ICYTAC   23898
INSTITUTO DE CIENCIA Y TECNOLOGIA DE ALIMENTOS CORDOBA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Effect of planetary ball milling on rice-flour viscosity profile
Autor/es:
LOUBES MA ; PALAVECINO P ; BARRERA GN ; TOLABA MP
Lugar:
CÓRDOBA
Reunión:
Congreso; V Congreso Internacional de Ciencia y Tecnología de Alimentos (CICYTAC 2014); 2014
Institución organizadora:
Ministerio de Ciencia y Tecnología de Córdoba
Resumen:
Rice flour is used to make rice pasta, rice bread and typical Asian foods. Rice flours are often modified to change the functional properties in order to extend its applications as a food ingredient. Different methods, like extrusion, fermentation, hydrothermal treatment and ball milling are being investigated to produce rice-flour modifications. Among the most important functional properties of flours are their pasting properties. Although the viscosity of rice starch, rice flours and other flour mixtures has been extensively studied, very limited research on the RVA profile of modified rice flours by high impact milling has been reported. The objective of this work was to study the influence of ball milling conditions on pasting properties of rice-flour. The effect of particle size and damaged starch content was also analysed. A Retsch PM100 mill with zirconium oxide jar and beads (30 mm diameter) using a ball to rice ratio of 3.35:1 was adopted. Ball milling protocol included grinding-pause cycles, the process conditions were set based on milling speed (450-650 rpm) and processing time (10-40 min). Pasting properties were evaluated using a Rapid Visco Analyser (RVA), damaged starch proportion was determined by enzymatic test and particle size by laser diffraction technique. Control sample was ground in a Butt mill. Significant effects of milling conditions on RVA parameters were found based on a full factorial design and RSM method. With the exception of setback, the interaction effect was significant. Therefore, the effect of milling time was dependent on milling speed level. At 450 and 550 rpm peak viscosity increases with increasing milling time up to a maximum value (6275 and 5969 cp respectively). This behaviour is due to the fact that the grinding in the first steps promotes increasing interaction among flour particles. However, for particle size lower than 100 microns, as it was obtained with increasing milling speed, a continuous reduction in peak viscosity was observed as milling progresses. At these milling conditions the increase of damaged starch content (up to 16.5 %) promotes a significant reduction on the viscosity profile. Damaged starch content showed significant correlations with peak viscosity (r = - 0.71), final viscosity (r = - 0.93) and setback (r = - 0.74) while the median for a volume distribution (D50) was correlated with setback (r = 0.93). Considering the results the proposed method provided a food ingredient which can be used as a good thickener. It is expected that the modifications introduced by the planetary ball mill can diversify the use of modificated flours beyond traditional applications