The provision of crops of a light fry colour, from store, is of the utmost importance to processors. Poor fry colour leads to rejection of crops on a quality basis. The application of Chlorpropham (CIPC) sprout suppressant, as a thermal fog is associated with a deterioration in fry colour. The BPC funded project at the University of Glasgow and its collaborator Sutton Bridge Experimental Unit investigates the effects of CIPC use on the processing quality of stored potatoes. CIPC is the only sprout suppressant available for medium and long-term storage for processing in Britain. In the UK the majority of CIPC treatments are conducted as thermal fog applications. This is considered to be the most practical means of achieving successful sprout control. The introduction of a hot fog into potato stores has a disruptive influence. It can physiologically alter the potatoes by creating a stressful environment. Tuber respiration rate increases and so the crop will age. Experimental trials conducted as part of this project have shown that it is the fogging process itself that is responsible for the decrease in crop quality following application, not the CIPC formulation applied. Studies revealed that both carbon dioxide and ethylene were produced naturally by crop and from the combustion of petrol used to generate thermal fogs. Initially the fry colour problems were linked with carbon dioxide in combustion gases and from increased respiration. However, carbon dioxide output from thermal fogger machines was less significant than expected. The levels were consistently lower than concentrations shown to have a deleterious effect in previous BPC funded work. Ethylene is present in thermal fogs as a by-product of burning the hydrocarbon fuel used to generate fog. The concentration of ethylene produced is associated with the running conditions of the fogger machine I.e. burner temperature, type and volume of fuel used etc. The ethylene created in a standard CIPC thermal-fog application is sufficient to induce a physiological response in tubers. Exposure of crop to ethylene effects respiration, dormancy period, sprout morphology, reducing sugar concentration and hence fry colour. The extent of the outcome depends on exposure time and concentration. Following assessment of the fogging situation, various means of reducing the impact of CIPC application on fry colour were evaluated. Different approaches were undertaken and included both attempting to control and remove the contaminants present in thermal fogs. By ventilating stores earlier than the recommended twenty-four hour period after treatment a vast improvement in fry colour was observed. In doing this the exposure time of crop to contaminants was greatly reduced. In the experimental work the stores were ventilated eight hours after treatment. This allowed adequate time for the effective fraction of the thermal god to settle.

The thesis consists of a study of chlorpropham distribution patterns and its behaviour within tuber components in commercial potato stores in the UK. The store examined were both cold (3-4 °C) and conventional (8-10 °C) stores. As a large number of samples from different stores were taken, it was important to have a quick and reliable analytical method for chlorpropham determination. This was developed and compared against the original accepted method. Both methods were more or less similar in their precision of results, with recoveries of 83.80 2.25 and 93.14 3.51 from spiked samples by blending and reflux extracting methods respectively. When the methods were compared for extracting the amount of chlorpropham in commercially treated stored samples, it gave recoveries of 2.49 0.25 and 2.58 0.17 for the blending and reflux methods respectively. Overall the reflux extracting method was quicker and easier and it was used for further work with some slight modification. The present study showed that the level and distribution pattern of chlorpropham was significantly different within the store and as well as between different commercial stores. The overall range of chlorpropham levels in the examined stores was 2.11-236.56 mg/kg. The amount of chlorpropham varied with respect to sampling sites of the examined stores. Each store has its own distribution pattern with some similarities. However there was a common trending all the stores examined in that the maximum level of chlorpropham was on the top surface and minimum on the lower levels of the stores. In the cold store examined 'A' ( 3-4 °C) the level of chlorpropham decreased continuously from the top height towards the bottom height of the store. However the amount of chlorpropham was excessive throughout the store, even in the middle of the boxes it exceeded the MRL (Maximum Recommended Level). The level of chlorpropham dropped from 128.39 mg/kg in the middle layer samples of the top box to 49.14, 20.15, 19.01, 8.03 3.97 and 4.54 mg/kg towards the bottom boxes of a six high column of boxes in the store respectively.

