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Industries and researchers join to improve manufacturing drying processes

URBANA, Ill. – One of the most energy-intensive stages in manufacturing paper, food, textiles, chemicals, and many other products is drying. Researchers from two colleges at the University of Illinois are working together to find more efficient and environmentally sustainable drying alternatives through a new research center, an effort sponsored by the National Science Foundation through its Industry/University Cooperative Research Centers program.

The new Center for Advanced Research in Drying is a joint effort between the Worcester Polytechnic Institute in Massachusetts and the University of Illinois at Urbana-Champaign, and is led by Jamal Yagoobi from the Department of Mechanical Engineering at Worcester Polytechnic Institute. Hao Feng, a food science researcher in the College of Agricultural, Consumer and Environmental Sciences at Illinois, will serve as the Urbana-Champaign campus site director for the center.

“The drying process has a direct effect on product quality, from the nutritional value of food to the durability of paper products and textiles,” says Feng. “Inefficient drying processes also create a significant environmental impact. By working to improve the drying process, we can enable production of products with better quality, speed up the delivery of products, and increase manufacturers’ profit margin so everyone benefits, and we can reduce its adverse effects on the environment.”

Irfan Ahmad, from U of I’s College of Engineering, is co-principal investigator/co-site and innovation director of the center. Ahmad is also executive director at the Center for Nanoscale Science and Technology, and a research faculty member in the Department of Agricultural and Biological Engineering.

“Innovation is at the heart of CARD to address such challenges as energy conservation, climate change, product safety and quality, using novel technologies such as micro and nanotechnology-based smart sensors and drying nozzles,” says Ahmad. “It also envisages new engineering education programs to nurture innovation in drying as a vital core competency for the next generation workforce.”

As defined by NSF’s I/UCRC program, the center must demonstrate measureable industry collaboration and involvement that accelerates fundamental research. Evidence of industry-defined fundamental research must show that the proposed industry participation extends the center’s capabilities into areas or projects that might not otherwise be researched.

NSF provides a framework for industries, universities, and the government to join together to solve problems that require a multi-disciplinary effort such as this one. Over 30 industry, organization, and government partners have shared their enthusiasm and financial support for the center’s research on drying.

It is the first center in the United States dedicated to developing energy-efficient technologies for drying moist, porous materials, a problem affecting the competitiveness of U.S. manufacturers across a wide range of industries. The center is one of three NSF I/UCRC centers led or co-led by University of Illinois researchers.

“Innovative drying technologies are critical to advanced, sustainable manufacturing technologies. Numerous challenges remain to be tackled with tangible academia-industry interaction such as CARD. I am sure CARD will play a leadership role in making a definitive contribution to the national and global effort in this field”, says Arun Majumdar, editor-in-chief of Drying Technology, and emeritus professor of bioresource engineering at McGill University in Canada.

For more information, visit the Center for Advanced Research in Drying.

Original story published here:

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3D micro X-ray images help answer questions about fried foods’ internal structure

3D solid network image of pores formed in a potato during frying. Image courtesy of Pawan Takhar.

URBANA, Ill. – What happens to food and its microstructure when it is fried is a complicated process, both scientifically and mathematically speaking. While consumers want a product that is crispy and tasty, food scientists seek to get a closer glimpse into what exactly is going on inside the food during frying in order to improve products.

Particularly, Pawan Takhar, a University of Illinois food scientist, is interested in the food’s uptake of oil during frying and how that oil gets distributed throughout the food. “Through conventional lab techniques we can already see how much oil content is in food material, but we didn’t know how it gets distributed throughout the material,” he says.

To understand the distribution of oil better, Takhar and his lab recently conducted a study using X-ray micro-computed tomography (micro-CT) to gain 3D images of the microstructure of fried potato disks after they had been fried for various lengths of time.

