Cocrystallisation involving the thioamide, amide and imide functional groups

The work presented in this dissertation focused on the development and characterisation of novel cocrystals that incorporated the thioamide, amide and imide functional groups. A particular emphasis was placed on the characterisation of these cocrystals by single crystal X-ray diffraction methods. In Chapter One a summary of the intermolecular interactions utilised in this work and a short review of the solid state and multicomponent systems is provided. A brief introduction to the ways in which different multicomponent systems can be distinguished, crystal engineering strategies and a number of cocrystal applications highlights the importance the understanding of intermolecular interactions can have on the physical and chemical properties of crystalline materials. Chapter Two is the first Results and Discussion chapter and includes an introduction that is specific to the chapter. The main body of this work focuses on the primary aromatic thioamide functional group and its propensity to cocrystallise with a number of sulfoxides. Unlike the amide functional group, thioamides are not commonly employed in cocrystallisation studies. This chapter presents the first direct comparison between the cocrystallisation abilities of these two functional groups and the intermolecular hydrogen bonding interactions present in the cocrystal structures are examined. Chapter Three describes the crystal landscape of a short series of secondary aromatic amides and their analogous thioamides. Building on the results obtained in Chapter Two, a cocrystal screen of the secondary thioamides with the sulfoxide functional group was carried out in order to determine the effect removing a hydrogen bond had on the supramolecular synthons observed in the cocrystals. These secondary thioamides are also utilised in Chapter Four, which examines their halogen bonding capabilities with two organoiodine coformers: 1,2- and 1,4-diiodotetrafluorobenzene. Chapter Five explores the cocrystallisation abilities of three related cyclic imides as coformers for cocrystallisation with a range of commonly used coformers. Chapter Six is an overall conclusions chapter that highlights the findings of the results presented in Chapters Two to Five. Chapter Seven details the instrument and experimental data for the compounds and cocrystals discussed in the Results and Discussion Chapters. The accompanying CD contains all of the crystallographic data in .cif format for the novel single crystal structures characterised in this work.

Market-oriented new product development of functional beverages

Strategic reviews of the Irish Food and Beverage Industry have consistently emphasised the need for food and beverage firms to improve their innovation and marketing capabilities, in order to maintain competitiveness in both domestic and overseas markets. In particular, the functional food and beverages market has been singled out as an extremely important emerging market, which Irish firms could benefit from through an increased technological and market orientation. Although health and wellness have been the most significant drivers of new product development (NPD) in recent years, failure rates for new functional foods and beverages have been reportedly high. In that context, researchers in the US, UK, Denmark and Ireland have reported a marked divergence between NPD practices within food and beverage firms and normative advice for successful product development. The high reported failure rates for new functional foods and beverages suggest a failure to manage customer knowledge effectively, as well as a lack of knowledge management between functional disciplines involved in the NPD process. This research explored the concept of managing customer knowledge at the early stages of the NPD process, and applied it to the development of a range of functional beverages, through the use of advanced concept optimisation research techniques, which provided for a more market-oriented approach to new food product development. A sequential exploratory research design strategy using mixed research methods was chosen for this study. First, the qualitative element of this research investigated customers’ choice motives for orange juice and soft drinks, and explored their attitudes and perceptions towards a range of new functional beverage concepts through a combination of 15 in-depth interviews and 3 focus groups. Second, the quantitative element of this research consisted of 3 conjoint-based questionnaires administered to 400 different customers in each study in order to model their purchase preferences for chilled nutrient-enriched and probiotic orange juices, and stimulant soft drinks. The in-depth interviews identified the key product design attributes that influenced customers’ choice motives for orange juice. The focus group discussions revealed that groups of customers were negative towards the addition of certain functional ingredients to natural foods and beverages. K-means cluster analysis was used to quantitatively identify segments of customers with similar preferences for chilled nutrient-enriched and probiotic orange juices, and stimulant soft drinks. Overall, advanced concept optimisation research methods facilitate the integration of the customer at the early stages of the NPD process, which promotes a multi-disciplinary approach to new food product design. This research illustrated how advanced concept optimisation research methods could contribute towards effective and efficient knowledge management in the new food product development process.

