Essential oils for preserving mucilage from chia seeds

Mucilage extracted from chia seeds (Salvia hispanica) is reckoning an increasing interest for its mechanical and nutritional properties. In food processing, the combination of different physical-chemical parameters is encountered; therefore, a thorough knowledge of the effect of these parameters on the raw material is required. Starting from the effect of temperature and pH on the rheological properties of chia mucilage suspensions (CM), the influence of ionic strength and time were considered together with the addition of stabilizing molecules. The rheological analysis performed on mucilage suspensions showed a plastic behaviour of the fluid. Among the parameters considered, the increase of temperature and ionic strength cause a decrease in the apparent viscosity of mucilage suspensions1,2 . Since freeze-dried mucilage dispersed in solvent undergoes modification, through autoxidation phenomena, that results in the change of the initial rheological characteristics. In order to limit the extent of depolymerization, an essential oil (lemongrass essential oil, LEO) is here emulsified with CM, and the rheological behaviors of samples in the presence and in the absence of LEO were compared. Flow curves of CM suspensions and of CM emulsions dispersing LEO (O/W-CM) demonstrated that both the systems can be classified as plastic fluids, and that during storage a general decrease of the viscosity of CM suspensions is detected, while the viscosity of the O/W-CM systems remaining constant3 . By means of an accelerated oxidative test, it was unveiled that the short-term stability of CM suspensions is attributable to the reaction of oxidation, and that the presence of LEO, due to its antioxidative properties, allowed for preventing degradation phenomena on the chia mucilage.