Category: Chemistry

The composition of foodstuffs, but also the sequence of dishes, is important for the perfect taste experience of a menu. This insight, based on experience, is well known. The molecular causes of the pleasure-enhancing effects, on the other hand, are still poorly understood.

Using the example of chicory, surrogate and roasted coffee, a study by the Leibniz Institute for Food Systems Biology at the Technical University of Munich (LSB) now explains for the first time why the order in which we eat food can be decisive for bitter taste perception and what role bitter taste receptors play in this process.

Chicory (Cichorium intybus L.) is a popular salad ingredient, and its bitterness harmonizes well with apples or balsamic vinegar. The roasted and ground bitter roots of the plant, on the other hand, contribute to the flavor similarity to roasted coffee in many coffee substitutes. The reason for this, however, is not clear. To investigate this question and learn more about the molecular basis of taste perception, the research team led by Maik Behrens, head of the Taste & Odor Systems Reception group at LSB, conducted extensive experiments.

Three bitter taste receptor types identified for chicory

The experiments focused on the three main known bitter substances present in chicory and chicory root-containing surrogate coffee. To determine which human bitter taste receptor types they activate, the team used an established cellular assay system.

As the test results show for the first time, the chicory bitter compounds activate only three of the approximately 25 bitter taste receptor types. However, these belong to the group of five receptor types identified to date that respond to bitter substances in roasted coffee. “Chicory bitter compounds thus exhibit a receptor activation profile that overlaps with those of the roasted coffee compounds tested to date and appear to mimic the bitterness of roasted coffee well. However, the profiles are not completely identical,” says Tatjana Lang of the LSB, who was substantially involved in the study.

It’s the sequence that counts

To check the extent to which the similarities and differences in the receptor activation profiles affect taste perception, the team also conducted sensory tests. If the test subjects evaluated roasted coffee shortly before eating chicory or drinking a coffee substitute, both foods tasted significantly less bitter than before. Conversely, consumption of chicory or surrogate coffee did not affect the perceived bitterness of a subsequently tasted roasted coffee.

“Our results suggest that the bitter substances of roasted coffee briefly make all three bitter taste receptor types that respond to chicory compounds less sensitive to the latter. Conversely, this debittering effect does not work, as presumably the chicory bitter substances are not able to desensitize all receptor types that detect bitter compounds in roasted coffee,” explains Roman Lang, who heads the Biosystems Chemistry & Human Metabolism group at LSB.

“Ultimately, our results suggest that precise knowledge of the receptor activation profiles of bitter compounds could in principle be used to predict or positively modulate the taste perception of foods,” adds principal investigator Maik Behrens. “Moreover, it can be assumed that such effects are not limited to the perception of bitter substances. Therefore, there is still much to be explored to understand the molecular mechanisms underlying complex taste sensations.”

More information: Roman Lang et al, Overlapping activation pattern of bitter taste receptors affect sensory adaptation and food perception, Frontiers in Nutrition (2022). DOI: 10.3389/fnut.2022.1082698

Provided by Leibniz-Institut für Lebensmittel-Systembiologie

Stress isn’t just the psychological pressure you feel in response to a looming deadline at work. It is also a description of the physical forces pushing, pulling, or twisting an object, structure, or material. Examples of stress include gravity dragging downward on a bridge, wind blowing against the side of a building, or even a waistband drawn taut by a big meal.

With stress affecting literally everything made and used by people, often in damaging ways, it is important to identify when and where it is happening and the extent to which it is occurring. This is not always easy, though, because many materials show no obvious signs of being under stress.

Caltech’s Maxwell Robb, an assistant professor of chemistry, has been working to make stress easier to identify through the creation of polymers that change color when a force is applied to them. Now, in a paper titled “Mechanically gated formation of donor–acceptor Stenhouse adducts enabling mechanochemical multicolour soft lithography” and published in Nature Chemistry, Robb shows how his team created a new type of these polymers that can be made to change to almost any colors the user wants. This is in contrast to the polymers he had previously developed, which could only change to a single, predetermined color.

To understand the Robb group’s latest research, it is helpful to first know how previously developed color-changing plastics work. To create a plastic that changes color in response to stress, you need a type of molecule known as a mechanophore. There are many kinds of these mechanophores, with only some being color changing, but almost all work in essentially the same way. The molecules exist in two states, and when they are subjected to an external force, they undergo a chemical reaction that converts them from one state to another. In the case of the mechanophores Robb’s team works with, one state is colorless and the other is colored.