Functional metagenomic analysis of the human gut microbiome to identify novel salt tolerance genes

The ability to adapt to and respond to increases in external osmolarity is an important characteristic that enables bacteria to survive and proliferate in different environmental niches. When challenged with increased osmolarity, due to sodium chloride (NaCl) for example, bacteria elicit a phased response; firstly via uptake of potassium (K+), which is known as the primary response. This primary response is followed by the secondary response which is characterised by the synthesis or uptake of compatible solutes (osmoprotectants). The overall osmotic stress response is much broader however, involving many diverse cellular systems and processes. These ancillary mechanisms are arguably more interesting and give a more complete view of the osmotic stress response. The aim of this thesis was to identify novel genetic loci from the human gut microbiota that confer increased tolerance to osmotic stress using a functional metagenomic approach. Functional metagenomics is a powerful tool that enables the identification of novel genes from as yet uncultured bacteria from diverse environments through cloning, heterologous expression and phenotypic identification of a desired trait. Functional metagenomics does not rely on any previous sequence information to known genes and can therefore enable the discovery of completely novel genes and assign functions to new or known genes. Using a functional metagenomic approach, we have assigned a novel function to previously annotated genes; murB, mazG and galE, as well as a putative brp/blh family beta-carotene 15,15’-monooxygenase. Finally, we report the identification of a completely novel salt tolerance determinant with no current known homologues in the databases. Overall the genes identified originate from diverse taxonomic and phylogenetic groups commonly found in the human gastrointestinal (GI) tract, such as Collinsella and Eggerthella, Akkermansia and Bacteroides from the phyla Actinobacteria, Verrucomicrobia and Bacteroidetes, respectively. In addition, a number of the genes appear to have been acquired via lateral gene transfer and/or encoded on a prophage. To our knowledge, this thesis represents the first investigation to identify novel genes from the human gut microbiota involved in the bacterial osmotic stress response.

Macroalgae and commercial macroalgal polysaccharides as potential functional ingredients in muscle foods

Ulva rigida (UR) and Palmaria palmata (PP) were included in farmed Atlantic salmon diets at levels of 0-15% for 19 and 16 weeks, respectively. Quality and shelf-life parameters of salmon fillets stored in modified atmosphere packs (MAP) (60% N2 : 40% CO2) at 4ºC were compared to controls fed astaxanthin. Salmon fillets were enhanced with a yellow/orange colour. Proximate composition, pH and lipid oxidation were unaffected by dietary UR and PP. Salmon fed 5% UR and 5-15% PP did not influence sensory descriptors (texture, odour, oxidation flavour and overall acceptability) of cooked salmon fillets. Pig diets were supplemented with commercial wet- and spray-dried macroalgal (Laminaria digitata) polysaccharide extracts containing laminarin (L, 500 mg/kg feed) and fucoidan (F, 420 mg/kg feed) (L/F-WS, L/F-SD) for 3 weeks and quality and shelf-life parameters of fresh pork steaks (longissimus thoracis et lumborum) stored in MAP (80% O2 : 20% CO2) were examined. Level (450 or 900 mg L and F/kg feed) and duration (3 or 6 weeks) of dietary L/F-WS and mechanisms of antioxidant activities in pork were investigated. L/F-WS reduced (p < 0.05) lipid oxidation and lowered levels of saturated fatty acids in fresh pork after 3 weeks feeding. L/F-SD was added directly to mince pork (0.01 - 0.5%) and quality and shelf-life parameters of fresh pork patties stored in MAP (80% O2 : 20% CO2) were assessed. Direct addition of the L/F-SD increased levels of lipid oxidation and decreased surface redness (a* values) of fresh pork patties. Lipid oxidation was reduced in cooked patties due to the formation of Maillard reaction products. Cooked pork patties containing L/F-SD were subjected to an in vitro digestion and a cellular transwell model to confirm bioaccessibility and uptake of antioxidant compounds. In mechanistic studies, fucoidan demonstrated antiand pro-oxidant activities on muscle lipids and oxymyoglobin, respectively.