ICYTAC   23898
INSTITUTO DE CIENCIA Y TECNOLOGIA DE ALIMENTOS CORDOBA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Study of starch destructuration in water/Ionic liquid mixtures
Autor/es:
SCIARINI LS; ROLLAND-SABATÉ A; GUILOIS S; LOURDIN D; LEROY E; LE BAIL P
Lugar:
Niza
Reunión:
Jornada; Jornada de Líquidos Iónicos y Biopolímeros; 2014
Institución organizadora:
Ecole de Mines
Resumen:
Starch is one of the most abundant biopolymers in nature, and, considering its low cost and renewability, can be considered as a raw material for the elaboration of biodegradable materials. In the last years, ionic liquids (ILs) have been proposed as solvents for starch dissolution and plasticization. However, the thermal behavior of starch when suspended in ILs is still unclear. Thus, the objective of this work was to study the effect of two ionic liquids (ILs), cholinium acetate (CholAc) and 1-ethyl 3-methyl imidazolium acetate (EMIMAc) on the thermal properties of regular corn starch. Solutions of different concentrations of ILs in water were used, from 100% w/w (pure IL) to 0% w/w (pure water). The behavior of starch suspensions when heated in these solutions (20% w/w starch) was analyzed by micro differential scanning calorimetry (µDSC) and light microscopy. Starch macromolecular characterization after heating was carried out with high performance size exclusion chromatography (HPSEC) coupled with multi angle laser light scattering (MALLS) and viscosimetry. µDSC results indicated that starch gelatinization was the dominating enthalpic transition when ILs content was lower than 60% w/w). When ILs concentration was higher, an exotherm was observed, and this transition occurred at higher temperatures as ILs concentration increased, while enthalpy value was also increased. Images of starch/IL/water systems before and after the exothermic or endothermic transition (depending on ILs %) were taken by using a light microscope. It was observed that before the transitions, starch was present in a granular form. After gelatinization, the presence of swelled granular remnants was evident, whereas after the exothermic transition a more homogeneous structure was detected, without any remaining granular structure. HPSEC-MALLS results clearly showed that, after heated in high concentrated ILs solutions, starch weight average molar mass was reduced from 4.4x108 to 0.8x108 g.mol-1, indicating a depolymerization of starch. From these results, it is concluded that starch can be readily solubilized using ILs (as shown by microscopic images). Solubilization without gelatinization was observed when 80% CholAc or 70% EMIMAc were used. However, care must be taken considering starch can be also modified during this process (shown with µDSC and HPSEC results).