Bacteriocins (BCNs) are ribosomally synthesized polypeptides or proteins with antimicrobial activity, produced by different groups of bacteria. Many lactic acid bacteria (LAB) produce BCNs with broad spectra of inhibition. The antimicrobial activity of BCNs against spoilage organisms (SPOs) has raised considerable interest in their application in juice preservation. The objectives of the study were to: (i) isolate, identify and screen BCN producing bacteria for antimicrobial activity against spoilage bacteria and fungi, (ii) optimize production of BCN from selected producers and (iii) investigate the industrial application of the BCN as a preservative in fruit juice. Eleven LAB strains of BCN producers were screened for antimicrobial activity. BCNs from Lactobacillus plantarum and Pediococcus pentosaceus 34 were the most effective against juice spoilage bacteria and fungi. The effect of medium components on bacteriocin production in L. plantarum and P. pentosaceus 34 was also determined. Clementine:Valencia (1:1) juice was used for the first time as the growth medium for L. plantarum and P. pentosaceus 34. The BCN from L. plantarum showed the highest activity and was, therefore, chosen for juice fermentation studies. The identification of L. plantarum was confirmed by biochemical tests, polymerase chain reaction (PCR) and sequencing of the recA gene. The highest BCN activity was observed for L. plantarum grown in De Man-Rogosa-Sharpe (MRS) and a combination of all supplements (i.e. peptone, MnSO4.H2O, Tween 80, glucose and whey), followed by MRS and Tween 80, peptone, MnSO4.H2O and MRS alone. MRS was a better medium for BCN production than juice [Clementine:Valencia (1:1)]. Size exclusion chromatography (SEC) was used to isolate the active L. plantarum BCN fraction which corresponded to an approximate molecular weight of 3.2 kDa and was proteinaceous in nature. Plantaricin structural genes (plnEF, plnJ, plnK, plnN) were detected in the L. plantarum strain by PCR and sequenced, and were chromosomally encoded as no plasmids could be detected. This implies that the BCN from L. plantarum is most likely a type of class IIa plantaricin which is responsible for the broad inhibitory activity observed. For the industrial application studies, L. plantarum BCN-containing cell free supernatant (BCNsup) added to “Ready to Drink” (RTD) Clementine:Valencia (1:1) juice at concentrations of 3 600 - 500 000 ppm decreased growth of SPOs, Lactobacillus acidophilus and Streptococcus thermophilus. At 250 000 ppm, the L. plantarum BCNsup achieved 5.3 and 6.8 log reductions of the L. acidophilus, after 24 and 48 h, respectively, which is larger than the USFDA (2001) requirement of a 5 log reduction in SPO activity, for preservation of fruit juices. However, there was a decrease in the activity when the BCNsup was applied to industrial (Valor) RTD juice (mango-orange) at decreasing concentrations of 100 000, 50 000 and 25 000 ppm. Organoleptic tests showed that the BCN did not alter flavor or taste of the juice and did not cause toxicity or allergic reactions. A food safety risk assessment was conducted in order to determine the Critical Control Point(s) [CCP(s)] at which the BCN could be applied to control identified microbiological hazards, and a Hazard Analysis and Critical Control Point (HACCP) plan was developed. This is the first report on the optimisation of L. plantarum BCN production in juice [Clementine:Valencia (1:1)], followed by inoculation into RTD juice (mango-orange), including a HACCP plan for the application of the BCN as a preservative in juice.

Certain compounds having the "carbonyl enediol" structure ( Formula omitted) , and also sodium chloride, were studied for use in glazes for frozen whole dressed fish. Incorporation of these compounds caused, in general, formation of thicker, glazes on the fish than did water alone and the glazes so formed were relatively non-cracking. The cyclic compounds, reductinic acid (in concentration 0.6475% or 0.00568M), and 1-ascorbic acid (1.0% or 0.00568M), afforded satisfactory protection against oxidative rancidity for periods of the order of 5 to 6 months. On the other hand, the acyclic compounds, reductone (0.5% or 0.00568M), diammonium dihydroxymaleate (0.518% or 0.00568M), dihydroxy maleic acid (0.84% or 0.00568M), gave comparatively poor protection. Sodium chloride (2.0%) gave about the same protection as water alone. The antioxidants probably protect the fish against oxidative rancidity by rendering atmospheric oxygen unavailable to the indigenous fats. / Science, Faculty of / Zoology, Department of / Graduate

