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Research on donkey milk · Study 65
The envelope of fat droplets: membrane proteins in donkey and human milk
Every fat droplet in milk is surrounded by a wafer-thin membrane containing hundreds of proteins. A Chinese team compared these membrane proteins in donkey and human milk.
Interactive · Basics
How a milk fat globule is built
- Fat coreMainly triglycerides – the actual milk fat.
- Inner envelopeA single lipid layer that already surrounds the droplet in the gland cell.
- Outer bilayer membraneTaken along when leaving the cell – this is where many membrane proteins sit.
- Sugar chains on the outsideCarbohydrates on proteins and lipids project outwards.
Schematic, not to scale. Together, the three envelope layers are called the MFGM (milk fat globule membrane).
Experimental setup · runs automatically
From milk droplet to protein list
The result
454 proteins, 293 differences
One dot = one protein. A protein counted as different if its amount was at least double or half at p < 0.05 – or if it was detectable in only one of the two milks.
Key findings · tap the bubbles
Eleven pathways, notably enriched
- Proteins
- Enrichment
- p-value
Named
Which proteins were more abundant in which milk
Top, yellow: more abundant in the donkey milk membrane – including all four caseins, lysozyme, osteopontin (SPP1) and several apolipoproteins. Bottom, purple: more abundant in human milk, such as lipoprotein lipase and the fatty acid-binding protein FABP3. Hover with the mouse or hold with a finger to pause.
Critical assessment
Six warning lights for this study
Interests
Eight authors were employed by a Chinese manufacturer of donkey-hide products.
Stage of lactation
Donkey milk from the 4th–5th month, human milk from the 6th–8th month – not matching.
Pooled samples
12 samples each, combined into four pooled samples. The number of independent replicates remains unclear.
Caseins in the membrane
Many of the “membrane proteins” in donkey milk are caseins – carried-over milk proteins are possible with this method.
No cow’s milk comparison
The authors themselves name this as a limitation of their study.
Method
Established mass spectrometry, clearly defined thresholds, raw data processing described comprehensibly.
Editorial assessment: The authors see donkey milk as a possible building block for infant formula. This was not examined. Donkey milk is not a substitute for breast milk or infant formula. Same research group as Study 64.
Research question for DON DONKEY’S®
What happens to the fat envelope during freezing?
The membrane of fat droplets is sensitive to cold and processing. How well it survives deep-freezing or drying has hardly been studied for donkey milk – a question we are following up.
Original publication
Quantitative Label-Free Proteomic Analysis of Milk Fat Globule Membrane in Donkey and Human Milk
Original title of the publication.
Zhang X., Jiang B., Ji C., Li H., Yang L., Jiang G., Wang Y., Liu G., Liu G., Min L., Zhao F. et al.
Frontiers in Nutrition · 2021 · volume 8, article 670099 · open access
Dong-E E-Jiao Co., Ltd., Shandong and Qingdao Agricultural Universities, Liaocheng University, Beijing Academy of Agriculture and Forestry Sciences (China)
Transparency: funded by programmes of Shandong Province and the Beijing Academy of Agriculture and Forestry Sciences. Eight authors were employed by a Chinese manufacturer of donkey-hide products. No product-related statement for DON DONKEY’S®.
Summarised and reviewed by the DON DONKEY’S editorial team on the basis of the original publication · as of October 2026
The study summarised above was carried out independently of DON DONKEY’S® and does not relate to our products. It serves solely to inform about the state of research.
DON DONKEY’S® donkey milk and donkey milk powder are foods. They are not intended to prevent, treat or cure any disease and do not replace medical advice.
From our shop
DON DONKEY’S® donkey milk
100 % donkey milk · raw milk, frozen
On this page we report the findings of a published study. Independently of that, you will find our donkey milk here: 100 % donkey milk, frozen as raw milk.
100 ml bottle / 100ml · Unit price: €249,00 / 1 l · incl. VAT, plus shipping
Also in our shop
Donkey Milk Powder
Donkey milk in powder form
For anyone who prefers a longer shelf life: our donkey milk in powder form – easy to store and portion.
20g · Unit price: €1.245,00 / 1 kg · incl. VAT, plus shipping