Non-Thermal Preservation of Fruit Juices

Consumers demand healthier fresh tasting foods without chemical preservatives. To address the need, food industry is exploring alternative preservation methods such as high pressure processing (HPP) and pulsed electric field processing. During HPP, the food material is subjected to elevated pressures (up to 900 MPa) with or without the addition of heat to achieve microbial inactivation with minimal damage to the food. One of the unique advantages of the technology is the ability to increase the temperature of the food samples instantaneously; this is attributed to the heat of compression, resulting from the rapid pressurization of the sample. Pulsed electric field (PEF) processing uses short bursts of electricity for microbial inactivation and causes minimal or no detrimental effect on food quality attributes. The process involves treating foods placed between electrodes by high voltage pulses in the order of 20–80 kV (usually for a couple of microseconds). PEF processing offers high quality fresh-like liquid foods with excellent flavor, nutritional value, and shelf life. Pressure in combination with other antimicrobial agents, including CO2, has been investigated for juice processing. Both HPP and PEF are quite effective in inactivating harmful pathogens and vegetative bacteria at ambient temperatures. Both HPP and PEF do not present any unique issues for food processors concerning regulatory matters or labeling. The requirements are similar to traditional thermal pasteurization such as development of a Hazard Analysis Critical Control Point (HACCP) plan for juices and beverages. Examples of high pressure, pasteurized, value added products commercially available in the United States include smoothies, fruit juices, guacamole, ready meal components, oysters, ham, poultry products, and salsa. PEF technology is not yet widely utilized for commercial processing of food products in the United States. The presentation will provide a brief overview of HPP and PEF technology fundamentals, equipment choices for food processors, process economics, and commercialization status in the food industry, with emphasis on juice processing. Paper published with permission.

Commercial Ethanol Production From Cellulosic Biomass in South Florida

Alico Energy, LLC, a subsidiary of Alico, Inc., has been awarded a grant from the State of Florida under the Florida Energy Act and a grant and loan guarantee from the U.S. Department of Energy to construct one of the nation’s first cellulosic ethanol facilities in South Florida. The Alico Energy biorefinery will be capable of co-producing ethanol and electricity from any carbon-based feedstock or waste, including citrus peel, and trimmings from citrus trees. The initial plant will produce only ethanol. The capacity to produce electricity will be added at a later date. Paper published with permission.

Innovative Mechanical Water Treatment for Evaporative Condensers at a Citrus Facility

This paper will describe the use of non-chemical technology for the treatment of cooling water from evaporative condensers at a citrus facility. The technology used is Controlled Hydrodynamic Cavitation (CHC). CHC is one of the most innovative technologies employed today and is unlike all other non-chemical technologies currently available that provide scale, corrosion, and microbiological control in addition to water conservation. The objectives of this study conducted in 2003–2004 were to: (a) provide scale, corrosion, and microbiological control to a state-of-the-art facility which cools one of the largest refrigerated enclosures in North America, (b) improve condenser operating efficiency over the existing condenser systems, (c) conserve water by minimizing condenser makeup, (d) produce a reduced quantity of condenser bleed with reduced levels of contaminants, and (e) implement environmental improvements and worker safety wherever possible. Based on the data obtained from the study, all objectives were met, operating expenditures were reduced, and the facility successfully continues to use the CHC technology. Paper published with permission.

Review of Dense Phase Carbon Dioxide Application to Citrus Juices

The United States is the second largest citrus producer in the world. Florida and California are the two major producing states. While oranges from California are mainly used for fresh fruit consumption, more than 90% of oranges produced in Florida are processed to juice (FAO 2008). Consumers demand high quality and convenient products with natural flavor and taste, and appreciate the “fresh” perception of minimally processed juices. They also look for safe, natural, and healthy products without additives and preservatives. New processing technologies promise to meet all these demands without compromising food safety. Commercial orange juice is thermally processed to inactivate pectinesterase (PE) and spoilage organisms. Active PE causes clarification of orange juice by cloud loss, which is considered a quality defect (Boff et al. 2003). Thermal processing can be detrimental to the organoleptic and nutritional qualities of the juice (Sloan 1995), so the development of non-thermal technologies (Barbosa-Canovas et al. 1998) is desirable in the citrus juice industry. Dense phase carbon dioxide (DPCD) is a non-thermal technology that can inactivate certain micro-organisms and enzymes at temperatures low enough to avoid the thermal effects of traditional pasteurization. This technology relies on the chemical effect of CO2 on micro-organisms and enzymes. DPCD pasteurization technology is commercially available. Most of the commercialization efforts so far have been from Praxair Inc. (Burr Ridge, IL). Based on technology licensed from the University of Florida (Balaban et al. 1988, 1998), Praxair developed a continuous system which uses the DPCD process as a non-thermal alternative to thermal pasteurization (Connery et al. 2005). This system has been commercialized under the Trade Mark “Better Than Fresh (BTF).” To date, Praxair has constructed four mobile BTF units for processing about 1.5 liters per minute for demonstration purposes. In addition, a commercial scale unit of 150 liters per minute was also constructed (Connery et al. 2005) and tested at an orange juice processing plant in Florida. There are other commercialization efforts. The excellent taste of the juice processed with this new technology was demonstrated in three independent sensory panels that compared juice treated with this system to that of fresh squeezed juice. In all the tests, no difference could be detected. It is important that CO2 is completely saturated in the juice if DPCD is to be successful. Saturation (equilibrium solubility) depends on the pressure, temperature, and composition of the juice. Until recently, the exact amount of CO2 to be used in DPCD processing was unknown since solubility data was unavailable at different pressures, temperatures, and juice compositions, and an excess amount was used. To optimize the use of CO2 in this non-thermal process, new equipment has been developed to measure the solubility of CO2 in liquid systems and juices. The objective of this paper is to present a general review of the applications of DPCD to citrus juices and to introduce the use of new equipment developed at the University of Florida to determine the solubility of CO2 in citrus juices. Paper published with permission.

Crossflow Filtration (Ceramic and Hollow Fiber Membranes) in the Citrus Industry

Crossflow filtration is becoming a cost-effective and preferred method of separation in the food and beverage industry. This paper introduces the concept of crossflow filtration and describes the different membrane technologies and materials. Additionally, advances in ceramic tubular and polymeric hollow fiber membrane technology are presented. New membrane configurations and their practical impact in the industry are discussed. Typical filtration applications in the citrus industry such as fruit juice clarification, clean-in-place (CIP) solutions recovery, and water recovery applications are highlighted. Paper published with permission.