Development of novel biocatalytic processes for the manufacturing of food flavours and fragrances.

Foods and beverages contain, generally in trace amounts, a number of different volatile organic compounds (VOCs) possessing strong and powerful odours and contributing to both agreeable and disagreeable flavours and fragrances. Among VOCs, the volatile sulphur compounds (VSCs) contribute to the flavours of bread, wine, cheddar cheese, chocolate and tropical fruit. From a chemical point of view, VSCs can exist as chiral isomers and their olfactory perception may depend on their enantiomeric form. For example the (R)-enantiomer of 3-thio-1-hexanol has a tropical fruit aroma, while its (S)-enantiomer has a sulphurous and herbaceous smell.

However, the chemical synthesis of chiral VSCs proves to be a challenge, and few synthetic approaches have been developed so far, with most requiring the use of polluting or expensive metal catalysts or rely on multi-step protection-deprotection sequences. It follows that a preeminent interest of food industries is the identification of new, sustainable and environmentally friendly approaches for the production of chiral VSCs.

This project aims to develop a sustainable biocatalytic approach aimed at the manufacturing of new VSCs as flavours and fragrances for foods in high enantiomeric excess through novel enzymatic methods that are more sustainable and efficient than the existing ones. Chiral sulphur compounds will be produced in the laboratory and biotransformed into the corresponding VSC with a range of enzymes. These biocatalysts will be further optimised in collaboration with the industrial partner, Prozomix Limited; a biotechnology company based in Northumberland with considerable experience in this area and existing diverse enzyme panels for immediate screening towards lead catalyst identification.

The olfactory properties of chiral VSCs will be explored by making use of existing contacts within food and flavour companies, such as Frutarom and Firmenich, and also by forging new relationships in this sector.