Neolithic ceramics reveal dairy processing from milk of multiple species

A new study has found evidence of cheesemaking, using milk from multiple animals in Late Neolithic Poland.

The research suggests that early farmers reduced the lactose content in milk by making it into cheese or other dairy products like yoghurt, and used dairy products from a number of different animals, such as cows, sheep or goats.

Lactose intolerance was a common condition in almost everyone in Europe during the Neolithic and until the Late Bronze Age when the genetic mutation became widespread, enabling adults to produce lactase, the enzyme which breaks down lactose in the body.

Researchers looked at the practice of dairy processing in the Late Neolithic, identifying high curd-content residues in pottery indicating cheesemaking, and revealing that multiple dairy species were utilised.

Dr Harry Robson, from the Department of Archaeology at the University of York, said: "These results contribute significantly to our understanding of the use of dairy products by some of the earliest farmers of Central Europe.

"Whilst previous research has shown that dairy products were widely available in some European regions during this period, here, for the first time, we have clear evidence for a diversified dairy herd, including cattle, sheep and goats, from the analysis of ceramics."

The scientists and archaeologists from the Universities of York, Cambridge, Toru? and Kraków used a multi-stranded proteomic and lipid-analysis approach to investigate ceramics and deposits on their surface, from the site of S?aw?cinek in central Poland.

The new development provides evidence that cheesemaking (and other curd-enriching dairy processing) can be directly detected by scrutinising the proportion of curd proteins, by comparing proteomic data. The results are also the first of their kind in Europe.

Despite widespread lactose intolerance in the period, there is evidence of dairy being consumed during the Neolithic, such as animal bones with kill patterns expected for dairy herds, dairy lipids in ceramic vessels, and dairy proteins in ancient dental calculus or plaque.

Lead author, Miranda Evans, PhD student at Cambridge's Department of Archaeology, said: "The proteomic results showed that the ancient residues closely resembled both the modern cheesemaking residues and cheese itself and not whole milk. This reveals that the people of S?aw?cinek practised cheesemaking or another form of curd-enriching dairy processing."

Evidence of multiple species used for cheesemaking was backed up by the presence of both cow and sheep or goat bones on the site."

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Ceramics that breathe oxygen at lower temperatures help us breathe cleaner air

Although much of the discourse on reducing vehicle emissions centres on electric vehicles (EV), their sales remain low -- with EV vehicles accounting for a mere 1% of car purchases in Japan in 2021. Meanwhile, the European Union is expected to pass stricter emission standards in the near future. This makes improving the performance and functionality of exhaust gas purification catalysts in petrol or diesel-powered vehicles a critical component in the push towards carbon neutrality.

Nearly all petrol or diesel cars are equipped with catalytic converters that remove harmful hydrocarbons, carbon monoxide and nitrogen oxide and convert them into safer gases such as nitrogen, carbon dioxide and water vapor. The toxic gases flow through a honeycomb structure, coated with exhaust gas purifying catalysts.

Ceramics with an oxygen storage capacity (OSC) play a crucial role in the purification process. They help remove noxious gases and prevent the precious metals in catalytic converters from coarsening, which degrades their purification capabilities.

To improve their potential, however, a lower operating temperature is required. But scientists have struggled to achieve this since reducing the temperature to less than 500 ºC results in slower ion diffusion.

Now, a research group at Tohoku University's Graduate School of Engineering has developed a Cerium-Zirconium-based (Ce-Zr) oxide with excellent OSC at 400 ºC by controlling its crystal structure. The OSC at 400 ºC was higher than conventional materials by a factor of 13.5, even without precious metal catalysts.

"The key to our success was introducing a tiny amount of transition metals, such as iron, to the Ce-Zr-based oxides," said Professor Hitoshi Takamura, leader of the research group.

The 'transition metal doping' had two notable effects in the oxides. It accelerated the oxygen diffusion by easing the formation of oxygen vacancies and promoted cation ordering.

"Cation ordering tidies up the crystal structure and makes oxygen readily released," explained Takamura.

The iron doping reduced the cation-ordering temperature, which in turn enabled a larger surface area for the Ce-Zr-based oxides. This enhanced their durability and ability to purify toxic gases.

In the future, Takamura and his group hope to test the material by loading it with palladium on honeycomb supports.

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