Understanding the switchable solvent extraction of phospholipids from dairy by-products
American Dairy Science Association
Journal of Dairy Science
tertiary amine, phospholipids, byproducts
Switchable solvents have been used for the extraction and subsequent separation of polar compounds. These solvents represent a new class of solvents having the capacity to change their polarity with an external stimulus. Recently, we have used a tertiary amine (N,N-dimethylcyclohexylamine, CyNMe2) as a switchable hydrophilicity solvent (SHS) for extracting phospholipids from different dairy matrices. The underlying principle behind the change in polarity is due to the formation of ammonium carbonate salt in the presence of CO2 . Upon removing the CO2 with nitrogen, the carbonate salt returns back to its original amine. Unfortunately, the extraction mechanism by which CyNMe2 acts is largely unknown, which may limit its further development. In this work, we extracted PLs from buttermilk and B-serum by CyNMe2. In addition, the extraction was systematically studied in terms of yield of PLs, gel electrophoresis, particle size, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). For comparison, the PLs were also extracted using Folch extraction. For buttermilk, the extraction of PLs by CyNMe2 resulted in yields remarkably higher (significantly different P < 0.05 according to Tukey’s test) than the control treatment (99.96 ± 1.21 and 11.37 ± 2.31%, respectively). Similarly, the recovered PLs in B-serum by CyNMe2 (7.57 ± 0.59%) were significantly different (P < 0.05 according to Tukey’s test) by then the control extraction (5.34 ± 0.61%). Analysis of gel electrophoresis revealed some degree of disruption of the protein matrix, being more extensive in the case of SHS. Images through CLSM of untreated samples showed aggregates of fat and protein entrapped, while the use of CyNMe2 resulted in disruption of such aggregates. Additionally, SEM images revealed the separation of the lipids from the protein network with the extraction by CyNMe2. Our results indicate that the extraction of PLs from buttermilk and B-serum is mainly ascribed to protein disruption, which may release the PLs into the aqueous medium. The outcomes of this study help to gain insights into the extraction mechanism by which CyNMe2 acts, and develop extraction strategies for protein matrices.
Rathnakumar, K. and Martinez-Monteagudo, S. I., "Understanding the switchable solvent extraction of phospholipids from dairy by-products" (2020). Dairy Science Publication Database. 2242.