antioxidants Article Impact of Cold versus Hot Brewing on the Phenolic Profile and Antioxidant Capacity of Rooibos (Aspalathus linearis) Herbal Tea 1, 2, 3, 3 Elisabetta Damiani y, Patricia Carloni y , Gabriele Rocchetti * , Biancamaria Senizza , Luca Tiano 1 , Elizabeth Joubert 4,5 , Dalene de Beer 4,5 and Luigi Lucini 3 1 Department of Life and Environmental Sciences, Università Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona, Italy;
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[email protected] (L.T.) 2 Department of Agricultural, Food and Environmental Sciences, Università Politecnica delle Marche, Via Brecce Bianche, I-60131 Ancona, Italy;
[email protected] 3 Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy;
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[email protected] (L.L.) 4 Plant Bioactives Group, Post-Harvest & Agro-Processing Technologies, Agricultural Research Council, Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa;
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[email protected] (D.d.B.) 5 Department of Food Science, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch) 7602, South Africa * Correspondence:
[email protected] These authors contributed equally to this work and are the first co-authors. y Received: 25 September 2019; Accepted: 20 October 2019; Published: 21 October 2019 Abstract: 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.