Variety, Novelty Characterize Processing and Nonthermal Papers

IFT’s New Products and Technology Subcommittee is especially selective, and each year presents some of the best-attended sessions. Appropriately, most of the papers concern ingredients and analytical techniques, but there are always some processing developments. Two this year concern fat-free frying and continuous flow microwave sterilization. Some new instrumental techniques are also being presented.

Fat-free Frying
The aim of deep-fat frying is to seal the food by immersing it in hot oil. A softer inner texture that contrasts with the crispy outside is the preferred texture. Due to the prevalence of obesity, deep-frying has become a technology with a negative health image. TNO developed a fat-free alternative process for deep frying based on superheated steam (SHS) as frying medium. On many applications, the process has been shown to closely resemble deep-frying effects, without adding fat to the product. The crispiness, color, and texture in general are all very much alike.

The success of the developed process is based on the fact that the processes of deep-frying in oil and “steam frying” are physically so alike. The heat transfer rate, the drying effect, the wet- and dry-bulb temperature—all are very comparable. This results in products that look and feel similar to fried. Successful SHS fried products thus include French fries, expanded pellet snacks, bakery products, nuts, and meat products.

In Session 084 on Monday morning, different products will be shown, which are likely to help attendees to judge the technology for potential use on products of interest. A commercialized product based on the technology also will be shown.

Continuous Flow Microwave Sterilization
A continuous flow microwave sterilization process has been developed and implemented for commercial aseptic processing and packaging of a low-acid, shelf-stable vegetable (sweet potato) puree. Researchers at North Carolina State University Department of Food, Bioprocessing, and Nutrition Sciences, USDA Agriculture Research Service (ARS), and Industrial Microwave Systems collaborated over a period of five years to develop and apply microwave-assisted aseptic processing to a number of low-acid vegetable purees in order to produce shelf-stable products. Very rapid come-up times (45 seconds or less) and high sterilization temperatures (135° C and higher) combined with rapid continuous flow cooling and aseptic packaging enable this process to achieve superior sensory quality (color, flavor, texture) and nutrient retention in food products that are otherwise difficult to process and preserve.

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YamCo, a consortium of North Carolina sweet potato growers, implemented and commercialized the developed process, yielding a superior quality product for further use by food processors. This installation represents the first industrial implementation of continuous flow microwave heating and sterilization technologies, which have numerous potential applications for similar products such as fruit and vegetable purees, pastes, and homogenates. The project also will be discussed in Session 084.

Moisture Sorption Isotherms
A moisture sorption isotherm for a food product is the relationship between water activity and moisture content at a given temperature. This relationship is complex and unique for each product due to different interactions between the water and the solid components at different moisture contents. Moisture sorption isotherms are sigmoidal in shape for most foods. Isotherms are important for new product development, ingredient research, shelf-life estimation, and for fully understanding the moisture within a product.

The traditional method to obtain a moisture sorption isotherm is to place a food, either dried (absorption), hydrated (desorption) or native (working), into controlled-humidity chambers at constant temperature and then measure the weight until equilibrium, as measured by constant weight, is established. Six to nine different humidity levels are needed, and vapor equilibration must be achieved, which may take one to three weeks. Due to the large amount of time and labor necessary to obtain an isotherm, they are not routinely made for food products.

Decagon Devices’ new AquaSorp IG instrument makes determination of isotherms quick and automatic; it will be discussed during Session 026 on Sunday afternoon. The AquaSorp IG is simple to use and consists of inserting a food sample into the instrument, setting a few parameters for the experiment, and walking away. The AquaSorp IG is the only isotherm instrument that directly measures water activity using Decagon’s patented chilled mirror dew point technique. Desorption and adsorption are achieved by flowing wet or dry air, respectively, and moisture loss and gain are determined by weight changes. The instrument generates the complete absorption and desorption isotherms in approximately 24 hrs with 50 points on each isotherm curve.

Rheological Properties
The rheological properties of food materials are critical in optimizing new products, controlling processes, and verifying final product quality. The viscosity of many food materials, like yogurt, is flow- and time-dependent. Yogurt is also shear-sensitive in the sense that its network breaks down under shear and partially recovers after a few hours at rest. In a yogurt plant, one valuable measurement at a good location helps to adjust the process in order to reach the final quality properties. This adjustment may be achieved with just a smoothing valve or through a recipe optimization.

