soybean slurries: a new method to prepare high energy density complementary foods for young children. Food Chemistry, 100, 623-631.) in combination with ALAB to prepare from a blend of rice/soybean flours semi-liquid fermented HED gruels with a high dry matter (DM) content (23-32%). In this study, it is shown that a mild pre-heating treatment which consists in suspending a rice/soybean flour blend in hot water (70°C) combined with high pressure homogenisation (HPH) can substitute gelatinisation before fermentation by the ALAB Lactobacillus plantarum A6 to prepare HDE gruels after cooking of the fermented slurry. As an alternative, allowing better condition of handling and storage, spray drying can be applied to such pre-heated HPH treated fermented slurries to obtain fermented flours which can be used further to prepare HDE gruels. © 2006 Elsevier Ltd All rights reserved.