Milkfat (Dairy Fat)
Synonyms: anhydrous milk fat (AMF), butterfat, milk lipids; fractions (olein/stearin)
Functions (food/cosmetic): emollient/occlusive and conditioning (cosmetics); structure, flavor, and aroma carrier (food)
Definition
The lipid fraction of bovine milk, composed mainly of triacylglycerols (TAGs) with minor di-/mono-glycerides, phospholipids (milk fat globule membrane, MFGM) and unsaponifiables (vitamins A, D, E, K; carotenoids; sterols). Available as butter (~82% fat) or AMF (≥99.8% fat).
Caloric value
≈ 895 kcal per 100 g (AMF). Table butter (~82% fat) ≈ 740 kcal/100 g.
Lipid composition (indicative; varies with breed/diet/season)
Saturated fatty acids (SFA): ~60–70% (palmitic ~25–30%, stearic ~10–12%, myristic ~8–12%; short-chain: butyric ~3–4%)
Monounsaturated (MUFA): ~25–30% (oleic ~20–25%)
Polyunsaturated (PUFA): ~2–4% (linoleic ~1–3%, α-linolenic <1%)
Natural trans: vaccenic ~1–3%; CLA ~0.3–1.5%
Phospholipids (MFGM): ~0.2–1%
Unsaponifiables: ~0.3–0.8% (fat-soluble vitamins, carotenoids, sterols)
Cholesterol: ~200–250 mg/100 g (AMF)
Physicochemical properties
Appearance: pale-yellow plastic solid when cool; golden liquid above melt
Melting range: ~28–36 °C (broad, multi-TAG mixture)
Smoke point (refined/AMF): ~175–190 °C
Saponification value: ~220–235 mg KOH/g
Iodine value: ~26–40
Density (20 °C): ~0.91 g/cm³
Production and processing
Milk → cream separation → pasteurization → churning (butter) → washing/working.
For AMF: clarify/“de-gum” butter to remove water and non-fat solids to ≥99.8% fat.
Fractionation via controlled crystallization yields stearin (harder) and olein (softer) fractions.
Functional properties
Cosmetics: emollient/occlusive, reduces TEWL, rich glossy texture; vehicle for lipophilic actives; structuring agent for sticks/balms (with waxes).
Food: crystallization provides structure; delivers characteristic buttery flavor; excellent carrier for fat-soluble aromas—key in bakery and confectionery.
Applications
Cosmetics: lip balms, barrier and nutritive creams, ointments, traditional soaps; sticks with waxes/butters.
Food: baked goods, chocolate/ganache, sauces/spreads, cultured dairy.
Pharma: lipophilic base in ointments where permitted.
Safety and regulatory
Allergens: milk allergens are proteins; milkfat/AMF has very low protein residues, but in severe milk-protein allergy it is prudent to avoid due to potential traces.
Comedogenicity: 2–3 (skin- and dose-dependent).
EU cosmetics (Reg. 1223/2009): permitted (INCI: Milk Fat / Anhydrous Milk Fat).
Food: standards of identity for butter/AMF; milk allergen declaration where applicable.
Stability and storage
Susceptible to oxidation (PUFA and cholesterol): use antioxidants (tocopherol) and barrier packaging (opaque, low O₂).
Shelf life: AMF 12–24 months (10–20 °C, light/oxygen limited); butter shorter and requires refrigeration.
Formulation compatibility (cosmetics)
Blends well with waxes (beeswax, candelilla, carnauba) and vegetable butters (shea, cocoa) to tune melting point and pay-off.
Good synergy with emollient esters; manage cooling curve to avoid graininess from recrystallization.
In O/W emulsions, manage melt temperature and choose robust emulsifiers for stability.
Nutritional notes (food)
Source of fat-soluble vitamins (A, D, E, K) and CLA; negligible lactose.
Relatively high SFA; dietary use should be balanced within overall fat recommendations.
Sustainability
Impact linked to dairy farming practices; consider grass-fed, organic, and high-traceability supply chains focused on animal welfare and emissions management.
Troubleshooting (formulation)
Rancidity/oxidative notes: add tocopherol, limit light/heat/air exposure.
Graininess in sticks/creams: optimize cooling profile and compatibility with waxes/esters.
Allergen claims: not suitable for “dairy-free/vegan” claims (animal origin).
Conclusion
Milkfat is a natural, complex lipid matrix offering intense emolliency, barrier function, and rich sensoriality in cosmetics and structure/flavor in foods. With appropriate antioxidant protection, packaging, and attention to allergen management, it delivers stable, high-quality performance across applications.
