chapter  5
- High-Intensity Pulsed Electric Field Applications in Fruit Processing
Pages 36

Nonthermal processes have gained importance in recent years due to the increasing consumer demand for food with a high nutritional value and “fresh-like” characteristics, representing an alternative to conventional thermal treatments. High-intensity pulsed electric ’elds (HIPEF) is a novel nonthermal technology that has been extensively studied for food processing. The application of electrical current for microbial inactivation and food treatment dates back to the beginning of the past century, but most of the advances were made in its last decade (Toep˜ et al., 2005). First HIPEF research studies were carried out in buffer or modeling solutions and later in food

5.1 Introduction .................................................................................................. 149 5.1.1 HIPEF Technology ........................................................................... 150 5.1.2 HIPEF Parameters ............................................................................ 151 5.1.3 HIPEF Equipment ............................................................................ 153 5.1.4 Energy Consumption and Cost ......................................................... 155

5.2 HIPEF-Assisted Processing of Fruits ........................................................... 156 5.2.1 Drying Processes .............................................................................. 156 5.2.2 Fruit Juice Expression ....................................................................... 158 5.2.3 Extraction and Recovery of Valuable Compounds ........................... 161

5.3 Preservation of Fruit Juices by HIPEF ......................................................... 164 5.3.1 Fruit Juice Pasteurization ................................................................. 164 5.3.2 Effects on Enzyme Activity .............................................................. 167 5.3.3 In˜uence on Product Quality ............................................................ 171

5.4 Advantages and Disadvantages of HIPEF .................................................... 173 5.4.1 Scale-Up Challenges ......................................................................... 174

5.5 Conclusions and Future Trends .................................................................... 174 Acknowledgments .................................................................................................. 175 References .............................................................................................................. 175

matrices such as milk and fruit juices. Food-related applications of HIPEF have been focused on attaining microbial and enzyme inactivation. The potential of HIPEF for food preservation is investigated based on the impact of processing parameters in obtaining safe high-quality HIPEF-treated ˜uid foods with an acceptable shelf life. Successful results have evidenced the suitability of HIPEF treatments at electric ’eld strengths higher than 10 kV/cm in processing several fruit juices since a high level of microbial destruction with little losses of ˜avor, color, taste, or nutrients has been achieved (Zhang et al., 1994; Barbosa-Cánovas et al., 1999; Barsotti and Chefter, 1999; Yeom et al., 2000a; Mosqueda-Melgar et al., 2008b; Aguiló-Aguayo et al., 2009a). Moreover, HIPEF has also received attention in the area of reversible and irreversible plant membrane permeabilization (Dörnerburg and Knorr, 1993; Knorr et al., 1994; Angersbach et al., 2000, 2002). The use of mild treatments (<10 kV/cm) as a pretreatment in food processing offers the potential as a complement to other processes (Olajide et al., 2006). Thus, the recovery and production of high-value metabolites (Brodelius et al., 1988; Dörnerburg and Knorr, 1993; Eshtiaghi and Knorr, 2002; Fincan et al., 2004), the improvement of fruit and vegetable juices yield (McLellan et al., 1991; Knorr, 1994; Bouzrara and Vorobiev, 2000; Ade-Omowaye et al., 2001a; Rastogi, 2003), and the acceleration of mass transport in drying processes (Angersbach and Knorr, 1997; Rastogi et al., 2000; Ade-Omowaye et al., 2001b; Taiwo et al., 2001; Tedjo et al., 2002) are some of the food processing areas in which HIPEF could offer great advantages.