**Zhiguang Huang 1,2, Haotian Zheng 3,4,\*, Charles S. Brennan 1,2,5,\*, Maneesha S. Mohan 1, Letitia Stipkovits 1, Lingyi Li <sup>5</sup> and Don Kulasiri <sup>1</sup>**


Received: 27 January 2020; Accepted: 23 February 2020; Published: 2 March 2020

**Abstract:** Milk phospholipids (MPLs) have been used as ingredients for food fortification, such as bakery products, yogurt, and infant formula, because of their technical and nutritional functionalities. Starting from either buttermilk or beta serum as the original source, this review assessed four typical extraction processes and estimated that the life-cycle carbon footprints (CFs) of MPLs were 87.40, 170.59, 159.07, and 101.05 kg CO2/kg MPLs for membrane separation process, supercritical fluid extraction (SFE) by CO2 and dimethyl ether (DME), SFE by DME, and organic solvent extraction, respectively. Regardless of the MPL content of the final products, membrane separation remains the most efficient way to concentrate MPLs, yielding an 11.1–20.0% dry matter purity. Both SFE and solvent extraction processes are effective at purifying MPLs to relatively higher purity (76.8–88.0% *w*/*w*).

**Keywords:** milk phospholipids; buttermilk; life-cycle assessment; carbon footprint; supercritical fluid extraction; membrane separation
