Newsletter: April 3, 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.

Mars Crop OptionResearchers cultivate crops in Mars-like environment
Growing crops on Mars isn’t just the stuff of science fiction. Scientists at Wageningen University & Research in the Netherlands have demonstrated that they can grow a variety of vegetable crops in a simulated Martian environment, and they’ve also mapped the most favorable locations for cultivating crops on the red planet. 

Wageningen researchers have been growing crops in conditions akin to those on Mars by using volcano-derived soil simulants supplied by NASA since 2013. To date, they’ve successfully cultivated more than a dozen crops, including beans, peas, tomatoes, and carrots. Wageningen senior ecologist Wieger Wamelink says the team’s current experiment cycle is focused on growing potatoes and peanuts. Peanuts are a good choice, he explains, because together with bacteria in the soil, legumes can bind nitrogen from the air and turn it into nitrate, which acts as fertilizer. 

Wamelink and Wageningen student Line Schug also recently tapped into information about the mineral content of the soil on Mars as well as climate and radiation levels to come up with a 3-D map that identifies the locations where plant species can grow best on the planet. Mars soil contains high levels of toxic heavy metals, including arsenic, cadmium, and lead. More research is needed, but in a prior study, the scientists analyzed crops grown in Mars soil simulants and determined that they were safe for human consumption. The environment on Mars also has the advantage of an adequate water supply for crop cultivation because there is a significant amount of ice beneath its surface, Wamelink reports. 

To support human life on Mars, just growing crops won’t be enough, however. Crop waste (and human waste as well) will need to be returned to the soil and broken down to allow the release of nutrients to support the next generation of crops. For this reason, Wageningen Mars research has also included experiments with earthworms, whose role will be to eat organic waste material, digest it, excrete it, and mix it with the soil, creating a nutrient-rich and fertile growing environment.  

“Bacteria can then further break down the organic matter and release the nutrients for the next generation,” Wamelink explains. What is more, he adds, by burrowing into the soil, the earthworms let in oxygen, which is important for the plants’ root systems. The Wageningen researchers recently demonstrated that earthworms can live and reproduce in the Mars soil simulant—another important step in creating a viable agricultural ecosystem on Mars.   



Rotting StrawberriesNanotech-based ‘nose’ sensitive to food spoilage odor
Rotting food produces a compound called cadaverine, the same odor produced by rotting bodies, or cadavers. A newly developed bioelectronic “nose” can detect low levels of the compound in foods much sooner than the human nose can detect. 

Tai Hyun Park, professor in the school of chemical and biological engineering at Seoul National University, and his research collaborators developed the oriented nanodisc-functionalized bioelectronic nose using a series of carbon nanotube transistors and nanodiscs. They first produced an olfactory receptor for the compound (a trace-amine-associated receptor 13c) that binds to cadaverine and then embedded the receptors onto nanodiscs. Then these nanodiscs were fit onto a carbon nanotube-based field-effect transistor with floating electrodes, thus creating the oriented nanodisc-functionalized bioelectronic nose. The researchers tested the mechanism on samples of salmon and beef at various stages of spoilage and found that it was both selective and sensitive in its ability to detect cadaverine at low levels. “These results indicate oriented nanodisc-functionalized bioelectronic nose devices can be utilized to evaluate the quality of food samples quantitatively, which should enable versatile practical applications such as food safety and preservative development,” write the researchers. 

In addition to conducting research on the nanodisc-based bioelectronic nose, Park also completed a review paper on bioelectronic noses and tongues with co-author Mani Son. One of the conclusions is that bioelectronic sensors that mimic a human’s senses of smell and taste function in the assessment of food quality by having the sensitivity and selectivity to detect odor and taste molecules in food samples. Park and Son write that the technology may be used in some interesting ways in the future. A portable bioelectronic nose and tongue will be the next-generation analytical tools for rapid on-site monitoring of food quality, while a bioelectronic nose and tongue can transmit data to brain machine interfaces and then to the brains of people who have lost their sense of smell and taste, they explain in the paper.



