Changes on indigenous microbiota, colour, bioactive compounds and antioxidant activity of pasteurised pomegranate juice Pedro Mena a , Salud Vegara b , Nuria Martí b , Cristina García-Viguera a , Domingo Saura b , Manuel Valero c,⇑ a Departamento de Ciencia y Tecnología de Alimentos, CEBAS-CSIC, P.O. Box 164, E-30100, Espinardo, Murcia, Spain b IBMC.-JBT Corp., FoodTech R&D Alliance, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández (UMH)-Campus de Orihuela, Carretera de Beniel km 3.2, 03312 Orihuela, Alicante, Spain c Departamento de Producción Vegetal y Microbiología, Escuela Politécnica Superior de Orihuela (EPSO), Universidad Miguel Hernández (UMH)-Campus de Orihuela, Carretera de Beniel km 3.2, 03312 Orihuela, Alicante, Spain article info Article history: Received 18 December 2012 Received in revised form 16 April 2013 Accepted 25 April 2013 Available online 9 May 2013 Keywords: Pomegranate juice Microorganisms Thermal pasteurisation Colour parameters Anthocyanins Antioxidant capacity abstract Juices prepared from arils of ‘Mollar’ pomegranates were analysed for naturally occurring microorgan- isms, CIE Lab colour parameters, total phenols, anthocyanins and punicalagins, ellagic acid content and antioxidant capacity before and after low-, mild- and high-temperature pasteurisations (LTPs, MTPs and HTPs): 65, 80 and 90 °C for 30 or 60 s. Mean aerobic plate count (APC), yeast and mold count (YMC), and lactic acid bacteria (LAB) for fresh juices were 5.7, 5.36 and 4.0 log CFU/mL, respectively. MTPs and HTPs were sufficiently effective to decrease APCs to nil or negligible levels. An increase in CIE a values and decrease in CIE b values were the characteristic colour changes in heat-treated juices. The effect of pasteurisations showed that total phenols, punicalagins and ellagic acid were not much affected by ther- mal processing. Total anthocyanin content and antioxidant capacity were substantially and significantly influenced by the heat treatment applied. A linear relationship was observed between Trolox equivalent antioxidant capacity (TEAC) values and total anthocyanins, suggesting that they contributed strongly to the antioxidant capacity of pomegranate juice. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction The pomegranate (Punica granatum L.) belongs to the family Punicaceae which includes one genus and two species, the other one being P. protopunica Balf. peculiar to the island of Socotra. It is native from Iran to the Himalayas in Northern India (Meerts et al., 2009). Today, the pomegranate is widely cultivated through- out Turkey, Iran, Syria, Azerbaijan, Armenia, Afghanistan, India, Pakistan, Bangladesh, Iraq, Lebanon, Egypt, China, Myanmar (Bur- ma), Saudi Arabia, Israel, Jordan, the drier parts of Southeast Asia, the Mediterranean region of Southern Europe, and tropical Africa. It is also cultivated in subtropical areas of South America [from the Southern United States (US) to Chile and Argentine], the drier parts of California and Arizona in the US and Mexico (Çam, HisIl, & Durmaz, 2009; Sepúlveda et al., 2010). Over 1000 cultivars of P. granatum exist (Levin, 1994). Spain is the major European producer of pomegranates and its production exceeded 22,000 tons in 2009 (MARM, 2010). Most of this production takes place in the Southeast of Spain, where the pomegranate tree is adapted to poor and saline soils of this semi-arid area, contributing to the reduction in the risk of desertification (Melgarejo, Salazar, & Artés, 2000). ‘Mollar’ and ‘Valenciana’ as the most widely spread cultivars in the local area, display very attractive sensorial characteristics for Spanish con- sumers (Mena, García-Viguera, et al., 2011). Due to the specific and health-related properties of the pome- granate’s phytochemicals (Mena, Gironés-Vilaplana, Moreno, & García-Viguera, 2011; Viuda-Martos, Fernández-López, & Pérez- Álvarez, 2010), this fruit which is traditionally used for production of grenadine syrup or consumed as fresh fruit, has gained increas- ing popularity in recent years. Pomegranates are delicious and fun to eat, but the fruit is difficult to peel and, therefore, a drawback exists to eating it more regularly. Accordingly, minimally fresh processed ‘ready-to-eat’ pomegranate arils (Ayhan & Estürk, 2009; Ergun & Ergun, 2009; López-Rubira, Conesa, Allende, & Artés, 2005) and, above all, processed products, such as canned bever- ages, jellies, jams and especially pomegranate juices, are preferred. Pomegranate juice is an important source of anthocyanins, ellagit- annins and ellagic acid derivatives (Borges, Mullen, & Crozier, 2010; Mahdavi, Nikniaz, Rafraf, & Jouyban, 2010). The levels vary in juices prepared from different pomegranate cultivars, maturity stage, growing region, cultural practice, storage conditions of fruits and extraction procedure (Gil, Tomás-Barberán, Hess-Pierce, Holcroft, & Kader, 2000; Tzulker et al., 2007). 0308-8146/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.foodchem.2013.04.118 ⇑ Corresponding author. Tel.: +34 96 674 96 83; fax: +34 96 674 96 19. E-mail address: m.valero@umh.es (M. Valero). Food Chemistry 141 (2013) 2122–2129 Contents lists available at SciVerse ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem