Optimization of favour formation in hard cheeses

Hard cheeses are normally made using thermophilic starters because of the high cooking temperatures (>39°C) involved. Mesophilic starters cannot presently be used because the high temperature would affect the subsequent acidification and flavor formation. Thermophilic starters tolerate the high temperature but are unable to produce some of the desirable flavor compounds produced by their mesophilic counterparts. The project aims to study whether this problem can be solved by changing process parameters and/or starter so that harder cheeses can be made using mesophilic starters.

By: Grith Mortensen

The project will investigate solutions so that the mesophilic starter can operate successfully at elevated cooking temperatures. The participants plan to use several approaches, where one involves changing the cheese fermentation process by removing oxygen. From previous research it is known that the presence of oxygen is detrimental for L. lactis, the dominant organism in mesophilic starters. They further wish to optimize the mesophilic starter in different ways to accommodate its use at elevated temperatures. For instance, the effect of different additives or changed growth conditions prior to inoculation in milk will be studied.

Finally, the participants want to create more temperature-robust versions of the mesophilic starter through adaptive evolution/random mutagenesis. In collaboration with ARLA Foods the novel processes/starter cultures will be tested in cheese trials.

Project period: January 2017 - December 2021

Budget: 5.648.000 DKK

Financing: Danish Dairy Research Foundation, Innovation Fund Denmark, DTU Food, Arla Foods Amba, Arla Foods Ingredients

Project manager: Christian Solem 

Institution: DTU Food

Participants: DTU Food, Arla Foods Amba, Arla Foods Ingredients



Dorau, R., Chen, L., Liu, J., Jensen, P. R., Solem, C. 2019. Efficient production of α-acetolactate by whole cell catalytic transformation of fermentation-derived pyruvate. Microb. Cell Fact. 18(1):217

Dorau, R., Chen, J., Jensen, P. R., Solem, C. 2020. Complete Genome Sequence of Lactococcus lactis subsp. lactis bv. diacetylactis SD96. Microbiol. Resour. Announc. 9(3)

Liu, J. M., Chen, L., Dorau, R., Lillevang, S. K., Jensen, P. R., Solem, C. 2020. From Waste to Taste-Efficient Production of the Butter Aroma Compound Acetoin from Low-Value Dairy Side Streams Using a Natural (Nonengineered) Lactococcus lactis Dairy Isolate. J. Agric. Food Chem. 68(21):5891-5899