Newsletter: February 27, 2018

Researched and written weekly by the editorial team of Food Technology magazine, the IFTNEXT Newsletter explores what are, arguably, the next big things in the science of food through original reporting of scientific breakthroughs, leading-edge technology, novel food components, and transdisciplinary R&D.

Edible electronics poised to grow the ‘Internet of Food’
Could edible electronics be used on produce on the future?Researchers from Italy’s Instituto Italiano di Technologia (IIT) have designed edible organic electronic components that can be transferred onto objects such as pharmaceutical pills and food. The process is very similar to the way kids’ transferable tattoos work—a thin layer of ethyl cellulose polymer is applied to a sheet of paper by a layer of starch or dextrin, which dissolves when water is applied, leaving the tattoo—the polymer—behind. While the idea of ingesting electronic devices to monitor a patient’s health is not new, the researchers have made it possible to produce them using an inkjet-printing technique that is much more affordable than current options.

“When we started working on this project, the main applications that we considered were biomedical,” explains research team lead Giorgio Bonacchini, a postdoctoral scholar at Tufts University, who conducted the research as a PhD candidate at IIT. For example, the researchers intended the edible electronics to enable medications to communicate electronically to doctors when they had been ingested by the patients.

The team soon realized that the technology they were developing could be useful for the food industry as well. “Our vision for this type of edible electronics is thus to allow for the fabrication of cheap and disposable electronic tags that can be placed directly in contact with food, either fresh or packaged, and which can even be eaten by customers without causing harm,” says Bonacchini. He notes that further studies are needed to ensure the biocompatibility of the electronics, but so far, the results are promising.

The researchers believe that their technology may have more applications for food before ingestion when first introduced but are exploring applications after ingestion. The tattoos could “potentially exploit the intimate contact between food and electronic device to perform analysis of the products’ quality,” says Bonacchini. “In general, they bring ICT [information and communication technologies] into food, establishing the so-called ‘Internet of Food’—a communication network that allows tracking, monitoring, and sensing.”

The researchers point out that the technology is still in the very early stages, but are excited by the potential uses they foresee. For example, they “envision the possibility for customers to buy products in the grocery stores, printing their own edible electronic tags in the store itself, which are then applied directly to the fresh goods. When they are home, their domestic appliances, such as smart refrigerators, through the Internet of Things could electronically monitor the quality of fruits, vegetables, meat, or cheese,” imagines Bonacchini.

The team is now working to develop sensors that could be embedded into the edible electronics, taking the technology one step closer to fruition. Another challenge the team must face is the integration of their edible electronics with edible batteries, which are in development by other researchers. “We intend to continue pursuing the development of this technology, as we have noticed large interest from both academic and industrial players, and hopefully in a few years we will have reached a technology viable for the market,” says Bonacchini.


Discovery sheds greater light on how we taste foods
Food technologists tasting samplesScientists continue to gain new insights into the science of taste, including the mechanisms that help differentiate one taste, such as sweet, from another, such as bitter. Previously published research found that a single protein—TRPM5—was responsible for identifying sweet, bitter, or savory tastes in food. Researchers recently discovered that a second protein—TRPM4—has a similar function in the taste system, and that both TRPM4 and TRPM5 are required for the detection of sweet, bitter, or umami taste stimuli.

The study was published in Proceedings of the National Academy of Sciences of the United States of America.

The researchers used a combination of RT-PCR and immunohistochemistry to identify that TRPM4 is expressed in taste cells, says Kathryn Medler, associate professor at the University of Buffalo and one of the study’s authors. Live cell imaging and behavior studies in transgenic mice that lack TRPM4, TRPM5, or both TRPM4 and TRPM5 helped to characterize the role of TRPM4 in taste transduction, explains Medler. From this the researchers found that both TRPM4 and TRPM5 contribute to the bitter-, sweet-, and umami-evoked signals in taste cells and that they appear to work together, or at least both contribute, to generate the normal control response to these stimuli, she adds.

“Understanding how the taste system works is important because the taste system sends signals to reward systems in our brain, in addition to the area of the brain responsible for our conscious perception of taste,” says Medler. “These reward centers contribute to our appetite and satiety. If these signals are dysregulated, it can affect our appetite and food intake, including both over- and under-eating, which can lead to either obesity or malnutrition. Therefore, it’s important to understand how the taste cells work so solutions can be designed to correct any problems that arise.”

Medler also explains that the discovery provides food industry professionals with an understanding to how taste works to guide them as they formulate food and beverage products. “Artificial sweeteners were developed to provide sweetness to food to encourage consumption without adding calories. As we increase our understanding of how the peripheral taste cells detect stimuli in the oral cavity and transmit that signal to the brain, it will allow for improvements in how these types of food additives are designed.”