A simple viscometer might be useful to provide a reference measurement in the case of purely viscous fluids. It does not provide very reliable measurement in the case of complex viscoelastic fluids like yogurt.

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The Viscoline, a sanitary pipe rheometer, was directly inserted in a main yogurt process pipe, which will be discussed in Session 112 on Monday afternoon. It is equipped with static mixers, sized so that no additional shear rate is applied to the material. Therefore, the texture of the yogurt is not affected by the measurement. Since it contains no moving parts, the Viscoline can handle typical process conditions and requires almost no maintenance. The patented measuring technique is based on mixing principles applied to pipes. The two power law process flow indexes continuously measured—the shear thinning index and the consistency index—provide viscosity data in real time, with a resolution of 0.1% of the full scale of measurement and a repeatability of 0.2%.

Alternative Processing Technologies
Session 016, sponsored by the Food Engineering Div. on Sunday afternoon, is one of two on the safety of foods processed using ohmic heating, microwaves, high pressure, and pulsed electric fields. This symposium describes the results of a major collaborative study funded by the USDA-CSREES, which is approaching its final stages. The other is Session 033 on Sunday afternoon. Ohmic heating and microwaves are discussed in the first session and high pressure and pulsed electric fields in the second. Closely related to the topic is Session 145, “Minimally Processed Foods and Their Safety:Opportunities and Challenges,” scheduled for Tuesday morning and sponsored by the Nonthermal Processing Div.

Food Engineering and Nonthermal Posters
Poster presentations are increasingly popular because of the convenience of viewing them at one’s leisure and the opportunity for interaction with the authors. The Food Engineering Div. has three poster sessions scheduled. Session 008, “Food Processing and Modeling,” will be held on Sunday afternoon and will feature 43 papers; Session 095, “Novel and Emerging Technology,” will be held on Monday afternoon with 38 papers; and Session 132, “Food Properties and Rheology,” is scheduled for Tuesday morning with 27 papers.

The Nonthermal Processing Div. presents Session 135, “Nonthermal  Processing,” on Tuesday morning with 31 papers. The distribution of topics in this session gives a perspective on the state of research in nonthermal processing. Paper topics break out as follows: high pressure, 14; pulsed electric fields, 6; ultra violet radiation, 4; sonication, 3; and high pressure carbon dioxide, e-beam radiation, X rays, and intermediate moisture, 1 each.

Cold Plasma
Session 064, “Cold Plasma: An Emerging Technology for Food Processing,” scheduled for Monday morning and sponsored by the Nonthermal Processing Div., will present the fascinating concept of cold plasma applied to foods. Cold plasma is an exciting area of engineering research with a wide range of potential applications in food processing. Various forms of this flexible technology have seen extensive implementation in non-food industries, but in recent years, newer cold plasma tools have allowed for the generation of plasmas suitable for application to foods. This session will give an introduction to cold plasma—what it is and how it can be generated and applied. Experimental results will be presented on how it kills pathogens such as E. coli O157:H7 and Salmonella on nuts, produce, seafood and other foods. Experts in the field from leading research institutions, including USDA ARS and the European NovelQ research consortium, will share their expertise, knowledge, and experience.

It is especially intriguing that cold plasma has been applied with success to fresh produce and almonds—foods that are difficult to treat by other methods.

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Ultrasonics
Session 143, “Applications of Ultrasound in Food Processing and Characterization,” sponsored by the Food Engineering Div. on Tuesday morning, addresses another relatively novel technology.

The applications of ultrasound in the food industry have been divided into two distinct areas that are mainly determined by ultrasound frequency and acoustic energy level. High-frequency (in MHz range) and low-energy ultrasound has been used in measurement of temperature and flow rate, determination of composition, determination of particle size, monitoring of phase transitions, study of gelation, ultrasonic imaging, fouling detection, and the study of molecular properties.

