Category Archives: food

Keanu Reeves molecule: protector of plants?

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Courtesy: Wallpaperstopick [downloaded from https://wallpaperstopick.blogspot.com/2012/05/keanu-reeves.html]

The Keanu Reeves molecule is produced by bacteria.according to a February 6, 2023 news item on phys.org,

Bacteria of the genus Pseudomonas produce a strong antimicrobial natural product, as researchers at the Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI) have discovered. They proved that the substance is effective against both plant fungal diseases and human-pathogenic fungi. The study was published in the Journal of the American Chemical Society and highlighted in an editorial in Nature.

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A February 6, 2023 Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute (Leibniz-HKI) press release (also on EurekAlert) by Charlotte Fuchs, which originated the news item, highlights both the published study and the special article in Nature magazine, Note: A link has been removed,

The newly discovered natural product group of keanumycins in bacteria works effectively against the plant pest Botrytis cinerea, which triggers grey mould rot and causes immense harvest losses every year. But the active ingredient also inhibits fungi that are dangerous to humans, such as Candida albicans. According to previous studies, it is harmless to plant and human cells.

Keanumycins could therefore be an environmentally friendly alternative to chemical pesticides, but they could also offer an alternative in the fight against resistant fungi. “We have a crisis in anti-infectives,” explains Sebastian Götze, first author of the study and postdoc at Leibniz-HKI. “Many human-pathogenic fungi are now resistant to antimycotics – partly because they are used in large quantities in agricultural fields.”

Deadly like Keanu Reeves

The fact that the researchers have now found a new active ingredient in bacteria of the genus Pseudomonas is no coincidence. “We have been working with pseudomonads for some time and know that many of these bacterial species are very toxic to amoebae, which feed on bacteria,” says study leader Pierre Stallforth. He is the head of the department of Paleobiotechnology at Leibniz-HKI and professor of Bioorganic Chemistry and Paleobiotechnology at Friedrich Schiller University in Jena. It appears that several toxins are responsible for the deadly effect of the bacteria, of which only one was known so far. In the genome of the bacteria, the researchers have now found biosynthesis genes for the newly discovered natural products, the keanumycins A, B and C. This group of natural products belongs to the nonribosomal lipopeptides with soap-like properties.

Together with colleagues at the Bio Pilot Plant of the Leibniz-HKI, the researchers succeeded in isolating one of the keanumycins and conducting further tests. “The lipopeptides kill so efficiently that we named them after Keanu Reeves because he, too, is extremely deadly in his roles,” Götze explains with a wink.

The researchers suspected that keanumycins could also kill fungi, as these resemble amoebas in certain characteristics. This assumption was confirmed together with the Research Centre for Horticultural Crops at the University of Applied Sciences Erfurt. There, Keanumycin was shown to be effective against grey mould rot on hydrangea leaves. In this case, culture fluid that no longer contained bacterial cells was sufficient to significantly inhibit the growth of the fungus.

“Theoretically, the keanumycin-containing supernatant from Pseudomonas cultures could be used directly for plants,” says Götze. Further testing will be carried out together with the colleagues in Erfurt. Keanumycin is biodegradable, so no permanent residues should form in the soil. This means that the natural product has the potential to become an environmentally friendly alternative to chemical pesticides.

Fungal diseases such as Botrytis cinerea, which causes grey mould rot, cause immense harvest losses in fruit and vegetable cultivation every year. More than 200 different types of fruit and vegetables are affected, especially strawberries and unripe grapes.

Possible applications in humans

“In addition, we tested the isolated substance against various fungi that infect humans. We found that it strongly inhibits the pathogenic fungus Candida albicans, among others,” says Götze.

Instead of plants, Keanumycin could therefore possibly also be used in humans. According to the tests conducted so far, the natural product is not highly toxic for human cells and is already effective against fungi in very low concentrations. This makes it a good candidate for the pharmaceutical development of new antimycotics. These are also urgently needed, as there are very few drugs against fungal infections on the market.

The work was supported by the Werner Siemens Foundation, the Leibniz Association and the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) as part of the Balance of the Microverse Cluster of Excellence, and funded by the Dr. Illing Foundation.

The study was highlighted by Nature in a “News & Views” article.

Here are citations and links to both the published study and the article in Nature,

Ecological Niche-Inspired Genome Mining Leads to the Discovery of Crop-Protecting Nonribosomal Lipopeptides Featuring a Transient Amino Acid Building Block by Sebastian Götze, Raghav Vij, Katja Burow, Nicola Thome, Lennart Urbat, Nicolas Schlosser, Sebastian Pflanze, Rita Müller, Veit G. Hänsch, Kevin Schlabach, Leila Fazlikhani, Grit Walther, Hans-Martin Dahse, Lars Regestein, Sascha Brunke, Bernhard Hube, Christian Hertweck, Philipp Franken, and Pierre Stallforth. J. Am. Chem. Soc. 2023, 145, 4, 2342–2353 DOI: https://doi.org/10.1021/jacs.2c11107 Publication Date:January 20, 2023 Copyright © 2023 The Authors. Published by American Chemical Society

and

Bacterial defence repurposed to fight blight (News and Views article) by Andrew Mitchinson. Nature 614, 39 (2023) DOI: https://doi.org/10.1038/d41586-023-00195-x Published: 30 January 2023

Both the study and the ‘News and Views’ article are behind a paywall.