During deep frying, as food is immersed in hot oil, water in that food quickly evaporates and steam pressure builds. This pressure affects the microstructure, including the porosity—the number and size of pores in the food—as well as the twistiness of the pathways between those pores (tortuosity). This determines how and how much oil gets taken up into the food.

For the study, russet potatoes cut into disks that were 45-mm in diameter and 1.65 mm thick were fried at 190 degrees Celsius for 20, 40, 60, or 80 seconds, freeze dried, and scanned.

Takhar says about 986 2D images of the potato samples were collected and then combined to produce 3D images. Using the 3D images, they were able to gain more information about the pores and pore networks in the material.

The researchers observed that as frying time increased, pore size increased, allowing for greater uptake of oil. They also saw a correlation between oil content and how the network of pathways between the pores changed throughout the frying time. These pathways act like channels for water and vapor flow and oil penetration in the food.

“As you fry the material, you can see how those pore structures are forming,” Takhar says. “We found that in the beginning of frying, the pore network is very complicated. The waviness in the pathway, the tortuosity, is very complex in the beginning so the material resists oil penetration. But as the frying progresses, those pathways become simpler. Pores open up and are easily accessible from the outside and oil can be taken up.”

Takhar also explains that oil was observed distributed across the full thickness of the potato disks. In thicker materials with lots of moisture (like chicken nuggets and French fries), they have observed the oil to remain near the surface as continuous evaporation helps to resist oil penetration.

“It is not easy to make a product that has no oil and still provides taste, flavor and texture that consumers enjoy,” he says. “People like that fried flavor and the texture of crispiness outside and softness inside. At the same time you want to reduce the oil content to make the food healthier. With this network study we wanted to see how those networks are formed, because networks are also related to texture.” It’s a combination of the oil content and air pockets in the pore structure that provide the desired crispy texture.

The findings from the potato disks in the study can also be applied to other fried foods, Takhar says. His lab has done previous research on frying using chicken nuggets and French fries.

While Takhar and his lab have done mathematical modeling of what happens during frying—just one previous paper outlines over 100 mathematical equations involved in the process—he says this study provides some experimental validation as to what is happening inside the food material.

“I would say we still only understand about 10 percent of what is taking place during frying,” says Takhar. He and his lab have studied the effects of frying for 10 years. “For an engineer or a food scientist, it’s the ultimate problem because it’s so complicated.

“Our aim is to make these products healthier, so that they have the same taste and texture but, at the same time, have lower fat content. That is our long-term goal with our research,” Takhar says.

“Microstructural characterization of fried potato disks using X-Ray micro computed tomography,” is published in the Journal of Food Science and can be found online athttp://dx.doi.org/10.1111/1750-3841.13219 Co-authors are Tanjila Alam, formerly a graduate student at the University of Illinois, and Pawan S. Takhar of the University of Illinois.

Funding was provided by USDA-NIFA.

The researchers acknowledge Beckman Institute at University of Illinois for providing assistance with the micro CT scanning experiments.

News Source:

Pawan Takhar, 217-300-0486

Original story posted here:

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Scientists tackle our addiction to salt and fat by altering foods’ pore size, number

URBANA, Ill. – Two University of Illinois food scientists have learned that understanding and manipulating porosity during food manufacturing can affect a food’s health benefits.

Youngsoo Lee reports that controlling the number and size of pores in processed foods allows manufacturers to use less salt while satisfying consumers’ taste buds. Pawan Takhar has found that meticulously managing pore pressure in foods during frying reduces oil uptake, which results in lower-fat snacks without sacrificing our predilection for fried foods’ texture and taste.

Both scientists are experts in food engineering and professors in the College of Agricultural, Consumer and Environmental Sciences’ Department of Food Science and Human Nutrition.

Regarding salt, Lee said, “Six in 10 American adults either have high blood pressure or are on the borderline of this diagnosis largely because they eat too much salt. Overconsuming salt is also associated with the development and severity of cardiovascular and bone diseases, kidney stones, gastric cancer, and asthma.”

