Next Article in Journal
Influence of Bioactive Compounds Incorporated in a Nanoemulsion as Coating on Avocado Fruits (Persea americana) during Postharvest Storage: Antioxidant Activity, Physicochemical Changes and Structural Evaluation
Next Article in Special Issue
Differentiation of Phenolic Composition Among Tunisian Thymus algeriensis Boiss. et Reut. (Lamiaceae) Populations: Correlation to Bioactive Activities
Previous Article in Journal
Impact of Intravenous Iron on Oxidative Stress and Mitochondrial Function in Experimental Chronic Kidney Disease
Previous Article in Special Issue
Isolation of Phytochemicals from Bauhinia variegata L. Bark and Their In Vitro Antioxidant and Cytotoxic Potential
Open AccessArticle

Impact of Cold versus Hot Brewing on the Phenolic Profile and Antioxidant Capacity of Rooibos (Aspalathus linearis) Herbal Tea

1
Department of Life and Environmental Sciences, Università Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona, Italy
2
Department of Agricultural, Food and Environmental Sciences, Università Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona, Italy
3
Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy
4
Plant Bioactives Group, Post-Harvest & Agro-Processing Technologies, Agricultural Research Council, Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
5
Department of Food Science, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch) 7602, South Africa
*
Author to whom correspondence should be addressed.
These authors contributed equally to this work and are the first co-authors.
Antioxidants 2019, 8(10), 499; https://doi.org/10.3390/antiox8100499
Received: 25 September 2019 / Revised: 15 October 2019 / Accepted: 20 October 2019 / Published: 21 October 2019
(This article belongs to the Special Issue Phenolic Profiling and Antioxidant Capacity in Plants)
Consumption of rooibos (Aspalathus linearis) as herbal tea is growing in popularity worldwide and its health-promoting attributes are mainly ascribed to its phenolic composition, which may be affected by the brewing conditions used. An aspect so far overlooked is the impact of cold brewing vs regular brewing and microwave boiling on the (poly) phenolic profile and in vitro antioxidant capacity of infusions prepared from red (‘fermented’, oxidized) and green (‘unfermented’, unoxidized) rooibos, the purpose of the present study. By using an untargeted metabolomics-based approach (UHPLC-QTOF mass spectrometry), 187 phenolic compounds were putatively annotated in both rooibos types, with flavonoids, tyrosols, and phenolic acids the most represented type of phenolic classes. Multivariate statistics (OPLS-DA) highlighted the phenolic classes most affected by the brewing conditions. Similar antioxidant capacities (ORAC and ABTS assays) were observed between cold- and regular-brewed green rooibos and boiled-brewed red rooibos. However, boiling green and red rooibos delivered infusions with the highest antioxidant capacities and total polyphenol content. The polyphenol content strongly correlated with the in vitro antioxidant capacities, especially for flavonoids and phenolic acids. These results contribute to a better understanding of the impact of the preparation method on the potential health benefits of rooibos tea. View Full-Text
Keywords: rooibos tea; metabolomics; polyphenols; in vitro antioxidant capacity; cold brewing; hot brewing rooibos tea; metabolomics; polyphenols; in vitro antioxidant capacity; cold brewing; hot brewing
Show Figures

Figure 1

MDPI and ACS Style

Damiani, E.; Carloni, P.; Rocchetti, G.; Senizza, B.; Tiano, L.; Joubert, E.; de Beer, D.; Lucini, L. Impact of Cold versus Hot Brewing on the Phenolic Profile and Antioxidant Capacity of Rooibos (Aspalathus linearis) Herbal Tea. Antioxidants 2019, 8, 499.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop