Newsletter: October 9, 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.

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garlicResearchers synthesize beneficial garlic compound
Scientists from Cardiff University, working with the Welsh company Neem Biotech, have synthesized a bioactive compound called ajoene, which was previously available only as an extract from garlic. This opens the door to scaling up production of the compound, which the researchers believe has the potential to be an effective weapon in the fight against antibiotic resistance.

Ajoene, a colorless liquid organosulfur compound, has been linked to a number of therapeutic benefits as an antibacterial, antimicrobial, and antifungal agent and potentially even as a chemotherapy drug. Ajoene’s therapeutic benefits stem from its ability to prevent bacteria from proliferating by interrupting chemical communication signals between bacteria.

When ajoene is produced from garlic, the yields are unreliable. Chemical synthesis is more cost-effective and consistent and may allow for the development of additional derivatives with therapeutic benefits, says researcher Thomas Wirth, a professor of organic chemistry at Cardiff University. To create ajoene in the lab, Wirth and his colleagues used the organic compounds propargyl bromide and dibromopropane together with some selenium-based reagents and thiourea/thioacetic acid, thus delivering the sulfur atoms to the synthesis.

“The remarkable antibacterial properties of this compound have shown great promise, and we hope that this new breakthrough will accelerate efforts to produce ajoene in large volumes and better test its effectiveness as a therapeutic drug,” Wirth summarizes. Research results were published in the chemistry journal Angewandte Chemie.


Dairy cows eatingResearchers examine feed nutrients to increase cows milk protein output
The Food and Agriculture Organization (FAO) of the United Nations estimates that 25% of total global greenhouse gas emissions are directly caused by crop and animal production and forestry. Scientists are researching ways to make animal production more sustainable by optimizing resource use to enhance nutrition and cut down on waste. At the University of Wisconsin’s Dept. of Dairy Science, Sebastian I Arriola Apelo, assistant professor of metabolism, is working on a way to optimize the feed for dairy cows so that more of the protein goes into producing milk and less is excreted as waste. According to Arriola Apelo, only about a quarter of the crude protein in dairy feed goes to producing milk. The rest is excreted as waste, adversely affecting the environment and milk producers’ bottom line.

“I see these losses as the result of a competition between the udder trying to remove amino acids [the building blocks of protein] as quickly as possible before the liver sweeps them away and converts them to urea that is excreted in urine,” explains Arriola Apelo. “Our hypothesis is that stimulating the udder to build proteins more rapidly will increase the rate of amino acid removal from the blood, leaving less for the liver to clear out.”

To understand the role of protein synthesis regulation in milk protein output, and how it can be manipulated with dietary interventions, Arriola Apelo uses in vitro and in vivo models, including milk-producing cells isolated from lactating cows’ udders and transgenic lactating mice. “We expect that understanding protein synthesis regulation at a cellular level will allow us to identify more efficient dietary approaches that maximize amino acid extraction by the udder and minimize urinary nitrogen excretion,” says Arriola Apelo.

To do this, the researchers use mice that are genetically manipulated to delete specific proteins from their milk-producing cells when lactation starts. These proteins can turn on and off different branches of the protein synthesis regulation system. Using this model, the researchers can determine which branch of system is more relevant for milk protein output, and then use dietary interventions to identify the nutrients these mechanisms are most sensitive to.

“We have some evidence to believe that milk protein output is mainly regulated by one of the branches, called mTOR, that regulates cellular protein synthesis, and we are testing different nutrient combinations to identify those that more strongly affect mTOR and milk protein output,” reveals Arriola Apelo. “We are also starting the first trials with lactating dairy cows to determine if the same nutrient combinations affect mTOR in the cows’ udders, and if that translates into more efficient use of digested amino acids.”

Nitrous oxide, one of the forms of nitrogen that is released into the environment, is more potent than carbon dioxide and methane as a greenhouse gas. Arriola Apelo and his fellow researchers hope their work will lessen the dairy industry’s environmental footprint. “There is preliminary evidence to believe that by formulating rations with specific nutrient combinations targeted to maximize amino acid extraction by the udder, nitrogen excreted in manure could be reduced by at least 20%,” says Arriola Apelo.


cantaloupeProbiotics protect cantaloupes from pathogens
Cantaloupes are subject to pathogenic contamination for a variety of reasons, including their proximity to soil and irrigation water, as well as contact with insects, animals, or humans during growth, harvesting, or processing. As a leading producer and consumer of cantaloupes, the United States has experienced large, multi-state foodborne disease outbreaks linked to the fruit, which have resulted in severe morbidity and mortality. But thanks to research conducted by scientists at the University of Connecticut’s College of Agriculture, Health and Natural Resources, a group of probiotics has been identified that successfully prevents the growth of pathogenic bacteria on cantaloupe rinds.

The most common way to clean cantaloupes in the United States is with chlorine, but the disinfectant typically yields only minimal reductions in pathogen populations due to the fruit’s corrugated surface, which facilitates bacterial attachment and protection from the disinfectant. In addition, chlorine has been shown to potentially remove normal beneficial bacterial flora, including the probiotics on cantaloupes, thereby increasing pathogen persistence on the fruit. A safe, effective, and easily implemented alternative was needed, and the researchers turned their attention to lactic acid bacteria (LAB).

LAB represent a majority of probiotic bacteria and are found in diverse environments, including plants and soil ecosystems. Many are traditionally used in fermented foods from animal and plant sources, and studies have highlighted their efficacy as biosanitizers for controlling plant pathogens and soil-borne pathogens. The researchers thought fortifying the surface of cantaloupes with well-characterized LAB could confer enhanced protection against foodborne pathogens, thereby serving as a natural biological control strategy.

“In our initial experiments, we removed cantaloupe rind plugs (2.5 cm diameter) using a cork borer, which were used to mimic cantaloupe surface,” says lead researcher Kumar Venkitanarayanan. “We then spray-inoculated the cantaloupe rinds with pathogens (Salmonella or Listeria), probiotics, or both pathogen and probiotics. The cantaloupe rinds were stored at room temperature, and the survival of pathogens and probiotics on the cantaloupe surface was determined. In addition, the viability of pathogens and probiotics on cantaloupes sprayed with 200 ppm of chlorine was determined.”

The researchers found that select probiotics were capable of significantly reducing the pathogens on the cantaloupe surface by day seven of storage compared with untreated cantaloupes. Notes Venkitanarayanan, “Probiotics are already used in many fermented foods, including yogurt and cheese; however, their application in improving food safety on fresh produce is limited, and needs to be validated. If found effective, probiotics could serve as a natural antimicrobial tool for effective decontamination of fresh produce.”

Venkitanarayanan believes that follow-up studies are needed to determine the efficacy of probiotics for controlling pathogens on whole cantaloupes, both at pre-harvest (farm settings) and post-harvest (packinghouse) stages. In addition, he says, “sensory and quality measurements on treated cantaloupes would also be beneficial.”

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