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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Gas chromatography/olfactometry and descriptive analysis of Valencia orange juice

Shah, Rohan 08 June 1998 (has links)
Heat treated orange juice, both pasteurized and concentrate, are being increasingly consumed in the U.S. Orange juice is primarily heat treated to increase its shelf life, by curbing the growth of microorganisms; and to inactivate pectin methylesterase, which demethylates pectin and leads to cloud loss in the juice. However, because of heat processing, orange juice undergoes undesirable flavor changes that decrease its acceptability to consumers. The objectives of this study were to differentiate between fresh frozen and heat treated orange juice employing descriptive analysis, and to determine by Osme, a gas chromatography-olfactometry (GCO) method, odor active volatiles that were either lacking or created in the heat treated juice. The second objective was to determine how changes in the odor-active volatile profile of heat treated orange juice, relates to changes in the aroma and flavor intensities of the samples as assessed by descriptive analysis. Through descriptive analysis, the panel was successful in significantly (p<0.05) separating the fresh, pasteurized, and concentrate samples. Orange, orange peel, sweet, and grassy descriptors were found to be important for fresh aroma and flavor, while cooked, yam, metallic, tamarind, green bean and artificial orange descriptors were higher in heat treated samples. Using Osme, it was possible to separate fresh frozen from heat treated orange juice, on the basis of their aroma profiles. Fresh frozen samples show a higher concentration of peaks tentatively identified as gamma-butyrolactone, citral, nonanal, carvone, perillaldehyde, carvyl propinate, valencene, and other unidentified peaks possessing descriptors such as floral, lime, citrus, pine, bamboo leaf, metallic, and vinyl. Pasteurized samples show a larger concentration of peaks tentatively identified as hexanol, octanol, nerol / carveol, myrcene, 2-octanone, p-cymene, terpenen-4-ol, betacitronellol, and other unidentified peaks with descriptors such as cilantro, vinyl, melon, mushroom, and metallic. Descriptors such as orange, orange peel, sweet, grapefruit, and grassy are more pronounced in the fresh samples and are similar to the odor descriptors of Osme peaks higher in the fresh samples. Descriptors such as cooked, artificial orange, yam, metallic, tamarind, and green bean are higher in the pasteurized samples, and are similar to the odor descriptors of peaks higher in these samples. / Graduation date: 1999
102

Investigation of alcoholic and malolactic fermentation using high performance liquid chromatography

Lee, Suk Hean January 2000 (has links)
No description available.
103

Investigating the inhibitory effects of cranberry juice metabolites on uropathogenic Escherichia coli for the prevention of urinary tract infections

