Extract of Stevia leaf of rebaudiana Bert has a content that is easily oxidized by the presence of light and heating so it is not stable during storage. A microencapsulation process is carried out which aims to protect the contents in the extract. This study aims to determine the effect of storage temperature on the physical stability of the microencapsulation of Stevia leaf of rebaudiana Bert with a combination of encap sulants inulin chitosan. A study was conducted to determine the effect of temperature on the mi-croencapsulation stability of Stevia leaf of rebaudiana Bert over a period of 1 month. Tests carried out on the microencapsulation of Stevia leaf of re-baudiana Bert include the examination of the physical parameters of the microcapsules, namely the microencapsulation yield, moisture content, sol-ubility, flow rate, non-encapsulated and encapsulated extracts content and determination of particle distribution and morphological form. The test results show that the storage temperature does not affect the microen-capsulation stability of Stevia leaf of rebaudiana Bert, because the SEM test results did not change i.e. the particle size distribution of 1 - 1000 μm. The average yield obtained from making microencapsulation of Stevia leaf extract of rebaudiana Bert was 98.20%. Storage temperatures of 5？C, 25？C and 40？C affect the physical stability of the microencapsulation of Stevia leaf extract of rebaudiana Bert due to changes in the profile of physical characteristics during storage.
Stevia leaf contains several sweetening compounds such as steviosida, rebaudiosida A, B, C, D, E and dulcoside A and B. Steviosida has no teratogenic effect [
This study aims to determine the effect of temperature (5˚C, 25˚C, 40˚C) on the microencapsulation stability of Stevia leaf of rebaudiana Bert conducted over a period of 1 month with physical characteristics as parameters tested. The temperature selection represents the storage conditions of cold temperature, room temperature and hot temperature. Storage conditions in the refrigerator range between temperature 5˚C ± 3˚C [
The choice of encapsulation is also very influential on the success of nanoencapsulation. Carbohydrates are widely used in encapsulation, but research on inulin as encapsulation is still limited. The use of inulin as encapsulant in nanoencapsulation also has limitations such as large particle size, besides that inulin also has a sticky character and hygroscopic thus limiting their use as encapsulants. To produce nanoscale particle size in the encapsulation of stevia leaf extract, the presence of inulin can be partially replaced by chitosan. Chitosan is a natural polymer that can be linked by crosslink when a crosslinked agent is added (Sarah, 2001).
The tools used are spray dryer (Buchi Mini Spray Dryer B-29-), rotary vacuum evaporator (Buchi R-114), Scanning Electron Microscope (JEOL JSM-5310LV-20 kV), analytical balance, homogenizer (Ultra TurraxÒ T50 Basic), and glassware. The materials used in this study consisted of stevia leaves obtained from Solo. Inulin, chitosan, 1% acetic acid, Tween 80 1%.
The microencapsulation of Stevia leaf extract made an emulsion system with the ratio of inulin encapsulation: chitosan is 25:75b/b. Chitosan is dissolved in 1% acetic acid and then Tween 80 1% emulsifiers are added. Furthermore, inulin is put into chitosan solution and homogenized using Homogenizer Ultra TurraxÒ T50 Basic with a speed of 5000 rpm for 5 minutes. Furthermore, the microencapsulation process of stevia leaf extract is carried out using the spray drying method at a feed rate of 15 ml/minutes and inlet temperature 120˚C. The resulting powder is a microcapsule whose properties are analyzed. Microencapsulation preparations that have been made are then divided into 3, then stored at temperature of 5˚C, 25˚C and 40˚C. Next, the physical parameters of the microcapsules were analyzed, namely the microencapsulation yield, the moisture content, solubility, flow velocity, the level of the non-encapsulated and encapsulated extracts and the determination of particle distribution and morphological form.
Microencapsulation yield was evaluated by comparing the weight of the material after processing it with the material before processed [
Microparticles are measured using a moisture meter (moisture balance) at temperature of 105˚C. Then the moisture content of the constant is calculated [
Solubility is evaluated by dissolving 1 gram of sample in 25 ml distilled water and then filtered, filtered paper to obtain residual weight, the results obtained are then calculated against the sample weight to determine the percent of sample that can be dissolved [
Flow speedy is evaluated by inserting a few samples in the flow funnel and then determining the time required for the entire sample to flow [
Determined by 1 gram of sample was immersed in 20 ml of ethanol, then filtered and the filtrate was measured using a spectrophotometer.
Determination of the size distribution of microparticles is done using a light microscope and Scanning Electron Microscope (SEM) [
The average yield obtained from making microencapsulation of Stevia leaf extract of rebaudiana Bert is 98.20%. The yield obtained is quite high, possibly due to the process temperature of low freeze dry so that there is no sublimated material other than water. From the SEM analysis results in
| Materials | F1 |
|---|---|
| Stevia leaf extract(ml) | 100 |
| Inulin (g) | 2.075 |
| Chitosan (g) | 6.225 |
| Acetic acid 1% (ml) | 8.3 |
| Tween 80 1% (ml) | 8.3 |
The results of microencapsulation physical stability test of Stevia leaf extract of rebaudiana Bert can be seen in
Unencapsulated extracts are more susceptible to oxidation and thus reduce the quality of microencapsules [
| Treatment. | Solubility (%) |
|---|---|
| 1 | 97.96 ± 0.01 |
| 2 | 97.94 ± 0.01 |
| 3 | 97.96 ± 0.11 |
| 4 | 97.95 ± 0.01 |
| 5 | 97.96 ± 0.20 |
| 6 | 97.96 ± 0.01 |
| 7 | 97.93 ± 0.01 |
| 8 | 97.96 ± 0.01 |
| 9 | 97.92 ± 0.02 |
| 10 | 97.96 ± 0.01 |
| 11 | 97.94 ± 0.01 |
| 12 | 97.96 ± 0.02 |
| 13 | 97.96 ± 0.01 |
Information: Treatment 1: 0 week storage; Treatment 2: 1 week storage at a temperature of 5˚C; Treatment 3: 1 week storage at a temperature of 25˚C; Treatment 4: 1 week storage at a temperature of 40˚C; Treatment 5: 2 week storage at a temperature of 5˚C; Treatment 6: 2 week storage at a temperature of 25˚C; Treatment 7: 2 week storage at a temperature of 40˚C; Treatment 8: 3 week storage at a temperature of 5˚C; Treatment 9: 3 week storage at a temperature of 25˚C; Treatment 10: 3 week storage at a temperature of 40˚C; Treatment 11: 4 week storage at a temperature of 5˚C; Treatment 12: 4 week storage at a temperature of 25˚C; Treatment 12: 4 week storage at a temperature of 40˚C.
Storage temperatures of 5˚C, 25˚C and 40˚C affect the physical stability of the microencapsulation of Stevia rebaudiana Bert leaf extract.
The Ministry of Research, Technology, and Higher Education for the SKIM Inter-College Research Grant Number DIPA-228/SP2H/LT/DPRM/2019.
The authors declare no conflict of interests.
Mutmainah, Martono, Y., Franyoto, Y.D. and Kusmita, L. (2019) Microencapsulation Stability of Stevia Leaf Extracts of Stevia rebaudiana Bert Using Inulin-Chitosan. Open Access Library Journal, 6: e5925. https://doi.org/10.4236/oalib.1105925