Flavour Profiles and Nutrient Quality: Determining the roles of lipid modifying enzymes, protein-aroma active compound interactions, and protein stability in plant-based food systems

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Plant-based foods such as pulses are rich sources of protein and are also economically important crops. However, the presence of off-flavour or aroma-active compounds and anti-nutritional compounds in pulses may lower the absorption of proteins and essential minerals and is a major food processing challenge. Although the functional attributes of pulses have been studied little is known of their protein interactions with off-flavour compounds. Lipid-modifying enzymes and storage conditions are known contributors of off-flavour development, but their roles have not been defined in Nova Scotia bean varieties. Furthermore, although proteins have no flavour of their own they can interact with off-flavour compounds and modify flavour profiles. For Nova Scotia bean varieties and chickpeas these interactions remain largely unexplored. Compared to animal sources of proteins, pulses have lower digestibility which may be attributed to the presence of anti-nutritional factors. However, it is not known what role the kinetic stability of proteins plays in the digestibility of these food systems. Thus, it is hypothesized that: lipid modifying enzymes and protein interactions play a significant role in the modification of flavour profiles of NS beans and chickpeas; and, the kinetic stability of proteins in these food systems has the potential to impact their digestibility. The long-term objective of this research program is to better understand the mechanisms underlying flavour development in plant-based foods and the contribution of, lipid modifying enzymes, protein interactions and protein kinetic stability to the development of flavour profiles and the nutrient quality of these food systems. A gas chromatography olfactory/ mass spectrometry approach will be used to identify the characteristic aroma-active compounds generated after traditional pre-treatments of NS beans and chickpeas. The impact of lipid-modifying enzymes and storage conditions on modifying these flavour profiles will also be evaluated. The key molecular changes that drive the retention or release of aroma-active compounds will be evaluated by modifying the pH and temperature of protein matrices and using different bond-disrupting agents. A proteomics approach will also be used to determine the abundance and identity of kinetically stable proteins in the samples of interest. The proposed research will provide novel discoveries and improve our understanding concerning protein interactions and their contributions to the modification of flavour profiles. Understanding the mechanisms that drive these interactions will enable prediction of flavour release profiles and help product developers meet flavour-delivery challenges. Moreover, newly discovered kinetically stable proteins could enhance ongoing efforts to improve the sustainability of pulse crops which will be an effective long-term strategy which that will be beneficial in improving the economic value of these food systems.