Autolysis of the yeast
The aim of the autolysis step is to obtain the solubilization of the yeast cell content. To do so, and after a cooling step to stop the multiplication of yeast population, the yeast cream is placed in large tanks at a temperature of 45-55 degrees Celsius. During this thermal process, the cell walls are broken down by the enzymes naturally present in the yeast. The macromolecules of the cell are cut into smaller molecules, obtaining the following “tasty” components: Protein portions (peptides, free-amino acids such as glutamic acid), Nucleic acid (RiboNucleic Acid (RNA), Oligonucleotides, nucleotides (IMP-GMP…)), polysaccharides (sugars, mannanes and glucans). It is necessary to monitor the lysis to obtain the “tasty” components at the correct ratio. Each parameter of the autolysis (temperature, and also pH) is crucial and influences the final tasting properties of yeast extract.