The influence of storage time on micronutrients in bottled tomato pulp Luis Eduardo Ordóñez-Santos a,b, * , Lourdes Vázquez-Odériz b , Enrique Arbones-Maciñeira c , Mª Ángeles Romero-Rodríguez b a Departamento de Ingeniería, Facultad de Ingeniería y Administración, Universidad Nacional de Colombia Sede Palmira, Carrera 32 N° 12-00 vía Candelaria, Valle del Cauca, Colombia b Áreas de Nutrición y Bromatología y de Tecnología de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Facultad de Ciencias, Campus de Lugo, 27002 Lugo, Spain c Departamento de Ingeniería Agroforestal, Universidad de Santiago de Compostela, Escuela Politécnica Superior, Campus de Lugo, 27002 Lugo, Spain article info Article history: Received 11 March 2008 Received in revised form 11 April 2008 Accepted 14 May 2008 Keywords: Lycopene b-Carotene Organic acids Total phenolics concentration HMF abstract Micronutrients were determined in bottled tomato pulp stored at room temperature (20.0 ± 1.8 °C) for 0, 60, 120 and 180 days. After 180 days, lycopene content had undergone no significant change (p > 0.05); ascorbic, malic and citric acid levels had fallen significantly (p < 0.001); and there were significant increases in b-carotene level (p < 0.001) and total phenolics concentration (p < 0.01). The fall in organic acid levels correlated well with the increase in 5-hydroxymethyl-2-furfural (HMF) (r 2 > 0.80). Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction Tomato is one of the most extensively marketed vegetable foods, with a worldwide production of 126 million Tm in 2005 (FAOSTAT, 2007). Its processed forms include pulp, purée, sauce, juice, paste and peeled whole tomato (Hayes, Smith, & Morris, 1998; Slimestad & Verheul, 2005). It is an important source of caro- tenes, organic acids and phenolics (Giovanelli & Paradiso, 2002; Loiudice et al., 1995). Consumption of its components, b-carotene and lycopene, has been related epidemiologically to lower inci- dence of cardiovascular disease and of prostate, gastrointestinal and epithelial cell cancer (Ishida & Chapman, 2004; Rao & Rao, 2007); its organic acids (which influence its shelf-life and organo- leptic properties, such as colour brightness and texture) contribute to acid–base balance for the consumer (Adedeji, Taiwo, Akanbi, & Ajani, 2006); and plant phenolics can have anti-inflammatory, anti-allergic and anti-thrombotic properties and may be beneficial in cardiovascular, neoplastic and neurological pathologies (Kusko- ski, Asuero, & Troncoso, 2005). The bioavailability of the nutrient content of tomato products depends on the processing that they have undergone and on the duration and conditions of storage (Sánchez, Plaza, De Ancos, & Cano, 2006). The effects of processing on lycopene, ascorbic acid and phenolics have been studied by several authors (Abushita, Daood, & Biacs, 2000; Calligaris, Falcone, & Anese, 2002; Dewanto, Wu, Adom, & Liu, 2002; Gahler, Otto, & Bohm, 2003; Noble, 1975; Re, Bramley, & Rice-Evans, 2002; Sahlin, Savage, & Lister, 2004; Shi, Maguer, Kakuda, Liptay, & Niekamp, 1999; Takeoka et al., 2001; Toor & Savage, 2006). However, there has been no comprehensive investigation of the stability of these and other micronutrients in tomato pulp during storage. The findings reported here fill this gap in our knowledge. 2. Materials and methods 2.1. Preparation and storage of tomato pulp A 50 kg sample of tomatoes (Lycopersicon esculentum Mill) for industry (cv. Red Spring) was purchased in Extremadura (Spain) during the summer of 2005, divided into six lots, and processed in a pilot-scale industrial plant in accordance with standard indus- try practices. The tomatoes of each lot were washed, diced mechanically in 1 cm cubes, heated at 80 °C for 1 min, and pulped at 3000 rpm for 2 min. The pulp was brought to pH 4.3 by addition of citric acid, transferred to 370 ml glass jars at 80 °C, sterilized by autoclaving at 120 °C for 30 min, and rapidly cooled to an average temperature of 24.5 °C by cascading water. The sterilization process parameters were chosen on the basis of previously determined heat penetration parameters (f h = 39.84 min, j h = 1.18) so as to achieve a lethality (F-value) 0308-8146/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2008.05.051 * Corresponding author. Tel.: +34 686214393; fax: +34 982285872. E-mail addresses: luedor4@hotmail.com, leordonezs@unal.edu.co (L.E. Ordóñez- Santos). Food Chemistry 112 (2009) 146–149 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem