4. Conclusions and outlook

The metabolic pathways leading to aroma compounds are extremely diverse, and our knowledge of them is still very patchy. The genetic tools that have been developed for microorganisms make them excellent models for gaining a better understanding of the metabolic pathways involved in flavor production, including those that are important for the quality of cultivated plant species. A study of some of these pathways shows that, while reactions begin with enzyme-activated steps, chemical steps are frequently added to the sequence of transformations, increasing the diversity of odorant molecules synthesized (sulfur compounds, fat oxidation products, diacetyl formation, lactone cyclization, etc.).

To produce flavour compounds efficiently by biological means, we need to match the precursors available with the complexity of the reactions required to transform the precursor...