Exploring the Volatile Profile of Vanilla planifolia after Fermentation at Low Temperature with Bacillus Isolates

<i>Vanilla planifolia</i> is grown as a high-value orchid spice for its odor and savor attributes that increase due to the curing process associated with microbial colonization. This tends to influence the aromatic properties of vanilla. Hence, 11 <i>Bacillus</i> sp. strains were isolated from <i>V. planifolia</i> and identified with 16S rRNA gene sequencing. The liquid culture (1 mL of 10⁷ CFU mL^-1) of selected <i>Bacillus vallismortis</i> NR_104873.1:11-1518, <i>Bacillus velezensis</i> ZN-S10, and <i>Bacillus tropicus</i> KhEp-2 effectively fermented green-blanched vanilla pods kept at 10 °C during the sweating stage. GC-MS analysis showed that the methanol extract of non-coated, and <i>B. vallismortis</i> treated vanilla detected three (3) volatile compounds, whereas seven (7) components were obtained in <i>B. tropicus</i> and <i>B. velezensis</i> treatment. 4H-pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl was found in <i>B. velezensis</i> ZN-S10, <i>B. tropicus</i> KhEp-2, and <i>B. vallismortis</i> while it was not present in the control samples. This ketone compound suggested a Maillard reaction resulting in brown-increased aroma pods. Linoleic acid and Hexadecanoic acid ethyl esters were detected only in ZN-S10 strain-coated vanilla. A novel 3-Deoxy-d-mannoic lactone was detected only in <i>B. vallismortis</i>-treated vanilla characterized as a new compound in <i>V. planifolia</i> which suggested that the new compound can be altered with the coating of bacteria in vanilla during fermentation. Thus, the <i>Bacillus</i> strains improved the volatile profile and exhibited a new aroma and flavor profile of vanilla owing to bacteria fermentation during the curing process.