This thesis is concerned with the following studies : 1- Ammonium analysis in soil and water including the determination of low levels of ammonium (<0.1 mg N/1) in groundwater and the colorimetric analysis of highly coloured groundwater samples. 2- An investigation of groundwater quality and soils at a contaminated industrial site. 3- Bioremediation treatment of the ammonium and nitrate contaminated groundwater using natural soil and vegetation and using soil incubation and pot experiments. These findings of a pot experiment suggest the possibility of applying the bioremediation treatment of the ammonium and nitrate contaminated water in the field. A field study should be undertaken to evaluate the efficiency of this bioremediation treatment. This field study would require a suitable uniform area to lay out the plots, preferably close to the source of water to be used. In addition, it is necessary to carry out a hydrological survey to determine the following aspects: 1-The size of groundwater reservoir. 2-The rate of removal of the water. 3-The time scale of the water application. The climatic conditions such as rainfall, potential evapotranspiration and temperature should be taken into consideration when carrying out the bioremediation treatment in the field as these climatic conditions affect the water requirements and the growth of grass. There are three options to apply the contaminated groundwater as follows : 1-To apply the contaminated groundwater at low or high volume depending on its level of nitrogen. 2-To blend well water with high level of nitrogen with well water with low level of nitrogen to achieve a realistic irrigation rate at a suitable nitrogen level. 3-To overirrigate in expectation that ammonium would be retained in the soil. The ryegrass used in this bioremediation treatment can be disposed of by incineration and landfilling the ash or landfilling the grass.

The research undertaken was designed to investigate the potential use of coppice woodland for the clean up and remediation of heavy metal contaminated soil. Particular attention was given to high yielding coppice woodland species, especially willow and poplar. This was because breeding and field trials have reported that some hybrid willow clones can produce biomass yields of up to 60 t ha-1 y-1. The experimental works undertaken comprised three experiments which have been referred to as the 'Field Studies', 'Pot Studies' and 'Hydroponic Studies' and describes the medium in which the trees were grown and studied. The experiments were devised to study the variation in the uptake of metals between different tree species growing in different environments. The findings of the studies generally indicate that metal uptake rates determined in the field were lower that the uptake levels recorded in the pot and hydroponic studies. These differences were attributed to the increased availability of the study metals in the pot and hydroponic studies. Zinc concentrations in the above ground tissue of willow determined from the three experiments ranged from 159 to 223 mg kg-1 in the field study, 281 to 2995mg kg-1 in the pot study and 40 to 5530 mg kg-1 in the hydroponic study. Zinc was the only metal accumulated to significant concentration within the biomass of fields samples. Zinc, copper, cadmium, nickel and chromium were accumulated in the biomass of seedlings grown in the pot studies and zinc, copper, cadmium, nickel, chromium and to a lesser extent lead were accumulated by some of the hydroponic study trees. Some of the uptake levels recorded were not dissimilar from accumulation levels reported in hyperaccumulater species and highlights the potential of some tree species to accumulate metals in above ground tissues (leaves, twigs and stem). The pot and hydroponic studies suffered high seedling fatality rates which were attributed to metal toxicity and/or salinity. These findings could indicate possible establishment problems when trying to plant trees on contaminated sites.

The objective of this work was to synthesise potential polymeric materials to use in agricultural applications, particularly as pesticide carriers. Synthesis of solid microcapsules, which contain hydrophobic pesticides, from functional polymers, was the primary goal. In addition, promising materials such as poly(dimethylsiloxane) (PDMS) and acid-labile containing polymers were also explored. The extraordinary reactivity of isocyanates towards nucleophiles offers an interesting synthetic tool as a catalyst-free reaction. Unfortunately, the high reactivity of isocyanate during the polymerisation process is a major concern, thus a facile approach in order to synthesise stable functional polymer was first investigated. Chapter 2 details the synthesis of two types of isocyanate side chain containing copolymers, poly(methyl methacrylate-co-isocyanatoethyl methacrylate) (P(MMAm-co-IEMn)) and poly(benzyl methacrylate-co-isocyanatoethyl methacrylate) P(BnMAm-co-IEMn), via Cu(0)-mediated controlled radical polymerisation. Both copolymers were functionalised with dibutylamine, octylamine, and (R)-(+)-α-methylbenzylamine, which further proved the successful incorporation of the isocyanate groups. Subsequently, P(BnMAm-co-IEMn) was used for the fabrication of liquid core microcapsules via an oil-in-water interfacial polymerisation with diethylenetriamine as a crosslinker. Furthermore, chapter 3 illustrates the synthetic route of solid microcapsules containing hydrophobic pesticides; this illustrates the incorporation of biodegradable materials, modern controlled radical polymerisation techniques and isocyanate chemistry. An α, ω-poly (ɛ-caprolactone) SET-LRP initiator is first prepared by esterification to obtain a degradable halide initiator. Subsequently, biodegradable P(BnMAn-co-IEMn) was polymerised via the conditions from chapter 2. An isocyanate-containing copolymer was used to fabricate a microcapsule which consists of imidacloprid (IMI), followed by water removal via spray dryer. Chapter 4 details an efficient tool to synthesise an amphiphilic copolymer containing PDMS. The versatility of hydrosilylation has been exploited for the preparation of an ABA block copolymer of PDMS and poly(ethylene glycol) methacrylate (PEGMA), which can be potentially used to prepare polymeric micelles. Also, to demonstrate the adaptability of this method, different methacrylates and vinyl terminated methacrylic macromonomers were applied to modified hydride terminated PDMS. Finally, the α, ω-hydroxyl terminated poly(acetal) SET-LRP initiator was synthesised from the condensation and esterification reaction. A favourable Cu(0)-mediated controlled radical polymerisation and degradation under an acidic conditions of acetal initiator was affirmed. Thus, this offers a great opportunity of using this initiator to synthesise isocyanate-containing copolymers, certainly, an acid-labile microcapsule to use as an agrochemical carrier is potentially achievable.

