Microencapsulation of probiotic microorganism by spray chilling and drying techniques and using possibilities in probitic cake production

Nowadays, product development studies involving microencapsulated probiotic microorganisms are often applied after a heat treatment. However, probiotic microcapsules, which are encapsulated in a heat stabilized matrix, can be applied to all types of process and food. The improvement of bakery products containing probiotic microorganisms can only be achieved by the production of new, high temperature tolerant probiotic microcapsules. For these reasons, there is a need for different combined microencapsulation techniques, such as spray drying and chilling, for increasing the tolerance of probiotic microorganisms to extreme conditions occurring in food process, storage and digestive system. In this study probiotic microorganisms (Saccharomyces boulardii, Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum BB-12) were encapsulated as single and double layered by spray drying and chilling technics and using possibilities of these microcapsules in chocolate cream filled, marmalade filled and chocolate coated cakes were also investigated. S. boulardii, L. acidophilus and B. bifidum enumeration, in vitro simulated gastric and intestinal test, heat stabilization test, storage stabilization test, moisture content and water activity, yield, tapped bulk density, particle size, DSC and SEM analysis were conducted with produced microcapsules. Additionally, cake samples were stored for 90 days at +4°C and microbiological, pH, titration acidity, texture and sensorial analysis were carried out by taken cake samples at 0th, 30th, 60th and 90th days. After the microencapsulation process, the highest S. boulardii, L. acidophilus and B. bifidum count were determined in microcapsule of P and the counts were 8.21, 8.10 and 8.25 log cfu/g, respectively. Additionally, survivability of microcapsules produced by spray chilling was higher than spray drying. According to in vitro gastric tests, the best protection was ensured in microcapsule of P and survivability of all probiotic microorganisms was more than 79% at the end of 180 min test period. The highest protection of S. boulardii and L. acidophilus was noted at microcapsule of GS in vitro intestinal tests and these counts were 7.44 and 7.11 log cfu/g, respectively. However, B. bifidum count was 6.78 log cfu/g in microcapsule of P and good survivability was detected at microcapsule of GS (89%). Moreover, survivability of probiotic microorganisms was detected more than 74% in all microcapsules at the end of 180 min. According to the results of the heat stabilization test, it was determined that the double layered microencapsulation did not affect the viability of S. boulardii and B. bifidum, but the survival of L. acidophilus was further protected. The counts of probiotics decreased with increasing incubation temperatures and S. boulardii, L. acidophilus and B. bifidum counts were determined as 28%, 47% and 48%, respectively at 80°C incubation temperature. On the other hand, non-microencapsulated free probiotic cells could not survive at increasing test temperatures. The highest protection was detected in microcapsule of P at +4°C storage for 45 days. Throughout the storage period, S. boulardii, L. acidophilus and B. bifidum counts were determined as 7.74, 6.86 and 5.91 log cfu/g, respectively. The survivability rate of each three probiotics was more than 60% at the end of the storage. Moisture content and water activity of microcapsules produced by spray chilling were 4.41% and 0.83, and these values were 11.00% and 0.53 for microcapsules produced by spray drying. Volume and surface mean diameter of microcapsules produced by spray drying were measured as 24.06 and 4.88 µm and these values were 612.54 and 244.55 µm for microcapsules produced by spray chilling. It was determined that the highest count of S. boulardii and L. acidophilus was obtained in the double layered microcapsules produced in the spray drying using the hydrophilic coating material and the outer layer using the hydrophobic coating material in the spray chilling system. After baking, S. boulardii and L. acidophilus count was 67.4% and 70.7%, respectively. Whereas B. bifidum count was not detected in each of microcapsules. On the first day of storage in chocolate cream filled, marmalade filled and chocolate covered cakes, the adequate probiotic microorganism number (>106 cfu/g) was achieved. However, during the storage period, the probiotic microorganisms count in the cake samples decreased, but the lowest decrease was detected in single layered microcapsules (P) produced by spraying chilling and in chocolate cream filled cake samples. Consequently, S. boulardii, L. acidophilus and B. bifidum were microencapsulated by spray drying and spray chilling technique as single or double layered. It has been determined that the microcapsule produced in the spray chilling system by hydrophobic wall material provides high protection against extreme conditions when compared with other microcapsule samples. Additionally, the double layer microencapsulation has been increased the in vitro gastric system and heat resistance of L. acidophilus. In this study, it was determined that double layered probiotic microcapsule sample (P/GS), ensured 103 log cfu/g survivability of S. boulardii and L. acidophilus in the cake samples with a central temperature of 102°C during baking. It was also found microcapsule of P, produced by spraying chilling method, provided higher probiotic microorganism protection in chocolate cream and marmalade filled cake samples during storage. When cake types were considered, chocolate cream filled cake samples were found to provide higher probiotic microorganism viability. As a result; double layered microcapsule (P / GS), inner layer produced with gum Arabic/cyclodextrin by spray drying and outer layer produced with hydrogenated palm oil by spray chilling in the cake mix, ensured 103 cfu/g probiotic microorganism survivability after baking of cakes. Additionally, it was determined that S. boulardii and L. acidophilus are suitable probiotic microorganisms for producing microcapsules with high thermal stability. It was evaluated that microcapsules produced with hydorogenated palm oil by spray chilling (P) could be used in choclate cream filled cake due to producing probiotic cake.