Zhang, Yuxian 21 August 2011 (has links)
"Regular ingestion of American cranberry (Vaccinium macrocarpon) has been traditionally utilized for its health benefits against urinary tract infections. The proanthocyanidins (PACs), in particular, the unique A-type double linkages of PACs present in cranberry, have been identified as the active components. However, A-type PACs and any other active agents have not yet been detected or identified in urine. Additional experiments are required to investigate the inhibitory effects and persistence of cranberry metabolites present in urine collected following CJC consumption, and to determine how these compounds act against uropathogenic Escherichia coli for the prevention of urinary tract infections. Two separate bioassays (a biofilm formation assay and a bacterial cell viability assay) were used to determine the in vitro effect of cranberry juice cocktail (CJC) oral consumption on bacterial anti-adhesion activity in a double-blind, placebo-controlled pilot clinical trial. A single dose of 16 oz. of CJC or a placebo beverage was given to ten healthy women, ages ranging from 18 to 27, and urine samples were collected in the following 48 hours. A washout period of seven days was allowed. Bacteria (Escherichia coli B37, CFT073, BF1023, HB101, and Staphylococcus aureus ATCC43866) were cultured in the urine samples, supplemented with media, and the amount of biofilm formed was measured using a crystal violet absorbance assay in a 96-well plate. In the urine of volunteers who had consumed CJC, biofilm formation was inhibited within 24 hours after CJC consumption, and started to increase after 48 hours by 49-67%. S. aureus showed the least biofilm formation after incubation with post-CJC urine. The results indicated that drinking CJC can be an effective preventive measure for bacterial adhesion and biofilm formation in healthy women. The anti-biofilm activity peaks between 24 and 48 hours after drinking CJC. The viability assay showed that the colony count after culturing in urine collected following consumption of CJC or placebo were not significantly different, implying that CJC works as an inhibitor by blocking bacterial adhesion instead of killing the bacteria or restraining its growth. Another randomized, placebo-controlled, double-blind, crossover study was conducted to further investigate the molecular-scale effect of cranberry juice metabolites on two P-fimbriated E. coli strains: B37 and CFT 073, as assessed by atomic force microscopy (AFM). Three female subjects were asked to consume 8 oz. CJC or water. The washout period was 7 days. The urine samples were collected at 2, 4 and 6 hours post-ingestion of CJC or water. Urine collected before consumption of CJC was used as a control. For this control urine, the average adhesion force between E. coli and uroepithelial cells was 13.09 ± 11.60 nN for CFT073 and 10.30 ± 5.50 nN for B37. For post-CJC urine treatment, the adhesion forces decreased to 2.94 ± 1.82 nN at 2 hours after consumption then increased slightly to 5.51 ± 2.78 nN at 6 hours after ingestion for CFT073, while they decreased to 4.77 ± 3.33 nN after consuming for 2 hours and seemed to be stable in the next 4 hours following consumption (5.52 ± 4.04 nN after drinking for 4 hours; 5.05 ± 4.42 nN after drinking for 6 hours) for B37. The adhesion forces in post-water consumption urine were similar to those of the background for E. coli B37; meanwhile a downward trend for the adhesion forces in post-water consumption urine compared to the background was observed for E. coli CFT073. However, these adhesion forces in post-water consumption urine were still higher than those measured after CJC consumption at the same time intervals. The mean differences between the cranberry and placebo groups were statistically different according to the two way ANOVA procedure followed by Holm-Sidak test. Our results suggest a significant inhibitory interaction between the daily consumption of 8 oz. cranberry juice and bacterial adhesive activity. These results help form the mechanistic understanding of how cranberry products can be used to prevent bacterial attachment to host tissue, and may lead to new therapeutic strategies to prevent the rising problem of bacteria antibiotic resistance.  "
104

Accelererat åldrande av produkter Apelsinjuice och hallondryck / Accelerated aging of products Orange juice and raspberry crush

Djurovic, Aldin January 2010 (has links)
Brämhults Juice AB is one of Sweden’s leading producers of fresh fruit juices and drinks. The fruit drinks last 3 days once opened and when stored in a refrigerator kept at 7°C. Since factors that shorten the drinks’ best before date are usually not noticed until the entire batch has expired, it would be advantageous to find a way to accelerate the drinks’ natural deterioration, so that an unusal short best before date is noticed before more products are shipped off to the stores. This was achieved by establishing the present microorganisms’ (presumably only Candida yeasts) optimal growth conditions (25°C), inoculating drink samples on a special type of agar that inhibits bacterial growth, spreading them out on the agar using sterile spreaders and eventually storing these drink samples in said ideal enviroment, so that the yeasts would grow at an increated rate and thus spoil the drinks prematurely. The cells were counted using viable count. In doing this, the drinks aged and reached the maximum allowed amount of colony forming units/ml in a matter of 1-2 days, rather than the 3 days it usually takes. While storing the samples at the optimal growth temperature is believed to have had the greatest impact on Candida growth rate, the presence of oxygen is also thought to have mattered, though exactly how much is unknown. Additionally, batch and product sample variety played a role, making it difficult to obtain consistent values throughout the laboration.
105

Influência do consumo de suco de laranja sobre marcadores bioquímicos, imunológicos e de estresse oxidativo em pacientes com hepatite C crônica /