“Power ultrasound,” or “high intensity ultrasound,” uses lower frequencies (typically 20–100 kHz) and produces sound intensities of 10–1,000 W/cm2. It finds applications in food processing operations such as emulsion generation, aggregated materials dispersion, drying, microbes and enzymes inactivation, heat and mass transfer enhancement, deforming, and the modification and control of crystallization process. There has been an increased interest in the food industry in utilizing ultrasound to enhance food safety and quality, to understand food property changes during processing, and to better control processing methods.

Co-products of Ethanol Production
The Food Engineering and Nonthermal Processing divisions do not have a monopoly on sessions of interest in processing. The Fermented Foods & Beverages Div. is presenting Session 186, “Co-products of Ethanol Plants: Food Application, Animal Nutrition, and Regulatory/QA Issues” on Tuesday afternoon. The increase in ethanol production, along with the corresponding decrease in the availability of traditional corn-derived ingredients, is a challenge facing many food companies across a broad array of industry categories. Ethanol co-products represent a nutritious and versatile source of ingredients for use in food processing and animal nutrition. Gaining knowledge of the ethanol production process, the application of ethanol co-products in product development, and an understanding of relevant regulatory and quality assurance issues will help the food industry adapt to the significant changes affecting the ingredient supply.

Juices and Concentrates
Session 204, “Processing Technologies for Juices and Concentrates Aimed to Maximize the Retention of Flavor and Phytochemicals,” is presented on Tuesday afternoon by the Fruit & Vegetable Products Div. The food industry is continuously searching for novel processing technologies that ensure microbial destruction and extend the shelf life of products without having adverse effects on quality attributes such as flavor, color, and phytonutrient retention. Moreover, current trends in food marketing show that consumers desire high-quality foods with “fresh-like” characteristics, enhanced shelf-life, and significant amounts of bioactive phytochemicals. Although the antioxidant, phytochemical, and flavor content of finished juices and beverages is affected by a number of pre-harvest (cultivar, location, harvest date) and post-harvest (storage conditions) factors, processing unit operations (extraction, clarification, concentration, and pasteurization) are the main factors affecting the flavor and phytochemical retention of these products. Topics include ultrafiltration, dense phase carbon dioxide, and spinning cone evaporation.

Space does not permit discussion of all the other interesting sessions, including one on the historical development of nonthermal processes, several on modeling and simulation, and the division lectures for Food Engineering and Nonthermal Processing.

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Exhibits
The following are brief descriptions of some of the processing-related exhibits at this year’s Food Expo.

• Continuous dry steam sterilization process, Safesteril, has been installed in more than 15 countries to treat products that include spices, seeds, herbs, botanicals, and dehydrated fruits and vegetables. The process is safe and natural. This year, a new optional feature, X2, which permits a processor to start with a single line and easily double production capacity later, became available. This feature is unique and is designed to address the needs of growing companies. B.N.W. Industries, www.safesteril.com, Booth 5307

• Carbonator/filler FT102X has been redesigned and improved in order to make it more versatile and user-friendly. It allows the user to carbonate beverages, including highly foaming products (premix or post-mix) up to 10g/L. With the integral touch-screen control panel, the user may select, control, and view parameters such as de-aeration, syrup dosing, pressurization, flushing, filling time, filling speed, and depressurization. The unit is capable of filling and capping glass and PET bottles and filling into cans.

A heater and internal spray ball contribute to the FT102X’s upgraded clean-in-place function. Armfield Limited, www.armfield.co.uk, Booth 3801

• Extrusion technology and process expertise has evolved to address the needs of the ever-changing food ingredients market. Besides traditional applications for breakfast cereals, the company offers process development for flavor encapsulation, texturization of vegetable and dairy proteins, modification of flour and starches, as well as patented technology for reconstitution and fortification of broken rice kernels. Rice flour and micronutrients are transformed into new grains indistinguishable from natural rice through an extrusion process. The fortified rice kernels show good physical stability with excellent retention of vitamins and minerals during storage, washing, and cooking. Buhler Inc., www.buhlergroup.com, Booth 2555

• Industrial wastewater treatment systems are designed and built on-site employing technologies that include both low-rate and high-rate anaerobic, sequencing batch reactor, and both aerobic and anaerobic membrane bioreactors. The company’s expertise allows it to treat almost any industry waste stream, ranging from those that are primarily soluble to those high in suspended solids and fats, oils, and grease. Bench- and pilot-scale studies are performed when deemed necessary to confirm treatability. ADI Systems Inc., www.adisystemsinc.com, Booth 540

