Grant: Research Tools and Instruments - Category 1 (<$150,000)

This application requests the purchase of a high performance liquid chromatograph (HPLC) to be used in characterizing the degradation of mustard glucosinolates by bacteria. Industrial deodorization of mustard powder permits this ingredient to be used as a protein supplement in processed meat products because the endogenous plant enzyme, myrosinase, is destroyed during thermal treatment, giving the powder neutral flavour and odour characters. Glucosinolates in the powder and amended products remain unchanged in terms of colour and flavour. We have discovered that many foodborne pathogens such as toxigenic E. coli, Salmonella, Campylobacter, and Listeria monocytogenes use a myrosinase-like enzyme(s), and intracellularly transform the mustard glucosinolates into isothiocyanates which are lethal to the producing organism. Thus, deodorized mustard can be used as a natural antimicrobial in food. Initial studies indicated that when glucose was readily available, myrosinase synthesis and glucosinolate utilization were repressed in target bacteria, so further study is planned to optimize enzyme synthesis by altering environmental exposures and studying genetic control of enzyme synthesis in growing and resting cells to broaden application of this unique antimicrobial approach. HPLC analysis of glucosinolate dissimilation represents the cornerstone of this work and is essential to identify factors influencing myrosinase synthesis and glucosinolate degradation by bacteria. At present the 22 year-old HPLC used for these analyses is prone to frequent failures and requires expensive replacement parts when these are available (operational software is only partially functional and the data storage format is obsolete). The high demand placed on use of this equipment makes access to alternate equipment, often remote from the Department, an impractical solution. Studies by 9 HQP working on NSERC Discovery-funded research conducted by the 3 applicants (Holley, 4 students; Arntfield, 2 students, protein-phenolic compound interactions on texture/flavour functionality; Scanlon, 3 students, gas phase effects on food texture) will be able to complete their work with this equipment.