OPTIMIZATION OF ISOLATION FLAXSEED MUCILAGE FROM METHANOLIC EXTRACT AND ITS FUNCTIONAL CHARACTERISTICS

Composite design of three factors, isopropanol concentration, holding time and temperature were studied as an independent variables factors influencing in the isolation of flaxseed mucilage from methanolic extract. Rheological properties, emulsifying activity index (EAI), emulsion stability index (ESI), foam capacity and stability of isolated flaxseed mucilage (IFM) and crude flaxseed mucilage (CFM) were determined in comparison to other gums (Arabic gum, guar gum, carboxy methyl cellulose, xanthan or corn starch). Predicting individual isolation yield (Y) was assumed by quadratic polynomial regression model for the independent variables. A 60.6 % isopropanol concentration, 28.7 min. and 31.2 °C were the optimum conditions to produce the higher isolated flaxseed mucilage yield. Isolation process improved the dynamic viscosity of IFM compared to the CFM. Also IFM could be competing each of xanthan and guar gums. Flow behavior indexes (n) of the different polysaccharides were less than 1.0 indicating their pseudoplastic nature. IFM had higher consistency index (К) and lower n values than CFM implying that solution was more viscoelastic and shear thinning. IFM enhanced the EAI and ESI in a model system and came in the second order behind a guar gum while CFM came in the seventh order. IFM appeared a good ability to stabilize the foam model system whereas came in the first order compared to other polysaccharides. Color parameters were improved in the IFM compared to CFM with a significant differences (P 0.05). It could be concluded that the IFM can be possible to use as a stabilizer or a thickening agent in food products.