Encapsulation of flaxseed mucilage with spray drying and freeze drying

In this thesis, encapsulation of flaxseed mucilage extracted using distilled water with added maltodextrin and without maltodextrin (control) was carried out in spray dryer and freze dryer. In the first stage of the study, for the extraction of flaxseed mucilage, experimental design was created with response surface method. Seed: water ratio (0,0333, 0,079, and 0,125), extraction temperature (20, 55, and 90°C) and extraction time (30, 75, and 120 minutes) were selected as independent variables. In order to examine the effect of the extraction conditions on the extracted flaxseed mucilage, average gel yield (%), average dry matter (%) and °Brix values were chosen as the responses. Since the highest average dry matter and °Brix value were obtained at the extraction temperature of 90°C with 120 minute extraction time and the seed:water ratio of 0,125, the flaxseed mucilage extracted under these conditions were used in further drying experiments. In the second step, neat flaxseed mucilage (control), and the mucilage mixtures with maltodextrin having dextrose equivalent (DE) of 5-7 and maltodextrin with dextrose equivalent of 18-20 were prepared. Mucilage powders were obtained by spray dryer and freeze dryer. Samples were characterized using moisture content, bulk density, tapped density, flowability and stickiness, solubility, particle size distribution, color, viscosity, thermal properties and microstructure analysis. The lowest moisture content was observed in the control powder sample produced with the freeze dryer (p<0,05). Using of maltodextrin significantly increased the bulk density (p<0,05), whereas no significant difference was observed between different DE maltodextrins (p>0,05). All mucilage powder samples were found to be as "very hard to flow and highly sticky". Compared to the freeze dried mucilage powders, longer time was required to dissolve the powders produced by spray dryer. The particle sizes of the powders produced by freeze dryer were found to be larger than spray dried samples (p<0,05). L* values of spray dried mucilage powders were found to be the highest, while a* and b* values of powders produced with freeze dryer were found to be higher than spray dried samples (p<0,05). The apparent viscosity was significantly reduced by using of maltodextrins in the production of powders by the spray dryer (p<0,05). In both drying methods, phase transition temperatures were shifted for mucilage powders including maltodextrin.