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Redox potential control in cheese making via an innovative use of lactic acid bacteria

Control of redox potential in cheese making via an innovative use of lactic acid bacteria for improving cheese quality and developing new cheeses.

The control of cheese quality requires a complete understanding of the cheese-making and ripening processes. Cheese ripening results from a succession of numerous chemical and biochemical reactions that depend on the composition of the raw materials used, the enzymatic properties of the enzymes and starters used and the technology used (milk heat treatment, humidity, salt content, acidification kinetics, lactic acid concentration and pH). Although most of these parameters are well controlled in cheese-making, another parameter, the oxydo-reduction potential, remains uncontrolled even though recent studies have demonstrated its importance in the quality of cheeses and strongly suggest a close link between its evolution and the microbiology of cheese. The objective of the project is therefore to control the oxydo-reduction potential (Eh) during cheese making, relying on the reducing capacity of lactic acid bacteria (LAB) used as a starter. This capacity of LAB to reduce the medium has recently been revealed but has not yet been taken into account in the selection of starter strains or used in cheese making. In terms of the selection of lactic acid bacteria with adapted reducing activities and in the control of the oxydo-reduction potential during cheese making through adapted microbiology, the project is expected to result in advances. In this project, academic teams will join small and medium-sized companies, a starter producer and a cheese maker, in order to propose a new use of lactic acid bacteria to more accurately control cheese quality and develop cheeses with new organoleptic and microbiologic properties. The project will be divided into 6 tasks: tasks 1, 2 and 4 are pre-competitive research tasks while the remaining three (3, 5 and 6) are development tasks: 1. Identification of the functions responsible for the reducing capacity of lactic acid bacteria using targeted and random mutagenesis in Lactococcus. 2. Selection of natural lactococci for their capacity to reduce the medium on the basis of functions identified in task 1. This task will require the set up of specific screening tests. 3. Measurement and control of oxydo-reduction potential during cheese making. This task will require the set up of Eh measurement and the effect of its modulation on cheese quality. 4. Physiology of reducing lactococci. In this task we will investigate the mechanisms involved in the reducing potential of mutants (obtained from task 1) and selected natural lactococci (obtained from task 2). 5. Development and optimisation of new starters. New starters containing natural lactococcal strains selected for their reducing capacity will be designed. Their production will be set up and optimised. 6. Cheese-making. Cheese-making trials will be performed taking into account the reducing capacity of the new starters and the desired evolution of Eh. Keywords: redox, cheese, lactic acid bacteria.
Acronym: 
LABREDOX
Project ID: 
3 562
Start date: 
01-09-2005
Project Duration: 
46months
Project costs: 
1 190 000.00€
Technological Area: 
Food Processing
Market Area: 
General food products

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