The team, led by Mariya Antonosyan of the Max Planck Institute for Geoanthropology together with Anahit Hovhannisyan and colleagues, analyzed dental calculus from 77 individuals excavated at 22 archaeological sites across Armenia, spanning the Late Neolithic to the Middle Ages. Dental calculus, the mineralized bacterial biofilm that accumulates on teeth, acts as a remarkable time capsule. As it forms during life, it traps fragments of proteins from everything a person ate, preserving them for millennia in a protective mineral matrix. Using liquid chromatography-tandem mass spectrometry, the researchers extracted and identified these ancient proteins, screening each sample against a curated database of oral and contaminant proteins to ensure that only well-preserved, authentic samples were analyzed.

Of the 77 samples, 60 showed well-preserved oral signatures, indicating their suitability for dietary analysis. Within this group, dairy peptides were identified in 16 individuals from nine sites. The overwhelming majority of these milk proteins were beta-lactoglobulin, a major whey protein found in ruminant milk, detected in 14 samples, while beta-casein appeared in two others. Crucially, some peptides allowed the researchers to identify the species of origin: seven peptide matches pointed to goat milk, four to cattle, and four to sheep, with a larger group of 55 matches that could not distinguish between sheep and cattle. This taxonomic resolution is what transforms a simple detection of milk into a nuanced picture of ancient herd management and dietary choice.

The chronological pattern that emerged is striking. The earliest individual in the study, an adult male aged 45 to 60 from the Late Neolithic site of Masis Blur, showed no direct evidence of milk consumption, nor did any of the Early Bronze Age individuals associated with the Kura-Araxes cultural complex. The earliest direct evidence of milk drinking in the Armenian dataset comes from the Middle Bronze Age, around the 2nd millennium BCE, when all four individuals analyzed, buried at the high-altitude sites of Sotk-2 and Sotk-10 near Lake Sevan, carried milk proteins in their calculus. From that point onward, milk consumption persisted continuously through the Late Bronze, Iron, Classical, and Medieval periods, with both the intensity of consumption and the diversity of exploited animals increasing over time.

Geography mattered as much as chronology. Milk proteins were recovered predominantly from high-altitude sites situated above 1,500 meters above sea level. Among prehistoric individuals with confirmed protein preservation, all seven who yielded dairy peptides came from sites above 1,600 meters, while six individuals from lowland sites showed no milk signal at all. The researchers suggest that milk may have functioned as an adaptive resource in harsh highland environments, where crop cultivation was difficult and livestock offered a reliable source of hydration and nutrition without the need to slaughter valuable animals. A parallel pattern has been observed on the Tibetan Plateau, where ancient milk proteins were found only at high-elevation sites beyond the limits of agriculture. Yet the relationship is not straightforward: seven high-altitude individuals from the Iron Age and Medieval periods passed preservation screening without yielding dairy proteins, indicating that elevation alone cannot explain the mosaic of dietary preferences across landscapes and centuries.

The genetic side of the study tells an equally compelling story. Adult digestion of lactose, the sugar in milk, depends on lactase persistence, a trait controlled by regulatory variants near the LCT gene. The team screened five known lactase persistence-associated variants in 158 modern Armenian individuals and found only the European variant, 13910C>T, at a modest frequency of roughly 6 to 8 percent. The other four variants, including the 13915T>G allele that predominates in the Near East just to Armenia’s south, were entirely absent. This finding resolves previously conflicting estimates for Armenians, which had ranged from 2.7 to 18 percent, and highlights the population’s distinctive genetic position at the crossroads of Europe and the Middle East.

Ancient DNA screening added a temporal dimension to this genetic picture. After imputing lactase genotypes in published ancient genomes from Armenia, the researchers directly examined sequencing reads covering the rs4988235 position using stringent filtering criteria designed to guard against false positives, a critical safeguard because the C>T transition at this site mimics characteristic ancient DNA damage patterns. The earliest confirmed carrier of the derived allele in Armenia dates to the Late Urartian period, around 680 to 550 BCE, approximately 3,000 years ago. Results for eight other samples, including Early Bronze Age specimens, could not be confirmed and may represent imputation artifacts. The confirmed appearance of the allele post-dates a documented Late Bronze and Iron Age genetic influx into the region, suggesting the variant may have been introduced through population interactions rather than arising locally.

Placed side by side, the proteomic and genetic data reveal a profound mismatch. Dairying in the South Caucasus intensified from at least the Middle Bronze Age onward, sustaining mobile pastoral communities, highland herders, and eventually the elite of medieval burial complexes, yet lactase persistence never became widespread in the population. The authors argue that cultural and dietary strategies, rather than genetic adaptation, were the key enablers of milk consumption. Fermentation into products such as matsun, Armenia’s traditional yoghurt, along with cheese-making and the mixing of milk with grains and other foods, reduces lactose content and allows lactose-intolerant people to benefit from dairy without discomfort. Armenia’s rich fermented dairy cuisine, which persists today, may itself be a living legacy of this ancient workaround.

