Newsletter: March 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.

Plant Cell CulturesGrowing plant cells as a viable food source
Lab-grown meat has been a popular topic in the news lately, but the cost of production for this type of cell culture has limited its growth. Scientists at VTT Technical Research Center of Finland are exploring a method of producing healthy plant-based food through plant cell culture (PCC), which has the advantage of having higher nutritional value and being faster, easier, and less expensive to produce than cultured meat.

“Plant cell culture is quite an established technology,” explains Heiko Rischer, docent and head of plant biotechnology at VTT. “However, the concept of using PCCs for food is relatively new.” PCCs, particularly from undomesticated plant species, have been used for the commercial production of phytochemicals to be used as pharmaceuticals, pigments, and ingredients for cosmetics and food.

“Most published reports either focus on utilizing the PCCs for extraction of specific ingredients or approach the topic from a rather theoretical point of view without providing reviewable scientific data,” writes Rischer and other VTT researchers in a study published in the journal Food Research International. The objective of the study was to examine the nutritional and sensory properties of dried and fresh cells grown from cloudberry, lingonberry, and stoneberry by using PCC technology. 

As Heiko explains, plant cell cultures can be established from virtually any plant species. “Only a very small part of the target plant is needed to initiate unlimited cell growth under sterile, contained conditions,” says Rischer. “These uniform cells are then grown in a nutrient solution composed of sugar, minerals, and organic ingredients.” Another advantage is that the process is scalable so that large quantities of biomass can be produced no matter the climate.

For the current study, the researchers found that the PCC samples had a pleasant, fresh, and mild flavor, which resembled that of the corresponding fresh fruits. The plant cells were shown to be nutritionally valuable. They had high protein content of 14%–19%, and in vitro analysis showed good protein digestibility. The samples had dietary fiber content that varied between 21% and 37%, and they were also found to be rich sources of unsaturated fatty acids.

The “nutritional quality of the plant cells really seem (as shown by their high protein and dietary fiber content, supported by bioactives/phenolics) to be promising alternatives for health-promoting foodstuff/superfoods,” says Emilia Nordlund, research team leader for food solutions at VTT.

For Rischer, the most surprising outcome of the study was to see that “almost all nutritional parameters are better [in the PCCs] than those in the corresponding fruits.” This bodes well for the potential of PCCs to be utilized as food products. “In the long term all kinds of products can be imagined either supplementing existing food or in their own right,” concludes Rischer.



Cow Eating GrassEasy analytical technique helps prove organic milk authenticity
A group of researchers at Iowa State University have come up with what they think could be a cost-effective and accurate method for determining if milk comes from grass-fed cows: using fluorescence spectroscopy to measure the amount of chlorophyll metabolites the milk contains. The approach works because the content of chlorophyll metabolites is significantly higher for milk from grass-fed cows than for milk from cows fed grain and silage. Fluorescence spectroscopy is an analytical technique that involves shining light on a sample and measuring the resulting luminescence; chlorophyll metabolites are easily detectable this way. 

“Despite the reported benefits of milk from grass-fed cows, there has been very little research on developing analytical methods to confirm the authenticity of products labeled as milk from grass-fed cows,” the researchers write in a discussion of their study published recently in the Journal of Agricultural and Food Chemistry. Part of the appeal of milk from grass-fed cows stems from the fact that studies have shown that it is a better source of healthful omega-3 fatty acids than milk from conventionally raised cows. 

To date, the researchers explain, gas chromatography, which is used to measure nutritional characteristics of milk, has been the go-to method for determining if milk comes from grass-fed cows. But this method is expensive and thus not feasible for widespread use by organic milk producers. U.S. Dept. of Agriculture (USDA) standards for organic milk require that it comes from cows that are at least partially grass-fed. Specifically, the USDA requires that cows be pastured for at least 120 days a year, and during that time, a minimum of 30% of their diet must come from pasture grass.

The Iowa State researchers used fluorescence spectroscopy to measure chlorophyll in a variety of different milk samples, including commercially purchased conventional and organic milk brands as well samples from a small Iowa dairy where the cows spend the majority of their time in the pasture during grazing season. Milk from that dairy had the highest concentration of chlorophyll metabolites among the samples tested, but the organic milk purchased from the supermarket also had significantly more chlorophyll metabolites than the conventional milk. 

Study author and Iowa State chemistry professor Jacob Petrich says more research is needed, and that these initial findings should be viewed as proof of concept. “A much broader range of samples encompassing a broad spectrum of diets and breeds must be taken into account,” he notes.



OatmealFiber-fermenting gut microbes may help manage type 2 diabetes
A new study led by a professor at Rutgers University establishes a new approach to preventing and managing type 2 diabetes. The study points to manipulating the gut microbiome to control the disease. 

