Xiaohong Jia has analysed a lot of beef in the last few years. Her doctoral disputation is on 12 February. She has been studying changes in the proteins during the 24 hours after the animal is slaughtered. She has compared tender and tough meat, as well as samples from living and slaughtered animals. It was during this work that Xiaohong Jia discovered a protein called Peroxiredoxin-6.
More research needed
"This protein was identified as a potential protein marker for tenderness. We found large quantities of protein Peroxiredoxin-6 in tender meat, but very little in tough meat. Peroxiredoxin-6 is a protective protein; it protects the cells in the living animal against things like stress and hot flushes . After slaughter, it can encourage the breakdown of muscle proteins, which leads to more tender meat," explains Xiaohong Jia.
"But in any case, more research will be needed to confirm the results of my studies. If it can be proven that there is a connection between the protein's protection and genes, this could be important for breeding potentially good beef in years to come," she adds.
Analysing several hundred proteins at the same time is called proteomics. The method is quite recent for food research - about 10 years old. Xiaohong Jia has used this method to study muscle proteins in meat and how they affect tenderness. Not many centres around the world use proteomics for research into food. The research specialists located in Ås, well represented by Nofima Mat, have a large research group in this area. Xiaohong's doctorate work has resulted in two published articles in the renowned Journal of Proteome Research and one in the journal Proteomics.
Post mortem testing
Changes in the intensity of proteins are important for understanding what it is that decides tenderness. Tests of the meat are made 0, 1, 3, 6, 9 and up to 24 hours after slaughter.
"I found that a number of metabolic energy proteins changed in intensity over time. This has an influence on the speed of the fall in pH and thereby the tenderness of the meat," says the doctoral candidate. At an early stage of her doctorate work, Xiaohong spent three months at Århus University in Denmark.