In early 1992, a Belgian scientist named Marcel Loncin, then Head of the Dept. of Food Engineering at the University of Karlsruhe, Germany, expressed a desire to endow a biennial prize that would honor and provide funding for a scientist or engineer conducting basic research applied to food processing and improvement of food quality.
His friends Werner Bauer and Theodore Labuza convinced him to consider endowing the prize with the Institute of Food Technologists. The contract was approved in October 1993, and the Marcel Loncin Research Prize, administered by the IFT Foundation, has been awarded by IFT every two years since 1994.
The prize provides $50,000 to an IFT member or nonmember to carry out a proposed two-year research project. The recipient of the prize must present the results of his or her research at the IFT Annual Meeting the third year after receiving the prize. The research can be in chemistry, physics, or engineering; should show potential cross-fertilization and cooperation among academia, industry, and government organizations where possible; and should help young scientists to also become successful.
I contacted each of the prize recipients to determine what their research funding has accomplished. Here’s what they told me.
Werner Bauer & Color Stability
Werner Bauer, today Executive Vice President, Technical, Production, Environment, Research & Development, Nestlé S.A., Lausanne, Switzerland, received the prize in 1994. A former student of Loncin’s, he was personally selected by Loncin as the first recipient of the prize, both to honor Bauer and to exemplify the caliber of person who should receive the prize in the future.
Bauer’s research project funded by the prize dealt with “Color Stability of Plant Pigments and Food Processing,” specifically the stability of chlorophyll, the most sensitive natural food color. “Chlorophyll contains magnesium ion within an intricate molecular structure—the photosynthetic organelle—and decomposes very easily,” Bauer said. “Food processing—heat and shear—damages these natural structures. The project focused on the mechanisms of these degradations—enzymatic degradation, metal ion exchange, pH sensitivities, etc.—and the possible stabilization of chlorophyll during food processing.”
--- PAGE BREAK ---
Bauer, who is also Professor at the Technical University of Munich, Germany, and Chair of the Dept. of Food Science at the University of Lausanne, Switzerland, conducted the project at the University of Lausanne, with his Ph.D. student Alexander P. Gauthier-Jaques. They first established a set of sensitive and quantitative analysis methods for the study. Then they investigated the enzymatic pathways of the degradation and established that the dephytylation reaction—enzymatic cleavage of the diterpene alcohol phytol from the chlorophyll molecule—was specific for intact chlorophyll a and b and was a prerequisite for further degradation. They characterized the kinetics and mechanisms of a complex network of intricate enzymatic reactions that occur during breakdown of spinach chlorophyll, primarily involving chlorophylases, Mg-dechelatases, and demethoxycarbonylase.
With regard to processing, the results showed that classical unit operations, such as thermal blanching, inactivated the enzymatic activities as predicted but led to other degradation reactions like demetalation, loss of the magnesium ion. “The project proved that a successful stabilization of a natural green food color by chlorophyll can only be achieved when the chlorophyll can reside within a membranous structure imitating the natural environment of this molecule,” Bauer explained.
“The results established clearly—and for the first time—that degradation of chlorophyll originates from the unavoidable destruction of the cellular environment, the chloroplast envelope, during processing, allowing the naturally separated and compartmentalized enzymes to attack the photosynthetic structures and chlorophylls,” Bauer said. “Effects of pH and metal losses or enzymatic reactions are only secondary processes which follow after structural disintegration.”
Suggested and applied solutions like thermal blanching, pH control, high hydrostatic pressure, and other methods of “soft processing” were shown not to work if the structural environment of chlorophyll is not preserved, he added. The project led to some suggestions as to how processing might be used to improve the structural environment of chlorophyll.
One of the indirect outcomes of this project was the notion of a “benefit of structure” for the stabilization of components. “Food microstructures can play a much wider role than only being a carrier for organoleptic product attributes (e.g., textures),” Bauer said. “This became an important insight in relation to the stabilization and delivery of nutritional functional molecules from foods.”
