Unlocking the mystery of Tibetan yak butter and its byproducts: processing, physicochemical characteristics, functional benefits, and applications

Consumers' interest in and demand for functional foods has increased in recent years. Exploring new functional food resources has become the needs of today's market. Among them, regional and ethnic foods with bioactive properties offer a new track for the development of functional foods with unique nutritional and sensory characteristics. The low prevalence of chronic ailments in inhabitants of the high-altitude Tibetan plateau drew our attention to a unique Tibetan ethnic food called Tibetan yak butter (TYB), which holds tremendous dietary, economic and cultural significance to the inhabitants of this region. Herein, we summarize the research on TYB and its by-products in recent years including processing, physicochemical characteristics and the potential health benefits of its bioactive constituents. In addition, numerous applications of TYB in both dietary and non-dietary settings are explored. TYB is a potential functional food ingredient and is now produced mainly by machine. It contains elevated levels of functional fatty acids and a unique microbiota, and has demonstrated the capacities to inhibit the proliferation of breast cancer cells, to prevent arteriosclerosis, to offer anti-obesogenic properties, and to promote the development of nervous system in infants. Casein and casein serum, the byproducts of TYB processing, have several physiological functions and are rich in milk fat globule membrane, which in itself has great commercial application prospect. At present, the utilization of TYB is very low, and to encourage consumption, it is necessary to optimize the processing conditions and develop new technologies.