Ohmic heating. Ohmic heating is a thermal processing method in which an alternating electrical current is passed through food products to generate heat internally. Ohmic heating is said to produce a uniform, inside-out heating pattern that heats foods faster and more evenly than conventional outside-in heating methods. According to Lima et al. , potential applications for ohmic heating relevant to fruit and vegetable processing include blanching, evaporation, dehydration, fermentation, and extraction. In tests at the Louisiana State University Agricultural Center, sweet potato samples were processed using ohmic heating prior to freeze drying. Ohmic heating reportedly increased the rate of freeze-drying up to 25% compared to samples that did not undergo ohmic heating, which led to significant savings in both processing time and energy use . However, ohmic heating parameters such as the frequency of the alternating current, the applied voltage, the temperature to which the sample is heated, and the electrical conductivity of the food can all have a significant effect on the performance of the process. Infrared drying. In conventional drying methods, substantial amounts of air must be heated and circulated around the product to be dried. In contrast, infrared drying uses infrared radiation to heat only the material that needs to be heated—not the surrounding air—and thus saves energy compared to conventional methods. For drying apple slices, a comparison of infrared drying with convective drying done using equivalent processing parameters showed that energy costs were lower and that the time of the drying process could be shortened by up to 50% using infrared methods . Pulsed fluid-bed drying. The pulsed fluid-bed dryer is a modification of the conventional fluid-bed dryer . In pulsed fluid-bed drying, grow bucket gas pulses cause high-frequency vibrations within the bed of product particles.

Reported advantages of the pulsed fluid-bed drying approach include easier fluidization of irregular particle shapes, fluidization with 30% to 50% less air than conventional methods , and reduced channeling of particles . Additionally, pulsed fluid-bed dryers are roughly half the size of conventional conveyor-type dryers. Successful trial applications in the food industry include the drying of carrot cubes and the drying of chopped onions. In the drying of carrot cubes, a pulsed fluid-bed dryer reduced the total drying time by two to three times compared to traditional fluid-bed drying methods while providing a final product that was highly uniform in color and moisture content. Similarly, for chopped onions, the final products were of high color and reconstitution quality and uniform in moisture content . Pulsed electric field pasteurization. Pulsed electric field pasteurization for juices may provide superior taste and freshness compared to juices undergoing conventional heat treatment. In the pulsed electric field process, liquids are exposed to high voltage pulses of electricity to inactivate harmful micro-organisms as well as enzymes that degrade the quality of fruit juices over time. The energy savings associated with pulsed electric field processing arise from the fact that the process operates at lower temperatures than conventional heat-based pasteurization methods and thus the pasteurized juices require less cooling energy . Pulsed electric field pasteurizing has been successfully employed by the Genesis Juice Corporation of Eugene, Oregon, in the production of organic bottled fruit juices . The company reported that the major motivation for using the new technology was to avoid the loss of flavor associated with conventional thermal pasteurization methods.Geothermal heat pumps for HVAC. 

Geothermal heat pumps take advantage of the cool, constant temperature of the earth to provide heating and cooling to a building. To date, most applications of geothermal heat pumps have been in the residential and commercial sectors rather than in the industrial sector. However, geothermal heat pumps may be a viable replacement for traditional HVAC systems in office or warehouse spaces in the fruit and vegetable processing industry. In winter, a water solution is circulated through pipes buried in the ground, which absorbs heat from the earth and carries it into the building structure. A heat pump system inside the building transfers this heat to air that is circulated through the building’s duct work to warm the interior space. In the summer, the process is reversed: heat is extracted from the air in the building and transferred through the heat pump to the underground piping, where heat is transferred back to the earth. The only external energy needed is a small amount of electricity to operate fans and ground loop pumps . The Geothermal Heat Pump Consortium claims that the technology can reduce space heating and cooling energy consumption by 25% to 50% compared to traditional building HVAC systems.Carbon dioxide as a refrigerant. In the food industry, CO2 can be used for quick freezing, surface freezing, chilling, and refrigeration. In cryogenic tunnels and spiral freezers, high pressure liquid CO2 is injected through nozzles that convert it to a mixture of CO2 gas and dry ice that covers the surface of the food product. Liquid CO2 is reported to generate faster cooling rates than conventional freezing processes. In addition, liquid CO2 freezing equipment eliminates the need for compressor systems, thereby taking up less room than comparable mechanical freezers. Since 2001, the frozen vegetable producer Ardo B.V., located in Zundert, the Netherlands, has been operating a 560 kW combined ammonia-CO2 freezer, which uses ammonia in the higher temperature range and CO2 in the lower temperature range.

