Alternatives to reduce the bitterness, astringency and characteristic flavour of antioxidant extracts Gastón Ares a, * , Cecilia Barreiro a , Rosires Deliza b , Adriana Gámbaro a a Sección Evaluación Sensorial, Departamento de Ciencia y Tecnología de Alimentos, Facultad de Química, Universidad de la República, Gral. Flores 2124, C.P. 11800 Montevideo, Uruguay b EMBRAPA Food Technology. Av. das Américas, 29.501. Rio de Janeiro - RJ, Brazil article info Article history: Received 8 September 2008 Accepted 17 March 2009 Keywords: Antioxidant extracts Bitterness Astringency Flavour modification Functional foods abstract There is increasing interest in the development and use of polyphenolic-rich antioxidant extracts as func- tional ingredients. However, their bitterness, astringency and characteristic flavour could limit their incorporation in foods and beverages. Four alternatives to reduce the bitterness, astringency, and charac- teristic flavour of antioxidant extracts of two Uruguayan native plants (Achyrocline satureioides and Baccharis trimera) were studied: sucrose, sucralose, polydextrose, and milk. All the evaluated alternatives highly significantly (p < 0.001) reduced the bitterness, astringency and characteristic flavour of the extracts. However, their effectiveness depended on the type and concentration of the antioxidant extract being considered. Milk was the most effective inhibitor of the bitterness, astringency and characteristic flavour of A. satureioides extracts; whereas when extracts from B. trimera were considered, sucrose was the most effective alternative. Results from the present work suggest that sweetened dairy products could be interesting carriers for the development of functional foods containing polyphenolic-rich anti- oxidant extracts. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Functional foods can be regarded as foods with a health benefit beyond satisfying traditional nutritional requirements (Sanders, 1998). The functional food market has been growing worldwide in the last decade (Menrad, 2003). New functional food products are continuously launched and consumers have more choices available. An alternative for developing new functional food prod- ucts is incorporating new functional ingredients. Polyphenolic compounds are secondary metabolites of plants (Yilmaz, 2006) that are known to have nutritional as well as medic- inal functions in the human body (Ames, Shigenaga, & Hagen, 1990; Nair, Li, & Kong, 2007; Walton, Rhodes, Michael, & Parr, 1999). Polyphenolics are responsible for the potential antioxidant activity and radical scavenging capacity of plants (Kanner, Granit, German, & Kinsella, 1994; Salah et al., 1995; Vinson & Hontz, 1995). Natural antioxidants are particularly important in antioxi- dative defense to protect cells against the deleterious effects of free radicals on macromolecules such as proteins, lipids, carbohydrates and DNA (Halliwell & Gutteridge, 1984). In this context, there is an increasing interest in the development and use of polyphenolic- rich antioxidant extracts from different plants as potential func- tional ingredients for foods and beverages. Achyrocline satureioides (‘‘Marcela”) and Baccharis trimera (‘‘Car- queja”) are native South-American plants. They are widespread in Argentina, Brazil, Paraguay, and Uruguay. Infusions, decoctions and tinctures of these plants have been used for many years in natural and popular medicine (Filot Da Silva & Langeloh, 1994). These plants have been reported to have a high concentration of polyphe- nolic compounds (De Oliveira et al., 2003; Desmarchelier, Coussio, & Ciccia, 1998), which make them an interesting source of these functional ingredients. Polyphenolic compounds are the main responsible for the bit- terness and astringency of tea, red wine and several types of fruits (Lesschaeve & Noble, 2005). Therefore, the addition of these com- pounds to food products in considerable amounts could change their sensory characteristics, which may lead to a decrease in consumer acceptability and willingness to purchase the product (Tuorila & Cardello, 2002; Verbeke, 2006). This could limit the use of polyphenolic extracts from natural plants as functional ingredients. For this reason, alternatives to reduce the bitterness and astringency of polyphenolic extracts should be evaluated. However, the modification of bitterness and astringency of food products is not an easy task (Keast, 2008). There are basically three types of taste interactions which could be used to reduce the bitter taste of a compound: physico- chemical interactions, secondary interactions between one component of the food and the taste receptors/transduction of other component, and central cognitive mixture suppression 0963-9969/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodres.2009.03.006 * Corresponding author. Tel.: +598 2 9245735; fax: +598 2 9241906. E-mail address: gares@fq.edu.uy (G. Ares). Food Research International 42 (2009) 871–878 Contents lists available at ScienceDirect Food Research International journal homepage: www.elsevier.com/locate/foodres