Partition of milk phospholipids during ice cream manufacturing.

ABSTRACT

The distribution of phospholipids (PL) within the fat and serum phase of ice cream manufacturing was evaluated through partition coefficients (KPL) after mixing, pasteurization, freezing, and hardening. Ice creams containing about 40.41 ± 3.45 (± standard deviation; control formulation) and 112.29 ± 9.06 (enriched PL formulation) mg of PL per g of fat were formulated with nonfat dry milk and ß-serum, respectively. Overall, the KPL were lower than 1, indicating that the PL were predominantly found in the fat phase, and only a small amount was left in the serum and sediment. Confocal micrographs visually confirmed this generalization. The addition of PL significantly increased the viscosity of the mixes between 4- and 9-fold, depending on the shear rate. Additionally, mixes containing high PL exhibited higher yield stress than those formulated with low PL (0.15 ± 0.09 and 0.016 ± 0.08 Pa, respectively). Ice creams with high PL delayed the onset of meltdown and exhibited a slower rate of a meltdown than low-PL ice creams (18.53 ± 0.57 and 14.83 ± 0.85 min, and 1.01 ± 0.05 and 0.71 ± 0.04% min-1, respectively). This study provides useful guidelines for manufacturing ice cream enriched in milk PL. Additionally, the use of ß-serum, a byproduct stream, as a source of PL is illustrated. The development will require studying the sensorial description of the product as well as consumer acceptance.