History
Donkey milk has been used by humans for alimentary and cosmetic purposes since Egyptian antiquity; doctors recommended it to treat several afflictions, due to its healing and cosmetic virtues.Production
The donkey is considered a seasonal polyestrous one, but the latitude in which the farm is located can greatly influence the reproduction cycle. The female is normally pregnant for about 12 months. Donkey milk production differs greatly from that of conventional dairy species, especially in terms of milk supply which is much more limited. The equid mammary gland has a low capacity (max 2.5 L) and a part of the milk production should be left to the foal and milking may be carried out two or three hours after separation from the foal. Donkeys should be milked three times a day from 20 to 90 days after foaling. A female gives between 0.5 and 1.3 litres of milk a day for about 6–7 months. The variability of donkey milk production is due to many factors, such as individual milkability, nutrition, genetics, management of reproduction, etc., in addition to milking management. Generally, a donkey farm (breeding), aimed at milk production is small, with some tens of heads and rarely more. In Europe, and specifically in Emilia Romagna (Italy) there is only one very large donkey farm with 800 head.Composition
Gross composition
Published data on donkey milk gross composition confirm the closer resemblance to breast milk for lactose, protein and ash levels when compared with cow, sheep and goat milk. Despite the high lactose content of donkey milk the average fat content is lower for this purpose. When used in infant nutrition, donkey milk is usually supplemented with vegetable oil (4 mL 100 mL−1 milk) to conform to human milk energy. The casein to whey protein ratio in donkey milk was lower compared to the value on cow milk. The non-protein nitrogen (NPN) accounts for an average of 16% of total nitrogen in donkey milk, is much closer than values reported for human milk (20%) but higher than those of domestic ruminants (5%). The amino acid profile of the donkey milk proteins shows a very similar percentage of essential amino acids (36.7 e 38.2 g amino acid /100 g protein) than in human milk proteins (40.7 g amino acid /100 g protein), according to Guo et al.Functional and bioactive components
Among the functional proteins detected in donkey milk, there are molecules active in antimicrobial protection such as lysozyme and lactoferrin. The lactoferrin content of donkey milk is intermediate between the lower values of cow milk and the higher values of human milk. Lactoferrin inhibits the growth of iron-dependent bacteria in the gastrointestinal tract. This inhibits certain organisms, such as coliforms and yeast, that require iron. Lysozyme in donkey milk is present in large amounts, indeed ranges from 1.0 mg/mL to 4 mg/mL, depending on the analytical method used (chemical or microbiological); this substance is present also in human (0.12 mg/mL) but only in trace amounts in cow and goat milk. Lysozyme in donkey milk is highly thermo-stable and is very resistant to acid and protease and may play a significant role in the intestinal immune response. In donkey mammary secretion, defatted or not, growth factors and hormones have also been determined. In detail, donkey mammary secretions contain human-like leptin at levels close to human milk (3.35 e 5.32 ng/mL milk). The bioactive peptides insulin like growth factor 1, ghrelin and triiodothyronine were also found in frozen donkey milk. These molecules, and many others present in human milk, are increasingly receiving attention from a nutraceutical point of view because of their potential direct role in regulating food intake, metabolism, and infant body condition.Nutritional use
Natural hypoallergenic milk for infants with cows’ milk protein allergy
Pasteurized donkey milk is used as a natural hypoallergenic milk, because it is tolerated by about 90% of infants with food allergies, e.g., cows’ milk protein allergy (CMPA), a common food allergy in childhood with a prevalence of approximately 3% during the first 3 years of life. However the infants tolerance of donkey milk must be evaluated first subjectively, under medical supervision and after carrying out specific allergy tests. As natural hypoallergenic formula it is preferred over those of soy or produced from protein hydrolysates because has a pleasant taste and does not cause allergies in some people who also have allergic reactions to soy proteins or protein hydrolysatesNatural infants "formula"
