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HERO ID
8199973
Reference Type
Journal Article
Title
The ramification of fermentation time on antioxidant properties of Napier grass herbal tea by black tea processing method
Author(s)
Ng, KS; Mohd Zin, Z; Mohd Maidin, N; Zainol, MK
Year
2020
Is Peer Reviewed?
0
Journal
Food Research
ISSN:
0095-974X
Publisher
Rynnye Lyan Resources
Volume
4
Issue
2
Page Numbers
349-357
Language
English
DOI
10.26656/fr.2017.4(2).265
Abstract
Tea fermentation relates to the enzymatic oxidation of the leaves of the tea and the formation of dark pigments. This method is usually conducted in a setting where temperature and humidity can be regulated. However, the impact of fermentation time on the antioxidant characteristics of Napier grass herbal tea is still unanswered. This study aimed to determine the effect of fermentation time on antioxidant properties of Napier grass black tea. Napier grass was subjected to fermentation for 3, 6, 9, 12 and 24 hrs. Fresh and dried samples were extracted in water (95°C, 30 mins) and the extracts were then analysed by total phenolic content (TPC) assay, total flavonoid content (TFC) assay, diphenyl-picryl-hydrazyl (DPPH) assay, Ferric reducing antioxidant potential (FRAP) assay, ferric thiocyanate (FTC) method and thiobarbituric acid (TBA) method. Sample fermented for 9 hrs showed the highest results in TPC (18.32±0.38) and FRAP assay (91.00±2.78). Whereas, the highest flavonoids and antioxidant activity were found in dried sample without fermentation (control) in TFC (97.82±13.00) and DPPH (90.02±1.11). However, samples fermented for 3 to 9 hrs showed no significant difference with that of the fresh sample in TFC and DPPH indicating 3 to 9 hrs fermentation time did not affect the antioxidant properties of Napier grass. In FTC and TBA, all the fermented samples showed lower antioxidant activity than that of fresh samples and control. The results suggested that 9 h of fermentation time is suitable for the preparation of Napier grass black tea as it exhibited high antioxidant properties in TPC, TFC, DPPH and FRAP assays. © 2019 The Authors. Published by Rynnye Lyan Resources.
Keywords
Antioxidant properties; Fermentation; Herbal black tea; Napier grass
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