Improving the quality of commercial brands requires identifying the molecules responsible for their aromatic qualities.
HARD SAUSAGES SUCH AS FRENCH saucisson are traditionally made by adding sugar, salt, saltpeter, herbs, and spices to a mixture of meats that is then put into a casing and left to dry for several months. This method, which does not rely on any fermentation agents (acidifying and aromatizing microorganisms), can produce both the best and the worst results. Insufficient acidification by bacteria naturally present in the meat carries the risk that pathogenic microorganisms will develop. Moreover, spontaneous flora do not invariably impart a pleasing taste to hard sausage.
In seeking to avoid this Charybdis through the use of controlled fermentation, the food processing industry sometimes falls into the clutches of Scylla: Commercial products often are too soft (the drying process often lasts less than a month), and many of them lack the aromatic quality associated with artisanal sausages. This situation is changing, for commercial manufacturers have an incentive to remedy these defects. In France they have charged researchers from the Institut National de la Recherche Agronomique (INRA) station at Clermont-Ferrand with the task of determining exactly what makes a good saucisson.
Jean-Louis Berdagué, Marie-Christine Montel, and Régine Talon set out to extract, and then identify, the aromatic components of hard sausages using high-resolution gaseous phase chromatography (whereby a carrier gas conveys the volatile molecules extracted from a sample into a capillary tube that differentially retains, and therefore separates, the constituent elements of the aroma) in combination with mass spectrometry (which identifies the components separated by means of chromatography). Thanks to these techniques it is now possible to characterize both the properties of the meat used in making a sausage and the curing process itself.
The Clermont-Ferrand team observed first that the aroma of hard sausage derives from about 100 organic compounds produced by the action of enzymes present in the meat and the fermentation agents. Subsequent analysis of sausages prepared from various bacterial combinations showed that the flora responsible for maturation play a crucial role in creating aromas.
In one experiment, six mixtures of acidifying bacteria (Lactobacillus and Pediococcus) and aromatizing bacteria (Staphylococcus) were used to produce thirty different sausages (five samples per bacterial mixture). The volatile compounds in these samples were then analyzed and their aromas evaluated by a dozen trained tasters who had agreed beforehand about the terms to be used to describe aromatic characteristics.
In a further step, a statistical analysis disclosed the relationships between aroma and the presence of the various compounds. More precisely, the oxidation of lipids was found to play a preponderant role in determining aromatic quality: A rancid smell is associated with the presence of aldehydes, alkanes, and alcohols, whereas the smell of good hard sausage is associated with the presence of methyl ketones and methyl aldehydes. Finally, the degradation of sugars favors the development of vinegar odors, created by acetic acid, or of butter aromas, created by 2,3-butanediol.
These studies revealed a situation analogous to the what one finds in the case of yogurt, where the quality of the final product depends on the use of bacterial strains from wholesome milk. Making aromatically rich sausages likewise depends on the quality of the strains used in the maturation process.
Packaging and Aromatization
Further studies carried out by the same team in Clermont-Ferrand in collaboration with Christine Viallon showed that both the length of the curing process and the type of packaging affect the aromatic quality of sausage. Prolonged drying often leads to a loss of aroma because water evaporation carries away with it the volatile compounds. Sausages harden as a result of drying, however, and the progressive concentration of salt brings out their flavor. The INRA team wondered whether wrapping the sausage in plastic film would prevent the loss of aroma through drying. They found that the use of film both limits drying and strongly modifies the degradation of sugars, with the result that products wrapped in this way are less sour and have a more buttery taste.
Finally, the mechanisms of aromatization were also studied. The Clermont-Ferrand researchers were able to detect traces of pepper (terpenes), garlic (sulfur molecules), and brandy (esters formed by the reaction of ethyl alcohol with the fatty acids produced by salting).
Commercial brands of sausage therefore may be expected in the future to reproduce the flavor of artisanal products. Better still, recent research suggests that synthetic aromas can be created that will improve the quality of unsatisfactory bacterial strains. A compound such as 1-octene-3-ol, introduced in the initial stage of fabrication by Didier Roux, a research scientist working with Capsulis S.A., has produced sausages having a delicate aroma of sous-bois (wild mushroom with hints of decomposing mossy undergrowth).