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Research on donkey milk · Study 99
Lipids and aroma compounds: colostrum vs. mature donkey milk
In milk from Dezhou donkeys, 1774 lipids and 35 volatile compounds were recorded. Between colostrum (day 3) and mature milk (month 3), 233 lipids and 11 volatile compounds differed significantly.
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The key figures
Study design
How it was studied
Milk samples from twelve Dezhou jennies (3–5 years, 260–340 kg) on a farm in Shandong, China, were examined: six samples of colostrum (3 days after birth) and six samples of mature milk (3 months after birth). All animals received the same ration. The lipids were extracted with chloroform/methanol and relatively quantified by UPLC-Orbitrap mass spectrometry; volatile compounds (VOCs) were determined by gas chromatography–ion mobility spectrometry (GC-IMS) with an internal standard. The analysis included OPLS-DA, metabolic pathway analyses, odour activity values (OAV) and ROC analyses to distinguish the two lactation stages.
Interactive chart · values from the study
Identified lipids by main category
Shares of the number of lipid molecules identified (Table 1), not of the amount of lipid.
Second analysis
Volatile compounds differing significantly
Means ± SEM (n = 6) from Table 2; M/D = monomer/dimer signal of GC-IMS. Acetone (5292.26 vs. 3479.42) not shown because of its different order of magnitude.
Results
What the study measured
In total, 1774 lipid molecules from six main categories and 30 subclasses were identified. By number, triglycerides dominated (61.95 %), followed by diglycerides (7.67 %), phosphatidylcholines (6.09 %), phosphatidylethanolamines (5.19 %) and sphingomyelins (4.62 %).
Colostrum and mature milk separated clearly in the OPLS-DA model. 233 lipids differed significantly: 136 were lower in mature milk (including 67 triglycerides, 15 phosphatidylethanolamines, 13 diglycerides), 97 higher (including 82 triglycerides).
The differing lipids were assigned to 20 KEGG metabolic pathways; the authors named glycerophospholipid, linoleic acid, sphingolipid, α-linolenic acid and glycerolipid metabolism as the most relevant.
Of the 35 volatile compounds recorded, 28.57 % each were aldehydes and ketones, 25.71 % esters and 8.57 % alcohols. Ketones made up the largest share by quantity; 15 compounds had an odour activity value above 1, including methyl 2-methylbutanoate, 2-pentanone and butyl acetate.
Eleven volatile compounds differed significantly. Ethyl hexanoate, both ethyl acetate signals and acetone were higher in mature milk (acetone 5292.26 vs. 3479.42), while 2-heptanone, 2-pentanone, 2-butanone-M and 3-methyl-3-buten-1-ol were higher in colostrum.
In the principal component analysis of the volatile compounds, the two stages separated (first component 84.1 %, second 8.1 %). Acetone, 2-heptanone and ethyl acetate reached an area under the curve above 0.9 in the ROC analysis and are named as possible discrimination markers.
Authors’ conclusion: In the view of Li et al. (2024), the lipid and aroma profiles of donkey milk differed clearly between colostrum and mature milk; 233 of the 1774 lipids and 11 volatile compounds were different, and in their view acetone, 2-heptanone and ethyl acetate were suitable as possible markers for distinguishing the lactation stages. The authors saw this as basic information for the quality assessment of donkey milk; health effects were not examined.
Critical assessment
Strengths and limitations
Only six samples from one farm were examined per stage, and according to the methods section, colostrum and mature milk came from different animals. Differences between the stages may therefore also be due to individual animals.
The lipids were quantified only relatively via peak areas; the percentages refer to the number of molecules, not their amount. No unit is given for the concentrations of the volatile compounds.
The 35 volatile compounds include monomer and dimer signals of the same substance and three unidentified signals; by our editorial count of Table 2, this corresponds to 26 entries, 23 of them identified substances.
The highlights mention nine metabolic pathways, the abstract and results 20. The abstract names ethyl acetate-M as a marker, the results ethyl acetate-D. Higher OAVs for octanal and hexanal in mature milk are described as significant, although their concentrations in Table 2 are not significantly different (p = 0.2430 and 0.1540).
The authors’ statements about a sweeter taste of mature milk are not based on a sensory test, and the presumed importance of phosphatidylethanolamines for foal development was not examined. Effects in humans were not the subject of the study.
The combination of high-resolution lipidomics and GC-IMS provides an extensive profile. The OPLS-DA model was checked with a permutation test, and Table 2 documents all volatile compounds with means and p-values.
Editorial assessment: The study describes analytically which lipids and volatile compounds can be detected in raw milk from Dezhou donkeys and how they differ between two lactation stages. No direct conclusions about taste, effects or individual commercial products can be drawn from it. To the research archive.
Research question for DON DONKEY’S®
Which lipids and volatile compounds does donkey milk contain, and how do colostrum (day 3) and mature milk (month 3) differ in these profiles?
Original publication
Characterization and discrimination of donkey milk lipids and volatiles across lactation stages
Original title of the publication.
Li M., Sun L., Du X., Zhao Y., Ren W., Man L., Zhu M., Liu G., Khan M.Z., Wang C.
Food Chemistry: X · 2024 · 23, 101740
School of Agriculture and Biology, School of Materials Science and Engineering, Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, Liaocheng University, Liaocheng, China
10.1016/j.fochx.2024.101740: 10.1016/j.fochx.2024.101740
Transparency: National Key Research and Development Program of China (2022YFD1600103, 2023YFD1302004), Shandong Provincial Natural Science Foundation (ZR2022QC130), Shandong Province Modern Agricultural Technology System Donkey Industrial Innovation Team (SDAIT-27), Support Program for Innovation and Technology in Universities of Shandong Province (2023KJ354), Key Technology Research and Development Program of Shandong (2021TZXD012) and Innovation and Entrepreneurship Training Program for College Students (CXCY2024273). The authors declare no competing financial interests or personal relationships that could have influenced the work. 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.
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