Uniquely cheesy
Cultures for cheese are approached in an entirely different manner than those for fermented dairy foods such as yogurt. With more than 1,400 natural cheese varieties cataloged in the World Cheese Exchange Database, all of them able to just state “cheese cultures” or even simply “cultures” on their ingredient statement, understanding them is a very complex process.
Screening and selection of cheese cultures is a core business of Nizo Food Research in The Netherlands.
“During ripening, flavor and texture development of the cheese occurs, which differentiates the many different varieties,” said Wim Engels, project manager of cheese fermentation. “The flavor generated during ripening can be influenced by many factors, including the rennet, the enzymes inherently present in the milk and, most importantly, the starter bacteria or the presence of an adjunct culture. By screening culture collections for flavor development, it is possible to select a culture or an adjunct strain that produces new flavors or flavor compounds, often in a shorter time.”
Nizo developed a screening model that allows for the simultaneous manufacturing of up to 600 individual miniature cheeses. With this system, the research institute may evaluate the impact of culture strains and their potential to produce desirable flavors in fresh milk samples and cheeses.
It also recently developed tools that enable the direct monitoring of population dynamics in mixed cultures using genome sequence information of lactic acid bacteria. The information then may be correlated to flavor profiles.
“This sequencing provides a clear understanding of the interactions between strains and how these interactions can be influenced in order to diversify or accelerate flavor development during cheese ripening,” Mr. Engles said.
Chr. Hansen has introduced three direct-vat set ripening cultures that enable cheesemakers to create well-defined and consistent flavor differentiations. The cultures are designed to bring a natural indulgent flavor to branded cheeses without extra ripening time. They also improve taste and flavor in cheeses marketed as low fat, low salt and vegetable fat, as well as enable the restoration of traditional cheese features in vacuum-ripened products.
“For several years, most of the ripening cultures devoted to continental and cheddar cheeses consisted of a certain kind of lactic acid bacteria (Lactobacillus helveticus), which is a powerful tool, but often linked to sweet notes,” said Soeren Herskind, vice-president-commercial development at Chr. Hansen’s global headquarters in Copenhagen. “This time our researchers set out to widen the palette of flavors, especially in a savory direction.
“Looking through our collection of more than 16,000 bacterial strains, we selected more rare and original types, such as Lactobacillus plantarum, Lactobacillus curvatus, Pediococcus acidilactici or Lactobacillus johnsonii, with different enzymatic activity providing different properties in the cheese,” he said.
Almost 1,000 strains were screened in order to select and compose the most powerful cheese ripening culture blends. With this library of metabolic characteristics, it is possible to pick and choose bacteria with specific features.