Lima, Cláudia Gonçalves de. January 2015 (has links)
Orientador: Thais Borges César / Banca: Lívia Gussoni Basile / Banca: Paulo Inácio da Costa / Banca: Thábata Koester Weber / Banca: Anderson Marliere Navarro / Resumo: O presente estudo teve como objetivo avaliar o efeito do consumo regular do suco de laranja nos parâmetros nutricionais, hemodinâmicos e bioquímicos de pacientes com hepatite C crônica. Participaram do estudo 66 indivíduos adultos de ambos os sexos, divididos em quatro grupos: Grupo com tratamento medicamentoso e com suco de laranja (MedSuco), Grupo sem tratamento medicamentoso e com suco de laranja (Suco), Grupo com tratamento medicamentoso e sem suco de laranja (Med) e Grupo sem tratamento medicamentoso e sem suco de laranja (Controle). Os participantes dos grupos Suco e MedSuco receberam 500 mL/dia de suco de laranja pasteurizado durante 8 semanas. As variáveis antropométricas utilizadas foram: peso, altura, dobras cutâneas do tríceps, bíceps, subescapular e supra ilíaca e circunferência da cintura. Para a avaliação hemodinâmica foram verificadas a pressão arterial sistólica e a diastólica, e para a avaliação dietética foi utilizado o registro alimentar, durante três dias alternados. Para a avaliação bioquímica foram realizadas dosagens de colesterol total, colesterol de HDL, triglicérides, glicemia de jejum, insulina, proteína C reativa, peroxidação lipídica, capacidade antioxidante, TNF-, interleucinas 6 e 10 e carga viral. Todas as avaliações foram realizadas antes e após o consumo do suco de laranja. Os resultados mostraram que após o consumo do suco de laranja, os pacientes do grupo Suco tiveram redução significativa do LDL-C (-9,9%), pressão arterial sistólica (-4.5%), insulina (-26.5%), índice HOMA (-32.0%), peroxidação lipídica (-68.5%), proteína C reativa (-48.8%) e TNF- (-11.7%), e aumento da capacidade antioxidante (1.2%); e os pacientes do grupo MedSuco tiveram redução significativa do LDL-C (-13.7%), pressão arterial sistólica (5.1%), HDL-C (-12.2%), peroxidação lipídica (-39.1%), proteína C reativa (-74.9%), TNF- (-8.8%) e carga viral (26.5%), e aumento da capacidade... / Abstract: This study aimed to evaluate the effect of regular orange juice consumption on nutritional parameters, hemodynamics and biochemicals of patients with chronic hepatitis C. The study included thirty-six adults of both sexes, divided into four groups: Group with drug treatment and orange juice (MedJuice), Group without drug treatment and with orange juice (Juice), Group with drug treatment and no orange juice (Med) and Group without drug treatment and no orange juice (Control). The participants of groups Juice and MedJuice received 500 mL / day of pasteurized orange juice for 8 weeks. The anthropometric variables were studied: weight, height, skin folds of the triceps, biceps, subscapular and suprailiac and waist circumference. For hemodynamic evaluation were found systolic and diastolic blood pressure, and for dietary assessment was used food records for three alternate days. For the biochemical evaluation were performed in total cholesterol, HDL cholesterol, triglycerides, fasting glucose, insulin, C-reactive protein, lipid peroxidation, antioxidant capacity, TNF-α, interleukins 6 and 10 and viral load. All evaluations were performed before and after consumption of orange juice. The results showed that after the consumption of orange juice, patients of Juice group had significant reduction in LDL-C (-9.9%), systolic blood pressure (-4.5%), insulin (-26.5%), HOMA index (-32.0%), lipid peroxidation (-68.5%), C-reactive protein (-48.8%) and TNF-α (-11.7%) and increase in antioxidant capacity (1.2%); and patients of MedJuice group had significant reduction in LDL-C (-13.7%), systolic blood pressure (5.1%), HDL-C (-12.2%), lipid peroxidation (-39.1%), C-reactive protein (-74.9% ), TNF-α (-8.8%) and viral load (26.5%) and increase in antioxidant capacity (2.5%). There was no significant decrease in anthropometric variables. Consumption of orange juice increased by 334.0% to intake of vitamin C and 63.6% folate intake of participants in the ... / Doutor
106

Infestação de Mahanarva fimbriolata (Stal, 1854) e controle químico na qualidade da matéria-prima e classificação do caldo de cana /