The energy savings of this system, in comparison to a conventional ammonia-based expansion system, have been estimated at around $66,000 per year. The estimated payback period is 11 years. .In many U.S. fruit and vegetable processing facilities, water is a resource that can be just as critical and costly as energy in the production process. Water is used throughout the fruit and vegetable processing industry for process cooling, boiler systems, water fluming, blanching, peeling, cooking, product rinsing, and equipment cleaning, as well as in the products themselves as a primary ingredient . In California alone, the water consumption of the fruit and vegetable processing industry has been estimated at nearly 23 billion gallons per year . The specific water usage required in fruit and vegetable processing depends heavily on the type of product manufactured as well as on the water management practices at individual facilities. Reported values of specific water usage in the U.S. fruit and vegetable processing industry range from several hundred gallons per ton of product to tens of thousands of gallons per ton of product . This range suggests significant variation in water usage across the industry. According to a study by the World Bank , however, good facility water management programs can often help reduce specific water usage to the “best practice” levels indicated in Table 15.1 for different processed fruit and vegetable products.This chapter provides a brief overview of basic, proven water efficiency measures applicable to typical fruit and vegetable processing plants. In addition to reducing facility utility bills for water purchases, improved water efficiency can also lead to reduced energy consumption for water pumping and treatment, reduced wastewater discharge volumes, dutch bucket for tomatoes and reduced wastewater treatment costs. Furthermore, the recovery and recycling of water can also provide opportunities for energy recovery, which can help to further reduce facility energy costs. Water efficiency also reduces loads on local fresh water and wastewater treatment plants, which leads to indirect energy savings in the industrial water supply chain. According to Envirowise, a UK government program that promotes business resource efficiency, fruit and vegetable processing companies that have not implemented any water saving measures can often reduce water and effluent costs by 50% through water efficiency programs . Companies that have already implemented some measures—but not a systematic approach—can often still achieve a 20% decrease in water and effluent costs.Use of water efficient building fixtures. For building fixtures such as toilets, showers, and faucets, water efficient designs can be installed that lead to significant water savings. For example, low-flow toilets typically require only 1.6 gallons per flush, compared to 3.5 gallons per flush required for standard toilets . Additional options include low-flow shower heads, aerating faucets, self-closing faucets, and proximity sensing faucets that turn on and off automatically.24 Dry conveyors. Where feasible, water flumes might be replaced by belt conveyors or chutes to save significant quantities of water . However, the applicability of this measure will depend on the extent to which existing water flumes are integrated with other facility processes , how susceptible the product is to bruising or damage, and the flexibility of the installed equipment layout. Use of small diameter hoses. All applications of hoses should be assessed, and, where feasible, the smallest possible diameter hoses should be installed. Small diameter hoses provide a low flow, high pressure condition, which can reduce the volume of water required for a given task .

Air cooling. The use of air cooling instead of water cooling can lead to water savings in situations where air is a feasible process cooling alternative . However, from an energy perspective, water cooling is generally preferable to air cooling . Thus, the switch to air cooling should be carefully examined for each prospective process application to determine whether or not a favorable compromise between energy use and water use exists. Use of automated start/stop controls. For end uses of water with intermittent demand, sensors can be employed to detect the presence of materials and to supply water only when it is required by the process. Such sensors will turn off water supplies automatically when not required and also during non-production periods, thereby saving water . Reducing demand for steam and hot water. Reducing the demand for steam and hot water not only saves energy but also reduces the need for treated boiler water. Typically, fresh water must be treated to remove contaminants that might accumulate in the boiler, so reducing demand not only decreases boiler water use, but can also reduce the amount of purchased chemicals for boiler water treatment . The combined energy, water, and chemicals savings associated with reducing steam and hot water demand make it a particularly attractive measure. Steam and hot water demand can be reduced through the general steam system energy efficiency strategies discussed in Chapter 7 of this Energy Guide, as well as through process specific modifications. For example, where feasible, dry caustic peeling methods can be employed in lieu of wet caustic peeling or steam-based peeling methods to reduce process water consumption. Dry caustic peeling has been shown to reduce water consumption by up to 75% compared to wet caustic peeling in the processing of beets . Additional examples include the use of air cooling instead of water cooling to cool products after blanching, or the use of steam-based blanching methods instead of water-based blanching methods. Reducing cooling tower bleed-off. Cooling tower “bleed-off” refers to water that is periodically drained from the cooling tower basin to prevent the accumulation of solids. Bleed-off volumes can often be reduced by allowing higher concentrations of suspended and dissolved solids in the circulating water, which saves water. The challenge is to find the optimal balance between bleed-off and makeup water concentrations without forming scales. The water savings associated with this measure can be as high as 20% . The Ventura Coastal Plant, a manufacturer of citrus oils and frozen citrus juice concentrates in Ventura County, California, was able to increase the concentration ratios of its cooling towers and evaporative coolers such that bleed-off water volumes were reduced by 50%. The water savings amounted to almost 5,200 gallons per day, saving the company $6,940 per year in water costs . With capital costs of $5,000, the simple payback period was estimated at around seven months.Dry cleaning of equipment and surfaces. Fruit and vegetable wastes and residues should be removed manually from floors and equipment before the application of cleaning water to reduce water consumption. Dry cleaning can be done using brushes, squeegees, brooms, shovels, and vacuums. Often, solid and liquid wastes are chased down floor drains using a hose; a better practice is to use brooms or shovels and to dump wastes into a container designated for solid waste . High pressure low volume sprays. In applications such as truck, container, surface, and floor cleaning, total water consumption can be reduced by using high pressure low volume spray systems, which employ small diameter hoses and/or flow restricting spray nozzles. Such systems can also be fitted with manual triggers, which allow personnel to regulate use, or automatic shut-off valves to further reduce water consumption .