The work in this project is concerned with the headspace analysis of potato volatiles. In the context of the thesis, the term potato volatiles deals with the headspace volatiles that are naturally evolved by raw potato tubers, and the anthropogenic volatile sprout suppressant chemicals that are applied to stored potato tubers. Both aspects of potato volatiles were investigated and consequently this thesis is divided into two sections: Section 1 deals with the headspace analysis of the volatiles that are produced by raw potato tubers; Section 2 deals with the headspace analysis of two widely used commercial potato sprout suppressants. After harvesting, potato tubers undergo a period of dormancy which is defined as the time when the tuber buds are not growing: when dormancy is broken, the buds grow and elongate into sprouts. The mechanism of tuber dormancy is extremely complex, and the transition from the dormant to non-dormant state is associated with several physiological changes in the composition of the tuber. The first section, Section 1, of the project is an account of the investigations of the volatile compounds that are naturally evolved by raw potato tubers, in relation to the question of tuber dormancy. It has been shown that the volatiles produced by dormant potato tubers have sprout suppressant properties, thereby delaying the breaking of tuber dormancy (Burton, W. G., 1952), (Burton, W. G., Meigh, D. F., 1971). Further to this, it has been shown that the dimethylnaphthalene class of compounds is present in raw potato tubers and has been shown to possess potent sprout suppressant properties Neigh, D. F., et al, 1973), (Beveridge, J. 1980). However, it was thought that dormant potato tubers evolved volatiles, apart from the dimethylnaphthalenes, that had sprout suppressant properties. The aim of the project was the isolation and identification of the headspace volatiles that are naturally evolved by raw potato tubers and to relate these volatiles to tuber dormancy. The bulk of the work was taken up with the development of the analytical techniques for the isolation and separation of raw tuber headspace volatiles. Various systems were tested for the containment and separation of the headspace volatiles, from the outset the porous polymer adsorbent Tenax G. C. was used to trap the headspace volatiles, and high resolution gas chromatography using capillary columns was used for their separation. Three systems were developed for sampling: the first using an aluminium tank proved to be unsuitable due to background volatiles arising from the tank, the second and third which were constructed from glass and PTFE were found to be successful from the point of view of isolating a sample of potato tuber volatiles free from background volatiles. These two systems were used to study the headspace volatiles produced by sprouted and dormant potato tubers and to relate the breaking of dormancy to any changes in the volatiles produced. In addition, a gas chromatographic system was developed for the transfer of volatiles adsorbed on a Tenax G. C. precolumn into a capillary column, the final system adopted involved the thermal desorption of the volatiles from the Tenax G. C. into a small volume cold trap to concentrate the volatiles into a small volume and then a rapid reheat of the cold trap for the introduction of the volatiles into the capillary column.