Measure the maturity of cask-aged whisky with gold nanoparticle test

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it’s not altogether a surprise that this research on whisky has Scottish origins. From an October 11, 2022 news item on Nanowerk (Note: A link has been removed),

Researchers at a Scottish university have found a way to use gold nanoparticles to measure the maturity of whisky, which could help distillers with one of the key challenges in the production process (ACS Applied Nano Materials, “Growth of Plasmonic Nanoparticles for Aging Cask-Matured Whisky”).

Chemists and bioscientists from the University of Glasgow developed the test, which harnesses a unique property of cask-aged whisky to measure its maturity.

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An October 11, 2022 University of Glasgow press release, which originated the news item, delves further into the work,

Each variety of whisky gains some of its colour flavour profile from being stored in wooden casks while it matures over a period of months or years. The flavour of the final product is created by a complex mix of factors known as ‘congeners’ – chemicals left in the spirit after it is distilled and other chemicals absorbed from the wood casks, which react with oxygen over time.

The unpredictable interactions of congeners, along with other factors like the size and shape of the cask and the number of times it has been used before, mean that each cask matures in its own way, and in its own time.

To ensure the consistency of their products, distillers employ highly experienced master blenders. They regularly sample the casks to check the whisky’s readiness for blending, bottling and sale as either a single malt or a mixed blend – a laborious and expensive task.

The researchers set out to develop a test which could do some of the work of the master blenders by using chemical reactions to determine the maturity or ‘age’ of whisky samples.

They built their test on a reaction which occurs when samples of whisky are mixed with a solution containing small quantities of a special type of gold. A chemical reaction in the whisky causes distinctively-coloured gold nanoparticles to form in the sample over a short period of time at room temperature.

The researchers mixed the gold solution with samples from 15 different whiskies distilled in Scotland, Japan and the US. They also tested multiple samples taken at regular intervals from a single cask over a period of six years, which were supplied by the Scotch Whisky Research Institute.

By measuring a property of each sample known as its localised surface plasmon resonance, they found that the unique chemical composition of the whiskies resulted in the creation of gold nanoparticles with distinctly different shapes, sizes and colours in each sample.

They also discovered that the speed of the production of the nanoparticles was connected with its maturity – the faster the nanoparticles formed, the more mature the whisky was.

The results suggest that the process could be used to develop a quick, reliable test for distillers to measure the maturity of their whiskies, reducing the need for master blenders to be involved in every step of the process.

Dr Will Peveler, of the University of Glasgow’s School of Chemistry, is the paper’s lead author. Dr Peveler said: “Age is more than just a number when it comes to whisky – the complex chemical reactions which occur in each cask make it impossible to estimate whisky’s maturity of flavour simply based on how long it’s been ageing.

“For as long as there’s been a whisky industry, distillers have been trying to find better ways to measure the maturity of individual casks to help them understand when they will be ready to use in a single malt or a mixed blend.

“What we’ve been able to do for the first time is show that the ageing-related chemistry of the whisky controls the formation of gold nanoparticles. That has allowed us to develop a unique ‘fingerprint’ not just for types of whisky we tested but also for how whiskies mature over time.

Co-author Dr Jenny Gracie, also of the School of Chemistry, added: “Currently, there are a number of other tests available to measure whisky maturity, which use specialist processes like chromatography and mass spectrometry. However, they are rarely available on the warehouse floor, and if samples have to be sent offsite for analysis, this slows everything down.

“We hope that in the future we can develop this initial finding into a quick, easy and portable kit that distillers can use to measure the maturity of their whiskies without having to send samples for time-consuming tests with specialist equipment.”

Here’s a link to and a citation for the paper,

Growth of Plasmonic Nanoparticles for Aging Cask-Matured Whisky by Jennifer Gracie, Francesco Zamberlan, Iain B. Andrews, Brian O. Smith, and William J. Peveler. ACS Appl. Nano Mater. 2022, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acsanm.2c03406 Publication Date: October 6, 2022 © 2022 The Authors. Published by American Chemical Society

This paper appears to be open access.

3D print healthy chocolates

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I’m a little late for Valentine’s Day, February 14, 2023, but it’s not too late for chocolate.

A February 14, 2023 news item on ScienceDaily describes research into 3D printing ‘healthy’ chocolates,

A Rutgers [Rutgers State University of New Jersey, US] scientist has developed a formulation of low-fat chocolate that can be printed on a 3D printer in pretty much any shape a person can conceive, including a heart.

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A February 13, 2023 Rutgers University news release (also on EurekAlert but published February 14, 2023) by Kitta MacPherson, which originated the news item, describes research into ‘functional foods’,

The work heralds what the researcher hopes will be a new line of “functional foods” – edibles specially designed with health benefits. The aim is to develop healthier kinds of chocolate easily accessible to consumers.

Reporting in the scientific journal, Food Hydrocolloids, a Rutgers-led team of scientists described the successful creation and printing of a mixture producing low-fat chocolate — substituting fatty cocoa butter with a lower-fat, water-in-oil emulsion.

“Everybody likes to eat chocolate, but we are also concerned with our health,” said Qingrong Huang, a professor in the Department of Food Science at the Rutgers School of Environmental and Biological Sciences. “To address this, we have created a chocolate that is not only low-fat, but that can also be printed with a 3D printer. It’s our first ‘functional’ chocolate.”

Huang, an author of the study, said he already is working on manipulating sugar content in the new chocolate formulation for low-sugar and sugar-free varieties.

