Crystallization and melting properties of mixtures of milk fat stearin and omega-3 rich oils

- Effects of S25 on the thermal behaviours of FO, LO and KO were investigated by DSC.
- Interactions between S25 and FO had adverse effect on their crystallization.
- S25/LO interactions promoted earlier crystallization of LO and stronger crystals.
- Effect of S25/KO interactions on crystallization was limited.
- LO might have the best oxidative stability upon the addition of S25.

Solid milk fat stearin (S25) can be a promising oxidation retarder due to its capacity to entrap liquid oils, especially for incorporating omega-3 (ω-3) rich oils into dairy products. Thermal properties of S25/ω-3 rich oil mixtures are necessary for such application. The effects of S25 on the crystallization and melting behaviours of ω-3 rich oils, namely fish oil (FO), linseed oil (LO) and krill oil (KO), were investigated by differential scanning calorimetry (DSC). Thermograms showed that with S25 concentration increasing, transitions of FO and LO shifted to lower and largely to higher temperatures, respectively, while crystallization temperature of KO slightly decreased. Negative, positive and low values of interaction enthalpy (ΔHint) suggested the adverse, beneficial and limited effect of S25 on the crystallization of S25/FO, S25/LO and S25/KO mixtures, respectively. LO could have the best oxidative stability upon the addition of S25 since their interactions facilitated earlier and stronger crystallization.