Developments of spray-dried Kombucha tea beverage
Kombucha tea (KT) is a healthy and refreshing beverage obtained from the fermentation of sugared tea by symbiotic cultures of acetic acid bacteria and fungi. However, KT will eventually turn too sour to drink and will become vinegar if over fermented. Therefore, this study aimed to evaluat...
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| Format: | Thesis |
| Language: | English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/85741/1/FSTM%202020%2011%20-%20IR.pdf |
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| Summary: | Kombucha tea (KT) is a healthy and refreshing beverage obtained from the fermentation of sugared
tea by symbiotic cultures of acetic acid bacteria and fungi. However, KT will eventually turn too
sour to drink and will become vinegar if over fermented. Therefore, this study aimed to
evaluate the effects of spray drying on the physicochemical, antioxidant and
antibacterial properties of KT. Two wall materials including maltodextrin (MD) and
Arabic gum (AG) were used. The physiochemical properties of the spray dried kombucha were
16.33±0.58 Brix° for total soluble solid, 3.48±0.13% for moisture content, 0.25±0.34 for water
activity, 3.28±0.03 for pH, 0.42±0.004 g/cm3 for bulk density and 47.27±2.50% for wettability.
The antibacterial activity significantly (p<0.05) after the kombucha fermentation, while no
significant effects observed for the spray drying process on the activity. Spray dried kombucha tea
powder produced using AG as wall material showed good physical properties, antioxidant properties
and strong antibacterial activity compared to MD. Moreover, second objective is to optimize the
condition of production of dried kombucha tea using selected wall materials.
Optimization for the spray dried conditions was carried out using surface methodology surface (RSM)
with box Behnken design (BBD) for the factors inlet temperature (140 – 180ºC), feed flow rate
(25-35 rpm) and aspirator rate (80-100). The optimal conditions estimated for the process were
inlet temperature at 178°C, feed flow rate at 25 rpm, and aspirator rate at 80%. The RSM model was
significant and inlet temperature was the variable with the greatest impact on most of the
responses. The third objective is to characterize the properties of optimized
powdered kombucha tea. Metabolomics profiling was performed using ¹H NMR based
technique. Major metabolites changes were observed for the significant decline of sucrose (17.8626
mmol/L) in unfermented tea and increase ethanol (1.8393 mmol/L) and glucose (2.6751 mmol/L)
in the fresh kombucha tea. The acetic acid was significantly reduced (0.053 mmol/L) and the
ethanol was totally degraded in the spray dry kombucha tea. The results indicated that the spray
drying process using 10% AG can improve the physiochemical properties of kombucha and sustain it
is antioxidant and antibacterial activities. Moreover, the spray drying process caused
degradation of ethanol making kombucha safe for alcohol allergic and
Halal concerned consumers. |
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