Packaging processes are generally powered using a combination of electric motors, solenoids, and compressed air actuators.The typical processes employed in fruit and vegetable canning are depicted in Figure 3.1. For both fruits and vegetables, inspection, grading, and washing are generally the first processing steps. Vegetables are then typically peeled if needed, subjected to size reduction to obtain the proper form, and blanched to inactivate enzymes. Immediately after blanching, vegetables are typically cooled in a water bath to prevent overcooking. For some vegetables, a heated brine solution is added at the filling stage, which generally consists of salt, sugar, and water. After washing, fruits may be cored and/or peeled, depending on the variety, and washed again to remove peeling residues. Fruits are then subjected to size reduction to obtain the desired form. Some canned fruit products, such as applesauce, are then cooked. Heated syrup or fruit juice is often added to fruits at the filling stage. After filling, the canned fruits and vegetables are exhausted, sealed, sterilized, and cooled before proceeding to final packaging operations.Figure 3.2 depicts representative process flows for the combined manufacture of canned diced tomatoes and canned tomato juices, pastes, and sauces. After inspection and grading, tomatoes are typically washed in a series of agitated water flumes. Next, color sorting is done either manually or automatically to remove green tomatoes, which are subsequently sent to pulping. The red tomatoes are then subjected to steam peeling, followed by manual sorting to remove tomatoes that have not been sufficiently peeled, hydroponic gutter which are also sent to pulping. Peeled red tomatoes are then diced and filled into cans using rotary brush fillers.The canned diced tomatoes are then exhausted, sealed, sterilized, and cooled before proceeding to final packaging operations.

The pulper is used to crush green and unpeeled tomatoes as well as pulping waste from the dicer. After pulping, the tomato slurry proceeds to the evaporator for concentration into juice, puree, and paste . Tomato purees are then typically mixed with other ingredients to create tomato sauce. Prior to filling, evaporated tomato products undergo continuous sterilization. Once filled the canned tomato juices, pastes, and sauces are sent to final packaging operations.The typical processing steps involved in fruit juice canning are depicted in Figure 3.3. After inspection, grading, and washing, juices are extracted from the fruits using mechanical expression or extraction methods. The juice is then often filtered to remove unwanted pulp, deaerated to remove excess oxygen, and deoiled. Next, the juice is pasteurized in a continuous fashion. For fresh juice manufacture, the pasteurized juice is immediately cooled and filled into a container before proceeding to final packaging operations. For canned juice manufacture, the pasteurized juice is hot filled into a container, which is subsequently exhausted, sealed, sterilized, and cooled before proceeding to final packaging operations.Energy represents a significant operating cost to the U.S. fruit and vegetable processing industry. In 2002, the industry spent nearly $810 million on purchased fuels and electricity, or roughly 4.5% of the industry’s total cost of materials . Of this, $370 million was spent on purchased electricity and $440 million was spent on purchased fuels . Electricity is used throughout the typical fruit and vegetable processing facility to power motors, conveyors, compressed air systems, and pumps, as well as building lighting and heating, ventilation, and air conditioning systems . Another major end use of electricity in the industry is refrigeration, which is used for process cooling, cold storage, and freezing applications. For all end uses, the U.S. fruit and vegetable processing industry consumed a total of 6.7 terawatt-hours of electricity in 2002, or nearly 10% of the electricity consumed by the entire U.S. food industry .

The major end use of fuels in the typical fruit and vegetable processing facility is in boiler systems for the generation of steam, which can be used in a wide variety of process heating, water heating, and cleaning applications . Although coal, residual oil, and distillate oils are sometimes used as fuels , currently natural gas accounts for over 90% of all fuels consumed by the U.S. fruit and vegetable processing industry . Thus, in discussions of both the end uses of fuels and the energy efficiency opportunities available for fuels in U.S. facilities, the remainder of this Energy Guide focuses exclusively on natural gas.In 2002, the U.S. fruit and vegetable processing industry consumed around 6.7 TWh of electricity, which equates to roughly 23 trillion Btu of final energy . The frozen fruit, juice, and vegetable manufacturing sub-sector was the industry’s largest consumer of electricity—due in large part to its extensive use of electricity for refrigeration—accounting for roughly 45% of the total electricity consumed by the industry in 2002. The fruit and vegetable canning sub-sector was the next largest user of electricity , followed by the dried and dehydrated food sub-sector and the specialty canning sub-sector . At least half of the industry’s electricity was expected to be consumed in the Western United States . The use of on-site electricity generation appears to be quite limited in the U.S. fruit and vegetable processing industry. In 2002, only 5% of the industry’s electricity was generated at individual facilities . The use of on-site generation was confined almost exclusively to the fruit and vegetable canning sub-sector, where the extensive use of steam in blanching, evaporating, pasteurizing, and sterilizing applications makes combined heat and power systems particularly attractive. The U.S. fruit and vegetable processing industry consumed an estimated 78 TBtu of natural gas in 2002.