Researchers create emulsions by breaking down two immiscible liquids into minute droplets. In emulsions, the two liquids will usually quickly separate – as is the case with oil and vinegar – unless they are held together by a third, stabilizing ingredient known as an emulsifier. (An egg is the emulsifier in a vinaigrette.)

Chocolate candy is generally made with cocoa butter, cocoa powder and powdered sugar and combined with any one of a variety of different emulsifiers.

For the study, the scientific team experimented with different ratios of the ingredients for a standard chocolate recipe to find the best balance between liquid and solid for 3D printing. Seeking to lower the level of fat in the mixture, researchers created a water-in-cocoa butter emulsion held together by gum arabic, an extract from the acacia tree that is commonly used in the food industry, to replace the cocoa butter. The researchers mixed the emulsion with golden syrup to enhance the flavor and added that combination to the other ingredients.

As delightful as it is to eat, Huang said, chocolate is a material rich with aspects for food scientists to explore.

Employing advanced techniques examining the molecular structure and physical properties of chocolate, researchers investigated the printed chocolate’s physical characteristics. They were seeking the proper level of viscosity for printing and looking for the optimal texture and smoothness “for a good mouthfeel,” Huang said. Experimenting with many different water-oil ratios, they varied the percentages of all the main ingredients before settling on one mixture.

In 3D printing, a printer is used to create a physical object from a digital model by laying down layers of material in quick succession. The 3D printer, and the shapes it produces, can be programmed by an app on a cellphone, Huang said.

Ultimately, Huang said he plans to design functional foods containing healthy added ingredients – substances he has spent more than two decades studying, such as extracts from orange peel, tea, red pepper, onion, Rosemary, turmeric, blueberry and ginger – that consumers can print and eat.

“3D food printing technology enables the development of customized edible products with tailored taste, shape and texture as well as optimal nutrition based on consumer needs,” Huang said.

Other researchers on the study included Siqi You and Xuanxuan Lu of the Department of Food Science and Engineering at Jinan University in Guangzhou, China.

Here’s a link to and a citation for the paper,

Development of fat-reduced 3D printed chocolate by substituting cocoa butter with water-in-oil emulsions by Siqi You, Qingrong Huang, and Xuanxuan Lu. Food Hydrocolloids Volume 135, February 2023, 108114 DOI: https://doi.org/10.1016/j.foodhyd.2022.108114

This paper is behind a paywall.

In Brazil: Applications open for July 3 – 15, 2023 School of Advanced Science on Nanotechnology, Agriculture and Environment

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According to the December 15, 2022 Fundação de Amparo à Pesquisa do Estado de São Paulo press release on EurekAlert applications will be received until February 5, 2023,

The São Paulo School of Advanced Science on Nanotechnology, Agriculture and Environment (SPSAS NanoAgri&Enviro) will be held on July 3-15 at the Brazilian Center for Research in Energy and Materials (CNPEM) in Campinas, São Paulo state, Brazil. 

Reporters are invited to reach the organizing committee through the email eventos@cnpem.br, for opportunities to visit the school and sessions.

Designed to meet an increasing level of content depth and complexity, the SPSAS NanoAgri&Enviro will cover the following topics: i) Nanotechnology, innovation, and sustainability; ii) Synthesis, functionalization, and characterization of nanomaterials; iii) Characterization of nanoparticles in complex matrices; iv) Synchrotron Light for nano-agri-environmental research; v) Biological and environmental applications of nanoparticles; vi) Nanofertilizers and Nanoagrochemicals; vii) Ecotoxicology, geochemistry and nanobiointerfaces; viii) Nanosafety and Nanoinformatics; ix) International harmonization and regulatory issues; x) Environmental implications of nanotechnology.

Discussions regarding those topics will benefit from the participation of internationally renowned scientists as speakers, including Mark V. Wiesner (Duke University), Iseult Lynch (University of Birmingham), Leonardo F. Fraceto (São Paulo State University – UNESP), Gregory V. Lowry (Carnegie Mellon University), Marisa N. Fernandes (Federal University of São Carlos – UFSCar), Caue Ribeiro (Brazilian Agricultural Research Corporation – EMBRAPA), and others.

The program also comprise didactic activities programmed among theoretical interactive classes, practical experiments (hands-on), and technical visits to world-class facilities and specialized laboratories from several institutions in São Paulo state.

The São Paulo Research Foundation (FAPESP) is supporting the event through its São Paulo School of Advanced Science Program (SPSAS http://espca.fapesp.br/home). Undergraduate students, postdoctoral fellows and researchers who are already working on subjects relating to the school can apply to receive financial support to cover the cost of air travel, accommodation and meals. Applications must be submitted by February 5, 2023.

More information: https://pages.cnpem.br/spsasnano/.

I looked up the criteria for eligible applicants and found this among the other criteria (from the Applications page),

Participating students must be enrolled in undergraduate or graduate courses in Brazil or abroad, being potential candidates for Master’s, Doctoral or Post-Doctoral internships in higher education and research institutions in the state of São Paulo. Doctors may also be accepted. [emphases mine]

If I read that correctly, it means that people who are considering or planning to further their studies in the state of São Paulo are being invited to apply.

I recognized two of the speakers’ names, Mark Wiesner and Iseult Lynch both of whom have been mentioned here a number of times as has Gregory V. Lowry. (Wiesner very kindly helped with an art/sci project I was involved with [Steep] a number of years ago.)

Good luck with your application!

Clay film keeps your apples fresh

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Which apple would you like to eat?

