Quality and shelf life of orange juice aseptically packaged in PET bottles Marı ´a Ros-Chumillas, Yulissa Belissario, Asuncio ´n Iguaz, Antonio Lo ´pez * Technical University of Cartagena, Agricultural Equipment and Food Engineering Department, Paseo Alfonso Xlll. 48, 30203 Cartagena, Spain Abstract A packaging study of orange juice aseptically packaged in bottles using different materials and filling procedures was conducted to determine their influence on the evolution of juice quality and shelf life. Glass, multilayer PET (polyethylene terephthalate) and mono- layer PET bottles were used. A characterisation study including DSC thermograms, intrinsic viscosity and scanning electron microscopy (SEM) photographs let identify the different material used, taking part in multi- and monolayer PET bottles for juices packaging. Mono- layer PET showed the lowest retention of ascorbic acid during storage and shelf life compared with multilayer PET and glass. But if different factors, such as oxygen scavenger, liquid nitrogen drop addition in headspace during filling, aluminium foil seal in screw-cap and refrigeration temperatures, are combined with the monolayer PET bottles, orange juice shelf life can be extended and values similar to glass and multilayer PET bottles can be obtained. Keywords: Orange juice; Aseptic packaging; PET bottling; Glass bottling; Shelf life 1. Introduction Over the past few years the consumption of fresh citrus fruits has decreased in developed countries. Processed products, especially juice, have become more popular because they are easier to be consumed and are products of a high nutritional quality. Among citrus juices, orange juice is the most appreci- ated and consumed because of its pleasant taste and its high content of vitamin C. Quality and shelf life determina- tion of an orange juice is strongly based on vitamin C evo- lution during storage although there are other quality parameters such as colour and flavor characteristics that are also very important (Lee & Coates, 1999; Meydev, Saguy, & Kopelman, 1977; Zerdin, Rooney, & Vermue ¨, 2003). Vitamin C is an essential nutrient for humans and, because of its high antioxidant power it provides protection against the presence of free radicals participating in the prevention of many diseases (Tannenbaum, Archer, & Young, 1985). However, and because of its nature, vitamin C is oxidized and lost during the storage period of the juice. The rate of degradation of the vitamin C highly depends on the storage conditions (Kabasakalis, Siopidou, & Moshatou, 2000). Among the factors affecting vitamin C loss in packed orange juice, temperature, dissolved oxygen and oxygen barrier provided by the container material should be considered (Tannenbaum et al., 1985). The choice of the packaging material for fruit juices is a crucial point regarding shelf life and much research has been done on this subject (Askar, 1999; Ebbesen, 1998; Siegmud, Derler, & Pfannhauser, 2004; Zerdin et al., 2003). However, aspects relating to product quality during the shelf life of the product as well as costs should be con- sidered, too. * Corresponding author. Fax: +34 968325433. E-mail address: antonio.lopez@upct.es (A. Lo ´ pez).