--- PAGE BREAK ---
The results of the project, which continued until 1998, have been used in other natural food color research and in a commercial process to stabilize basil in frozen food application.
The prize funding is also to contribute to the success of other scientists, and Bauer’s project accordingly led to his student Alexander Gauthier-Jaques’ Ph.D. dissertation. Gauthier-Jaques also spent some time in Florida at Disney’s EPCOT Center, where he established the food science show laboratory and worked with local universities on the influence of increased carbon dioxide contents on chlorophyll production in peas. After completing his studies, he joined the Swiss bank UBS as a biotechnology expert, working in venture capital financing and as fund manager.
John Blanshard & Flavor Retention
John M.V. Blanshard, Emeritus Professor of Food Science in the Dept. of Applied Biochemistry and Food Science, Nottingham University, Nottingham, England, received the prize in 1996 for his project, “Flavor Retention and Release by a Filled Biopolymer Matrix.”
Blanshard intended to study the impact of a food matrix on the retention and subsequent release of flavor upon mastication. The goal was to study flavorb�13;biopolymer interactions and attempt to monitor flavor perception using functional magnetic resonance imaging (fMRI), a method for scanning the brain.
Blanshard and his Ph.D. student, Imad Farhat, studied the interaction of flavor with starch and found that the interaction depended on whether the flavor molecule was linear or cyclic. They used a linear organic molecule, octan-2-one, and a cyclic one, dimethycyclohexanone, and studied the formation of complexes with amylose. They characterized the structure of the resulting complexes, using differential scanning calorimetry, X-ray diffraction, and nuclear magnetic resonance.
The techniques developed in the project were subsequently used in several other projects by other Ph.D. students on the interactions of starch with hydrophobic species such as lipids, long-chain alcohols, and ketones and their relevance to processing (extrusion, baking) and properties (hydration, mechanical). This work formed the platform from which a recent project, funded by industry, on encapsulation of flavors in starchy materials was based.
The project also produced some of the early fMRI images of the human response to flavor. The fMRI scans show brain activity when a flavor such as vanillin is introduced into the mouth. A technique called APCI-MS was used to ensure that the fMRI protocols used actually transported the aromas to the olfactory receptors in the nose. The results established both the feasibility of the technique and a track record for the research team. Since then, the team has developed new paradigms for fMRI, and the group’s capability in this area has led to research contracts with major food companies.
--- PAGE BREAK ---
Blanshard retired at the conclusion of the two-year project and was succeeded in this area of research by Andrew Taylor, Professor of Flavor Technology at the University of Nottingham. Taylor said that Blanshard’s project sought to investigate the relationship between molecular structure, flavor availability, and sensory perception. “Our group has developed that field extensively over the last 10 years through the establishment of a Sensory Science Centre to complement the flavor and structural analytical capabilities,” Taylor said. “This line of research continues today under the theme ‘interaction of food with the body.’ We are studying the way food structure influences flavor perception, digestion, nutrient uptake, and satiety in a series of interlinked research projects.”
“The knowledge from the Loncin work has contributed to our know-how, which we use to attract further research funding,” he added. “This may take the form of university research or contract research and consultancy. Currently, the Division of Food Sciences holds about $10 million in research for a faculty head count of 15.”
Blanshard’s postdoctoral student, Imad Farhat, later became a faculty member at the university, reaching the associate professor level before recently joining Firmenich, a major flavor company in Switzerland, as global technology manager.
Theodore Labuza & Snack Food Texture
Theodore P. Labuza, Morse Alumni Distinguished Professor of Food Science and Engineering at the University of Minnesota, St. Paul, received the prize in 1998 for his project, “Glass Transition and Texture of Snack Foods.”