Caption: Extent of decay in apples treated with clay film and cling wrap. Credit: Miharu Eguchi National Institute for Materials Science eguchi.miharu@nims.go.jp

This research into food packaging comes from Japan’s National Institute for Materials in a March 8, 2022 press release (also on EurekAlert but published on April 12, 2022),

An international research team consisting of NIMS, The University of Queensland and National Taiwan University has succeeded in creating a clay film with its gas permeability optimized for long-term storage of fresh produce by adjusting the sizes of the clay nanosheet particles comprising it. The team then uniformly coated the surfaces of various fruits with the film. This treatment kept the fruits’ respiration rates low without completely depriving them of oxygen, preventing them from decaying.

Efforts have been made to develop gas barrier films using clay nanosheets. Although some researchers attempted to improve the film properties of clay nanosheets by adding organic polymers to them, films can also be formed using only clay nanosheets without additives. Only a few studies had previously evaluated the physical properties of clay films composed solely of clay nanosheets.

This international joint research team focused on the gas permeability of clay films and found that a film composed of clay nanosheets with particle sizes in the range of several dozen nanometers (1 nm = one millionth of 1 mm) had relatively high permeability to gas molecules as they can pass through gaps between particles. This gas permeability is equivalent to that of plastic bags with minute pores used to store fresh produce. These bags are able to adequately reduce oxygen supply to fresh fruit, preventing it from ripening too rapidly. The gas permeability similarities between the clay film and the plastic bags inspired the research team to assess the ability of the clay film to preserve the quality of fresh produce for long periods of time.

In this research, the team applied a suspension of clay nanosheets to the surfaces of various fruits (e.g., apples, bananas and oranges) to form uniform films on their surfaces. The team also prepared untreated fruits and fruits covered in cling wrap for comparison. The gas emissions and appearance of these treated and untreated fruits were monitored for several months. As shown in the figure [above], the untreated apples (the first photo from the left) had decayed by the end of the experimental period and the apples covered only in cling wrap (the fourth photo from the left) had also decayed and grown mold. By contrast, the apples coated with the clay film (the two middle photos) did not decay or grew mold, presumably because the film reduced the external oxygen supply needed for ripening and mold growth. In addition, the clay film was confirmed to be in tight contact with the surfaces of the apples it coated, suggesting that it may be able to effectively block the diffusion of ethylene into the air, a phytohormone which plays an important role in inducing fruit ripening.

In addition to its potential ability to restrict the external oxygen supply and ethylene diffusion, the clay film may be able to prevent odor compounds produced by fresh produce from diffusing into the air, possibly making them less attractive to pests. In future research, the team plans to improve the ease of application and strength of the clay film to make it more suitable for preserving the quality of fresh produce during its transportation to the market.

This project was carried out by an international joint research team consisting of Miharu Eguchi (Senior Researcher, Mesoscale Materials Chemistry Group, International Center for Materials Nanoarchitectonics, NIMS) and researchers from The University of Queensland and National Taiwan University. This work was supported in part by  JST-ERATO Yamauchi Materials Space-Tectonics Project.

Here’s a link to and a citation for the paper,

Highly adhesive and disposable inorganic barrier films: made from 2D silicate nanosheets and water by Miharu Eguchi, Muxina Konarova, Nagy L. Torad, Te-An Chang, Dun-Yen Kang, Joe Shapter and Yusuke Yamauchi. J. Mater. Chem. A, 2022,10, 1956-1964 DOI: https://doi.org/10.1039/D1TA08837H First published 02 Dec 2021 Print version published January 28, 2022

This paper is behind a paywall.

Say goodbye to crunchy (ice crystal-laden) in ice cream thanks to cellulose nanocrystals (CNC)

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The American Chemical Society (ACS) held its 2022 Spring Meeting from March 20 – 24, 2022 and it seems like a good excuse to feature ice cream.

Adding cellulose nanocrystals prevents the growth of small ice crystals (bottom left) into the large ones (top left) that can make ice cream (right) unpleasantly crunchy. Scale bar = 100 μm. Credit: Tao Wu

A March 20, 2022 news item on phys.org introduces an ice cream presentation given at the meeting on Monday, March 20, 2022,

Ice cream can be a culinary delight, except when it gets unpleasantly crunchy because ice crystals have grown in it. Today, scientists report that a form of cellulose obtained from plants can be added to the tasty treat to stop crystals cold—and the additive works better than currently used ice growth inhibitors in the face of temperature fluctuations. The findings could be extended to the preservation of other frozen foods and perhaps donated organs and tissues

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A March 20, 2022 ACS press release, which originated the news item, provides more details about crunchy ice cream and how it might be avoided,

Freshly made ice cream contains tiny ice crystals. But during storage and transport, the ice melts and regrows. During this recrystallization process, smaller crystals melt, and the water diffuses to join larger ones, causing them to grow, says Tao Wu, Ph.D., the project’s principal investigator. If the ice crystals become bigger than 50 micrometers — or roughly the diameter of a hair — the dessert takes on a grainy, icy texture that reduces consumer appeal, Wu says. “Controlling the formation and growth of ice crystals is thus the key to obtaining high-quality frozen foods.”