The study also uncovered intriguing social dimensions. In the Late Classical period, individuals from the Odzaberd site displayed the earliest evidence of goat milk consumption in the assemblage, with some showing diversified profiles spanning sheep, goat, and cattle milk, possibly reflecting mixed herding practices or access to trade networks. In the Medieval Aghtsg burial complex, dairy proteins were detected exclusively in two individuals interred in sarcophagi, markers of elevated social status, hinting at preferential elite access to milk, although better preservation conditions inside sarcophagi cannot be ruled out. Meanwhile, the absence of horse milk proteins in the South Caucasus, despite their identification in the neighboring North Caucasus steppe, suggests that horse milking may have been a specifically steppe-based adaptation of mobile horse-reliant groups.

The researchers caution that absence of evidence is not evidence of absence: missing milk proteins may reflect sampling bias, small sample sizes, or individual dietary choices rather than a true lack of consumption. Only one Late Neolithic individual and no Chalcolithic individuals from Armenia were available for analysis, leaving the earliest chapters of the region’s dairy history open. Future work combining larger sample sets, ceramic residue analysis, and stable isotope studies of human bones and teeth promises to refine the picture. Even so, this first integrated genetic and palaeoproteomic reconstruction for a single region across such a wide temporal span delivers a powerful message: for six millennia, the people of the Armenian highlands drank their milk on their own cultural terms, and their genes never needed to catch up.

Subject of Research: Millennial-scale dairy consumption and lactase persistence in ancient Armenia

Article Title: Palaeoproteomic and genetic insights into millennial-scale dairy consumption in Armenia

Article References: Antonosyan, M., Hovhannisyan, A., Roberts, P., Cassidy, L. M., Mkrtchyan, S., Simonyan, H., Bobokhyan, A., Aghikyan, L., Piliposyan, A., Badalyan, R., Yeranyan, N., Gnuni, A., Avetisyan, H., Badalyan, M., Gabrielyan, A., Sarkisian, N., Grigoryan, A., Simonyan, H., Safaryan, M., … Wilkin, S. (2026). Palaeoproteomic and genetic insights into millennial-scale dairy consumption in Armenia. iScience, 29(11), Article 117829. https://doi.org/10.1016/j.isci.2026.117829

Image Credits: AI Generated

DOI: 10.1016/j.isci.2026.117829

Keywords: palaeoproteomics, dental calculus, dairying, lactase persistence, ancient DNA, Armenia, South Caucasus, Bronze Age, fermented dairy, matsun, beta-lactoglobulin, highland pastoralism

The core challenge the researchers set out to solve is a molecular conflict of interest. Egg white is packed with high-quality proteins — ovalbumin, ovotransferrin, ovomucin and others — that gel, foam and emulsify beautifully, making it an attractive textural modifier for dairy products. But egg white also contains lysozyme, a potent antibacterial enzyme that cleaves the β-1,4 glycosidic bonds in bacterial cell wall peptidoglycan. That is excellent news for food preservation and terrible news for yogurt starters, which rely on Gram-positive lactic acid bacteria — Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus — to ferment lactose into lactic acid. Adding raw egg white to yogurt milk risks sabotaging the very organisms the fermentation depends on.

The team, led by Yunxiao Xie and Fang Geng, applied a pretreatment strategy they had developed in earlier work, abbreviated UHSD: liquid egg white is first blasted with 20 kHz ultrasound in pulsed mode for ten minutes while kept cold, then heated in a water bath at 72 °C for ten minutes, and only then spray-dried into a powder. The ultrasound cavitation and mechanical shear unfold protein aggregates, and the subsequent moderate heating promotes controlled aggregation and disulfide exchange between lysozyme and other egg white proteins. When the researchers measured apparent lysozyme activity using Micrococcus lysodeikticus cells as a substrate, the results were striking. Fresh egg white showed an apparent activity of 5660 U/mg. Conventional spray drying alone cut that by 54.6 percent, but the full ultrasound–heat–spray-drying sequence reduced it by 90.3 percent — a dramatic taming of the antibacterial enzyme while keeping the functional proteins largely intact.

With the pretreated powder in hand, the researchers formulated yogurts in which the powder partially replaced milk at 0, 1, 2 and 4 percent by mass, heat-treated the mixes at 72 °C for 30 minutes, inoculated them with a commercial two-strain starter, and fermented for ten hours. Every batch set into a stable gel with no visible whey separation, and all samples met the Chinese national standard minimum titratable acidity of 60 °T for fermented milk. Color measurements showed the supplemented yogurts became progressively lighter, with reduced red and yellow components — a subtle whitening effect that could be commercially appealing. Texture analysis, however, revealed a dose-dependent trade-off: hardness was unchanged at 1 and 2 percent addition but dropped significantly at 4 percent, and springiness peaked at the 1 percent level before falling at the highest dose.