Amorphous materials exhibit a property called the glass transition temperature (Tg), which is a function of the amount of plasticizer, the molecular weight of components, and the amount and type of bonding. Labuza hypothesized that at some point above Tg, enough water is present in a crisp snack food system to physically change it from its glassy state into an undesirable soggy or rubbery state. With high-sugar cookies, which are initially in the rubbery state and thus soft, he hypothesized that the hardening during storage is initiated by a sugar crystallization step causing loss of sugar plasticizer followed by moisture redistribution into ungelatinized starch granules. This leads to the undesirable hardening.
“At the time of the award,” Labuza said, “there was a conflict between those food scientists who used water activity (aw) as a major paradigm for understanding of dry and intermediate-moisture food stability and those who said that aw was useless and everything could be described by the concept of Tg.” He sought to reconcile this conflict by showing that Tg was a critical parameter for understanding physical state changes, i.e., the reversible transition from amorphous glass to amorphous rubber/crystallization.
--- PAGE BREAK ---
Labuza said that if sugar/ carbohydrate is in the amorphous glassy state—as in hard candy, cotton candy, crackers, and potato chips—the moisture content at room temperature (defining Tg as room temperature), where the state change occurs in real time, is above the Brunauer-Emmet- Teller (BET) monolayer value determined from a sorption isotherm. At that point, cotton candy, for example, collapses, recrystallizing in 2–3 days.
At temperatures above the Tg, other phenomena occur at increasing rates, following Arrhenius or Williams-Landau- Ferry kinetics. These include onset of stickiness of hard candies and sugar-containing powders at about 10°C above the Tg for the moisture content of the food; loss of crispness at ~8–10°C above the Tg; and flow under the force of gravity (i.e., collapse) at >50°C above the Tg (e.g., “melting” of cheese on a pizza in an oven).
In the project, Labuza and his students—Fern Panda now at General Mills, Cami Payne at Richardson Foods, Laura Bellcourt, and his son Peter Labuza, to name a few—combined the standard equilibrium diagram—freezing point, boiling point, and melting point lines as a function of moisture—with the Tg vs moisture content curve to create a state diagram, using the principle expounded by Roos and Karel. Key, Labuza said, is that Tg is complementary to the effect of aw on food stability. “Tg is important enough to be included in every food chemistry course,” he added, “and differential scanning calorimetry can be used to teach how to measure Tg in a food analysis course.”
The major result of the project, Labuza said, was that “Tg and state diagrams complement knowledge of water activity and allow one to understand physical state changes easily by construction of a state diagram. These findings did not, however, displace water activity as a fundamental concept for food stability, rather it complemented it.”
The project, which is still continuing, led to additional directions of research, including study of soft cookies, protein bar hardening, flow of hard candy at high temperature, inhibition of sucrose crystallization, and creation of state diagrams. Commercial applications resulting from the project have included means to inhibit sucrose crystallinity in cookies and hardening of protein bars.
Syed Rizvi & Supercritical Fluid Extrusion
Syed S.H. Rizvi, Professor of Food Process Engineering and International Professor of Food Science, Dept. of Food Science, Cornell University, Ithaca, N.Y., received the prize in 2000 for his project, “Thermodynamics and Mechanics of Deposition of Flavor/Lipid in Extruded Microcellular Foods.”
Thermoplastic extrusion is widely used to manufacture expanded, coarsely structured products like breakfast cereals and snack foods. A high-pressure extrusion process, called SCFX, involving injection of supercritical carbon dioxide (SC-CO2) at low shear and low temperatures has opened up possibilities for a new generation of microcellular products. The overall goal of Rizvi’s project was to develop a fundamental understanding of the process dynamics for generating starch-based microcellular foams and selective deposition of solutes on the internal cell walls of the foamed extrudates using SCFX.
--- PAGE BREAK ---
Rizvi and his student Han Tutanathorn used the SCFX process with SC-CO2 as a plasticizer as well as a blowing agent at temperatures below 100°C to produce unique composite structures with smooth surface and porous interior. The biopolymeric microcellular structures ranged in cell size from 50 to 200 microns and cell density from 1.8 x 107 cells/cm3 to 4 x 107 cells/cm3. The final cellular geometry and expansion ratio of the extrudates depended on the fluid injection rate, nozzle temperature, melt viscosity, and drying strategy used. “Apart from controlling the number and size of microcells and thus the mechanical properties and texture of the extrudates,” Rizvi pointed out, “and unlike the steam-based extrusion process, SCFX also lends itself to the use of heat-sensitive ingredients in the extrudate formulations to make expanded products and to encapsulate bioactives and flavorants within the cellular matrix.”