Because 70 percent of the salt Americans consume comes from processed foods, Lee began to study the relationship between the microstructural properties of these foods and the way salt is released when it is chewed.

“Much of the salt that is added to these foods is not released in our mouths where we can taste it, and that means the rest of the salt is wasted,” he said. “We wanted to alter porosity in processed food, targeting a certain fat–protein emulsion structure, to see if we could get more of the salt released during chewing. Then food manufacturers won’t have to add as much salt as before, but the consumer will taste almost the same amount of saltiness.”

Increasing porosity also changed the way the foods broke apart when they were chewed, exposing more surface area and increasing saltiness, he said.

“When foods crumble easily, we further reduce the amount of salt that is needed. Changing the number or size of pores in the food’s surface can help us to accomplish this,” he said.

Takhar said that his porous media approach to understanding the behavior of water, oil, and gas during frying will help create strategies that optimize the frying process, reduce oil uptake, and produce lower-fat foods.

The articles Takhar publishes in academic journals feature page after page of complex mathematical equations that describe the physics involved in the transport of fluids and in textural changes in foods. These equations then guide the simulations that he performs in his laboratory.

“Frying is such a complicated process involving more than 100 equations. In a matter of seconds, when you put the food in the fryer, water starts evaporating, vapors form and escape the surface, oil penetration starts, and heat begins to rise while at the same time there’s evaporative cooling off at different points in the food. Some polymers in the food matrix may also change their state, and chemical reactions can occur. It’s not an easy set of changes to describe,” he said.

Within 40 seconds of frying, the texture of gently fried processed foods like crackers is fully developed, the scientist said. “That’s the cracker’s peak texture. Any longer and you’re just allowing more oil to penetrate the food.

“A lot of frying research has focused on capillary pressure in the oil phase of the process, but we have found that capillary pressure in the water phase also critically affects oil uptake,” Takhar said.

Capillary pressure makes overall pore pressure negative, and that negative pressure tends to suck oil from inside. His simulations show when that pressure is becoming more negative.

“The trick is to stop when pore pressure is still positive (or less negative)—that is, when oil has had less penetration. Of course, other variables such as moisture level, texture, taste, and structure formation, must be monitored as well. It’s an optimization problem,” he noted.

When this exquisite balance is achieved, lower-fat, healthier fried foods are the result, he added.

“Temporal Sodium Release Related to Gel Microstructural Properties—Implications for Sodium Reduction” was published in a recent issue of Journal of Food Science. Lee and Wan-Yuan Kuo are co-authors of the study, which will continue to be funded by USDA. “Modeling Multiscale Transport Mechanisms, Phase Changes, and Thermomechanics during Frying” was published in a recent issue of Food Research International. Co-authors are Takhar and Harkirat S. Bansal of the U of I and Jirawan Maneerote of Kasetsart University in Bangkok, Thailand. The Takhar study was funded by USDA and the Royal Thai Government.


News Sources:
Youngsoo Lee, 217-333-9335
Pawan Takhar
, 217-300-0486

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Two University of Illinois food scientists receive USDA food safety grants

URBANA, Ill. – Two University of Illinois professors have received $861,714 in grant money from USDA’s National Institute of Food and Agriculture (NIFA) to fund research that will improve the nation’s food quality.

A four-year grant for nearly $500,000 was awarded to Pawan Takhar, a U of I associate professor of food engineering, to study damage to foods caused by ice recrystallization during freeze-thaw cycles. Shyam S. Sablani, associate professor of biological systems engineering at Washington State University, is a co–principal investigator on the project.

“Millions of dollars’ worth of food products are damaged during shipping and storing due to moisture migration and ice crystal growth caused by freeze-thaw cycles. Data generated from our physics-based mathematical modeling and experimentation will help the food industry improve the operation and design of its freezing units,” Takhar said.

