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Durum wheat grains are used for producing food, such as pasta or couscous. The grain mechanical properties which are linked to its internal micro-structure (i.e. endosperm porosity) are known to determine its ability to produce semolina during milling. The proportion of grains having porous endosperm in a batch appears therefore as a critical quality factor for the durum wheat value chain. Our objective was to investigate the ability of X-ray micro-tomography (μCT) method to describe the porous or vitreous counterpart structures in the endosperm of durum wheat grains. We selected two different durum wheat samples displaying vitreous or partially porous endosperms. The grains were analyzed using μCT at two pixel sizes (1 μm or 7 μm). The μCT data collected at 7 μm pixel size were used for qualitative classification of grains according to apparent distribution curve of the porosity parameters. Analysis of μCT images at 1 μm pixel size allowed us to propose pore size classification in the vitreous and porous parts of the endosperm in three durum wheat grain. Results are used to better describe the durum-wheat endosperm microstructure, but requires long scanning periods. Image 1 • μCT was used to describe the internal microstructure of durum wheat grains endosperm. • μCT at 7 μm pixel size allowed qualitative discrimination of grains according to vitreousness. • μCT at 1 μm pixel size allowed describing distribution of internal porosity in the endosperm. • Porosity characteristics can be used to describe the dense and porous structures. [ABSTRACT FROM AUTHOR]

This paper describes a mixed fermentation model made by assembling block hosting models for the growth of lactic acid bacteria (Lactobacillus plantarum) and a yeast strain (Pichia kluyveri), metabolic production and the physical-chemical changes which occur during the fermentation of gowé. The growth model for P. kluyveri was developed on a synthetic medium following the gamma concept taking into account the effect of pH, temperature, concentrations in glucose, lactic acid and ethanol. Additional parameters for the previously defined L. plantarum growth model were also determined (glucose and ethanol concentrations). The model was validated in three different gowé processing conditions. Even if the model underestimates LAB growth, it explains what occurs in the product and enables in silico extrapolation to various fermentation conditions. The predicted hydrolysis rates of native and gelatinised starches showed that increasing malt content is not an efficient way to increase the sweetness of gowé in contrast to increasing the level of pre-cooking. The builing-block model developed in this study could be applied to many other fermented foods and particularly to non-alcoholic but acid and sweet cereal based beverages. • The gamma parameters for the growth of Pichia kluyveri were determined. • The simultaneous growth of P. kluyveri and Lb. plantarum was modelled. • Both strains compete for glucose that depends of amylolysis of gelatinized starch. • The developed global model allows optimizing rapidly the fermentation conditions. [ABSTRACT FROM AUTHOR]

Ablo is a rice or maize-based steam-cooked bread-like product, very popular in Benin, Togo and Ghana. This study optimized the processing steps of rice ablo using response surface methodology. The effect of precooking (proportions of flour and water, duration), kneading (wheat level, duration), fermentation (yeast level, temperature, duration) conditions to dough (gelatinization level, fluidity, proofing) and ablo (ethanol content, pH, density, cooking expansion, firmness, alveolar structure) properties were studied. It was demonstrated that ablo texture can be controlled by the fluidity of the fermented dough. Fluid fermented dough (at least 0.5 cm/s) expands adequately during steam-cooking and results in a less dense ablo in line with commonly consumed ablo. The optimal dough fluidity comes from a low gelatinization level of the precooked dough (less than 20%) and an intense fermentation (high yeast dose and long fermentation). Surprisingly, dough proofing appears to have no effect on final ablo expansion. [ABSTRACT FROM AUTHOR]