The thesis deals with the use of a dilatometer in studying some of the physico-chemical phenomena occurring in fresh fish flesh when subjected to freezing at temperatures ranging from 0° C to -30° C. Two different kinds of fish flesh, marine lingcod (Ophiodon elongatus) and fresh water rainbow trout (Salmo gairdnerii) were used for comparison. True freezing point determinations of samples of fresh flesh cut from the above species of fish were made and found to be the same, viz, -1.5°C (29.1°F.). The percentage of water removed as ice at varying temperatures below the initial freezing point were calculated by necessary adjustments of experimentally determined values. A permanent net decrease in volume accompanying freezing and thawing of the samples of flesh was observed and measured. This change in volume is probably due to the denaturation of the protine, and was found to be 0.075%. The coefficient of cubical expansion (∝) of anhydrous fish muscle was measured for the first time and found to have the average value of 0.000118 over a temperature range from -30°C. to +20°C. / Science, Faculty of / Zoology, Department of / Graduate

The effects of various aging, thawing and storage methods on the tenderness of frozen broiler Pectoralis major muscle were studied. Initial experiments were carried out to establish standard methods of freezing, cooking and tenderness evaluation to be used in subsequent experiments. The effects of varying the aging, thawing and storage techniques were then investigated using the established methods. Whole carcasses were frozen in a liquid nitrogen blast freezer after cooling in ice water for periods of 1 to 10 hours after slaughter, stored for 1 week at -31°C and thawed for varying lengths of time. The P. major muscles were removed and cooked in boiling water between metal plates. Tenderness evaluations were carried out using the Allo-Kramer shear press. The length of thawing time was shown to greatly influence the degree of toughness of the cooked muscles. When a thawing period of 4 hours in water at 25°C was used, a decrease in toughness took place in carcasses frozen between 1 and 2 hours post-mortem. This was followed by an increase to maximum toughness in birds frozen between 4 and 8 hours post-mortem. Maximum tenderness occurred in birds frozen 10 hours after death. Thawing birds in air at 4°C for 24 and 4 8 hours decreased the level of toughness attained after freezing 4 to 8 hours post-mortem. It did not significantly alter the degree of tenderness reached after 10 hours. Similarly, the decrease in toughness in birds frozen between 1 and 2 hours post-mortem, remained significant. Longer storage (3 months) at -23°C followed by rapid thawing eliminated both the decline in toughness of carcasses frozen between 1 and 2 hours post-mortem and the maximum toughness level attained by carcasses frozen 4 to 8 hours after death. An attempt was made to explain the decrease in toughness in carcasses frozen between 1 and 2 hours postmortem in terms of the aging temperature and medium used prior to freezing. No difference in the pattern was observed, however, when other pre-freezing aging techniques were used. Increases in the sarcomere lengths of muscle frozen at 2 hours post-mortem were observed, corresponding to the increase in tenderness occurring in carcasses frozen at this time. Isometric tension measurements, however, did not correlate well with these observations. Taste panel members were unable to discern differences in the tenderness of muscle frozen between 1 and 3 hours post-mortem although excellent correlations were obtained between Allo-Kramer shear press values and sarcomere length measurements. The results of these experiments therefore show that the ultimate tenderness of broiler muscle can be greatly influenced by the interaction of pre-freezing aging time, length of storage and thawing techniques used prior to cooking. / Land and Food Systems, Faculty of / Graduate

Newtown Pippin and Winesap apples were taken from terminal storage, and prepared as slices to be processed in re-tortable pouches to determine an optimum process using the relatively new pouch technology. Preprocessing treatments included calcium chloride as a texture modifier, sodium bisulfite as a microbial inhibitor and colour stabiliser, and sodium acid pyrophosphate as a colour stabilizer. These reagents were added to the slices by vacuum infusion, hot blanching or cold dipping to determine their effects on the final product. The slices were packed in 300 gram pouches that were evacuated, then flushed with either nitrogen or carbon dioxide before sealing. The samples were stored at 22 and 35°C and were examined by physical, chemical and sensory methods, at intervals of two weeks, six weeks and five months after processing to determine the changes occurring within the samples. During storage, quality changes did occur, which affected the acceptance of the samPles/ particularly at the higher temperatures. Texture was vastly improved with the addition of calcium ions to old apples. Colour remained significantly lighter in samples with higher SO₂ levels. The addition of pyrophosphate was also shown to increase the lightness of the samples. The levels of reducing sugars and pH were shown to increase with the length and temperature of storage. Preparatory methods were also shown to have a great influence on the quality of the final product. Hot blanching of apple slices lead to a lower quality product than either vacuum infusion or cold dipping. Vacuum infusion was by far the most efficient preparatory method but resulted in a product with a translucent appearance and a bland flavour. Cold dipping produced the best final product. The use of carbon dioxide atmospheres within the pouch produces a lower pH and a softer texture in the samples. Nitrogen was found to be the better of the two gases for quality maintenance. In general, it was determined that apples from terminal storage were more difficult to process into a product of good quality than were apples stored for only a short time after harvest. / Land and Food Systems, Faculty of / Graduate

This thesis will analyze each of the characteristics that render modern residential architecture ripe for demolition. I will perform regional case studies of areas with high concentrations of modern residences and evaluate the successes and failures of modern preservation in those areas. The thesis will layout a more pragmatic approach to the preservation of modern residences taking into account the requirements of preservationists, homeowners, and the real estate market. / 0 / SPK / specialcollections@tulane.edu

This thesis includes a basic discussion on the evolution and basic anatomy of the mid-century curtain wall through an analysis of early precedents and historic construction catalogues. Typical deterioration mechanisms are discussed, especially those specific to poor thermal performance. A basic discussion is included on the foundational principles of thermal patterns exhibited in fenestration systems, which leads the informed reader into the case study simulation discussions. The simulation studies were conducted with THERM and WINDOW software developed by the Lawrence Berkley National Laboratory, which operates under the auspices of the United States Department of Energy for the purpose of advancing building science technology. The results of this study strongly suggest that poor envelope performance should not be categorized as an impossible obstacle – it is a technical issue that can be resolved through reasonably minimal interventions. The thermal simulations reveal substantial improvement over the existing baseline, and in many cases, exceed modern energy code. / 0 / SPK / specialcollections@tulane.edu

This thesis will examine theories and methodologies regarding the balance of natural aesthetics and architectural conservation in the preservation of architectural remains. Ruins have been used as historic garden "follies" for centuries, this thesis will examine how practitioners have balanced the ecological needs of the gardens with the conservation and preservation of ruins. The primary case study used for this thesis will be the Gardens of Ninfa in the Province of Latina, Italy, where conservators and landscapers have worked to preserve the gardens of the noble Caetani family and the Roman and Medieval ruins contained within the gardens for centuries. This thesis will examine how they chose to treat, interpret, and display the ruins within the existing garden landscape. This thesis will also explore the consequences of this approach based on the backdrop of the established theoretical principles of John Ruskin and Eugène-Emmanuel Viollet-Le-Duc, as well as the prevailing Italian theories on restoration of ancient ruins as given by prominent Italian theoreticians. Also examined will be the demonstrated capability and discussion of biologically-based conservation methods used in ruins conservation practice. / 0 / SPK / specialcollections@tulane.edu

0 / SPK / specialcollections@tulane.edu

This thesis describes a series of investigations into the problems that hamper the progress of myocardial preservation for transplantation in man. Six positive aspects of cardiac preservation have emerged from this study: - (1) A clear fluid hyperosmolar solution was formulated that adequately preserved viability of pig and baboon hearts. (2) A pneumatically powered portable preservation unit was designed which successfully preserved pig and baboon hearts when assessed by either functional testing or orthotopic transplantation. (3) A method of in vitro testing of hearts was developed that correlated with results from orthotopic transplantation. (4) A technique of cardiac autotransplantation in baboons was perfected. (5) The high release of lysosomal acid phosphatase during the period of hypothermic preservation was shown to be non-pathological and was reversible after a period of warm blood perfusion. (6) Successful preservation of human hearts for periods longer than 4 hours, not previously achieved, was obtained. The preservation solution and the portable preservation unit that emerged from this experimental study were thoroughly investigated before clinical application. During the development of this perfusate the author had numerous consultations and discussions with colleagues and senior members of neighbouring departments.