2024-01-03 12:00:18
Sharp cheddar. ALAMY
Notes of butter and nuances of hazelnut… each flavor of cheese is the result of a close collaboration of micro-organisms during its manufacture. A study, published on December 21 in Nature Communications, looks at the role of these interactions in the taste of cheddar. Like other fermented foods, it is the product of the activity of several bacteria. But it is above all the addition of a sourdough culture which determines the texture and flavor. The scientific team led by the Dane Chrats Melkonian tested, for a year, different batches of cheddar by varying the combination of two bacteria used in the food industry, Streptococcus thermophilus (thermophilic streptococcus) and Lactococcus (les lactocoques).
“The study shows the construction of microbial interactions. To my knowledge, no research has explored this theme in such detail.” underlines Anne Thierry, from the Milk and Egg Science and Technology Unit (STLO) of the National Research Institute for Agriculture, Food and the Environment (Inrae) Brittany-Normandy.
Milk, the raw material for cheese, is a rich medium containing different proteins and peptides, fat and other nutrients. When it is transformed into cheese, a gigantic network of interactions is created. In this quest for the origin of cheddar’s taste, scientists have focused on bacterial activity.
Complexity of bacterial interactions
Three levels of interactions have been identified. First between S. thermophilus et Lactococcus. The first bacteria plays a crucial role: “It proved beneficial both for the growth of Lactococcus and for the final metabolic profile of the cheese,” underlines the study.
By conducting an experiment where S. thermophilus is absent, researchers observed significant differences in the concentration of lactic sugars such as lactose and galactose. In the absence of this bacteria, lactose was not fully consumed, and galactose was simply not produced. These results highlight the importance of this bacteria in the fermentation process, showing its direct influence on the taste aspects of cheese.
The study goes further by focusing on different subspecies of Lactococcus. “These strains have a lot in common, but at the bacterial level, small genomic differences can be of critical importance in fermented food products,” explains Anne Thierry. This is the second level of interaction described.
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#inimitable #taste #bacterial #interactions