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A fruit and vegetable-rich diet has been associated with decreased risk of developing chronic diseases such as cardiovascular disease and cancer in humans. These protective effects have been attributed in part, to the presence of phytochemicals in fruit and vegetables, in particular flavonoids and phenolic compounds. Some plants have been used in traditional medicine for healing, ritual ceremonies and as health tonics or food supplements. Recent interest in the health-promoting properties of Malaysian traditional vegetables has been based on claims about their uses in health and medicine. However, scientific information to support these claims is largely unexplored. The overall objectives of the present study were to investigate, determine and quantify the phytochemicals, particularly phenolic compounds, in the seven samples from five species of selected Malaysian traditional vegetables (Anacardium occidentale, Centella asiatica, Colubrina asiatica, Pluchea indica and Premna cordifolia) and to evaluate their activities in vitro, including antioxidant and antibacterial activities of extracts of these plants and individual phytochemicals. In the first section of this project, discussed in Chapter 3, Malaysian traditional vegetable extracts were screened for phenolic compounds using several complimentary techniques, namely high performance liquid chromatography (HPLC) and HPLC-tandem mass spectrometry and the total phenolic content determined using the Folin-Ciocalteu assay. Flavonol glycosides were predominant in most of the species, particularly A. occidentale with levels ranging from 6434 to 12420 µg/g fresh weight. Chlorogenic acids were the main components identified and quantified in C. asiatica and P. indica. The total phenolic content of the vegetables were between 100 ± 7.8 and 415 ± 20 mg/ kg gallic acid equivalent (GAE) in batch 1 but lower in batch 2 ranging from 62 ± 2.5 to 386 ± 41 mg/ kg GAE. The total phenolic content of plant extracts was positively correlated with total antioxidant capacity, determined by 2, 2’-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and ferric reducing antioxidant potential (FRAP) assays. A. occidentale exhibited the highest total phenolic content and total antioxidant activity, whereas Colubrina asiatica, which had the lowest total phenolic content, also had low antioxidant activity in vitro. Phenolic content and antioxidant activity were significantly (p<0.05) influenced by environmental factors, as in this study, plant materials in batch 1 which was harvested in rainy season, had a higher total phenolic and antioxidant content than batch 2, which was harvested in the dry season. Based on the hypothesis that other components in addition to phenolics also contributed to the total antioxidant activities in the plants, the next objective, which was presented in Chapter 4, was to investigate the occurrence of phytochemicals such as triterpenes, carotenoids, α-tocopherol and vitamin C. The level of total triterpenes, biomarkers of C. asiatica was not significantly different between batches. The main component was madecassoside with 91 ± 4.8 µg/g fresh weight in batch 1 and 77 ± 3.4 µg/g fresh weight in batch 2. The level of carotenoids and vitamin C were low compared to previous reports. This was almost certainly due to dried samples being used in the present study, as some of the compounds would have broken down during drying process. This would have particularly affected the levels of vitamin C, which contributed only 0.9 to 5.5% to the total antioxidant activity of the plants under study. Total antioxidant activities of plant essential oils were determined using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and the result was in agreement to the total antioxidant activities of plant extracts, which A. occidentale having the highest amount. The highest antioxidant activity exhibited by A. occidentale oil was attributed to the presence of high amounts of γ-terpinene (28%) and terpinen-4-ol (4.2%), both of which were shown to have strong radical scavenging activity. The high phenolic content, antioxidant activity and occurrence of volatile components exhibited by A. occidentale has led to the final objective of this study, which is presented in Chapter 5. This was to screen for antimicrobial activities of A. occidentale extracts and essential oil against selection of Gram-positive (Enterococcus faecalis, Staphylococcus aureus, Meticillin-resistance Staphylococcus aureus (MRSA), coagulase negative Staphylococci (CoNS) and Lactobacillus acidophilus), Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) and fungi (Candida albican) using disc diffusion and minimum inhibitory concentration (MIC) methods. Investigation of the modes of action was determined using growth inhibition curve, scanning (SEM) and transmission (TEM) electron microscopy. A. occidentale was shown to have promising effects at 25 mg/ml with regard to inhibiting the growth of Gram-positive bacteria including MRSA. The essential oil and its major component, γ-terpinene at only 2.5% (v/v) inhibited the growth of all Gram-positive and Gram-negative bacteria. None of the A. occidentale extracts or oil exhibited antibacterial activities against Lactobacillus acidophilus, an important strain of bacteria found in the human gut. This indicates selective effects of A. occidentale. A. occidentale extract and oil inhibited the growth of S. aureus cells within a 2-hour incubation observed in time-kill experiments. SEM and TEM examination revealed that the oil and its component, γ-terpinene, inhibited the bacteria through bacteriostatic and bactericidal effects which damaged the bacterial cell wall. Testing the oil and γ-terpinene against epidemic-MRSA (EMRSA) biofilms indicated an anti-adhesive effect, which disrupted the bacterial colonies in the biofilms to produce more extracellular polysaccharides (EPS). The effects of A. occidentale oil were comparable with tea tree oil, a widely used topical antiseptic. All the Malaysian traditional vegetables under study are claimed to have medicinal properties and health effects. The results in the present study have provided some information on phytochemical and nutritional properties of Malaysian traditional vegetables, and as a consequence provide a sound scientific base for promoting their consumption particularly in Malaysia.