Encapsulation of beetroot betalains

In this thesis study, beetroot betalains were encapsulated using ionic gelation technique as an encapsulation method. The study consisted of five steps. In the first step, the optimum encapsulation process parameters were determined using Design-Expert (versiyon 7.0.0, Statease Inc., Minneapolis, MN, USA) program and responce surface methodology. In this step, the parameters which are effect to encapsulation process selected as coating material concentration (1, 2, 3%), core material concentration (70 °Bx beetroot juice concentrate) (5, 10, 15%) and waiting time (5, 32, 5, 60 min.). Sodium alginate was used as a coating material for encapsulation. In the second step, red calcium-alginate beads were produced by ionic gelation method using optimum process parameters. In the third step, beads were dried at 40 ºC during 20 hours using vacuum dryer. In the fourth step, changes of betalain stability and color values (L*, a*, b*) of beads which were produced at optimum conditions and dried using vacuum dryer were investigated during storage. Beads were storaged in jar coated with aluminum foil during 6 weeks at room temperature (25 ºC). Each week, samples were analyzed to detemine changes of betalain stability and color values. In the fifth and last step, beads were used as a colorant in yogurt and investigated efficiency. Optimum process parameters according to highest betalain amount in the beads were determined as 1,7% coating material concentration, 14,81% core material concentration and 5 min. waiting time. During the 6 weeks +a* (redness) value of beads have decreased. Reduction of +a* value were found statictically insignificant at the first 2 weeks (p>0,05) and significant from the third weeks (p<0,05). Furthermore, 16,17% of betalain was lost according to initial betalain amount of beads at the first 3 weeks. From the fouth weeks change of betalain amount was found statistically insignificant (p<0,05). It was determined that 79,48% of total betalain was preserved after 6 weeks. Release study was carried out in pure water and acidified water (pH 2.2) to make a comparison. At the end of the study, it was determined that 4.7% of the total betalains in the capsules in acidified pure water and 4.5% in pure water were transferred to the release medium. Capsule characteristics were determined by SEM (scanning electron microscope). When the images enlarged at 100, 250, 500, 2500 and 5000 times are examined, it is seen that the capsules are porous. It has been observed that the porous structure of the capsules release of bioactive components and betalaine in the release environment is effective. In order to investigate the use of dry capsules as colorants in model food, the capsules were homogenized for 2 min with the aid of ultra-turrax by adding 0.1 g, 0.3 g, 1 g, 3 g and 5 g into 100 g of whole fat yoghurt and the color values obtained were determined. The values of + a * (redness) of yoghurt colored with red calcium alginate capsules were 4.63 ± 0.02, 16.56 ± 0.03, 20.00 ± 0.04, 28.31 ± 0.09, 31, 79 ± 0,03.