Madaleno, Leonardo Lucas. January 2006 (has links)
Orientador: Márcia Justino Rossini Mutton / Banca: Odair Aparecido Fernandes / Banca: Newton Macedo / Resumo: O objetivo do presente estudo foi avaliar o efeito da infestação de cigarrinha-das-raízes e controle químico tardio na qualidade da matéria prima e clarificação do caldo de cana. Foram realizados contagens de ninfas e perfilhos, avaliações biométricas, análises tecnológicas do caldo extraído e processo de clarificação. O delineamento experimental inteiramente casualizado com parcelas sub subdivididas, com três repetições, foi adotado para os parâmetros contagem de ninfas, perfilhos e avaliações biométricas. Para as análises tecnológicas do caldo e purificação foram adotados o delineamento fatorial em blocos casualizados, com três repetições. Os resultados obtidos foram submetidos à análise de variância e teste de Tukey (P=0,05). A infestação de cigarrinha-das-raízes diminuiu com a utilização tardia de thiamethoxam, que induziu o aumento da massa seca de folhas nos níveis mais elevados de infestação. A massa seca dos colmos aumentou nas parcelas tratadas com a dosagem de 0,3 kg ha-1 nos meses próximos a colheita, enquanto o inseticida provocou aumento de massa seca de folhas, bainhas e palmitos. O ataque de ninfas diminuiu o Brix, a Pol e o ATR no caldo e a aplicação tardia de thiamethoxam aumentou a acidez total, o que pode ter interferido no aumento da cor do caldo e na diminuição da massa seca e densidade da borra no processo de clarificação. / Abstract: This research was undertaken to evaluate the effects of spittlebug infestation and late chemical control on sugarcane quality and juice clarification. Nymphs and tillers were counted, plant growth was measured and juice technological analysis and clarification process were performed. The experiment was arranged in completely randomized design in split split-plots with three replications to nymphs and tillers counts and plant growth analysis. The statistical design for technological analysis and purification was randomized complete blocks, in a factorial arrangement. The data were submitted to ANOVA and means were compared by Tukey test (P=0.05). Spittlebug infestation was reduced with late thiamethoxam application and the insecticide increased leaf dry matter at higher infestation levels. The dosage 0.3 kg ha-1 allowed a stalk dry matter increase in months prior to harvest, while induced higher dry matter of leaves, sheaths and tops. The attack of nymphs decreased Brix, Pol and TRS in the cane juice. Late chemical control increased juice total acidity, increased juice color and reduced the dry matter and mud density in the clarification process. / Mestre
107

Perfil de compostos fenólicos do suco de laranja integral pasteurizado comercial /

Alves, Maria Rita Olivati Estevam. January 2018 (has links)
Orientador: Magali Monteiro da Silva / Banca: Alexandre Ferreira Gomes / Banca: Marina Ansolin / Resumo: Objetivo: O objetivo desse trabalho foi avaliar o perfil de compostos fenólicos do suco de laranja integral pasteurizado de marcas comerciais. Métodos: Foram reunidas informações sobre os compostos fenólicos considerando suas características químicas, bioatividade, técnica analítica utilizada para a sua determinação, e os principais compostos presentes em citros. Sucos de laranja integral pasteurizado de nove marcas comerciais foram adquiridos em Araraquara e região, SP. Foram adquiridas três embalagens de cada marca, com diferentes prazos de validade, referentes a diferentes lotes. Sucos de cada marca e lote foram liofilizados e submetidos à extração com solução de metanol:água (90:10, v/v), e os extratos foram submetidos à limpeza em cartucho SPE C18. A separação dos compostos foi realizada no sistema HPLC-DAD, empregando coluna C18 com fase móvel de água:ácido fórmico (99,9:0,1, v/v) e acetonitrila, em modo gradiente, vazão de 1 mL.min-1, temperatura de 50 ºC e volume de injeção de 20 µL. Foi também empregado o sistema UPLC-UV/MS, com escalonamento das condições para escala sub-2 µm. Os extratos foram injetados no sistema HPLC-DAD e UPLC-UV/MS para a identificação e quantificação dos compostos fenólicos. Resultados: Os principais compostos fenólicos das frutas cítricas descritos na literatura são os flavonoides, particularmente as flavanonas narirutina e hesperidina. Nesse trabalho foram identificados 60 compostos do suco de laranja, dos quais 54 são compostos fenólicos. O... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Objective: The aim of this work was to evaluate the profile of phenolic compounds of pasteurized orange juice from commercial brands. Methods: The phenolic compounds where characterized considering chemical structure, bioactivity, and techniques for analytical determination, as well as the main compounds present in citrus. Pasteurized orange juices from nine commercial brands were purchased in Araraquara and region, SP. Three packages from each brand were acquired, with different shelf life corresponding to different lots. Juices were lyophilized and extracted with methanol:water solution (90:10, v/v), and the extracts were cleaned in C18 SPE cartridges. Separation of the compounds was performed in an HPLC-DAD system, using a C18 column with mobile phase of water:formic acid (99.9:0.1, v/v) and acetonitrile in gradient mode, with a flow rate of 1 mL.min-1, temperature of 50 ºC and injection volume of 20 μL. An UPLC-UV/MS system was also used, with scaling conditions for sub-2 μm scale. The extracts were injected into the HPLC-DAD and UPLC-UV/MS system for identification and quantification of the phenolic compounds. Results: The main phenolic compounds of citrus fruits described in the literature are flavonoids, particularly the flavanones narirutin and hesperidin. In this work 60 compounds were identified in orange juice, of which 54 are phenolic compounds. The flavonoids rutin, eriocitrin, narirutin, naringin, hesperidin, naringenin, nobiletin and tangeritin, and the caffeic, p-coumaric and ferulic acids were identified in all juices. The levels of phenolic compounds varied amongst brands and lots. The results of the PCA... (Complete abstract click electronic access below) / Mestre
108