There are still questions to be answered and many discoveries to be made in the area. “TRPM5, which has an established role in taste transduction, is known to have thermal sensitivity which affects sweet intensity,” says Medler. “It would be interesting to determine if TRPM4 has a similar sensitivity to temperature. We could certainly expand our taste stimuli tested to determine if our initial findings are representative of all bitter, sweet, and umami stimuli or if there is some selectivity in the role of TRPM4. Our data suggest a functional coupling of TRPM4 and TRPM5 that varied with the different stimuli we tested. Future studies could explore and establish that relationship better.”


Bioprocess creates new uses for dairy waste stream
The bio-oil made from acid whey could be used as animal feed or aviation fuel.Scientists have used microbiota similar to those found in the human gut to convert “acid whey” wastewater from dairy processing into a new bio-oil with applications as an animal feed or—with further processing—as fuel for airplanes.

The study results were published in an article in the December 2017 issue of the scientific journal Joule. In that article, the researchers explain that makers of Greek yogurt produce large volumes of acid whey, which has been successfully converted into methane gas by using anaerobic digesters. But they point out that revenue from methane is relatively low.

Their work involved converting acid whey into valuable medium-chain carboxylic acids (MCCAs), which can be used in livestock feed additives or as precursors for biofuels. Their approach is significant because it relies on microbiome cultures and requires no additional chemicals.

Researcher Lars Angenent, a professor of environmental biotechnology at the University of Tübingen in Tübingen, Germany, explains that the process involved use of a tank called a reactor microbiome that included many different types of bacteria. “This microbiome is an open culture, which means bacteria from the outside environment can also enter and grow, similar to our gut microbiome,” he says.

In the process, two microbiomes were kept under different temperatures. The first one, kept at 50°C, converted sugars into an intermediate acid—“the same acid that makes milk in your fridge taste sour if you keep it there too long,” says Angenent. A second microbiome (at 30°C) elongated the carbon backbone of the chemicals, creating the bio-oil.

Angenent explains that converting the oil to aviation fuel requires an additional, abiotic process (no microbes are used) that includes electric power. “Luckily,” says Angenent, “in Germany, there is too much renewable power at certain times, and we would wait to make the conversion to a fuel when the electric power price is low.”


Potent antioxidant may be key to defeating fatty liver disease
Fruits high in PQQ antioxidantsNon-alcoholic fatty liver disease has become a major public health issue, increasingly leading to cancer and liver transplants. But a powerful antioxidant found in kiwi fruit, bananas, celery, parsley, and papaya has been found to halt or prevent progression of the disease in the offspring of mice fed a high-fat, Western-style diet, according to a study published in Hepatology Communications by researchers at the University of Colorado Anschutz Medical Campus.

“Fatty liver disease is the No. 1 liver disease in the world,” says Karen Jonscher, associate professor of anesthesiology and a physicist at CU Anschutz, who, along with study co-author Jed Friedman, has been exploring the programming of liver disease. “Our previous work in mice and non-human primates suggested that exposure of a fetus to a maternal high fat diet could cause persistent alterations in the liver of the offspring, leading to increased fat and inflammation in the liver.”

Curious about the effect that antioxidants used to treat the mother might have on offspring, the researchers decided to try pyrroloquinoline quinone (PQQ), a potent antioxidant found in many common plant foods. Jonscher explains, “Antioxidants such as vitamin C and vitamin E have been used in animal and human studies with little or mixed effects. We thought that a stronger antioxidant might be more helpful. Since PQQ also has been shown to be anti-inflammatory, we thought it would be a good compound to test in this model, where the endpoint is inflammatory liver disease.”

The researchers found that they could halt and prevent liver disease from developing in young mice whose mothers were fed PQQ. “More research in this area would be useful, particularly determining the effect of food processing on PQQ levels and assessing PQQ in foods at the consumer level,” says Jonscher. “Given the high amount of processed foods we eat, it is possible that we are consuming a diet deficient in PQQ. Genetic engineering of bacteria and plants to produce PQQ may be a potential approach to increase initial levels in raw materials and compensate for food processing.”

Jonscher believes that more work needs to be done to understand the critical developmental windows during which the programming of liver disease occurs and when intervention can be effective. “We need to understand what happens after birth—what is the contribution of mother's milk, if any, to programming of inflammation through altering the early microbiome? Finally, what can we do when disease is already established? Can we prevent it from accelerating to the point where a transplant is needed? Or even reverse disease? All of these questions still need to be addressed, in mice and, eventually, in humans.”

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