When mechanophores are incorporated into a plastic, they experience the force that is applied to the plastic and thus will change color, allowing the location of that stress to be visualized.

The team’s latest work is based on similar principles but with a twist. The mechanophore they have developed doesn’t change color directly with force but rather produces an intermediate compound that can be converted to myriad brightly colored dyes called donor–acceptor Stenhouse adducts (DASAs).

The colorless mechanophore molecules are also incorporated into plastic, but, in this case, they remain essentially colorless even after they are subjected to stress. Instead, the change in their molecular structure makes them able to undergo a secondary chemical reaction, a process referred to as mechanochemical gating. Once in that chemically receptive state, they are “developed” with a chemical bath that tacks another molecular piece onto their structure. These pieces cause the larger molecule to become brightly colored; the researcher can tune the color to any desired hue by changing the molecular fragment that is tacked on.

“The beauty of this is we have one central mechanically responsive molecule,” Robb says. “And that makes it a general chemical platform, because just by changing the identity of the chemical that you use in the second step, you can generate this extremely diverse library of dyes.”

As a demonstration of the platform, researchers in Robb’s lab prepared a sheet of stretchy polymer containing their new mechanophore molecule and stamped it with a pattern that provided stress in specific areas. The material was then placed in a chemical bath that turned the pattern purple. The plastic was stamped a second time with a new pattern and developed with a different chemical that turned the newly stamped area blue. And finally, the plastic was stamped a third time and developed with a bath that turned the most recently stamped area green. Together, the three stamped patterns created a multicolor flower image within the plastic itself. And because DASAs also change their color with light, the image could be made to disappear using a flashlight.

Of course, the technology was not created just for the sake of printing simple pictures in plastics. Robb says the ability to leave chemically reactive imprints in three dimensions in polymer materials could also open the door to patterning other kinds of chemicals in three-dimensional space, such as proteins, which would have applications in tissue engineering. Additionally, he says that the lab is working to further take advantage of the time element associated with the photoresponse of DASAs, making the printing 4D.

“It’s actually really interesting for future directions of using this for things like encryption technologies,” he says.

More information: Anna C. Overholts et al, Mechanically gated formation of donor–acceptor Stenhouse adducts enabling mechanochemical multicolour soft lithography, Nature Chemistry (2023). DOI: 10.1038/s41557-022-01126-5

Journal information: Nature Chemistry 

Provided by California Institute of Technology 

Recently, a research team led by Prof. Chen Tao from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) revealed the formation and evolution of the point defect of antimony selenosulfide. This work was published in Advanced Materials.

Antimony selenosulfide, i.e., Sb₂(S,Se)₃, features great stability, no inclusion of rare or toxic elements, excellent photovoltaic property, and low cost, which make it an ideal photovoltaic material. Due to the quasi-one-dimensional structure and high extinction coefficient of the material, it has unique advantages in fields such as ultralight devices, portable power sources, or building-integrated photovoltaics.

To improve the performance of devices, it is necessary to understand the basic properties of this new photovoltaic material.. The research team focused on the point defect of antimony selenosulfide. They utilized optical deep-level transient spectroscopy (O-DLTS) to detect the characteristics of the defect of antimony selenosulfide driven by temperature. Researchers then investigated the variation of the material composition during annealing to reveal the formation and evolution of the point defect.

The initial hydrothermal deposition results in the formation of point defects with high formation energy, which was the result of random deposition of ions driven in hydrothermal condition, according to the researchers. Post-annealing and the thin-film crystallization led to the loss of sulfur and selenium anions as well as the formation vacancy defect (V_S(e)). Since the formation energy of cation/anion inversion defects is relatively low, antimony ions would transfer and fill anion vacancies, eventually forming the Sb_S(e) inversion defect.

The study deepens the understanding of the formation and evolution of point defects of antimony selenosulfide and offers a new method to study such processes. It also provides a guidance for designing methods to produce films and inhibiting the formation of deep-level point defects.

More information: Bo Che et al, Thermally Driven Point Defect Transformation in Antimony Selenosulfide Photovoltaic Materials, Advanced Materials (2022). DOI: 10.1002/adma.202208564

Journal information: Advanced Materials 

Provided by University of Science and Technology of China

In the age-old battle against mosquitos, DEET has proven effective at keeping this nemesis at bay, but the repellent is smelly and its protection is short-lived. Now, researchers report in the Journal of Agricultural and Food Chemistry that they have designed safe alternatives that have some advantages over DEET, including a nice smell and much longer protection from bites.