The Nicotine Content of a Sample of E-cigarette Liquid Manufactured in the United States

Raymond, Barrett H. 01 April 2017 (has links)
Background: Use of electronic cigarettes (EC) has dramatically increased in the United States since 2010 with a forecasted growth of 37% between 2014 and 2019. There is little research on e-liquid nicotine concentration from domestic manufacturers. However, limited research outside of the U.S. found wide inconsistencies between the labeled concentration of nicotine in e-liquids and the actual nicotine concentration. Methods: The seven most popular online manufacturers or distributors were identified. E-liquid samples of the five most popular flavors from each manufacturer were purchased in nicotine concentrations of 0 mg/ml and 18 mg/ml. Of the samples purchased (n=70), all were labeled as produced in the United States of America (USA). The researchers anonymized the samples before sending them to an independent university lab for testing. Results: The 35 e-liquid samples labeled 18 mg/ml nicotine measured between 11.6 and 27.4 mg/ml (M=18.7 SD=3.3) nicotine. The labeled 18 mg/ml samples measured as little as 35% less nicotine and as much as 52% greater nicotine. In the 35 samples labeled 0 mg/ml, nicotine was detected (>0.01 mg/ml) in 91.4% of the samples (Range = 0 to 23.9 mg/ml; M=2.9; SD=7.2). Six samples from two manufacturers labeled as 0 mg/ml were found to contain nicotine in amounts ranging from 5.7 mg/ml to 23.9 mg/ml. Conclusion: This study demonstrates the nicotine labeling inaccuracies present in current e-liquid solutions produced in the U.S. Incorrect labeling poses a significant risk to consumers and supports the recent regulation changes enacted by the FDA. Additional routine testing of nicotine concentrations should be conducted to evaluate the effectiveness of the regulations on future e-liquid production.
109

Fate of vitamin C in commercial fruit juices

Nagra, Surinder Unknown Date (has links)
Vitamin C occurs in relatively high concentrations in fresh and processed fruits and vegetables but is found to a lesser extent in animal tissues and animal-derived products. Nearly 90 % of vitamin C in the human diet is obtained from fruits and vegetables but this can be indirect by way of commercially prepared fruit juices. These juices are often enriched with vitamin C which has been synthetically prepared. There is a wide range of such juices on the New Zealand market, and they are a significant source of dietary vitamin C for many in the population. The focus of this research is on the Keri range of juice products.The present study monitors the fate of vitamin C during storage of Keri juices up to the best-before date, and under a range of other storage and consumption situations. Two methods were adopted for determining ascorbic acid (AA, the chemical identity of vitamin C). These were the titrimetric method, which is based upon the reduction of the dye 2,6-dichlorophenolindophenol by AA in acidic solution, and liquid chromatography, which is used to separate AA from its immediate oxidation product dehydroascorbic acid. In the latter method these two analytes can be measured independently. The liquid chromatography was less successful than the simpler titrimetric method, so most of the work was done by titration. However, the concentration of dehydroascorbic acid, which has vitamin C activity in vivo, remained uncertain. Moreover, the titrimetric method could not be applied to juices with high purple anthocyanin concentrations, like blackcurrant, because the colour change at the titration end point could not be detected. pH adjustment to change colour was ineffective, and decolourisation with charcoal led to the rapid and complete destruction of AA. The concentration of AA in Keri juices at the time of manufacture were always much higher than claimed on the labels. Storage for up to nine months at room temperature resulted in a loss in AA of between 37 and 68 %, depending on the juice and exposure to fluorescent light. However, the time of storage was a much more dominant factor than light exposure. The kinetics of loss, straight lines, were most easily explained by an aerobic model of AA degradation from oxygen diffusing across the polyethylene tetraphthalate bottle wall. Overall, the label claims made were defensible in terms of the best-before date, because it took at least 100 days of storage before the AA concentration in the most susceptible juices fell below the claimed value. This is because these drinks are fast moving consumer goods and storage beyond 100 days is unlikely. (Nonetheless, the supplier (Keri Juice Company) has since adopted its new unitised method of formulating juice. This has resulted in an initially higher concentration of vitamin C as compared to the juices under investigation.) In the nine months storage experiment there was some evidence for the presence of dehydroascorbic acid in blackcurrant drinks, but not in another three juices. Pasteurisation during preparation of these drinks resulted in up to 7 % loss of AA, probably due to oxygen dissolved in water, and accelerated by heat of pasteurisation. Higher temperatures in later storage also accelerated losses. Progressive exposure of juice to air during simulated consumption of 3 L bottles over a week also accelerated losses. Finally, exposure to sunlight in a diurnal temperature environment accelerated losses five-fold higher than in total darkness. Filtration of ultraviolet light approximately halved the loss due to sunlight. Overall however, it can be concluded that AA in the Keri range of juices is very resistant to degradation of AA.
110