Youngsoo Lee, a U of I assistant professor of food science, was awarded a USDA NIFA grant for over $360,000 for research that will enable food manufacturers to design solid food systems that will enhance saltiness and achieve sodium reduction in a broad range of products.

“Six in 10 American adults either have high blood pressure or are on the borderline of this diagnosis largely because they eat too much salt,” he explained.

Because 70 percent of the salt Americans consume comes from processed foods, Lee studies the relationship between the microstructural properties of these foods and the way salt is released when it is chewed.

“Much of the salt that is added to processed foods is not released in our mouths where we can taste it, and that means the rest of the salt is wasted,” he said. “We want to alter porosity in these foods to see if we can get more of the salt to be released during chewing. Then food manufacturers won’t have to add as much salt as before, but the consumer will taste almost the same amount of saltiness.”

Soo-Yeun Lee, a U of I associate professor of food science, and Jan Ilavsky, a physicist at Argonne National Laboratory, are co–principal investigators on Lee’s grant-funded research.


News Sources:
Youngsoo Lee, 217-333-9335
Pawan Takhar
, 217-300-0486

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“Jailbreaking” yeast could amp up wine’s health benefits, reduce morning-after headaches

URBANA – University of Illinois scientists have engineered a “jailbreaking” yeast that could greatly increase the health benefits of wine while reducing the toxic byproducts that cause your morning-after headache.

“Fermented foods—such as beer, wine, and bread—are made with polyploid strains of yeast, which means they contain multiple copies of genes in the genome. Until now, it’s been very difficult to do genetic engineering in polyploid strains because if you altered a gene in one copy of the genome, an unaltered copy would correct the one that had been changed,” said Yong-Su Jin, a U of I associate professor of microbial genomics and principal investigator in the Energy Biosciences Institute.

Recently scientists have developed a “genome knife” that cuts across multiple copies of a target gene in the genome very precisely—until all copies are cut. Jin’s group has now used this enzyme, RNA-guided Cas9 nuclease, to do precise metabolic engineering of polyploid Saccharomyces cerevisiae strains that have been widely used in the wine, beer, and fermentation industries.

The possibilities for improved nutritive value in foods are staggering, he said. “Wine, for instance, contains the healthful component resveratrol. With engineered yeast, we could increase the amount of resveratrol in a variety of wine by 10 times or more. But we could also add metabolic pathways to introduce bioactive compounds from other foods, such as ginseng, into the wine yeast. Or we could put resveratrol-producing pathways into yeast strains used for beer, kefir, cheese, kimchee, or pickles—any food that uses yeast fermentation in its production.”

Another benefit is that winemakers can clone the enzyme to enhance malolactic fermentation, a secondary fermentation process that makes wine smooth. Improper malolactic fermentation generates the toxic byproducts that may cause hangover symptoms, he said.

Jin stressed the genome knife’s importance as a tool that allows genetic engineers to make these extremely precise mutations.

“Scientists need to create designed mutations to determine the function of specific genes,” he explained. “Say we have a yeast that produces a wine with great flavor and we want to know why. We delete one gene, then another, until the distinctive flavor is gone, and we know we’ve isolated the gene responsible for that characteristic.”

The new technology also makes genetically modified organisms less objectionable, he said. “In the past, scientists have had to use antibiotic markers to indicate the spot of genetic alteration in an organism, and many persons objected to their use in foods because of the danger of developing antibiotic resistance. With the genome knife, we can cut the genome very precisely and efficiently so we don’t have to use antibiotic markers to confirm a genetic event.”

The research was reported in a recent issue of Applied and Environmental Microbiology.

Co-authors of “Construction of a Quadruple Auxotrophic Mutant of an Industrial Polyploid Saccharomyces cerevisiae Strain by Using RNA-Guided Cas9 Nuclease” are Guochang Zhang, In Iok Kong, Heejin Kim, Jingjing Liu, and Yong-Su Jin, of the University of Illinois at Urbana-Champaign, and Jamie H.D. Cate of the University of California, Berkeley, and Lawrence Berkeley National Laboratory. The research was funded by the Energy Biosciences Institute.