One fix would be to copy nature’s solution: “Some fish, insects and plants can survive in sub-zero temperatures because they produce antifreeze proteins that fight the growth of ice crystals,” Wu says. But antifreeze proteins are costlier than gold and limited in supply, so they’re not practical to add to ice cream. Polysaccharides such as guar gum or locust bean gum are used instead. “But these stabilizers are not very effective,” Wu notes. “Their performance is influenced by many factors, including storage temperature and time, and the composition and concentration of other ingredients. This means they sometimes work in one product but not in another.” In addition, their mechanism of action is uncertain. Wu wanted to clarify how they work and develop better alternatives.

Although Wu didn’t use antifreeze proteins in the study, he drew inspiration from them. These proteins are amphiphilic, meaning they have a hydrophilic surface with an affinity for water, as well as a hydrophobic surface that repels water. Wu knew that nano-sized crystals of cellulose are also amphiphilic, so he figured it was worth checking if they could stop ice crystal growth in ice cream. These cellulose nanocrystals (CNCs) are extracted from the plant cell walls of agricultural and forestry byproducts, so they are inexpensive, abundant and renewable.

In a model ice cream — a 25% sucrose solution — the CNCs initially had no effect, says Min Li, a graduate student in Wu’s lab at the University of Tennessee. Though still small, ice crystals were the same size whether CNCs were present or not. But after the model ice cream was stored for a few hours, the researchers found that the CNCs completely shut down the growth of ice crystals, while the crystals continued to enlarge in the untreated model ice cream.

The team’s tests also revealed that the cellulose inhibits ice recrystallization through surface adsorption. CNCs, like antifreeze proteins, appear to stick to the surfaces of ice crystals, preventing them from drawing together and fusing. “This completely contradicted the existing belief that stabilizers inhibit ice recrystallization by increasing viscosity, which was thought to slow diffusion of water molecules,” adds Li, who will present the work at the meeting.

In their latest study, the scientists found that CNCs are more protective than current stabilizers when ice cream is exposed to fluctuating temperatures, such as when the treat is stored in the supermarket and then taken home. The team also discovered the additive can slow the melting of ice crystals, so it could be used to produce slow-melting ice cream. Other labs have shown the stabilizer is nontoxic at the levels needed in food, Wu notes, but the additive would require review by the U.S. Food and Drug Administration.

With further research, CNCs could be used to protect the quality of other foods — such as frozen dough and fish — or perhaps to preserve cells, tissues and organs in biomedicine, Wu says. “At present, a heart must be transplanted within a few hours after being removed from a donor,” he explains. “But this time limit could be eliminated if we could inhibit the growth of ice crystals when the heart is kept at low temperatures.”

…

Interesting to see that this research into ice cream crystals could lead to new techniques for organ transplants.

Cellulose nanocrystals (CNC), protein, and starch eletrospun to develop ‘smart’ food packaging

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A December 29, 2021 news item on ScienceDaily announces research into ;smart’ sustainable packaging from a joint Nanyang Technical University and Harvard University,

A team of scientists from Nanyang Technological University, Singapore (NTU Singapore) and Harvard T.H. Chan School of Public Health, US, has developed a ‘smart’ food packaging material that is biodegradable, sustainable and kills microbes that are harmful to humans. It could also extend the shelf-life of fresh fruit by two to three days.

The waterproof food packaging is made from a type of corn protein called zein, starch and other naturally derived biopolymers, infused with a cocktail of natural antimicrobial compounds. These include oil from thyme, a common herb used in cooking, and citric acid, which is commonly found in citrus fruits.

…

A December 28, 2021 Nanyang Technological University press release (PDF), also on EurekAlert but published December 27, 2021, which originated the news item, offers a few more details about the research (Note 1: Links have been removed; Note 2: I had to dig into the abstract to find the cellulose nanocrystals),

In lab experiments, when exposed to an increase in humidity or enzymes from harmful bacteria, the fibres in the packaging have been shown to release the natural antimicrobial compounds, killing common dangerous bacteria that contaminate food, such as E. Coli and Listeria, as well as fungi.

The packaging is designed to release the necessary miniscule amounts of antimicrobial compounds only in response to the presence of additional humidity or bacteria. This ensures that the packaging can endure several exposures, and last for months.

As the compounds combat any bacteria that grow on the surface of the packaging as well as on the food product itself, it has the potential to be used for a large variety of products, including ready-to-eat foods, raw meat, fruits, and vegetables.

In an experiment, strawberries that were wrapped in the packaging stayed fresh for seven days before developing mould, compared to counterparts that were kept in mainstream fruit plastic boxes, which only stayed fresh for four days.

The invention is the result of the collaboration by scientists from the NTU-Harvard T. H. Chan School of Public Health Initiative for Sustainable Nanotechnology (NTU-Harvard SusNano), which brings together NTU and Harvard Chan School researchers to work on cutting edge applications in agriculture and food, with an emphasis on developing non-toxic and environmentally safe nanomaterials.

The development of this advanced food packaging material is part of the University’s efforts to promote sustainable food tech solutions, that is aligned with the NTU 2025 strategic plan, which aims to develop sustainable solutions to address some of humanity’s pressing grand challenges.

Professor Mary Chan, Director of NTU’s Centre of Antimicrobial Bioengineering, who co-led the project, said: “This invention would serve as a better option for packaging in the food industry, as it has demonstrated superior antimicrobial qualities in combatting a myriad of food-related bacteria and fungi that could be harmful to humans. The packaging can be applied to various produces such as fish, meat, vegetables, and fruits. The smart release of antimicrobials only when bacteria or high humidity is present, provides protection only when needed thus minimising the use of chemicals and preserving the natural composition of foods packaged.”