Gas Liquid ChromotographFailsafe profiling of food nutrients
Capturing food nutrient profiles is rife with challenges, including the common difficulty scientists face when trying to reproduce results using different methods. But W. Craig Byrdwell, an analytical chemist in the Agricultural Research Service (ARS) Food Composition and Methods Development Laboratory (FCMDL), has developed a groundbreaking method that resolves discrepancies and paves the way for better determining dietary recommendations. 

Using four mass spectrometers, two liquid chromatographs, and a gas chromatograph, he embarked on a mission to find a comprehensive approach to analysis. Byrdwell started with vitamin D, a nutrient that, he says, “had a lot of contradictory information and results of questionable quality.” In examining oysters and other foods in which vitamin D had been reported, for example, he proved that the nutrient was essentially absent. “The conclusion that we came to regarding UV detection,” he says, “is, ‘don’t trust … verify.’”

Byrdwell’s use of multiple mass spectrometers provides a degree of certainty in the identification of target nutrients that other methods cannot provide. In addition, he routinely employs certified Standard Reference Materials from the National Institute of Standards and Technology to validate his methods and ensure the numbers are objectively accurate. “The implications are that the numbers we get are definitive and backed up by multiple detection methods,” he says, a fact that has enabled him to identify nutrients such as tocopherols (vitamin E) that have not been identified in some sources before. 

Byrdwell’s lab constantly works to derive more information related to the bioavailability of nutrients. “For instance,” he explains, “using a single normal liquid chromatograph, we can identify the fat-soluble vitamins and the molecular species of triacylglycerols (TAG) in a wide range of samples. But … we want to also determine the relative amounts of regioisomers of triacylglycerols, because plants synthesize TAGs with structural specificity, and enzymes in the human gut metabolize them with structural specificity.” His solution? “To incorporate regioisomer analysis into existing analyses, without losing any of the other beneficial aspects of our analysis.” Since the isomers have identical masses, mass spectrometry alone was not enough, which is why, he says, “we added a new type of chromatographic separation as the second dimension in a 2D-LC analysis to differentiate the isomers.”  

Similarly, Byrdwell and his team have incorporated trans fatty acid analysis into their fat-soluble vitamin and TAG analysis to detect trans fats while they’re still intact. This is important because partially hydrogenated oils, which contain trans fats, have been linked to cardiovascular disease. And while trans fatty acids can be identified using gas chromatography, it relies on breaking down the TAG molecules first, not detecting them intact.  

Despite the complex arrangements Byrdwell uses to extract the maximum structural information possible, he advises others to “take only the parts of our experiments that they need to get the information they want. I push the boundaries of what’s possible to demonstrate what can be done, and let readers choose those aspects that are most useful to them.” 



Pearl MilletUnderstanding the genetics behind heat and drought tolerance
The recent publication of the genome sequence of pearl millet, a drought-resistant crop, gives scientists key knowledge into agronomic traits of plants growing in extreme environments. 

The world is facing a huge challenge of feeding the growing population, and poor diet and nutrition are leading to an increase in disease and malnutrition, says Rajeev K. Varshney, global research program director at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and one of the study researchers. He adds that there is a need to diversify our diets and eating habits to address the concerns, and this is where pearl millet can play a role. “Pearl millet is a nutritious dryland cereal, rich in protein, fiber, and essential micronutrients like iron, zinc, and folate. Nutrition studies have shown it has the potential to fight iron deficiency, the most widespread micronutrient deficiency and major cause of anemia, affecting the health and development of a third of the global population.”

The knowledge learned from this study can have profound effects, Varshney says. “Our research findings on genome sequencing of this crop will catalyze breeding efforts to improve this crucial staple food for the food security and resilience of millions of people in arid and semi-arid Africa and Asia, in particular.” In fact, scientists have already identified what Varshney calls “candidate genes” for several traits like heat and drought tolerance. “Now scientists should be able to develop high-yielding and better varieties of pearl millet by using genome information in breeding programs,” he says. This information will be useful in the development of heat- and drought-tolerant varieties of other cereals as well. “In summary,” Varshney says, “this research will contribute significantly to global food and nutrition security.”

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Published every Tuesday, this newsletter explores what are, arguably, the next big things in the science of food.