Rizvi and his students used methyl anthranilate, a fluorescent flavor compound commonly found in grapes, as an SC-CO2 solute and demonstrated the efficacy of depositing the injected flavor compound within the interior cell wall of the SCFX extrudates. A 3-dimensional intensity profile based on the fluorescent image showed areas of high fluorescence intensity along the internal edges of the cells, meaning that SCFX preferentially deposits flavorants on the inside surface of the closed cells of the extrudates. “To the best of our knowledge,” Rizvi said, “this unique approach to flavor deposition in extrudates in continuous extrusion processes has not previously been reported.”
Also unique to SCFX extrudate, he said, is the closed-cell microcellular structure and nonporous surface, which should trap the deposited flavor and other bioactive materials and prevent their loss by diffusion or oxidation. Prevention of oxidation would occur because the microcells are initially totally filled with CO2, thus minimizing exposure to oxygen.
The final results of the project included development of a novel technology for generation of microcellular structures and simultaneous deposition of SCCO 2–soluble flavorants within the porous microcells. “This approach can further be extended to selective deposition of functionally superior solutes on the interior surface of extruded microcells, where they would be readily available for maximum impact,” Rizvi said. Thus, the project “has given us a unique approach to extrusion processing as well as a new technology for incorporation of flavorants and other bioactive materials on the inner surface of porous extrudates.”
Several papers on process dynamics of starch-based microcellular foams produced by supercritical extrusion have resulted from the project, as well as Tutanathorn’s M.S. thesis on “Flavor Application and Encapsulation by Supercritical Fluid Extrusion.” A number of students who have studied SCFX are now working in industry and academia, both in the United States and abroad, Rizvi said.
“This work has led us to examine the thermodynamic requirements for and mechanisms of high-pressure extrusion with SC-CO2 to facilitate the delivery of flavorants and nutrients via expanded food products like snack foods, breakfast cereals, and baked goods,” Rizvi said. He acknowledged the support of Wenger Manufacturing, Inc., Sabetha, Kans., in providing a state-of-the-art, high-pressure extrusion system especially designed for SCFX, and added that “we are currently working with industry to fine-tune applications to various food and pharmaceutical products.”
--- PAGE BREAK ---
Jozef Kokini & Dough Mixing Efficiency
Jozef L. Kokini, Professor II Food Engineering, Chair, Dept. of Food Science, and Director, Center for Advanced Food Technology, Rutgers University, New Brunswick, N.J., received the prize in 2002 for his project, “Simulation and Validation of Mixing Efficiency in Batch and Continuous Dough Mixers.”
Kokini’s project focused on using numerical simulation to predict the performance of batch and continuous mixers, so that design guidelines could be developed on how to configure and manufacture them.
Kokini and his students Lakshmi Prakash, Robin Connelly, Bharani Ashokan, Lindsay Oravik, and Kiran Vyakaranam determined that when the rheology changes dramatically, the performance of the mixer changes as well and that as the material becomes more and more viscoelastic—especially on the elastic side—the mixing efficiency is strongly affected by the ability to create extensional flows within the mixer. “This was previously not well understood,” Kokini said, “and is a breakthrough in the way we characterize mixing performance.”
The other major finding of the project, he added, was that the geometry of the mixer was quite important in terms of increasing efficiency during mixing. “The geometry that promotes extensional flows with viscoelastic materials generates the highest mixing efficiency,” he said.
Kokini’s group also tested a number of mixing measures, such as the Manas Zloczower concept, and showed that they are very reliable predictors of mixing efficiency in a wide range of mixers.