DEET disrupts a mosquito’s ability to locate humans. Until recently, it was considered the gold standard among topical repellents, but some find its strong odor offensive. It has to be reapplied frequently, and at high concentrations, it can damage synthetic fabrics and plastics. Another popular repellent known as picaridin is now regarded as a better alternative, since its protective effect lasts longer, and it doesn’t have an odor or damage items. However, like DEET, it has to be reapplied after swimming or sweating.

So, Francesca Dani and colleagues wanted to look for alternatives to these established products. In prior work, the team used as starting materials two plant-based natural repellents that offered only short-term protection from mosquitos. The researchers converted these terpenoids into cyclic acetals and hydroxyacetals, thereby extending their protective timespan beyond that of DEET. But the researchers wanted to improve on these initial products.

In the current work, the team synthesized additional cyclic hydroxyacetals from inexpensive, commercially available carbonyls. The new cyclic compounds had pleasant, much fainter odors and were easier to dissolve in water, meaning they can be formulated without high concentrations of alcohol. Some were as effective as DEET and picaridin at repelling Asian tiger mosquitos, which have spread widely in the U.S. and carry diseases, including encephalitis, dengue and dog heartworm.

And like picaridin, they provided human volunteers more than 95% protection from bites for at least eight hours, while DEET’s protection rapidly declined below that level after just two hours. Toxicity of some of the most active new compounds was comparable to or lower than the traditional repellents.

Two hydroxyacetals were also less likely to cause immune reactions or to penetrate cell layers than picaridin. The researchers conclude that their compounds represent a new class of promising mosquito repellents that can compete favorably with DEET and picaridin in terms of efficacy and safety.

More information: Immacolata Iovinella et al, Cyclic Acetals as Novel Long-Lasting Mosquito Repellents, Journal of Agricultural and Food Chemistry (2023). DOI: 10.1021/acs.jafc.2c05537

Journal information: Journal of Agricultural and Food Chemistry 

Provided by American Chemical Society 

Researchers at Oak Ridge National Laboratory have zoomed in on molecules designed to recover critical materials via liquid-liquid extraction, or LLE—a method used by industry to separate chemically similar elements.

The team had previously designed a novel ligand, or collector molecule, to grab select lanthanides from rare-earth mineral solutions.

Lanthanides are rare-earth metals critical to energy and national security technologies for magnets, electronics and catalysts. They occur together naturally in mineral ore deposits, but their chemical similarities make separating individual elements difficult. LLE methods leverage self-separating liquids such as oil and water to isolate a target material. One example is dividing light and heavy lanthanides. The new study describes how the process unfolds, finding that an unexpected T-shaped cluster forms around target metals, acting like a magnet to create larger aggregates.

“These atomic-scale details are difficult to observe and could help us improve future rare-earth separation strategies,” said ORNL’s Alex Ivanov.

The research is published in The Journal of Physical Chemistry Letters.

More information: Darren M. Driscoll et al, Noncoordinating Secondary Sphere Ion Modulates Supramolecular Clustering of Lanthanides, The Journal of Physical Chemistry Letters (2022). DOI: 10.1021/acs.jpclett.2c03423

Journal information: Journal of Physical Chemistry Letters 

Provided by Oak Ridge National Laboratory 

Antibiotic resistant bacteria are becoming more and more of a concern as traditional sources of anti-microbial treatments become less effective. Therefore, researchers at Ben-Gurion University of the Negev are looking farther afield for promising compounds to treat wounds and infections.

Prof. Shoshana (Mails) Arad and Prof. Ariel Kushmaro, Prof. Levi A. Gheber and Ph.D. student Nofar Yehuda joined a metal and a polysaccharide together and discovered the new compound worked well against bacteria and fungus (Candida albicans) because of the longer and denser spikes on its surface that poked holes in the membrane and killed off the bacteria and the fungus.

“A polysaccharide is a carbohydrate with linked sugar molecules and by adding a metal (Cu), we were able to create an effective new material,” according to the researchers.

Their findings were published recently in Marine Drugs as the new compound is derived from marine red microalga Porphyridium sp.

Commercialization of these new compounds could come sooner rather than later.

“In light of the increased resistance to antibiotic and antifungal agents, there is a growing need for the development of new and improved treatments. BGN Technologies holds a patent application ready for licensing in the field,” say BGN’s Galit Mazooz-Perlmuter and Anat Shperberg Avni. BGN Technologies is Ben-Gurion University’s technology transfer company.