Liping Zhao, a professor at Rutgers’ New Jersey Institute for Food, Nutrition, and Health, collaborated with Yan Lam, an assistant professor at Rutgers, and researchers at Shanghai Jiao Tong University to determine that a diet high in diverse fibers provides better control of blood glucose levels, weight management, and lipid levels in type 2 diabetics. “Diets high in fiber contain large amount[s] of non-digestible carbohydrates, which [we] cannot [digest] on our own and are instead fermented by gut bacteria,” Zhao says. “Through such fiber fermentation, gut bacteria bring many benefits to human health, including the production of short-chain fatty acids.” 

Short-chain fatty acids (SCFAs) lower the pH of the colon, thereby transforming the gut into an inhospitable environment for pathogenic bacteria, feeding beneficial gut microbes, fortifying the intestinal lining, increasing satiety, and reducing inflammation. “Previous studies have suggested that overall diversity of the entire gut microbiota was positively correlated with improved health outcomes,” Zhao says. “We, however, have found that it is the increased diversity of key SCFA-producing bacteria that truly matter[s].”

During the randomized controlled study, certain patients with type 2 diabetes consumed high-fiber diets that included whole grains and traditional Chinese medicinal foods that are rich in dietary fibers and prebiotics. To identify key SCFA-producing microbes, Zhao and his colleagues performed a wide-ranging survey of gut microbes, which identified 141 different strains of bacteria that produce SCFAs. “To our surprise, only 15 out of these 141 strains were promoted by the high-fiber treatment,” Zhao reveals. “This guild of 15 positive responders … became predominant in the new gut ecosystem.” The 15 strains also produced more acetic acid and butyric acid—two SCFAs that stimulate cells in the gut to produce a peptide hormone that promotes secretion of insulin, an important factor in controlling blood glucose levels and preventing type 2 diabetes. 

“Our study opens new evidence-based and data-driven avenues for the food and nutrition industries. Ecologically, a healthier gut microbiota may be built on the foundation of a guild of fiber-fermenting bacteria,” Zhao asserts. “Because individual gut microbiota is vastly diverse and highly personalized, we now have the opportunity to design a fiber-rich diet for individuals based on their microbiome profiles to help them. … This research thus adds a new dimension to personalized nutrition.” 



VineyardSatellite-based computer modeling system enhances water management
Irrigation practices and technologies that maximize efficiencies are essential to successful vineyard management. A new computer model that uses satellite data to determine water needs and stress in vineyards could help vineyard managers better administer irrigation applications, improve yields and grape quality, and conserve groundwater.

“Our research group has worked for many years on developing tools to monitor crop water use and stress from satellites,” says Martha Anderson of the U.S. Dept. of Agriculture's Agricultural Research Service (ARS) Hydrology and Remote Sensing Laboratory, who, along with fellow researcher William Kustas, worked with the E. & J. Gallo Winery in California to develop the model. “The tools are now mature enough that we are starting to find ways to use them in real agricultural management applications.”

The model works by tapping into satellite data that measure land surface temperature and provide information about soil and vine moisture levels and rates of water use, or evapotranspiration (ET). One of the model’s unique aspects is its ability to separate the vine canopy from the soil surface temperatures, enabling the capture of precise data. “This includes good assessments of actual water use, current stress status within the vineyard, and spatial variability within fields and between fields, over the landscape,” says Anderson. “This spatial context can also be useful for growers—how is my vineyard faring compared to surrounding vineyards?”

Early use of the model over several test sites has generated ET and stress “datacubes” that span several years. “These datacubes consist of stacks of daily images at 30m spatial resolution,” explains Anderson. “[They] have been compared with ground-based ET observations collected at multiple flux towers within the modeling domain, in vineyards as well as rice, alfalfa, and wetland sites. The model compares well with the observations, giving us increased confidence in their accuracy outside of the validation sites.”

Given these encouraging results, Anderson and Kustas plan to use their remote-sensing products later this year in a pilot experiment in a vineyard system equipped with variable rate drip irrigation (VRDI) technology. “We will use real time satellite maps of ET and %ETc (percentage of potential crop evapotranspiration expected if water was not a limiting factor) to control irrigation in plots to achieve prescribed levels of stress in each plot,” says Anderson. “This will simulate grower use of [the] products to adaptively manage irrigation throughout the season to achieve target stress goals. We will also be able to measure sensitivity in the products to different levels of irrigation within the same larger vineyard system.”

Anderson and Kustas believe their model can provide valuable information used in irrigation management for other crops, including orchards, row crops, and irrigated pastures. And because the system is based on satellite imagery, it holds the potential to be used outside the United States as well. 

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