Tea Leaves Trap Contaminants, Sorghum Aids 3D Food Printing, and More

SAFETY & QUALITY

Tea leaves trap heavy-metal contaminants

Researchers at Northwestern University have demonstrated that brewing tea helps remove metal contaminants such as lead and cadmium from water through adsorption, the process of heavy-metal ions adhering to the surface of tea leaves, according to an article published in the American Chemical Society (ACS) publication ACS Food Science & Technology.

“We’re not suggesting that everyone starts using tea leaves as a water filter,” said Vinayak P. Dravid, the study’s senior author and a professor of materials science and engineering at Northwestern, who was quoted in an article on the university’s website. “In fact, we often utilize model experiments and tweak diverse parameters to probe and understand the scientific principles and phenomena involved in capture/release cycles of contaminants.”

The researchers point out that tea leaves have a high active surface area, which makes them effective at both releasing flavor chemicals rapidly into water and functioning as an adsorbent material. The study investigated the impact of different types of tea, tea bags, and brewing methods on heavy-metal adsorption. The researchers tested several tea varieties, including “true” teas such as black, green, oolong, and white, as well as rooibos and chamomile teas. In addition, they looked at the different effects of commercially bagged versus loose-leaf teas.

The tea samples were steeped for various time periods, ranging from a few seconds to 24 hours, in differing water solutions with known amounts of lead, cadmium, copper, chromium, and zinc. After steeping, the researchers measured how much of the metal content remained in the water.

“Cellulose bags work best—and they don’t release microplastics,” reported the research team. The longer the steeping time, the more metal was removed from the water. This research might help explain why populations that drink more tea have a lower incidence of heart disease and stroke, observe the authors of the study. In addition, having an extra cup of tea each day might be beneficial to individual tea drinkers, they add.

AGRICULTURE

Pearl millet as a gluten-free alternative

Fermented pearl millet might be acceptable to American palates, according to research published recently in the international journal Foods. The analysis was done by scientists at Drexel University, the University of Pennsylvania, City University of New York (CUNY), and the Monell Chemical Senses Center. Pearl millet, which is nutrient dense, is not widely used in the United States but has been cultivated for centuries in India and African countries in drought conditions.

The study’s authors conclude that fermented pearl millet flour can effectively replace up to 20% of whole wheat flour in sandwich-style whole grain bread without affecting consumer acceptance or willingness to purchase it. “Beyond this amount, however, flavor acceptability declined, which emphasizes the need to balance nutritional improvements with sensory appeal,” note the article’s authors.

Because pearl millet bran contains a substantial amount of phytic acid, which reduces the absorption of micronutrients such as calcium and iron, the researchers used fermentation to lower the phytic acid levels when preparing the millet. In their first pilot study, they found that the longer the fermentation time, the lower the millet’s phytic acid levels. But they also discovered that, for flat breads made entirely of pearl millet, American consumers became increasingly dissatisfied with the taste the longer the millet was fermented.

In the second pilot study, the research team substituted fermented pearl millet in whole grain sandwich bread, in differing amounts, to find out how much fermented pearl millet U.S. consumers would accept. After taste-testing sandwich breads made with anywhere from 0% to 50% fermented millet flour, the study participants zeroed in on the 20% threshold, beyond which the bread’s taste was adversely affected.

“Our goal is to identify the ‘sweet spot’ where we maximize both health benefits and consumer acceptance, ensuring that underutilized nutrient-rich foods, like millet, can become more widely integrated into the U.S. diet,” said lead author May M. Cheung, a graduate of Drexel University’s doctoral program in nutrition sciences and an assistant professor of nutrition sciences at CUNY, who is quoted in an article on the Drexel website.

SUSTAINABILITY

Pork’s promising environmental profile

Through data models, researchers at the College of William & Mary have concluded that substituting pork for beef and seafood in the American diet would have a beneficial impact on the environment, according to an article in the journal Frontiers. From publicly available repositories, the study’s authors gathered data on dietary intake among more than 17,000 adults in the United States, greenhouse gas emissions, cumulative energy demand, water scarcity footprint, land use, pesticide use, fertilizer nutrients, food prices, and diet quality. The investigators then created a food substitution model to assess the change in sustainability impact when one to three servings of beef, seafood, poultry, eggs, or legumes were replaced by pork.

Modeled substitution of pork for beef resulted in an 11% to 35% reduction in greenhouse gas emissions, land use, pesticides, and fertilizer nutrients, while substituting pork for seafood resulted in a 6% reduction in cumulative energy demand. In contrast, substituting pork for poultry, eggs, or legumes increased the adverse environmental impact by up to 5%.

“Despite the prominence of pork in consumer diets, it is often not disaggregated from beef in research and policy documents,” the article states. “This has led to gaps in knowledge about the role of pork in sustainable diet patterns, which limits policy action.” The U.S. government can play an important role in improving data collection methods that distinguish pork from other meats, the researchers emphasize.

HEALTH

Could kefir help combat Alzheimer’s?

A systematic review of the literature, published this year in the journal Brain Behavior and Immunity Integrative, suggests that kefir—a fermented milk drink containing a variety of probiotics—might have potential uses in Alzheimer’s disease management. However, more rigorous research studies, including longitudinal studies and large-scale randomized clinical trials, are needed to evaluate the long-term effects of kefir combined with other preventive measures on cognitive decline, conclude the article’s authors, who are from research organizations and universities in Brazil and Uruguay and the World Health Organization.

The review examined seven peer-reviewed studies involving invertebrates, murine models, and human participants. “In animal models, the primary outcomes were antioxidant effects, reduced beta-amyloid deposition, and attenuation of vascular damage and neurodegeneration,” the article states. “In human studies, kefir supplementation resulted in decreased levels of inflammatory cytokines, reactive oxygen species, and oxidative proteins, and was associated with improvements in memory.”

RESEARCH

Sorghum aids 3D food printing

University of Arkansas researchers have demonstrated that sorghum proteins provide a resilient base for 3D food printing, which has demonstrated fast-expanding applications in the design of alternative food products, according to an article published this year in the International Journal of Biological Macromolecules. The article’s authors, Sorour Barekat and Ali Ubeyitogullari, point out that it’s challenging to develop plant protein bio-inks with accurate printability (the bio-ink’s ability to maintain its shape and layers without gaps). Printability is influenced by the bio-ink’s formulation, rheology, gelatinization properties, microstructure, thermodynamic properties, crystallinity, and so on.

In this study, the researchers formulated gels with varying concentrations of sorghum protein, concluding that gels with 25% sorghum protein showed the best 3D printability. The hydrophobicity of sorghum proteins (their ability to repel water) helps with product cohesion.

“So far, most of the efforts in research on proteins for 3D food printing have been on hydrophilic proteins, and there has been a need for new hydrophobic proteins that are ideally from cost-effective and sustainable protein sources for 3D printing,” explained Ubeyitogullari, an assistant professor of food engineering with the University of Arkansas Food Science and Biological and Agricultural Engineering Departments, quoted in an article on the university’s website.

Sorghum, a gluten-free grain with unique phenolic compounds, is relatively inexpensive compared to other crops and is an appealing protein source due to its reputed health-promoting benefits, such as inhibiting inflammatory responses and reducing cholesterol levels.ft