Dissertation
Potential interference of fungal endophytes in Vanilla planifolia on vanilla flavor compounds biosynthesis
Natural vanilla flavor is one of the most important in the world. However, the cost of this flavor is expensive. Production of this flavor by alternative methods, could reduce the cost.
- Author
- Khoyratty, S.
- Date
- 27 October 2020
- Links
- Thesis in Leiden Repository
Natural vanilla flavor is one of the most important in the world. However, the cost of this flavor is expensive. Production of this flavor by alternative methods, could reduce the cost. Towards this end, using microbiological methods, fungal endophytes were isolated and identified, by morphological characters and PCR-based methods, from vanilla pods, the site of vanilla flavor. The fungal endophytes were tested for their involvement in the synthesis of vanilla flavor. In this way, three vanilla pod endophytes Hypoxylon investiens, Pestalotiopsis microspora, Diaporthe phaseolorum were found to modify the amounts of vanilla flavor and aroma metabolites vanillin, vanillyl alcohol, p-hydroxybenzoic acid, p-coumaric acid, p-xylene, α-phellandrene, 3-carene, α-terpineol, p-hydroxybenzaldehyde, α-cubebene, β-caryophyllene in Vanilla material containing media (in vitro) as well as in living Vanilla plant material (in vivo - acclimatized plants and calli). These metabolites were synthesized either de novo or through biotransformation reactions of precursors. That the latter describes the involvement of several metabolites related to vanilla flavor, implies complex flavor notes, typical of natural vanilla flavor, as opposed to the synthetic version. The analytical methods used include GC-MS, HPLC, 1H and 2D NMR. The results support the hypothesis that endophytes play a role in vanilla flavor metabolite biosynthesis.