Browsing by Author "Molina, M.T."

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    Rotary-moulded biscuits: Dough expansion, microstructure and sweetness perception as affected by sucrose:flour ratio and sucrose particle size
    (2021) Molina, M.T.; Vaz, S.M.; Leiva, Á.; Bouchon, P.
    Sucrose not only provides sweetness, but also modifies the thermal/viscoelastic behavior of dough during baking. Most research on biscuit manufacturing has been focused on sugar-snap and wire-cut biscuits, and there is a lack of accumulated knowledge with respect to rotary-moulded biscuits. The aim of this study was to analyze the effect of the sucrose:flour ratio and the particle size of sucrose on dough expansion and starch gelatinization during the baking of rotary-moulded biscuits, together with their link to sweetness perception. X-ray micro-CT and scanning electron microscopy were used to ascertain the link between sensory attributes and biscuit structural properties. Image analysis showed that biscuits with lower levels of sucrose resulted in a microstructure with smaller air pores and thinner walls, which may be related to a lower degree of grittiness and hardness at the first bite. Furthermore, the results revealed the partial gelatinization of starch in all formulations, along with a gelatinization degree that increased from 6 % to 40 % as the sucrose content decreased from 40 % to 10 % (d.b.). Interestingly, biscuits that were formulated with powdered sucrose at the highest concentration attained an expanded and non-collapsible structure, a behavior that could be linked to the low degree of starch gelatinization.
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    The effect of arabinoxylan and wheat bran incorporation on dough rheology and thermal processing of rotary-moulded biscuits
    (2021) Molina, M.T.; Lamothe, L.; Gunes, D.Z.; Vaz, S.M.; Bouchon, P.
    Wheat bran incorporation into biscuits may increase their nutritional value, however, it may affect dough rheology and baking performance, due to the effect of bran particles on dough structure and an increase in water absorption. This study analyzed the enrichment effect of wheat bran and arabinoxylans, the most important non-starch polysaccharides found in whole wheat flour, on dough rheology and thermal behaviour during processing of rotary-moulded biscuits. The objective was to understand the contribution of arabinoxylans during biscuit-making and their impact when incorporated as wheat bran. Refined flour was replaced at 25, 50, 75, or 100% by whole flour with different bran particle sizes (fine: 4% > 500 mu m; coarse: 72% > 500 mu m). The isolated effect of arabinoxylans was examined by preparing model flours, where refined flour was enriched with water-extractable and water-unextractable arabinoxylans. Wheat bran had the greatest impact on dough firmness and arabinoxylans had the greatest impact on the elastic response. The degree of starch gelatinization increased from 24 to 36% in biscuits enriched with arabinoxylans or whole flour and coarse bran. The microstructural analysis (SEM, micro-CT) suggested that fibre micropores may retain water inside their capillaries which can be released in a controlled manner during baking.