More information: Nofar Yehuda et al, Complexes of Cu–Polysaccharide of a Marine Red Microalga Produce Spikes with Antimicrobial Activity, Marine Drugs (2022). DOI: 10.3390/md20120787

Provided by Ben-Gurion University of the Negev 

Critical Materials Institute researchers at Oak Ridge National Laboratory and Arizona State University have studied the mineral monazite, an important source of rare-earth elements, to enhance methods of recovering critical materials for energy, defense and manufacturing applications.

Rare-earth elements occur together naturally in mineral ores such as monazite but are economically challenging to recover. New approaches to separate the valuable ore from unwanted materials are needed.

The research team combined theory and experiment to gain atom-level insights on monazite, providing a first look at surface features important to the design of flotation collector molecules—materials that work like life jackets to buoy up monazite particles on air bubbles from mixed mineral slurries.

“Our efforts address materials needed for froth flotation techniques used to separate high-grade ore from low-value materials during processing. Fundamental research can help us tailor future collectors to make monazite recovery more efficient and cost-effective,” said ORNL’s Vyacheslav Bryantsev.

The work is published in The Journal of Physical Chemistry C.

More information: Luke D. Gibson et al, Characterization of Lanthanum Monazite Surface Chemistry and Crystal Morphology through Density Functional Theory and Experimental Approaches, The Journal of Physical Chemistry C (2022). DOI: 10.1021/acs.jpcc.2c06308

Journal information: Journal of Physical Chemistry C 

Provided by Oak Ridge National Laboratory 

Copper is all around us. The metal is both ever-present and invisible in our world. Copper makes reading the words on this screen possible. And the global spread of artificial light, electric power and telecommunications all required ever-increasing quantities of copper.

Where does all of this copper come from? How was it produced, distributed, controlled, and sold on an ever-increasing scale? These are some of the questions addressed in a recenty published book, Born with a Copper Spoon: A Global History of Copper.

The book is a global study of a metal that has transformed the globe. Contributors to the book cover North America, Latin America, Europe, Central Africa, the Middle East, East Asia and Oceania and stretch from the early nineteenth to the early twenty-first centuries.

Why are these important questions? Because of the ubiquity of copper and the fact that the world’s collective rehab from fossil fuels may cause a renewed addiction to a new mineral-based economy. Electrification, the pillar of the green transition, requires huge amounts of copper. Projections expect a doubling of copper consumption by 2035 in order to reach zero-emission energy goals. Faced with the enormous task of electrification, the share of the global energy sector will increase to 40 % of total copper consumption in the next two decades

They are also important questions because countries that have an abundance of copper have failed to benefit from it. Zambia is a case in point. It produces 6% of the world’s copper but is still one of the poorest countries in the world.

Born with a Copper Spoon requires us to think differently about our material lives and energies we use, by looking at the places where our minerals are actually produced and the way in which the production and distribution of these minerals are organized.

Will the next world of copper finally evolve as the long-anticipated resource blessing, or is a new global scramble, in which states and companies seek to secure access to the precious metal, going to determine otherwise? Copper became associated with the idea of a resource curse for many people. Zambia’s first President Kenneth Kaunda once remarkedthat his country is “paying the price for having been born with a copper spoon in our mouths.”

He knew too well that the abundance of copper had caused Zambia a host of problems.

Worlds of copper

Our book looks at different ‘worlds of copper’ that have arisen over the last century and a half. The term ‘world of copper’ was first coined by British historians Chris Evans and Olivia Saunders to describe a globally integrated production system that connected the smelters of South Wales to copper mines across the globe between 1830 and 1870.

We see this as the first world of copper. This world was then supplanted by a second world of copper centered on the US. This involved the rise and dominance of American mining companies as huge integrated enterprises controlling the production, processing and distribution of the commodity. “From mine to consumer” was the slogan of the notorious American copper mining company Anaconda, active in Montana and Chile. Underpinning the American world of copper was control over the production chain through the use of new business organizations and technologies.

Technological changes in mining and processing that were quite literally ground-breaking allowed for ever-greater quantities of copper to be mined and processed. Open pit extraction was first developed in North America and soon spread to Latin America and Central Africa, with often comprehensively destructive environmental consequences. Many of these pits are still being mined today.

