Full-bodied cheese taste, quick and effective

The term kokumi comes from Japanese and refers to a full-bodied and long-lasting taste experience. The taste impression is particularly pronounced in aged cheeses, mainly due to the increasing concentration of gamma-glutamyl dipeptides. These are small molecules that form a link between glutamic acid and another amino acid.

Depending on how the two amino acids are linked, researchers distinguish between gamma, alpha and X-glutamyl dipeptides, the latter two not contributing to the kokumi effect. The high polarity of glutamyl dipeptides, as well as their high structural similarity with different aromatic inputs, represent a major challenge for food analysis.

Effective analysis method developed

Nevertheless, the team led by lead researcher Andreas Dunkel from the Leibniz Institute succeeded in developing a new, efficient analysis method based on ultra-high performance liquid chromatography-mass spectrometry. For the first time, it can accurately and selectively determine the concentrations of all 56 gamma-glutamyl dipeptide variants in just 22 minutes. Optimized sample preparation allows for the analysis of 60 cheese samples per day.

“This is a significant improvement over other methods. Our tests have shown that our method is faster, more efficient and yet reliable: it provides reproducible results and detects even the smallest concentrations,” says first author Sonja Maria Fröhlich, doctoral student. student at the Leibniz Institute. To further study the influence of ripening time on gamma-glutamyl dipeptide concentrations, the researchers applied the method to 122 cheese samples from Europe and the United States after the testing phase. Cheese ripening times varied from two weeks to 15 years.

Mold Cultures Accelerate Flavor Development

The results show that, as expected, glutamyl dipeptide concentrations increase with maturity. “Interestingly, the addition of blue and white mold cultures led to significantly higher concentrations of gamma-glutamyl dipeptide, even at shorter maturation times,” explains Andreas Dunkel, who leads the group of research on integrative food systems analysis at the Leibniz Institute.

The food chemist adds: “The concentration profiles we determined for different ripening stages and different types of cheese can be used in the future as a database for prediction models. The latter could, for example, be used to objectively monitor the evolution of aromas during cheese ripening, to shorten ripening times or to develop new plant-based cheese products that are very well accepted by consumers.

“In line with an interdisciplinary approach to research in food systems biology, one of our goals is to combine the results of analytical research with bioinformatics methods to develop predictive models suitable for supporting sustainable food production. C “This is also the starting point of the project led by Andreas Dunkel,” concludes Veronika Somoza, director of the Leibniz Institute.