The fruit and vegetable canning sub-sector was the industry’s largest consumer of natural gas, accounting for nearly one half of all industry natural gas consumption in 2002 . The frozen fruit, juice, and vegetable manufacturing sub-sector was the next largest user of natural gas, consuming an estimated 21 TBtu of natural gas in 2002, followed by the dried and dehydrated foods manufacturing subsector and the specialty canning sub-sector . At least one half of the industry’s natural gas was expected to be consumed in the Western United States . Table 4.1 summarizes the electricity and natural gas use of the U.S. fruit and vegetable processing industry. In total, the industry consumed an estimated 101 TBtu of final energy in 2002. Combined, the fruit and vegetable canning sub-sector and frozen fruit, juice, and vegetable manufacturing sub-sector accounted for around 75% of the industry’s total final energy use. Figures 4.4 and 4.5 depict the end uses of energy in these two important sub-sectors.The energy consumed by steam-based processes at individual canneries depends heavily on the type of equipment employed, the product manufactured, and equipment configurations. For example, steam blanchers have been reported to consume anywhere from 0.37 kg steam/kg product to 0.94 kg steam/kg product . Water blanchers have been reported to consume anywhere from 0.22 kg steam/kg product to 0.52 kg steam/kg product . Another major consumer of energy is the washing of incoming fruits and vegetables, which, depending on the facility, can use either hot water or ambient water and generally involves a high degree of mechanical agitation. For washing systems that use hot water, water efficiency measures and measures for recovering energy from hot water can be key strategies for reducing process energy consumption. For further details on water efficiency, see Chapter 15 of this Energy Guide. Table 4.3 shows energy intensity data for key processes used in juice canning. The two washing operations—incoming product washing and container washing—are seen to be the most energy-intensive processes involved, together consuming 434 Btu/lb of hot water. Thus, as for fruit and vegetable canning, water efficiency and heat recovery are likely to be key energy saving strategies in juice canning. The pasteurization process is the most significant consumer of steam, followed by the heat sterilization process. Tables 4.2 and 4.3 suggest that for most canneries, steam and hot water represent by far the most dominant uses of process energy in the facility, while process electricity use is generally of lesser significance.Representative process energy intensities for frozen fruit manufacture are provided in Table 4.4. As for canneries, hydroponic nft channel the processes of washing and blanching are likely to be the largest consumers of steam in a typical fruit freezing facility. However, unlike canneries, it can be seen that electricity use is as significant as steam use in the facility, primarily due to the electricity intensity of the freezing process. While the energy intensity of freezing at individual plants can vary widely based on the technology employed—typical energy intensity values for freezing technologies range from 250 Btu/lb to 1,750 Btu/lb —in general, freezing will be the most energy intensive operation in fruit freezing facilities by a significant margin.Similarly, the freezing process is the most energy intensive operation in the manufacture of frozen French fried potatoes, as can be seen in Table 4.5. After freezing, the next largest consumer of energy in frozen French fried potato manufacture is typically the frying process, which consumes a significant amount of direct fuel to heat the frying oil. Table 4.6 provides representative process energy intensity data for the manufacture of frozen concentrated citrus juice, one of the most significant product outputs of the U.S. fruit and vegetable processing industry . As in fruit freezing facilities, the freezing process accounts for the largest share of electricity use in frozen concentrated juice manufacturing facilities. However, the concentration process is the most energy intensive process by a significant margin, consuming an estimated 900 Btu of steam per pound of citrus juice concentrate. Thus, in addition to freezing, the concentration process is likely to be one of the most attractive opportunities for energy efficiency in the typical frozen concentrated juice facility.Lastly, representative process energy intensity data for dehydrated mashed potato manufacture are provided in Table 4.7. Peeling, precooking, and cooking are estimated to be very energy intensive processes. However, the most energy intensive process by far is the drum drying process, which consumes an estimated 6,000 Btu of steam per pound of dehydrated mashed potatoes. In fact, the drying process is one of the most energy intensive processes employed in the entire U.S. food processing industry, with typical energy intensity values ranging from around 1,500 Btu per pound of water in the product to over 28,000 Btu per pound of water in the product .Many opportunities exist within U.S. fruit and vegetable processing facilities to reduce energy consumption while maintaining or enhancing productivity. Ideally, energy efficiency opportunities should be pursued in a coordinated fashion at multiple levels within a facility. At the component and equipment level, energy efficiency can be improved through regular preventative maintenance, proper loading and operation, and replacement of older components and equipment with higher efficiency models whenever feasible. At the process level, process control and optimization can be pursued to ensure that production operations are running at maximum efficiency. At the facility level, the efficiency of space lighting, cooling, and heating can be improved while total facility energy inputs can be minimized through process integration and combined heat and power systems, where feasible. Lastly, at the level of the organization, energy management systems can be implemented to ensure a strong corporate framework exists for energy monitoring, target setting, employee involvement, and continuous improvement. The remaining chapters in this Energy Guide discuss some of the most significant energy efficiency measures applicable to fruit and vegetable processing at the component, process, facility, and organizational levels. This focus of this Energy Guide is on energy efficiency measures that are proven, cost effective, and available for implementation today. Whenever possible, measure descriptions include case studies of fruit and vegetable processing plants that have successfully implemented the measure, both in the United States and abroad. Many case studies include specific energy and cost savings data as well as typical investment payback periods. For measures where data are not available for fruit and vegetable processing facilities, this Energy Guide presents case study data from other sub-sectors of the food industry and occasionally from non-food industries to illustrate typical measure savings. Lastly, for most measures references to the technical literature and online resources are provided, which can be consulted for further information. For individual fruit and vegetable processing facilities, the actual payback period and savings associated with a given measure will vary depending on facility activities, configuration, size, location, and operating characteristics. Thus, the values presented in this Energy Guide are offered as guidelines.