Open AccessEffect of varying processing methods (optimal conditions) on chemical properties of herbal leaf tea produced from “Voi” (Syzygium nervosum) leaves
Author(s) -
N.P. Minh,
N.M. Chanh
Publication year - 2022
Publication title -
food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.218
H-Index - 7
ISSN - 2550-2166
DOI - 10.26656/fr.2017.6(2).741
Subject(s) - steeping , blanching , roasting , chemistry , food science , syzygium , dpph , tannin , ferric , antioxidant , herbal tea , botany , biology , organic chemistry
human health. Syzygium nervosum leaves contain numerous bioactive components withdifferent functional properties. Syzygium nervosum leaves can be processed into dried teaconvenient for daily consumption. This research evaluates the effect of various thermaltreatments like blanching, convective drying, roasting and steeping to the anti-nutritionalfactors, phenolics and antioxidant capacities in the S. nervosum dried leaf tea. Raw S.nervosum leaves were treated under different conditions of blanching (100/5, 95/10,90/15, 85/20, 80/25oC/s), convective drying (65/10, 60/12, 55/14, 50/16, 45/18oC/hrs),roasting (150/2, 145/3, 140/4, 135/5, 130/6oC/mins), and steeping (100/2, 90/3, 80/4, 70/5,60/6oC/mins). In each processing step, samples were taken to analyze tannin content,phytate content, oxalate content, total phenolic content, diphenylpicrylhydrazyl (DPPH)free radical scavenging and Ferric reducing antioxidant power (FRAP). Results show thatS. nervosum leaves should be blanched at 90/15oC/s, convective drying at 55/14oC/hrs,roasting 140/4oC/mins, steeping in hot water at 80/4oC/mins to remove anti-nutrientswhile preserving the highest phenolics and antioxidants in the S. nervosum dried leaf tea.Results of this research will contribute important scientific data for processors andconsumers in the exploitation of this medicinal plant as a healthy food drink.