title: Antioxidant capacity and phenolic composition of fermented Centella asiatica herbal teas.
abstract: BACKGROUND
  C. asiatica was exposed to various fermentations: no fermentation (0 min), partial fermentation (120 min) and full fermentation (24 h). Total phenolic content (TPC) and ferric-reducing antioxidant power (FRAP) of C. asiatica infusions were studied as a function of water temperature (60, 80 or 100 °C), the brewing stage (one, two or three) and the brewing time (1, 3, 5, 10, 15 or 20 min). The optimum brewing procedure was adopted to study the antioxidant properties and phenolic compounds in C. asiatica infusions.
  
  
  RESULTS
  The optimum extraction efficiency of C. asiatica infusions was achieved at 100 °C after a 10 min brewing time, and decreased substantially after applying multiple brewing steeps. However, no significant different was found between the second and third infusions. The non-fermented C. asiatica (CANF) infusion had the highest antioxidant activity. Gallic acid, naringin, chlorogenic acid, catechin, rutin, rosmarinic acid and quercetin were identified to present. Luteolin and kaempferol were only found in 80% methanol extraction method.
  
  
  CONCLUSIONS
  C. asiatica herbal teas should be prepared at 100 °C for 10 min to obtain the optimum antioxidant capacity. Multiple brewing steps in C. asiatica herbal tea are encouraged due to the certain amount of antioxidant obtained.
authors: Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia, 11700 Minden, Penang, Malaysia. fazilah@usm.my
authors: Fazilah
authors: F
authors: Ariffin
authors: Shio
authors: S
authors: Heong Chew
authors: Kaur
authors: K
authors: Bhupinder
authors: Alias A
authors: AA
authors: Karim
authors: Nurul
authors: N
authors: Huda
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D001628:Beverages / Q000032:analysis*; D028041:Centella / Q000737:chemistry*; D005285:Fermentation; D010636:Phenols / Q000032:analysis / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D013696:Temperature
chemical_list: D000975:Antioxidants; D010636:Phenols; D010936:Plant Extracts