The American world of copper denotes both the power of American companies, as well as the model of controlling copper chains that is eagerly copied by non-American copper companies. This patterns becomes global: it is applied in Japan, the European empires that control the Copperbelt as well as in Latin America.

In the mid-twentieth century, the American world of copper disintegrated during decolonisation in the face of resource nationalism and a shifting geography of production. A wave of nationalizations by new states brought about a postcolonial world of copper, built around state power, economic sovereignty and state-level international co-operation. Developing states saw copper as their ticket to economic development and modernity. The dream of the red metal was however short-lived.

This postcolonial world of copper collapsed in the 1990s after a long slump in the industry. Multinational private companies reasserted themselves over the industry, but the US and European companies never regained their once dominant position.

Each copper world was marked by several defining features: underlying institutions, organizations, labor practices and produced by global connections and interactions. Identifying and understanding consecutive worlds of copper is crucial to how we understand the development of the global copper industry.

Our current energy transition could herald a new copper world. Renewed demand for copper will likely intensify mining activity in DR Congo, Zambia and other parts of the African continent and could place states in a stronger bargaining position.

The need to think differently

Copper’s status as a global industry has waxed and waned. The history of the metal is not a story of steadily increasing and depending global connections as we move towards the present. It is also a history of disconnections and efforts to de-couple regions from the global economy.

Our book is a contribution to global history and the story of copper is necessarily a global one as extracting, refining, buying, shipping and consuming the metal takes place around the world. Global history is about more than connections, however.

Our book is also about periods of deglobalisation and attempts to sever connections, especially in the mid-twentieth century when a bitter contest over ownership of mineral resources briefly threatened a major realignment of the world economy. In 1967, several of the world’s largest copper producers (Congo, Chile, Peru and Zambia) met in Lusaka to establish a copper cartel that would control the industry and turn an abundance of natural resources into national economic growth.

That’s an ambition that still needs to be fulfilled.

Provided by The Conversation 

This article is republished from The Conversation under a Creative Commons license. Read the original article.

On average, we open seven packaged items per day, most of them food items. All of this together makes for a mountain of plastic. But more and more often our tomatoes, apples and cookies are packaged in cardboard. To help speed up the transition of plastic to paper, TU/e chemist Sterre Bakker researched what coatings can be used to make cardboard a more suitable food packaging material.

About 20% of waste consists of packaging, but packaging food is not all bad. Good packaging protects the item during transport, which means less food needs to be thrown out. Packaging also keeps out moisture, bacteria and fungi. This gives our food a longer shelf life, also resulting in less food going to waste. Keeping a bag of mixed vegetables or a pack of beef in the fridge for a week without it going off? Impossible without the packaging.

More alternatives are being used to reduce plastic packaging waste. Over the past few years, paper and cardboard have become more common packaging materials. But transitioning from plastic to paper is not as easy as it seems, TU/e researcher Sterre Bakker explains. “Plastic has a number of highly practical characteristics. You can use it for airtight packaging and it is an excellent barrier for water and grease. It’s strong but also light, which works well for the transport sector. It requires a lot of effort to find a suitable alternative that meets the same requirements and can be used at a large scale.”

Freedom to publish

For her Ph.D., Bakker investigated how cardboard can be used to make food packaging more sustainable. This Friday (Jan. 27, 2023) she will defend her thesis at the department of Chemical Engineering and Chemistry. To bridge the gap between the laboratory and the packaging sector, she collaborated with chemicals company BASF.

When asked if this collaboration caused any confidentiality issues, Bakker shakes her head. “I consciously sought collaboration with industry; I wanted to get a PHD, but in applied research. This allowed me to make a contribution to society. As I wanted to have the freedom to talk and publish about my findings, we used a model coating. It’s not exactly the same as the manufacturer’s, but it’s very similar. So that was a good compromise.”

Water-based coating

For dry food items, such as rice and oatmeal, cardboard packaging works fine. But putting milk or a hamburger in a cardboard box is more complex, Bakker explains. “A suitable coating is crucial. Water and grease have very different ways of getting through a coating. For a good water barrier, the chemical reaction that occurs while the coating is drying up is very important, but for grease you need a coating that’s intact. This explains why the inner lining of a milk carton is so thick: it consists of several layers of hydrophilic and hydrophobic coatings. In addition to the relatively large amount of plastic used, the mixture of coatings makes it hard to recycle. This is what we would like to improve.”

