**Abstract**

 Buttermilk is a by-product obtained from the batting insertion in the process of obtaining cream and butter and it is constituted by fat globules which are surrounded by milk fat globule membranes (MFGMs). During the stirring process, the membrane is ruptured and the various components present therein are released. Because it has a high nutritional content and low cost, buttermilk has drawn attention in the prospect of new forms of application. In addition, its disposal is expensive and not biologically viable. The objective of this work is to present a compilation of the technological and biological activities of buttermilk. Among the technological properties, it is worth mentioning its application as in the production of functional foods, a conduit for the incorporation of probiotics, inhibition of bacterial adherence on industrial surfaces, as well as the encapsulation of easily degraded activities and fermentative processes. Among the biological properties, its antioxidant, hypocholesterolemic, antimicrobial, and anticancer activities stand out. In conclusion, the reuse of buttermilk is economically and sustainably viable and encourages increasing research related to its use.

**Keywords:** buttermilk, technological properties, biological properties, butter, milk fat globule membranes