Professor Philip Demokritou, Adjunct Professor of Environmental Health at Harvard Chan School, who is also Director of Nanotechnology and Nanotoxicology Center and Co-director of NTU-Harvard Initiative on Sustainable Nanotechnology, who co-led the study, said: “Food safety and waste have become a major societal challenge of our times with immense public health and economic impact which compromises food security. One of the most efficient ways to enhance food safety and reduce spoilage and waste is to develop efficient biodegradable non-toxic food packaging materials. In this study, we used nature-derived compounds including biopolymers, non-toxic solvents, and nature-inspired antimicrobials and develop scalable systems to synthesise smart antimicrobial materials which can be used not only to enhance food safety and quality but also to eliminate the harm to the environment and health and reduce the use of non-biodegradable plastics at global level and promote sustainable agri-food systems.” 

Providing an independent assessment of the work done by the NTU research team, Mr Peter Barber, CEO of ComCrop, a Singapore company that pioneered urban rooftop farming, said: “The NTU-Harvard Chan School food packaging material would serve as a sustainable solution for companies like us who want to cut down on the usage of plastic and embrace greener alternatives. As ComCrop looks to ramp up product to boost Singapore’s food production capabilities, the volume of packaging we need will increase in sync, and switching to a material such as this would help us have double the impact. The wrapping’s antimicrobial properties, which could potentially extend the shelf life of our vegetables, would serve us well. The packaging material holds promise to the industry, and we look forward to learning more about the wrapping and possibly adopting it for our usage someday.”

The results of the study were published in the peer-reviewed academic journal ACS Applied Materials & Interfacesin October [2021].

Cutting down on packaging waste

The packaging industry is the largest and growing consumer of synthetic plastics derived from fossil fuels, with food packaging plastics accounting for the bulk of plastic waste that are polluting the environment.

In Singapore, packaging is a major source of trash, with data from Singapore’s National Environment Agency showing that out of the 1.76 million tonnes of waste disposed of by domestic sources in 2018, one third of it was packaging waste, and over half of it (55 per cent) was plastic.

The smart food package material, when scaled up, could serve as an alternative to cut down on the amount of plastic waste, as it is biodegradable. Its main ingredient, zein, is also produced from corn gluten meal, which is a waste by-product from using corn starch or oils in order to produce ethanol.

The food packaging material is produced by electrospinning[1] the zein, the antimicrobial compounds with cellulose, a natural polymer starch that makes up plant cell walls, and acetic acid, which is commonly found in vinegar.

Prof Mary Chan added: “The sustainable and biodegradable active food packaging, which has inbuilt technology to keep bacteria and fungus at bay, is of great importance to the food industry. It could serve as an environmentally friendly alternative to petroleum-based polymers used in commercial food packaging, such as plastic, which have a significant negative environmental impact.”

Prof Demokritou added: “Due to the globalisation of food supply and attitude shift towards a healthier lifestyle and environmentally friendly food packaging, there is a need to develop biodegradable, non-toxic and smart/responsive materials to enhance food safety and quality. Development of scalable synthesis platforms for developing food packaging materials that are composed of nature derived, biodegradable biopolymers and nature inspired antimicrobials, coupled with stimuli triggered approaches will meet the emerging societal needs to reduce food waste and enhance food safety and quality.”

The team of NTU and Harvard Chan School researchers hope to scale up their technology with an industrial partner, with the aim of commercialisation within the next few years.

They are also currently working on developing other technologies to develop biopolymer-based smart food package materials to enhance food safety and quality.

Here’s a link to and a citation for the paper, followed by the key (nanocellulose crystal mention) sentences in the abstract,

Enzyme- and Relative Humidity-Responsive Antimicrobial Fibers for Active Food Packaging by Zeynep Aytac, Jie Xu, Suresh Kumar Raman Pillai, Brian D. Eitzer, Tao Xu, Nachiket Vaze, Kee Woei Ng, Jason C. White, Mary B. Chan-Park, Yaguang Luo, and Philip Demokritou. ACS Appl. Mater. Interfaces 2021, 13, 42, 50298–50308 I: https://doi.org/10.1021/acsami.1c12319 Publication Date: October 14, 2021 Copyright © 2021 American Chemical Society

This paper is behind a paywall.

Excerpt from abstract,

Active food packaging materials that are sustainable, biodegradable, and capable of precise delivery of antimicrobial active ingredients (AIs) are in high demand. Here, we report the development of novel enzyme- and relative humidity (RH)-responsive antimicrobial fibers with an average diameter of 225 ± 50 nm, which can be deposited as a functional layer for packaging materials. Cellulose nanocrystals (CNCs) [emphasis mine], zein (protein), and starch were electrospun to form multistimuli-responsive fibers that incorporated a cocktail of both free nature-derived antimicrobials such as thyme oil, citric acid, and nisin and cyclodextrin-inclusion complexes (CD-ICs) of thyme oil, sorbic acid, and nisin. …

I have been following the CNC story for some time. If you’re curious, just use ‘cellulose nanocrystal(s)’ as your search term. You can find out more about ComCrop here.

Internet of living things (IoLT)?

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It’s not here yet but there are scientists working on an internet of living things (IoLT). There are some details (see the fourth paragraph from the bottom of the news release excerpt) about how an IoLT would be achieved but it seems these are early days. From a September 9, 2021 University of Illinois news release (also on EurekAlert), Note: Links have been removed,

The National Science Foundation (NSF) announced today an investment of $25 million to launch the Center for Research on Programmable Plant Systems (CROPPS). The center, a partnership among the University of Illinois at Urbana-Champaign, Cornell University, the Boyce Thompson Institute, and the University of Arizona, aims to develop tools to listen and talk to plants and their associated organisms.