The Energy Biosciences Institute is a public-private collaboration in which bioscience and biological techniques are being applied to help solve the global energy challenge. The partnership, funded with $500 million for 10 years from the energy company BP, includes researchers from UC Berkeley; the University of Illinois, and the Lawrence Berkeley National Laboratory. The research was conducted in the Energy Biosciences Institute, a public–private collaboration funded by the energy company BP. The EBI includes researchers from UC Berkeley, the University of Illinois, and the Lawrence Berkeley National Laboratory. Details about the EBI can be found on the website: www.energybiosciencesinstitute.org .


News Source: Yong-Su Jin, 217-333-7981

Original story from FSHN website publised March 16, 2015 and found here: http://fshn.illinois.edu/news/jailbreaking-yeast-could-amp-wines-health-benefits-reduce-morning-after-headaches

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New Faculty Lectures Online

Two lectures from FSHN faculty members Hao Feng and Juan Andrade, as presented at the February 2015 “Food Systems for Food Security Symposium” symposium on the University of Illinois campus, are now available:

“Food Dehydration Reduction of Postharvest Losses” by Dr. Hao Feng. Lecture slides are here.

“Innovations to Achieve Nutrition Security in Low-income Countries” by Dr. Juan Andrade. Lecture slides are here.

 

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Food Dehydration Reduction of Postharvest Losses – Prof. Hao Feng, February 10, 2015

“Food DehydrationReduction of Postharvest Losses,” Hao Feng, Ph.D, Professor, Department of Food Science and Human Nutrition (fshn.illinois.edu), University of Illinois at Urbana-Champaign. 

Lecture slides:
http://intlprograms.aces.illinois.edu…

Event: Food Systems for Food Security Symposium
February 10, 2015, ACES Library, Information and Alumni Center, Urbana, Illinois
http://intlprograms.aces.illinois.edu…
http://intlprograms.aces.illinois.edu/content/food-systems-food-security-symposium

Sponsor: International Food Security at Illinois
College of Agriculture, Consumer and Environmental Sciences
University of Illinois at Urbana Champaign

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Hao Feng

Power ultrasound as a new food and bioprocessing modality, novel chemical and physical treatments for improving the quality and safety of fresh and fresh-cut produce, conversion of biomass for production of biofuel and value-added products, food dehydration, heat and mass transfer analysis, and determination of physical and transport properties of food and biological materials.


Professor; haofeng@illinois.edu; more detail here.


 

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Jozef L. Kokini

Dr. Jozef L. Kokini

Rheological properties of foods; food nanotechnology; structure, texture, flavor relationships; developing bioactive nutraceuticals.


Professor Emeritus; kokini@illinois.edu; more detail here.


 

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Pawan Takhar

Dr. Pawan Takhar

Dr. Takhar uses porous media physics to study food and bioprocessing applications via mathematical modeling and experimental validation. He focuses on making further improvements in the multiscale hybrid mixture theory (HMT) with applications in swelling biopolymers. His research group has applied the theory for predicting fluid transport and stress-crack initiation in foods; performing macroscale and microstructural experiments (using NMR imaging, X-ray tomography and scanning electron microscopy) for obtaining further insight into transport mechanisms; solving unsaturated transport problems such as frying and starch expansion during extrusion; designing controlled release applications; and adapting the concepts from transport theories to work with food safety problems (fractional differential equations based new application in this field). Numerous bioprocesses such as drying, sorption, solvent transport, controlled release, conditioning, cooking, storage etc. can be addressed using his general approach on transport mechanisms. His team has also performed validation experiments on continuous and intermittent drying, and sorption to develop strategies for obtaining foods with reduced fractures and fried foods with lower fat content.


Associate Professor; ptakhar@illinois.edu; more detail here.


 

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