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

食品和饮料通常含有痕量的多种不同的挥发性有机化合物（VOC），其具有强烈和强烈的气味，并产生令人愉快和不愉快的味道和香味。在挥发性有机化合物中，挥发性硫化合物（VSCs）有助于面包，葡萄酒，切达奶酪，巧克力和热带水果的味道。从化学的角度来看，VSCs可以作为手性异构体存在，并且它们的嗅觉感知可能取决于它们的对映体形式。例如，3-硫代-1-己醇的（R）-对映体具有热带水果香味，而其（S）-对映体具有硫磺和草本气味。然而，手性VSCs的化学合成被证明是一个挑战，迄今为止开发的合成方法很少，大多数需要使用污染或昂贵的金属催化剂或依赖于多步保护-脱保护序列。因此，食品工业的一个突出兴趣是确定新的，可持续的和环境友好的方法来生产手性VSCs。本项目旨在开发一种可持续的生物催化方法，旨在通过比现有方法更可持续和更有效的新型酶法来生产新的VSCs，作为高对映体过量的食品香料和香精。手性硫化合物将在实验室中产生，并通过一系列酶生物转化为相应的VSC。这些生物催化剂将与工业合作伙伴Prozomix Limited合作进一步优化;一家位于诺森伯兰郡的生物技术公司，在这一领域拥有丰富的经验，现有多种酶面板可用于立即筛选铅催化剂鉴定。将通过利用食品和调味品公司（如Frutarom和菲尔梅尼希）的现有联系，探索手性VSC的嗅觉特性，并在这一领域建立新的关系。

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.