INTRODUCTION

Fruits and their juices are important sources of mineral nutrients in human nutrition (Pennington and Fisher, 2010; Ribeiro et al., 2009; Wall, 2006). The worldwide consumption of fruit juices has been increasing requiring more and better production efficiency, sustained by technological development (AIJN, 2010). In general, the 100% fruit juice products are obtained by two different types of processing. Pure juices are produced directly by fruit extraction, usually by squeezed fruit, as raw material, obtained without dilution and without the addition of sugars (Bates et al. 2001). Juices from concentrate are produced by adding an adequate amount of water to concentrate previously obtained by partial dehydration of the fruit juices (Ashurst, 2005; Keshani et al., 2010; Mobhammer et al., 2006). The addition of sugars, up to 150 g/L is allowed in Portugal, but only if clearly stated on the product label. These products are manufactured in varieties containing only one fruit or mixtures of two or more fruits; they are pasteurized and presented to the market in two states of preservation: refrigeration with three months shelf life and at room temperature with twelve month shelf life.

The Portuguese legislation on fruit juices follows the Codex Alimentarius standards (FAO/OMS, 1992; FAO/WHO, 2005), best practices code of AIJN (Association of the Industry of Juices and Nectars) and defines the sales name of these products as: "… juice" for juices obtained by extraction and "… juice made from concentrate" for juices obtained by dilution of concentrate. Furthermore, it defines the ingredients and substances allowed, treatments, raw materials (as being all the fruits, although not considering the tomato as a fruit), and it also refers to t...

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...heir chemical composition (Bevelacqua et al., 2011; Rodushkina and Magnusson, 2005; Ros et al., 2007; Tangahu et al., 2011).

The fruit cultivar, agricultural practice and processing may be crucial factors determining the elemental content of the juice (Cisse et al., 2005; Fernandes, et al., 2011; Jalbani et al., 2010; Léchaudel and Joas, 2007 , Nienaber and Shellhammer, 2005).

From a general point of view, pre and post harvest factors determine the expected mineral nutritional value of fruit juices. In this work it was made an elemental characterization of fruit juices available in the Portuguese market. It was also correlated the elemental characterization of the fruit juices with pre harvest factors, like for example agriculture type (conventional or organic) and post harvest factors, like for example the mineral elements of dilution water used in the manufacture.