• Sanitary spiral wound modules, Spira-Cel, come in many different molecular weight cut-offs to meet specific separation needs. The company offers these modules in standard sizes as well as custom sizes that can be configured for high and low pH’s and temperatures up to 176° F. Their design significantly improves module hydrodynamics at minimum energy output, and due to their enhanced resistance to soluble compounds, the modules are suited for harsh, chemically demanding applications. Microdyn Technologies Inc., www.microdyn-nadir.de, Booth 2639

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• Mixer and dryer features an Easy Clean design that simplifies the task of cleaning difficult applications and reduces the downtime required for it. The design provides a substantial benefit to manufacturers concerned with cross-contamination from batch to batch because of allergens, flavors, colors, and formula changes; it is available on batch or continuous mixers. The Ploughshare Mixer and Jacketed Vacuum Dryer has large doors across the front of the mixer to provide for full access to the interior of the vessel, which is designed and built for full vacuum operation. The stainless steel jacket of Labyrinth Design is rated at 90 psig at 330° F and ensures uniform flow for heating or cooling. Littleford Day Inc., www.littleford.com, Booth 5208

• Fluidizing paddle blender, OptimaBlend, balances mixing speed and efficiency with low equipment cost and power consumption. Inner and outer paddles are featured on the triple-action, multi-zone rotor. Units are available in carbon steel, stainless steel, and sanitary construction for a wide variety of solids-to-solid and solids-to-liquid blending applications. The OptimaBlend is designed to mix five times faster and with less degradation than a ribbon blender, offers high mix efficiencies with low co-efficient of variation values, and boasts easy clean-out. American Process Systems, www.apsmixers.com, Booth 5201

• Small-scale cacao bean winnower is suitable for artisan chocolate makers and chocolate R&D projects. Made of stainless steel, the winnower can process up to 150 kg/hr and has a footprint of only 4 ft x 12 ft. Bean breaker designs are available for raw or roasted beans. A raking system facilitates the flow of nibs through a series of 4 screens, while shell fragments are vacuumed off and collected. Options include a pneumatic system for loading beans into the breaker and customer-specified screen sizes. The company’s Controlled Planetary Mixing System has been redesigned to support chocolate R&D. A ball milling attachment grinds nibs to make chocolate liquor. The machine can then be used to conch, refine and temper chocolate. Bottom Line Process Technologies Inc., www.blt-inc.com, Booth 2262

• Twin-screw extruders mix and theromo-mechanically cook ingredients while maintaining essential proteins, amino acids, and minerals. They are useful tools for processors seeking to develop value-added products such as functional ingredients, whole grain foods, textured proteins, modified starches, multigrain breakfast cereals and snacks, and filled products. The Evolum 25 and Evolum 32 were developed to assist in the production of new extruded food products and to enable seamless transfer from R&D to full production by ensuring reliable scale-up. Increasing its pilot-plant capabilities, the company has added a new production extruder, the BC 72, which complements the Evolum 53. A new EV300 Evolum Dryer completes the expansion, offering a wide range of drying solutions. Additionally, the company’s confidential trials help processors to avoid downtime and lost throughput that may occur with in-house testing and provide an efficient way to bring ideas from R&D to the consumer through evaluation of test samples for marketplace performance and acceptance. Clextral Inc., www.clextral.com, Booth 3109A

• Double seamers are noted for their versatility and durability for low-volume packaging applications with metal, plastic, or composite containers. The full-range, heavy duty, Model UD-AL seamer is versatile and suitable for low-production applications that require atmospheric double seaming. This model can close containers with diameters of 2–6 in. Its Air Lift feature helps to eliminate variance in base-plate pressure and eliminates the need for manual lifting of the container. The Model 25D is a table-top seamer capable of closing cans with diameters of 2–4¼ in and is suitable for those with limited space. Its simple design and easy-to-install change parts offer ease of operation and maintenance, as well as flexibility. Dixie Canner Co., www.dixiecanner.com, Booth 1918