The structural story behind those numbers emerged from microscopy and rheology. Scanning electron micrographs of freeze-dried yogurt showed that the control gel was relatively loose, with large pores, while the egg white-supplemented samples displayed progressively smaller gel particles and a more uniform, compact three-dimensional network — most pronounced at 4 percent. Rheological testing showed all samples were shear-thinning pseudoplastic fluids, but apparent viscosity shifted upward with increasing powder addition, and both the storage modulus G′ and loss modulus G″ rose across the frequency range, with G′ consistently exceeding G″, confirming elastic, weak-gel behavior throughout. In short, the egg white proteins were genuinely participating in the acid-induced casein network, cross-linking the gel and stiffening its response to deformation.

Yet a denser microstructure did not translate into proportionally better macroscopic performance. The 1 percent group achieved the highest water-holding capacity, significantly above all other groups, while the 4 percent group showed no advantage over the control, which held 64.3 percent of its water. The explanation lies in acidification. At 4 percent addition, the final pH rose by 2.3 percent relative to the control’s 4.38, and titratable acidity fell by 4.4 percent to 93.8 °T. Because yogurt gelation depends on acid gradually neutralizing the electrostatic repulsion between casein micelles as pH approaches their isoelectric point, a weaker fermentation slows and shallows that aggregation. The powder partially replaced milk, so the higher pH also reflects altered buffering and substrate availability — and the authors are careful to note that their design cannot separate the effect of added protein and solids from the specific contribution of the ultrasound–heat pretreatment itself, since a conventional spray-dried powder control was not included.

The most novel part of the study is its use of metatranscriptomics — sequencing the expressed RNA of the entire microbial community — to see how the starter cultures actually responded. From nine samples across the control, 1 percent and 4 percent groups, the team generated over 608 million raw reads, averaging roughly 7.77 gigabases per sample with Q30 quality scores above 95.7 percent. After removing ribosomal RNA, assembling transcripts de novo and annotating predicted proteins against the NR, KEGG, eggNOG and CAZy databases, they found that Bacillota transcripts dominated at over 98 percent in every group, with Streptococcus thermophilus and Lactobacillus delbrueckii as the core expressed species — exactly the signature of a healthy yogurt ferment. Ordination analyses showed the control clearly separated from both supplemented groups in transcriptional space.

The functional annotations told a coherent story. In the 4 percent group, transcript abundance assigned to glycolysis/gluconeogenesis, pyruvate metabolism and carbon metabolism all declined, consistent with the observed higher pH and lower acidity — the bacteria were transcribing fewer genes for lactose breakdown and lactic acid production. Carbohydrate-active enzyme genes showed the same pattern: glycoside hydrolase transcript abundance in the 4 percent group fell to about 48.7 percent of control levels, and glycosyltransferases to about 41.1 percent. Meanwhile, LEfSe analysis flagged lactic acid bacteria taxa such as Lactobacillaceae as differential in the 1 percent group, whereas the 4 percent group showed relatively higher representation of low-abundance, non-core taxa — possibly because the weakened acidification relaxed the selective pressure that normally suppresses non-yogurt microbes, and possibly because residual lysozyme, to which Gram-negative bacteria are more tolerant, subtly shifted the competitive balance. The authors stress that transcript abundance is not direct evidence of altered enzyme activity or metabolite concentrations, and that enzyme assays and metabolomics would be needed for confirmation.

The practical takeaway is a dose window rather than a free pass. At around 1 percent, the pretreated egg white powder delivered the best overall package: the highest springiness, the best water retention, a more compact gel network and a microbial community whose transcriptional profile remained firmly lactic-acid-bacteria dominated. At 4 percent, the same powder produced a visually denser network but softer texture, weaker acidification and a transcriptional drift toward non-core taxa. For an industry eager to boost protein content and improve texture with clean-label ingredients, that distinction matters enormously. The study also demonstrates the power of metatranscriptomics as a quality-control lens for fermented foods: instead of merely counting microbes, it reveals which metabolic programs are actively running, catching functional shifts that pH and texture measurements alone could only hint at. Future work with composition-matched controls will need to isolate what the ultrasound–heat pretreatment itself contributes, but the concept — defusing egg white’s antibacterial arsenal while enlisting its gelling proteins — now has both a physical and a molecular evidence base.

Subject of Research: Effects of ultrasound–heat pretreated egg white powder on yogurt quality, gel properties and microbial metatranscriptomic profiles

Article Title: Effects of ultrasound–heat pretreated egg white powder addition on the quality, gel properties, and metatranscriptomic profiles of yogurt

Article References: Xie, Y., Wang, X., Shui, Y., Hu, G., He, H., Wang, J., & Geng, F. (2026). Effects of ultrasound–heat pretreated egg white powder addition on the quality, gel properties, and metatranscriptomic profiles of yogurt. Food Chemistry: X, 39, Article 104550. https://doi.org/10.1016/j.fochx.2026.104550

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104550

Keywords: yogurt, egg white powder, ultrasound, lysozyme, gel properties, metatranscriptomics, lactic acid bacteria, food texture, spray drying, water-holding capacity, rheology, fermented dairy