Interactions between plasticised PVC films and citrus juice components

Fayoux, Stéphane C., University of Western Sydney, Centre for Advanced Food Research January 2004 (has links)
The study presented here consists in an original piece of work to better understand complex food packaging interactions. The majority of investigations on food polymer interactions related to orange juice and this provided a good base to our study (Literature reviews: cf. Chapters 1a and b). Additionally a rather remarkable finding in 1994 was that limonin, a trace bitter material found in some varieties of orange juice was rapidly absorbed by highly plasticised polyvinyl chloride (PVC plastisol) (Chapter 2). Several commercial absorbants are available for debittering, relying on limonin absorption on the large surface area of the highly porous absorbant pellets. However, the absorptive properties of the smooth plastisols apparently relied on a different mechanism. Limonin is a very large (470.5 g/mol) compound, but some preliminary experiments with another much smaller orange juice constituent d- of absorbates in plastisols, methods used earlier (Moisan 1980, Holland and Santangelo 1988) to measure solubilities and diffusion constants in packaging films could be advantageously used to survey these properties in a wide range of materials, including model compounds of various types, and a number of compounds which may be found in citrus juices (Chapters 3, 4 and 5). Experimentally, the method found most suitable was to use a ‘test film’ of pure plastisol which was wrapped tightly on both sides by a similar ‘supply film’ blended with 1 Molar test material (also called ‘absorbate’), setting up a concentration gradient. The inner test film was removed at regular intervals (minutes to hours) to measure (mainly by weighing) the uptake of the test reagent with time. Rather unexpectedly, it was found in a number of cases that the test film lost weight, either from the beginning, or after a period of time. Three main types of behaviour were identified: Type A lost weight from the beginning and over a long period of time, Type B gained weight initially and then lost weight, and Type C gained weight until a steady state was reached. Often the maximum, or near maximum, mass increase occurred within around 100 minutes, indicating a very rapid, liquid-like diffusion mechanism, in harmony with the rapid uptake of d-limonene and limonin. The major parameters of interest with these compounds are their diffusion rates and their solubilities, and in the presence of aqueous media (orange juice and other foodstuffs) the partition coefficient between the plastisol and water, which is related to the hydrophobicity function LogP for the compound. The major complicating factor in these measurements is the observation that the plasticiser materials themselves also migrate, in the reverse direction, because of the lower effective concentration in the supply film. This effect tends to be small, but is one explanation for the mass loss observed above, and cannot be ignored over the long term, nor in its practical applications to contamination in foods. There are many possible applications for the techniques described above. The removal or addition of compounds in food packaging itself is one. Upgrading foods, such as orange juice, commercially, is another. In many cases ‘scalping’ off-flavours or other minor components takes place exclusively through solid or liquid contact with the packaging. The removal from the headspace measured by the current gas permeation methods is irrelevant for the vast numbers of involatile, but easily diffusable compounds. For such compounds these novel applications are simple and rapid, require little specialised equipment, and fill a niche in the armoury of food and packaging chemists. / Doctor of Philosophy (PhD)

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