| dc.description.abstract | Phytochemicals are bioactive compounds widely abundant in fruits, vegetables, grains, nuts, and seeds, with a growing body of evidence supporting their role in promoting health and preventing disease. Their contribution as a natural food colouring, their application in flavour development, and their potent antioxidant properties highlights their importance in food research and development. However, few health claims related to phytochemicals have been authorised due to limited validated biomarkers, inadequately characterised model food systems, and inter-individual variation in bioavailability. The aim of this research was to characterise phytochemicals throughout the production of vegetable- based baked snacks, furthering the understanding of phytochemicals in the food industry.
The impact of agricultural practices, methods of vegetable preparation and pre- processing, and baking conditions on phytochemical retention and bioaccessibility were explored. The use of LED illumination during cultivation was shown to be a potential route for tailoring the phytochemical content of crops. Air-drying, freeze-drying, and individually quick freezing were studied as methods of vegetable pre-processing compared to using fresh vegetable ingredients. Fresh or frozen vegetable ingredients combined with a hybrid baking method, utilising microwave drying, was found to be optimal for the delivery of phytochemicals in baked snack forms. Throughout this research, the importance of the phytochemical class and chemical structure was highlighted.
Finally, the first use of mid-infrared (MIR) spectroscopy for characterising and quantifying glucosinolates in broccoli was described, demonstrating its potential as a more efficient, cheaper, and greener method of phytochemical analysis. The ground-state structures, chemical properties, and MIR spectra of core broccoli compounds, glucoraphanin and sulforaphane, were first predicted using ab initio methods. The predicted key spectral features corresponding to glucosinolate absorbance helped to inform which regions to train chemometric models on. These chemometric models, developed using MIR spectra and high- performance liquid chromatography reference data, established MIR as a potential screening tool for both phytochemical content in broccoli samples, and as a means of distinguishing between broccoli varieties. | en_GB |
