Optimization of fermentation time and grain concentration for water kefir production from butterfly pea flower (Clitoria ternatea)

Abstract

Herbal tea is known rich in bioactive compounds and pigments. Herbal tea can be derived from Butterfly pea flowers. Butterfly pea has a high level of anthocyanins and flavonoid levels. However, butterfly pea has not been used optimally in fermentation products such as water kefir. Water kefir has many benefits and potential antioxidant sources. This research aimed to optimize fermentation time (24-48 hours) and concentration grain (5-15%) for the production of butterfly pea water kefir with a good antioxidant activity using response surface methodology. Central Composite Design was used to develop models of the response. The response used in this research is antioxidant activity, flavonoid, anthocyanin and brightness. The optimum condition was obtained at 36 hours 2 minutes of fermentation time, and 15% of grain concentration using Design Expert 10.01. The optimum combination for butterfly pea water kefir resulted in 58 ppm of antioxidant activity, 39 of brightness, 81 mg/g QE of flavonoid and 4.2 ppm of anthocyanin. A validation experiment showed that no significant difference between actual and predicted values based on paired t-test (p>0.05) using Minitab 17.0.