• Ceramic membrane filters are designed to meet fine-filtration process needs for clarifying, separating, and decontaminating liquids. These replaceable micro-, ultra- and nano-filters are heat and oxidant sterilizable, making them useful for sanitary applications such as juice clarification, starch filtration, sugar concentration, and corn/wheat syrup clarification. Cross-flow filtration allows long-term stable production rates, extending time between required cleanings. Because of their ceramic structure, these filters are able to withstand pasteurization temperatures and harsh cleaning protocols and have expected lifetimes of years rather than months. Their compact design contributes to lower capital and operating costs because fewer filters, valves, and pumps are required. LCI Corporation, www.lcicorp.com, Booth 5216

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• Small-scale production processors provide UHT, aseptic, pasteurization, hot-fill, and continuous cooking processes. New this year are MTI Pilot Plants and MTI BioPharm small-scale production, continuous-flow thermal sterilizers, pasteurizers, and reactors. The company’s UHT/HTST pilot processors yield production-quality fluid food products. BioPharm processors are designed for high-value/low-volume products such as pharmaceuticals, growth media, and biotech products. Both series of equipment offer flow rates of .5–6 L/min (model dependent) and combine uniform thermal exposure and precision control, while offering ease of use. Hold tubes are easily changed. These processors are SIP/CIP cleanable, are available with cGMP construction and work with optionssuch as in-line homogenization and ultra-clean filling. MicroThermics Inc., www.microthermics.com, Booth 2623

• Liquid foods modular process plant delivers comprehensive UHT processing capability on a small scale. The modular plant is available with plate heat exchanger, tubular heat exchanger, scraped surface heat exchanger and/or a direct steam injection system with only a nominal flow rate of 20 L/hr. The plant also is available with a variety of blending tanks, homogenizers, deaerators, buffer tanks, and filling/closing systems, with all processes integrated into one frame. Hygienic design is standard with all process plants, and, if required, the plant can be upgraded to aseptic standards and incorporate the state-of-the art aseptic filling bench, Asepto-Fill. The SCADA software system facilitates operation, and recipes can be logged to further simplify the operation. Additionally, the company offers the CF121, a table-top/bench-top, post-mix carbonator/filler. The system is simple to operate: It has only four buttons, and the user need only set the CO₂ content and filling height. It is especially suitable for applications where the goal is to fill a limited number of bottles, varying the CO₂ levels and syrups. OMVE Laboratory & Pilot Equipment, www.omve.com, Booth 625

• High pressure processing equipment, The Wave 6000/420, works in the industry at up to 6,000 bar (87,000 psi) and is capable of processing products at a rate of up 2 tons/hr. Its process chamber has a 420 L capacity and a diameter of 380 mm for optimization of product loading and cycle production capacity. This equipment can perform a complete cycle at the maximum working pressure in less than 6 min. NC Hyperbaric, www.nchyperbaric.es, Booth 1554

• ERP software, Batchmaster Food, is a specially enhanced version of the company’s integrated process manufacturing application suite. The software combines the company’s established and extensive functionality for the process manufacturing industry with the features the contemporary food manufacturer requires for regulatory compliance. The application has been successfully implemented by manufacturers of ingredients, cakes, chocolate, foodservice products, and others. Batchmaster Software, www.batchmaster.com, Booth 808

• Custom engineering solutions are available to help processors handle projects that range from a retrofit of an existing system to developing a new plant. The company’s technical resources will help take a project from initial concept through design, installation, and training. Areas of expertise include drying and particulate processing systems, thermal concentration and separation, liquid processing, membrane filtration, powder packaging and conveying systems, and controls and automation. Niro Inc., www.niroinc.com, Booth 1123

• Food coating system in pilot-plant scale with industry applications that include baked goods, frozen meals, snacks, and fresh-cut produce will be presented. The company’s patented ultrasonic spraying technology provides superior transfer efficiency over conventional air-pressure spraying systems. Accordingly, there is less bounce back of liquid from the target and the potential to save more than 50% in improved cost of goods. Sono-Tek Corp., www.sono-tek.com, Booth 5204  

by J. Peter Clark,
Contributing Editor,
Consultant to the Process Industries, Oak Park, Ill.
[email protected]