Research on donkey milk · Study 80

Protein in a tiny bubble: donkey milk in nanoliposomes

A Serbian-Slovenian team tested in the laboratory how much protein from skimmed donkey milk can be encapsulated in tiny fat bubbles, so-called nanoliposomes.

Important: A formulation study in the laboratory. All that was measured was how much protein was encapsulated – no tests on the skin, on cells or on humans and no statement about an effect.

0per cent encapsulation rate with 10 % donkey milk solution (laboratory value)

Year · country2017 · Serbia and Slovenia

MaterialSkimmed donkey milk, 1, 2, 5 and 10 % in water

DesignFormulation experiment in the laboratory

MeasureEncapsulation rate of the proteins (Lowry method)

Three terms first

What was measured here?

NanoliposomeA tiny bubble whose envelope consists of phospholipids – fat-like molecules with a water-loving head and a fat-loving tail. Inside, it can take up dissolved substances.

Encapsulation rateShare of the protein that is no longer dissolved in the supernatant after centrifugation and is therefore assigned to the bubbles.

Total − supernatantTotal× 100

Lowry methodA classic colour test for determining the amount of protein in a solution. It does not distinguish which protein is being measured.

Experimental protocol · runs automatically

Four steps against the clock

DissolveSkimmed donkey milk was made up in water into 1, 2, 5 and 10 per cent solutions.
Mix 1 : 2Each solution was added in a ratio of 1 : 2 to a 1 per cent nanoliposome solution. The paper does not say which part is the 1 and which the 2.
2 hours in the ultrasonic bathLeft to swell at room temperature so that the bubbles load up with the solution.
Centrifuge & measurement6,500 revolutions per minute at 4 °C – the paper does not state the duration. Then protein in the supernatant determined according to Lowry.

Result · choose a concentration

Where does the protein go?

Encapsulation rate per concentration

For 1, 2 and 5 %, the paper gives a common value (“about 83.5 %”). According to the figure, 10 % differed from this with p < 0.001. Standard deviations and the number of replicates are not given. The supernatant share is calculated (100 % minus encapsulation rate).

Critical assessment · tap the layers

Six filter layers: what the study does not show

Possible conclusions rain down from above. Each layer holds back one that the paper does not support. What arrives at the bottom is what was actually measured.

What gets throughIn the laboratory, depending on concentration, about 83.5 % or 88.9 % of the measured protein was not found in the supernatant and was assigned to the nanoliposomes. The study shows no more than that.

Level of evidenceFormulation experiment in the laboratory (in vitro), without cells, animals or humans. Describes a technical property, not an effect.

Editorial assessmentThe authors see possible applications in dermatology and cosmetics. This was not examined – we do not adopt it. Same first author as Study 32.

Research question for DON DONKEY’S®

Which proteins from donkey milk end up in the bubble – and which stay outside?

The Lowry method measures only the total amount. Whether lysozyme, lactoferrin or caseins are encapsulated differently remains open. We are watching whether follow-up studies record the individual proteins separately and describe their methods completely.

Compare with Study 32 (same first author)Compare with Study 30 (skin model)Measure individual proteins

Original publication

Nanoliposome Encapsulation with Donkey Milk Bioactive Proteins and Its Possible Application in Dermatology and Cosmetics

Original title. The applications named were not examined in the study.

Kocić H., Stanković M., Arsić I.
Acta Facultatis Medicae Naissensis · 2017 · volume 34, issue 3, pp. 199–204 · open access
Faculty of Medicine, University of Maribor (Slovenia); Faculty of Medicine, University of Niš, Department of Pharmacy (Serbia)

DOI: 10.1515/afmnai-2017-0021

Transparency: the paper contains no information on funding or conflicts of interest. 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

End of the study summary

Note on our products

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.

Transparency: The study used skimmed donkey milk of unstated origin for a laboratory experiment – not the milk of our partner farms. Our donkey milk is a food, not a cosmetic.

€24,90

100 ml bottle / 100ml · Unit price: €249,00 / 1 l · incl. VAT, plus shipping

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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.

Transparency: The study used skimmed donkey milk of unstated origin, not our donkey milk powder.