This method followed Herbach et al. (2006) with slight modifications. For extraction, the fruits were halved and
peeled manually. The flesh was squeezed through a commercial sieve and the resulting juice was filtered
using miracloth. The pectin substances in the filtered juice were eliminated by precipitation with water at a
ratio of 2 mL water to 1 mL red dragon fruit juice. The filtrate was centrifuged at 10,000 rpm for 10 minutes to
remove precipitate. The supernatant was stored at 4°C for next procedure.