The ultimate goal is to make continuous mixers mix as efficiently as batch mixers but with much shorter residence times. “Mixing dough in a batch mixer takes about 30 minutes,” Kokini said, “but we want to have 1 or 2 minutes in continuous mixers. We are making very good progress in that direction. Fourteen years ago, we had no idea whether we could do this, but we are quite close now.”
The project has resulted in more than a dozen publications in premier engineering journals around the world and has also led to new directions in research. “We started looking at bubble formation and nucleation in dough mixers as a result of the various flow patterns in a mixer,” Kokini said. “This is important because most dough applications lead to expanded products like bread, where the introduction of air cells is actually quite critical to the process.”
“We are contributing toward making continuous dough processing more efficient, leading to products with improved quality,” Kokini added. “We are making mixing a more quantitative science, whereas 14 years ago it was a more chaotic empirical science. We are laying out design principles allowing the development of optimal mixer geometries.”
The project is still continuing. Kokini’s group obtained funding from other sources and is working with various companies. The two Ph.D. students who already graduated, Lakshmi Prakash and Robin Connelly, are now Director of Research for Sabinsa Corp., a nutraceutical company in New Jersey, and Assistant professor of Food Engineering at the University of Wisconsin, respectively, and the other students are about to finish their M.S. and Ph.D. degrees.
--- PAGE BREAK ---
Dietrich Knorr & High-Pressure Processing
Dietrich Knorr, Professor and Head, Dept. of Food Biotechnology and Food Process Engineering, and Director of the Institute of Food Technology and Food Chemistry at the Berlin Institute of Technology, Berlin, Germany, received the prize in 2004 for his project, “Inactivation Kinetics of Bacterial Spores, Viruses, and Prions During Short- Time High-Pressure Processing.”
The goal of Knorr’s project was to design pressure–temperature– time processing schemes for high-pressure (up to 1,500 MPa) inactivation of food-related bacterial spores, prions, and viruses while attempting to retain food quality and functionality.
Knorr, his coworker Volker Heinz, and his students studied combined high-pressure and temperature inactivation of spores of Alicyclobacillus acidoterrestris, Clostridium botulinum, Bacillus subtilis, Bacillus amyloliquifaciens, and Bacillus stearothermophilus, as well as the influence of agglomeration on thermal inactivation of B. stearothermophilus, pH of water and buffer systems under adiabatic conditions up to 1,000 MPa, and heat and high-pressure inactivation of avian influenza virus. The project has resulted in at least 15 papers and presentations.
Major findings at the end of the two-year funding period include kinetic data for pressure/ temperature inactivation of selected viruses, bacterial spores, and prions. A better understanding of the pressure/temperature inactivation mechanisms for spores was also achieved.
“The results obtained so far,” Knorr said, “have had significant impact on the development of pressure-assisted sterilization processes, design of high-pressure equipment, development of processes for concurrent inactivation of bacterial spores and prions, and the possible development of processes for virus-free poultry meat with high quality and functionality.”
Knorr’s work also led to the initiation of a large European Union–sponsored project (www.novelQ.org), one of the ultimate goals of which is to overcome scientific and technological hurdles of high-pressure application. He pointed out that commercial high-pressure sterilization processes as well as processes for viral inactivation have been initiated and more than 90 industrial high-pressure installations exist worldwide.
The prize has also helped to bolster the career of Knorr’s coworker on the project, Volker Heinz, who is now codirector of the German Institute of Food Technology (DIL), a research center with approximately 125 employees.
Knorr said that the research will continue, especially on viruses and spore inactivation kinetics and mechanisms. Work has also begun on answering fundamental questions regarding process inhomogeneities, agglomerates of spores in food systems, and pressure and temperature dependence of buffers used in high-pressure research.
As a result of the award, he added, additional highly sophisticated high-pressure research units could be developed and obtained, including an isothermal/isobaric high-pressure system for temperatures up to 120°C and pressures up to 1,400 MPa. In addition, in cooperation with equipment manufacturers, high-pressure, short-time processing units (e.g., pressure buildup to 1,000 MPa in less than 10 sec) could be developed.
