Anthocyanins degradation during storage of Hibiscus sabdariffa extract and evolution of its degradation products André Sinela a , Nadirah Rawat b , Christian Mertz b,⇑ , Nawel Achir c , Hélène Fulcrand d , Manuel Dornier c a Instituto Superior de Tecnologia Agro-alimentar de Malanje (ISTAM), EN 230 km 2, Malanje, Angola b Centre International de Recherche Agronomique pour le Développement (CIRAD), UMR95 Qualisud, TA B-95/16, 73 rue J.F. BretonF-34398, Montpellier Cedex 5, France c Montpellier SupAgro, UMR95 QualiSud, F-34093 Montpellier, France d Institut National de la Recherche Agronomique (INRA), UMR1083 SPO, F-34060 Montpellier, France article info Article history: Received 1 April 2016 Received in revised form 8 July 2016 Accepted 10 July 2016 Available online 12 July 2016 Keywords: Hibiscus sabdariffa Delphinidin 3-O-sambubioside Cyanidin 3-O-sambubioside Thermal degradation Kinetics abstract Degradation parameters of two main anthocyanins from roselle extract (Hibiscus sabdariffa L.) stored at different temperatures (4–37 °C) over 60 days were determined. Anthocyanins and some of their degra- dation products were monitored and quantified using HPLC–MS and DAD. Degradation of anthocyanins followed first-order kinetics and reaction rate constants (k values), which were obtained by non-linear regression, showed that the degradation rate of delphinidin 3-O-sambubioside was higher than that of cyanidin 3-O-sambubioside with k values of 9.210 7 s 1 and 8.410 7 s 1 at 37 °C respectively. The temperature dependence of the rate of anthocyanin degradation was modeled by the Arrhenius equation. Degradation of delphinidin 3-O-sambubioside (Ea = 90 kJ mol 1 ) tended to be significantly more sensitive to an increase in temperature than cyanidin 3-O-sambubioside (Ea = 80 kJ mol 1 ). Degradation of these anthocyanins formed scission products (gallic and protocatechuic acids respectively) and was accompanied by an increase in polymeric color index. Ó 2016 Elsevier Ltd. All rights reserved. 1. Introduction Anthocyanins represent the largest group of water soluble pig- ments in plants. They are highly appreciated in the food industry for their coloring properties, which can give food various hues of red and violet. Many edible plants are sources of anthocyanins, these include roselle calyces (Hibiscus sabdariffa)(Cisse et al., 2009; Du & Francis, 1973; Wong, Yusof, Ghazali, & Che Man, 2002). Hibiscus sabdariffa is an herbaceous plant, cultivated largely in tropical and subtropical areas of both hemispheres. Its calyces (consumed in large quantities in Africa and Asia as a beverage fol- lowing maceration in water) contain high amounts of antho- cyanins, especially delphinidin 3-O-sambubioside and cyanidin 3- O-sambubioside, up to 2.5 g/100 g DM (Du & Francis, 1973; Juliani et al., 2009; Wong et al., 2002). Recently, research carried out on anthocyanins has drawn much attention as they do not only impart beautiful coloration to food products but also have antioxidant properties and health benefits such as enhancement of sight acuteness, antioxidant capacity, con- trolling Type II diabetes, reduction of coronary heart disease and prevention of cancer (Peleg, Kim, & Normand, 2015; Thilakarathna & Rupasinghe, 2013). Heat processing (e.g., pasteurization and sterilisation) is an extremely common and effective method of preserving beverages but may result in quality loss (Kırca & Cemeroglu, 2003). Indeed, elevated temperatures can affect anthocyanin stability and cause monomeric anthocyanins to polymerize, resulting in browning, which is undesirable in products such as fruit juices because consumers perceive it as an indication of inferior quality (Kirca & Cemeroglu, 2003; Somers, 1968). A lot of studies have reported that degradation of anthocyanins, at relevant temperatures (up to 100 °C) in food processing or during storage follows first-order kinetics (Ahmed, Shivhare, & Raghavan, 2004; Cemeroglu, Velioglu, & Isik, 1994; Kirca & Cemeroglu, 2003; Patras, Brunton, O’Donnell, & Tiwarib, 2010). The aim of this study is to independently determine the kinetic parameters for delphinidin 3-O-sambubioside and cyanidin 3-O- sambubioside during calyces extract storage at various tempera- tures as well as analyzing changes in color and extract composition from a kinetic and mechanistic point of view. This will be helpful to limit anthocyanins degradation in Hibiscus extract during storage. http://dx.doi.org/10.1016/j.foodchem.2016.07.071 0308-8146/Ó 2016 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail addresses: andre_sinela@yahoo.com.br (A. Sinela), nadirah.rawat@gmail. com (N. Rawat), christian.mertz@cirad.fr (C. Mertz), nawel.achir@supagro.inra.fr (N. Achir), fulcrand@supagro.inra.fr (H. Fulcrand), manuel.dornier@cirad.fr (M. Dornier). Food Chemistry 214 (2017) 234–241 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem