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Sorbic acid and sulphur dioxide are often used together, as preservatives,in many foods. Sorbic acid is known to undergo degradation in aqueous solutions, and this degradation appears to be accelerated in the presence of sulphur dioxide. The interaction between sorbic acid and sulphur dioxide is the subject of this thesis. The work is subdivided into five chapters, as follows: The first chapter deals with the chemistry of sorbic acid acid and sulphur dioxide. The second chapter describes a study of the degradation products of sorbic acid, in aqueous systems, in the presence of sulphur dioxide and a possible mechanism for the occurrence of these products is proposed. Chapter three deals with the preparation and degradation of 6-[[13]C] sorbic acid in order to find evidence for, or against, the mechanism proposed in chapter two. It also gives details of syntheses attempted in order to obtain 6-[[13]C] sorbic acid. The interaction of sorbic acid and sulphur dioxide in real food systems is the subject of the fourth chapter. The food systems studied were mayonnaise, tomato puree, orange juice and cottage cheese. The effect of packaging on the rate of degradation of sorbic acid was also investigated. The final chapter deals with a microbiological study of two homologues of sorbic acid, 2,4-heptadienoic acid, 2,4-octadienoic acid. The fungicidal activity of these two compounds, towards selected fungi, was analysed. 4-0xobut-2-enoic acid, a degradation product of sorbic acid in aqueous systems, was also analysed as a possible fungistat.

Master of Science / Department of Horticulture, Forestry, and Recreation Resources / Kimberly A. Williams / Despite extensive evidence that appropriate use of floral preservatives extends postharvest longevity of most fresh flowers, their use by traditional full-service florists has been observed to be highly variable. This research was developed to determine if knowledge about floral preservatives increases consumers’ perception of quality, purchase intention, and price of a floral arrangement. A survey was administered to 222 participants at two locations in Manhattan, Kansas during April 2010. Seventy-three percent of respondents fell within the age range of Gen Y. The survey instrument contained four levels of presentation of a floral arrangement that were associated with increasing knowledge about the use of a floral preservative on consumers’ perceptions about the quality and price of that arrangement. Results were analyzed via within-subjects ANOVA, Bonferroni post-hoc tests, t-tests, and regression analyses. Participants of the survey rated the quality of a floral arrangement higher from Level 2 (presence of floral preservative not explicit) to 3 (presence of floral preservative explicit) and Level 3 to 4 (after reading 191 word count message about floral preservative function and effectiveness). Their intent to purchase the floral arrangement generally increased with each level of presentation. Participants increased the price that they were willing to pay for the floral arrangement at each level of presentation, starting at $25.49 at Level 1 (no floral preservative use indicated) to $29.17 at Level 4. Participants were more knowledgeable about the benefits of floral preservatives and believed that floral preservatives increased the value of floral arrangements after reading a message describing their function and effectiveness more so than before reading the message. Younger participants were more willing to pay more for floral arrangements with floral preservatives than older participants. As consumers become more aware of the use of floral preservatives and more knowledgeable about how and why they are effective, they attribute higher quality to floral arrangements with preservatives, are willing to pay more for arrangements with preservatives, and their purchase intention frequency increases. Florists should consider providing a message about the function and effectiveness of floral preservatives to their customers, and then market their use of these materials.

Giant clams (Tridacnidae) are economic species which have been the main materials for ganbei. Due to a huge decline in population size, it was reported as an endangered species in CITES list. In this study, the effects of different preservative methods on the expression of DNA sequences in giant clams were examined and whether ganbai is made from giant clams were also determined. I collected samples from Kenting, Green Island, Orchid Island, Shaio-Liu-Chu and Penghu Islands. And, ganbei were bought from markets. Species identification was based on four DNA sequences (COI, 16S, 18S, 28S) and morphological characters. The distinction power of four preservative methods (-70 ¢J frozen, 70 % ethanol, dried and freeze dried) on clam samples was evaluated. DNA sequences of CO1 and 16S are the best fragments to distinguish samples at species level. Additionally, a cryptic species of Tridacna noae was found from Tridacna maxima. The 18S and 28S sequences have low variation among giant clam species which are more suitable for higher level of phylogeny. The DNA fragments with different preservative methods were mostly in good condition having extracted DNA size up to 10 Kb. The sequencing divergences of the four preservation were 0 - 0.020 within an individual and 0 - 0.070 among individuals. In conclusion, the four preservative methods are similar in sequence expression. Ganbei made from giant clams was not found in the market. Instead, commercial ganbei are made from scallops, mostly Patinopecten yessoensis and some Argopecten irradians.

No description available.

Borate can be a potential candidate to protect building envelope components from biodegradation as it has low toxicity and can penetrate wood without pressure treatment, even in the refractory species commonly used in construction industries as structural components. In this research, wood moisture content, grain direction, formulation and species that affect the diffusion of borate in refractory species were investigated. Two highly concentrated formulations were applied and a novel approach (borate bandage) was used to keep the preservative on the surface and enhance the diffusion by reducing surface drying. From ANOVA test for different diffusion periods and depths of penetration, it was found that grain directions and moisture content are significant factors. A mould test was performed, the diffusion co-efficients were calculated and some recommendations were made about the quantity required to protect a specific volume of wood considering the distance moved by diffusion and volume treated in different directions.

Borate can be a potential candidate to protect building envelope components from biodegradation as it has low toxicity and can penetrate wood without pressure treatment, even in the refractory species commonly used in construction industries as structural components. In this research, wood moisture content, grain direction, formulation and species that affect the diffusion of borate in refractory species were investigated. Two highly concentrated formulations were applied and a novel approach (borate bandage) was used to keep the preservative on the surface and enhance the diffusion by reducing surface drying. From ANOVA test for different diffusion periods and depths of penetration, it was found that grain directions and moisture content are significant factors. A mould test was performed, the diffusion co-efficients were calculated and some recommendations were made about the quantity required to protect a specific volume of wood considering the distance moved by diffusion and volume treated in different directions.

The polyene macrolide antibiotic natamycin (Antibiotic A-5283) is commonly used to retard the growth of surface molds on various cheese varieties. Natamycin is commonly applied to the surface of cheese by dipping or spraying, using an aqueous dispersion containing 200 to 300 ppm of the additive. The large molecular weight of natamycin, 666 g/mol, and conjugated double bond structure causes it to be extremely insoluble in water and most food grade solvents. The inability to apply natamycin in true solution creates void non-treated areas on the food surface. These non-treated areas promote the growth of fungal organisms. A water soluble N-alkyl semisynthetic derivative of natamycin was synthesized by the Michael addition reaction of the parent with a N-substituted malemide. A comparative study investigating the effectiveness of the semisynthetic derivative of natamycin and the parent antibiotic in suppressing mold growth on one month aged shredded Cheddar cheese modified atmosphere packaged (MAP) was performed. A 20 ppm natamycin treatment effectively suppressed visible mold growth (<104 CFU/g) in MAP samples for up to 30 days after opening. The 20 ppm semisynthetic derivative performed similarly to the 10 ppm natamycin treatment in retarding mold growth. Visible mold growth did not occur for these treatments in MAP samples until 20 days after opening. Analysis of storage conditions revealed that an outgrowth of mold in shredded cheese occurred in MAP packages stored longer than 15 days. This bloom in mold growth was attributed to the degradation of natamycin and the semisynthetic derivative throughout storage. The stability and degradation of natamycin and the derivative were monitored throughout the study. Antibiotic concentration on the cheese surface was quantified by molecular absorption spectrometry. Results from this study showed, heavily contaminated samples caused the rate and loss of natamycin and the derivative to increase. Antibiotic concentration decreased at a similar rate in MAP and open package conditions. Natamycin and derivative were found to have similar degradation properties. / Master of Science

Master of Science / Food Science / J. Scott Smith / The objective of this study was to observe the effect of natural cocoa powder versus 200 ppm of tocopherols on delaying the onset of oxidative rancidity in peanuts, peanut butter, and peanut oil. The samples were obtained from a single lot of blended Runner peanuts after roasting, grinding, and pressing. The samples were treated within a week of initial roasting with either 200 ppm of mixed tocopherols or 2.5% cocoa powder. The development of oxidation was monitored by peroxide value (PV) and gas chromatography monitoring of hexanal development. The peanut butter samples were assessed by a professional sensory panel using descriptive analysis for the development of rancidity. The data was analyzed using JMP SAS software. In peanuts, the cocoa powder sample developed significantly lower levels of oxidation identifiers than the tocopherol or control samples. In peanut oil, there was no significant difference in levels of oxidation identifiers between the treatments. In peanut butter, the PV was significantly higher in the tocopherol sample than the cocoa powder or control samples, but no significant difference was observed in hexanal. The results of the sensory analysis indicated that the cocoa powder depressed the perception of both positive and negative attributes compared to the tocopherol and control samples. This study showed that cocoa powder may be a more effective preservative than an untreated sample or a sample treated with 200 ppm of tocopherols in peanuts and peanut butter; however, cocoa powder at 2.5% w/w basis did not perform as a significant antioxidant in peanut oil.

Nesse estudo, utilizamos a oleoresina de capsaicina, extraído da pimenta Malagueta (Capsicum frutensens) e da pimenta Dedo-de-moça (Capsicum baccatum), para a preservação de amostras de madeira contra o ataque do fungo Paecilomyces variotti. Os preservantes naturais foram aplicados em corpos de prova de madeiras do gênero Pinus sp. e Hymenae sp. (Jatobá) com as dimensões 5,0 x 3,0 x 1,0 (cm). A seguir, esses corpos de prova foram expostos ao fungo para o acompanhamento do seu desenvolvimento. As análises mostraram que o preservante natural retardou o crescimento do fungo, sendo a oleoresina de capsaicina extraído da pimenta Malagueta a mais eficiente se comparada à oleoresina extraída da pimenta Dedo-de-moça e ao óleo de linhaça. A partir da medida de ângulo de contato observou-se que o preservante de oleoresina da pimenta Malagueta proporcionava uma maior molhabilidade para as duas espécies de madeiras. A técnica de FTIR-ATR indicou que os preservantes não modificaram a estrutura das madeiras e a análise de raios X revelou que o desenvolvimento do fungo provocou uma perda de estabilidade e periodicidade nas estruturas das madeiras. Através do teste de proporção utilizado para a análise do desenvolvimento do fungo, comprovou-se estatisticamente que o seu crescimento foi menor para as amostras com os preservantes das pimentas. Pelo MEV foi possível visualizar as estrutura de hifas do fungo sobre a madeira. E a perda de massa para ambas as espécies de madeiras foram menores quando foram utilizados os preservantes, sendo o Pinus a espécie que sofreu maior degradação. / In this study, were used the oleoresin capsaicin, extracted from Capsicum frutensens and Capsicum baccatum, for the preservation of wood samples against the attack of the Paecilomyces variotti fungus. The natural preservatives were applied to Pinus sp. and Hymenaea sp. (Jatobá) specimens with the dimensions 5.0 x 3.0 x 1.0 (cm). Subsequently, these specimens were exposed to fungus and their development was monitored. . Analyses showed that the natural preservative slowed the growth of the fungus. Action of the oleoresin capsaicin extracted from Chilli pepper is the most efficient when compared to pepper oleoresin extracted from Capsicum frutensens and Capsicum baccatum and also with the linseed oil. The contact angle measured showed that the preservative of Oleoresin Chilli Pepper offered a higher wettability for both wood species. FTIR-ATR technique indicated that the preservatives did not change wood structure and X-ray analysis revealed that the development of the fungus caused a loss of stability and periodicity in the wood structures. At proportion test to analyze the development of the fungus, it was shown statistically that their growth was lower for the samples with preservatives peppers. It was possible to visualize the hyphae structure by scanning electronic microscopy technique. Mass loss of both wood specie was lower when preservative was used, and Pine species was more degraded.