Donkey's milk is similar to human milk for its lactose, proteins, minerals, amino-acid content. In terms of energy despite the high lactose content of donkey milk the average fat content is lower if used predominantly before weaning. When used in infant nutrition before weaning, due to its low fat content to mimic breast milk, like all infant formulas, donkey milk should be integrated with a source of fat particular attention must also be given to essential fatty acids. Omega‐3 and omega‐6 fatty acids, particularly docosahexaenoic acid (DHA), are known to play an essential role in the development of the brain and retina. Intakes in pregnancy and early life affect growth and cognitive performance later in childhood,ensuring adequate intakes of fat, essential fatty acids and especially DHA through these life stages is crucial, cost effective dietary sources of these fatty acids are needed to ensure adequate essential fatty acid and DHA intakes in these populations. The integration of these substances can take place with supplements of essential fatty acids (omega-3; omega-6) and vegetable oil certified for babies; this aspect is important to exclude the presence of spores that can pass the gastric mucosa in the first 4 months. For children who are not allergic to cow or goat milk, a part of fat can be compensated naturally by adding 1-2% of cow or goat butter. In any case, the integration of fats and essential fats can be done through the integration of donkey milk with artificial formulas for infants. From the point of view of hygienic-sanitary safet, like all milks, donkey milk and its ingredients must be pasteurized before taking; the process of pasteurizing donkey milk deactivates bacterial and viral contaminants. Donkey milk contains immune-enhancing compounds (in particular lysozyme and lactoferrin) to help protect infants from disease. In addition, the flavour and appearance of donkey milk have been found to be attractive to children.Diet supplement
Donkey’s milk is recommended for countering stomach acid, promoting the growth of intestinal flora, calming coughs and pertussis (a.k.a. whooping cough), and for use in the treatment of immune-mediated disordersCommercial forms
Raw donkey milk
Donkey milk milked and cooled. According to European legislation, like all milks of animal origin, it must be pasteurized before being used. It can be kept for 3 days at refrigerator temperature. It is possible to freeze it for 2–3 months to extend its shelf life. In any case, it must be pasteurized and consumed before usePasteurized donkey milk
Donkey milk is pasteurized in a closed circuit of pasteurization and bottling (aseptic) at at least 72 °C for 15 seconds or equivalent times and temperatures. In case of pasteurization in discontinuous systems, the temperature must be higher depending on the method used and the type of plant and destinationFreeze drying (lyophilized)
Donkey milk can beFermented donkey milk (kumis)
The use of fermented equid milk is an ancient tradition in central Asia, likeCosmetic use
Cosmetics with donkey milk
In recent years, the cosmetic industry is mainly focused towards products made with natural ingredients and it is oriented to a sustainable consumption. Because of their natural origin, milk components correspond in many fields to the needs of cosmetology. Recent scientific study on a cream containing of lyophilized donkey milk showed different benefits for the skin. These results are related to the effectiveness of donkey milk components like proteins, minerals, vitamins, essential fatty acids, bioactive enzyme and coenzyme which allow the skin a balanced nourishment and a proper hydration. In particular vitamin C content in donkey milk is almost 4 times more of cow's milk. Donkey milk contain more lactoferrin of cow milk and a considerable mounts of lysozyme, from 1.0 mg/mL to 4 mg/mL (depending on the analytical method used: chemical or microbiological), instead cow's milk only traces. For this reason, it has the potentiality, when properly formulated, to reduce problem skin with eczema, acne, psoriasis and herpes and properties in calming the irritation symptoms as reported by some authors. Some authors have preliminarily evaluated whether the use of a face cream made from donkey milk affected the perception of some sensory aspects. The results showed that treated cream resulted appreciated by dry skin consumers for the following sensory aspects: spreadability, total appearance, smoothness, moisturisation and total effectiveness . The overall judgement also resulted highest for face cream made with donkey milk. Today, donkey milk is still used in the manufacture ofHistory
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