--- PAGE BREAK ---
José Aguilera & Structure–Property Relationships
José Miguel Aguilera, Professor of Food and Chemical Engineering, Dept. of Chemical and Bioprocess Engineering, Pontificia Universidad Católica de Chile, received the prize in 2006 for his project, “Structure–Property Relationships in Foods.” He intends to demonstrate that useful numerical data can be extracted from images, analyzed by suitable algorithms, and used later for engineering modeling and food product design.
“Properties and engineering phenomena in foods are related to their structure,” Aguilera said. “Abundant recent evidence suggests that transport properties, texture, sound, surface color, and even nutritional properties of foods depend on how the food matrix is structured. The study of structure–property relationships in foods is the basis of a new discipline called food materials science.”
Aguilera plans to use image analysis to quantify the surface roughness of chocolate bars and relate it to color, color patterns, and gloss; to study the effect of size, shape, and size distribution of bubbles on physical properties of aerated gels; and to determine the relation between microstructural features of starch granules during gelatinization and the release of sugars assessed by simulated in-vitro digestion. “Quantifying the microstructure of foods will assist in developing meaningful structure–property relationships for use in engineering modeling and food product design,” Aguilera said.
He will be working on the project with French postdoctoral fellow Olivier Skurtys.
Appreciation for the Prize
I asked the recipients if they had any comments about the Marcel Loncin Research Prize.
--- PAGE BREAK ---
“This prize is an outstanding way to combine basic science and research with industrial applications,” Bauer replied.
“The prize is viewed in Europe as one of the premier awards for food science,” Blanshard’s successor Taylor said. “We were pleased to see another European, Dietrich Knorr, win the prize in 2004.”
“The prize came at the right time, when research funds for this work did not exist, and opened up the door to opportunity,” Labuza said.
“It is a fabulous prize, which provides a unique opportunity to explore novel and cuttingedge ideas and build the next level of sophistication in food science and engineering research,” Rizvi replied.
“The prize was an excellent catalyst to show that what we were working on was really worthy of a long-term focus of concentration,” Kokini said. “It is a fantastic opportunity for those in food science who are conducting cutting-edge work to gain recognition and encouragement to continue their work and also support students who conduct research.”
“I highly value the fact that the Marcel Loncin Research Prize has become a truly international award,” Knorr said. “Four of the seven awardees are from outside the United States.”
“To my knowledge, this is the largest and most prestigious prize in food technology research and should be promoted as such by IFT,” Aguilera stated. “Winners have been leaders in their respective fields, working on some of the most exciting research topics that will result in better-quality, healthy, and safe foods.”
How to Apply
The next Marcel Loncin Research Prize will be awarded at the IFT Annual Meeting + Food Expo® in New Orleans, La., June 26–30, 2008. Applications will be accepted from September 1, 2007, until December 1, 2007. Application forms and further information will be available on IFT’s Web site, www.ift.org, under “Awards.”
He was also assistant professor and later professor at Centre d’Enseignement et de Recherches des Industries Alimentaires (CERIA) in Brussels from 1942 until 1970. He was scientific adviser at Ecole Nationale Superieure des Industries Alimentaires (ENSIA) in Massy near Paris beginning in 1961 and professor and head of the Food Engineering Dept. at Karlsruhe University in West Germany beginning in 1972.
A member of the French Academy of Agriculture and recipient of numerous awards, Loncin was the author of more than 250 papers, mainly on food technology, and books, one of the best known being Food Engineering, Principles and Selected Applications, coauthored with R.L. Merson and published by Academic Press in 1979.
At the time of his death in 1994, Loncin was still involved in research on activity of water at the solid–gas interface, emulsion technology, interfacial phenomena, and drying technology.
by Neil H. Mermelstein, a Professional Member of IFT, is Executive Editor of Food Technology magazine ([email protected]).