Bakker set out in search of a single coating impermeant to water, oxygen and grease. To this end, she studied an innovative, water-based coating, with the special addition of a water-soluble, synthetic resin to stabilize polymer particles. This resin makes it possible to transform a water-soluble surface into a water-resistant one. “When the coating dries up, it’s not only the water that evaporates but also a base. The resin undergoes a chemical reaction and this means the coating no longer dissolves in water.”

Multifunctional coating

Bakker used a scanning electron microscope and infrared spectroscopy to carry out in-depth research into the different barrier characteristics of the coating, as well as to optimize the production process. This is all very relevant to industry, she emphasizes, as synthesizing the coating is easy to scale and not overly complex. What’s more, at a certain temperature the color of the coating can be changed by adding a specific molecule. This quasi-alternative expiration date makes the coating multifunctional.

Bakker shows her final result: a shiny piece of thick carton that actually resists both water and grease. “This coating already has a lot of advantages in comparison to current coatings. Although it does require raw fossil materials, the layer can be made much thinner now. We’ve also demonstrated through several experiments that the coating can be peeled off the cardboard more easily, which means it’s very suitable for recycling. We’ve taken the first steps, obviously in the hope of eventually creating a biobased coating that eliminates all plastic from food packaging.”

Tea lover

The above should serve as a reminder, Bakker reiterates, of cardboard being much stronger than we give it credit for. Like women, she says with a smile. Bakker is quite comfortable in the space she created for herself in the male-dominated coating and packaging industry. And as a tea lover she will obviously bring her tea box—cardboard of course—to her new place of work, Allnex in Bergen op Zoom. Before we leave she’s keen to show us the quote adorning her thesis: “A woman is like a teabag; you never know how strong it is until it is in hot water.”

Sterre Bakker defends her thesis at the department of Chemical Engineering and Chemistry on January 27, 2023.

Provided by Eindhoven University of Technology 

The dairy industry strives to preserve the quality and safety of milk products while maintaining the freshest possible taste for consumers. To date, the industry has largely focused on packaging milk in light-blocking containers to preserve freshness, but little has been understood about how the packaging itself influences milk flavor. However, a new study in the Journal of Dairy Science confirms that packaging affects taste—and paperboard cartons do not preserve milk freshness as well as glass and plastic containers.

Lead investigator MaryAnne Drake, Ph.D., of the North Carolina State University Department of Food, Bioprocessing and Nutrition Sciences, Raleigh, NC, U.S., explained that “milk is more susceptible to packaging-related off-flavors than many other beverages because of its mild, delicate taste.” Besides light oxidation, “milk’s taste can be impacted by the exchange of the packaging’s compounds into the milk and by the packaging absorbing food flavors and aromas from the surrounding refrigeration environment.”

To quantify the flavor impacts of packaging, the researchers examined pasteurized whole and skim milk stored in six half pint containers: paperboard cartons, three plastic jugs (made from different plastics), a plastic bag, and glass as a control. The milk was stored in total darkness to control for light oxidation and kept cold at 4°C (39°F).

The samples were tested on the day of first processing, then again at 5, 10, and 15 days after. A trained panel examined the sensory properties of each sample, and the research team conducted a volatile compound analysis to understand how the packaging was intermingling with the milk. Finally, the samples underwent a blind consumer taste test on day 10 to see whether tasters could tell any difference between milk stored in the paperboard carton or the plastic jug compared with milk packaged in glass.

The results showed that package type does influence milk flavor, and skim milk is more susceptible to flavor impacts than whole milk. Of the different packaging types, paperboard cartons and the plastic bag preserved milk freshness the least due to the paperboard’s absorption of milk flavor and the transfer of paperboard flavor into the milk. Milk packaged in paperboard cartons, in fact, showed distinct off-flavors as well as the presence of compounds from the paperboard. The final results show that while glass remains an ideal container for preserving milk flavor, plastic containers provide additional benefits while also maintaining freshness in the absence of light exposure.

Paperboard cartons are the most widely used packaging type for school meal programs in the United States, so these findings are especially relevant for the consideration of how young children consume and enjoy milk.

“These findings suggest that industry and policymakers might want to consider seeking new package alternatives for milk served during school meals,” said Drake. Over time, the consequences of using milk packaging that contributes significant off-flavors may affect how young children perceive milk in both childhood and adulthood.

More information: D.C. Cadwallader et al, The role of packaging on the flavor of fluid milk, Journal of Dairy Science (2022). DOI: 10.3168/jds.2022-22060

Journal information: Journal of Dairy Science 

Provided by Elsevier