“CROPPS will create systems where plants communicate their hidden biology to sensors, optimizing plant growth to the local environment. This Internet of Living Things (IoLT) will enable breakthrough discoveries, offer new educational opportunities, and open transformative opportunities for productive, sustainable, and profitable management of crops,” says Steve Moose (BSD/CABBI/GEGC), the grant’s principal investigator at Illinois. Moose is a genomics professor in the Department of Crop Sciences, part of the College of Agricultural, Consumer and Environmental Sciences (ACES). 

As an example of what’s possible, CROPPS scientists could deploy armies of autonomous rovers to monitor and modify crop growth in real time. The researchers created leaf sensors to report on belowground processes in roots. This combination of machine and living sensors will enable completely new ways of decoding the language of plants, allowing researchers to teach plants how to better handle environmental challenges. 

“Right now, we’re working to program a circuit that responds to low-nitrogen stress, where the plant growth rate is ‘slowed down’ to give farmers more time to apply fertilizer during the window that is the most efficient at increasing yield,” Moose explains.

With 150+ years of global leadership in crop sciences and agricultural engineering, along with newer transdisciplinary research units such as the National Center for Supercomputing Applications (NCSA) and the Center for Digital Agriculture (CDA), Illinois is uniquely positioned to take on the technical challenges associated with CROPPS.

But U of I scientists aren’t working alone. For years, they’ve collaborated with partner institutions to conceptualize the future of digital agriculture and bring it into reality. For example, researchers at Illinois’ CDA and Cornell’s Initiative for Digital Agriculture jointly proposed the first IoLT for agriculture, laying the foundation for CROPPS.

“CROPPS represents a significant win from having worked closely with our partners at Cornell and other institutions. We’re thrilled to move forward with our colleagues to shift paradigms in agriculture,” says Vikram Adve, Donald B. Gillies Professor in computer science at Illinois and co-director of the CDA.

CROPPS research may sound futuristic, and that’s the point.

The researchers say new tools are needed to make crops productive, flexible, and sustainable enough to feed our growing global population under a changing climate. Many of the tools under development – biotransducers small enough to fit between soil particles, dexterous and highly autonomous field robots, field-applied gene editing nanoparticles, IoLT clouds, and more – have been studied in the proof-of-concept phase, and are ready to be scaled up.

“One of the most exciting goals of CROPPS is to apply recent advances in sensing and data analytics to understand the rules of life, where plants have much to teach us. What we learn will bring a stronger biological dimension to the next phase of digital agriculture,” Moose says. 

CROPPS will also foster innovations in STEM [science, technology[ engineering, and mathematics] education through programs that involve students at all levels, and each partner institution will share courses in digital agriculture topics. CROPPS also aims to engage professionals in digital agriculture at any career stage, and learn how the public views innovations in this emerging technology area.

“Along with cutting-edge research, CROPPS coordinated educational programs will address the future of work in plant sciences and agriculture,” says Germán Bollero, associate dean for research in the College of ACES.

…

I look forward to hearing more about IoLT.

Cellulose nanofiber (CNF) coating protects plants against rust disease

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A September 8, 2021news item on ScienceDaily describes some new research into rust disease,

A water-absorbent coat to keep rust away? It may seem counterintuitive but when it comes to soybean plants and rust disease, researchers from Japan have discovered that applying a coating that makes leaf surfaces water absorbent helps to protect against infection.

Caption: Researchers from the University of Tsukuba have found that coating soybean plant leaves with cellulose nanofiber (CNF) gives protection against an aggressive fungal disease. The CNF coating changed leaf surfaces from water repellent to water absorbent, and suppressed pathogen gene expression associated with infection mechanisms, offering resistance to the destructive Asian rust disease. This is the first study to examine CNF application for controlling plant diseases, and it offers a sustainable alternative to managing plant disease.. Credit: University of Tsukuba

A September 7, 2021 University of Tsukuba press release (also on EurekAlert but published September 8, 2021), which originated the news item, describes the disease and proposed solution in more detail,

In a study published this month in Frontiers in Plant Science, researchers from the University of Tsukuba have revealed that coating soybean plant leaves with cellulose nanofiber changes the leaf surface from water repellent to water absorbent and offers resistance against Asian soybean rust.

Rusts are plant diseases that get their name from the powdery rust- or brown-colored fungal spores on the surfaces of infected plants. Asian soybean rust (ASR) is an aggressive disease of soybean plants, causing estimated crop yield losses of up to 90%. ASR is caused by Phakopsora pachyrhizi, a fungal pathogen that requires a living plant host to survive. The timely application of fungicide is currently the only way of controlling ASR in the field. But the use of fungicides can be problematic, resulting in negative environmental effects, increased production costs, and fungicide-resistant pathogens.

“We investigated cellulose nanofiber (CNF) as an alternative method of controlling ASR,” says senior author of the study, Professor Yasuhiro Ishiga. “Specifically, we wanted to know whether coating soybean plant leaves with CNF protected plants against P. pachyrhizi.”

Of the available methods for isolating CNF, aqueous counter collision (ACC) has been shown to alter the hydrophilic (water absorbent) and hydrophobic (water repellent) properties of surfaces, switching one to the other. Previous research has indicated that CNF obtained via ACC has higher wettability than CNF isolated by other methods.

“We showed that CNF can change the soybean leaf surface from hydrophobic to hydrophilic,” explains senior author, Professor Yuji Yamashita. “This offers resistance against P. pachyrhizi.”

The team found fewer lesions and significantly reduced formation of P. pachyrhizi appressoria, which are specialized pre-infection structures used to break through the outer surface of the host plant, on CNF-treated leaves compared with control (untreated) leaves. The results also revealed suppressed gene expression linked to the formation of pre-infection structures in P. pachyrhizi on treated versus control leaves.

“In particular, chitin synthase gene expression was suppressed, and P. pachyrhizi needs chitin synthases to form pre-infection structures,” says Professor Ishiga.

This study is the first to investigate the application of CNF for controlling plant diseases in the field, and this technique offers new possibilities for sustainable and eco-friendly management of plant diseases.

Here’s a link to and a citation for the paper,

Covering Soybean Leaves With Cellulose Nanofiber Changes Leaf Surface Hydrophobicity and Confers Resistance Against Phakopsora pachyrhizi by
Haruka Saito, Yuji Yamashita, Nanami Sakata, Takako Ishiga, Nanami Shiraishi, Giyu Usuki, Viet Tru Nguyen, Eiji Yamamura and Yasuhiro Ishiga. Front. Plant Sci., 03 September 2021 DOI: https://doi.org/10.3389/fpls.2021.726565

This paper appears to be open access.

Use AI to reduce worries about nanoparticles in food

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A June 16, 2021 news item on ScienceDaily announces research into the impact that engineered metallic nanoparticles used in agricultural practices have on food,

While crop yield has achieved a substantial boost from nanotechnology in recent years, alarms over the health risks posed by nanoparticles within fresh produce and grains have also increased. In particular, nanoparticles entering the soil through irrigation, fertilizers and other sources have raised concerns about whether plants absorb these minute particles enough to cause toxicity.

In a new study published online in the journal Environmental Science and Technology, researchers at Texas A&M University have used machine learning [a form of artificial intelligence {AI}] to evaluate the salient properties of metallic nanoparticles that make them more susceptible for plant uptake. The researchers said their algorithm could indicate how much plants accumulate nanoparticles in their roots and shoots.

A June 16, 2021 Texas A&M University news release (also on EurekAlert), which originated the news item, describes the research, which employed two different machine learning algorithms, in more detail,

Nanoparticles are a burgeoning trend in several fields, including medicine, consumer products and agriculture. Depending on the type of nanoparticle, some have favorable surface properties, charge and magnetism, among other features. These qualities make them ideal for a number of applications. For example, in agriculture, nanoparticles may be used as antimicrobials to protect plants from pathogens. Alternatively, they can be used to bind to fertilizers or insecticides and then programmed for slow release to increase plant absorption.

These agricultural practices and others, like irrigation, can cause nanoparticles to accumulate in the soil. However, with the different types of nanoparticles that could exist in the ground and a staggeringly large number of terrestrial plant species, including food crops, it is not clearly known if certain properties of nanoparticles make them more likely to be absorbed by some plant species than others.

“As you can imagine, if we have to test the presence of each nanoparticle for every plant species, it is a huge number of experiments, which is very time-consuming and expensive,” said Xingmao “Samuel” Ma, associate professor in the Zachry Department of Civil and Environmental Engineering. “To give you an idea, silver nanoparticles alone can have hundreds of different sizes, shapes and surface coatings, and so, experimentally testing each one, even for a single plant species, is impractical.”

Instead, for their study, the researchers chose two different machine learning algorithms, an artificial neural network and gene-expression programming. They first trained these algorithms on a database created from past research on different metallic nanoparticles and the specific plants in which they accumulated. In particular, their database contained the size, shape and other characteristics of different nanoparticles, along with information on how much of these particles were absorbed from soil or nutrient-enriched water into the plant body.

Once trained, their machine learning algorithms could correctly predict the likelihood of a given metallic nanoparticle to accumulate in a plant species. Also, their algorithms revealed that when plants are in a nutrient-enriched or hydroponic solution, the chemical makeup of the metallic nanoparticle determines the propensity of accumulation in the roots and shoots. But if plants are grown in soil, the contents of organic matter and the clay in soil are key to nanoparticle uptake.

Ma said that while the machine learning algorithms could make predictions for most food crops and terrestrial plants, they might not yet be ready for aquatic plants. He also noted that the next step in his research would be to investigate if the machine learning algorithms could predict nanoparticle uptake from leaves rather than through the roots.

“It is quite understandable that people are concerned about the presence of nanoparticles in their fruits, vegetables and grains,” said Ma. “But instead of not using nanotechnology altogether, we would like farmers to reap the many benefits provided by this technology but avoid the potential food safety concerns.”

This image accompanies the paper’s research abstract,

[downloaded frm https://pubs.acs.org/doi/full/10.1021/acs.est.1c01603]

Here’s a link to and a citation for the paper,

Prediction of Plant Uptake and Translocation of Engineered Metallic Nanoparticles by Machine Learning by Xiaoxuan Wang, Liwei Liu, Weilan Zhang, and Xingmao Ma. Environ. Sci. Technol. 2021, 55, 11, 7491–7500 DOI: https://doi.org/10.1021/acs.est.1c01603 Publication Date:May 17, 2021 Copyright © 2021 American Chemical Society

This paper is behind a paywall.