<p>U radu je ispitana interakcija tri vrste komercijalnih prehrambenih vlakana (Fibrex, inulin HPX i inulin GR) sa strukturnim komponentama hlebnog testa. Na različitim pH vrednostima (pH 7, pH 5, pH 4 i pH 3) ispitane su fizikohemijske osobine vlakana, pri čemu Fibrex ima najveći kapacitet zadržavanja vode od 421% dok inulin GR najmanji od svega 4.2%. Na osnovu reolo&scaron;ke osobina testa sa vlaknima u količini od 5 i 10% dobijen je uvid u interakciju vlakana sa proteinskim kompleksom i klajsterisanim skrobom. Reolo&scaron;ke osobine hlebnog testa zavise od količine i vrste inkorporiranih vlakana&nbsp; dok pH vrednost vode za zames ima mali uticaj na ove pokazatelje. Dodatkom 5 i 10% fibrex-a i inulina HPX dobija se hleb dobrog kvaliteta, sa značajnim padom svarljivih ugljenih hidrata i promenjenog nutritivnog sastava koji ima osobine funkcionalne hrane pri čemu fibrex tamni boju a inulin HPX i GR vizuelno ne menja boju hleba u odnosu na hleb bez vlakana. Statistička obrada podataka je potvrdila pozitivan uticaj vlakana na testa u zamrznutom stanju. Koeficijenti diskriminacije pokazuju da je najveći uticaj vlakana na zavr&scaron;nu fermentaciju testa je posle 1 dana (199.006 i 5.739), a pozitivan uticaj vlakana na zapreminu hleba izražen je posle 30 dana (9.416) a na kvalitet sredine posle 60 dana (.841). Termodinamičkim merenjima kinetike zamrzavanja/odmrzavanja testa sa vlaknima utvrđeno je da inulina GR doprinosi skraćenju postupka &scaron;to potvrđuje koeficient determinacije R2 (0.966 i 0.981) dok testo sa fibrexom ima najmanji koeficijent determinacije R2 (0.939 i 0.951) &scaron;to pokazuje da ovo vlakno najlo&scaron;ije utiče na kinetiku zamrzavanja/odmrzavanja. Kinetika zamrzavanja/odmrzavanja može se definisati matematičkim modelom koja odgovara jednačini sa kvadratnim polinom , odnosno jednačini za nestacionarni temperaturni profil sa kvadratnim članom Y= b₀+b₁^*X +b₂^*X².</p> / <p>The interaction of three different commercial<br />fibers (Fibrex, inulin HPX and inulin GR) with<br />structural elements of bread dough was tested.<br />Physico/chemical fiber characteristics at<br />different pH values point that the greatest<br />water binding capacity (421%) is attributed to<br />fibrex, contrary to the value of 4,2%<br />experienced for inulin GR. Rheology of dough<br />containing 0 to 10% of either fiber type proved<br />the insight in the interaction between fibers<br />and proteins and also fibers and starch gels.<br />Dough rheology is influenced the most by fiber<br />characteristics and incorporated quantity,<br />contrary to pH value of water at mixing stage.<br />Statistical data interpretation proved the<br />positive contribution of fibers on dough at<br />freezing<br />Discrimination coefficients are confirming that,<br />on the whole, the greatest influence fibers have<br />on final proof after1 day of freezing (199.006<br />and 5.739) and their beneficial influence is<br />experienced after 30 and 60 days of freezing on<br />bread volume (9.416) and bread crumb quality<br />(0.841), respectively. Thermodynamic<br />measuring of freezing/thawing kinetics of<br />dough containing fibers point that inulin GR is<br />beneficial in shortening the procedure,<br />confirmed by values for determination<br />coefficient R&sup2; (0.966 and 0.981), contrary to the<br />contribution of Fibrex where the smallest<br />values for those coefficients were experienced,<br />R&sup2; (0.939 and 0.951 proving that fibrex is not<br />contributing to the freezing/thawing kinetics.<br />Freezing/thawing kinetics can be adequately<br />defined by the mathematical model of square<br />polynomial, i.e. equation for the non stationary<br />temperature profile with square Y= b₀+b₁^*X +b₂^*X².</p><p>Data presented in this thesis show that,<br />understanding interactions between fibers and<br />dough structure, by the addition of 5 or 10% of<br />either Fibrex or inulin HPX, high quality bread<br />attributed with a significant decrease of<br />digestible carbohydrates and modified nutritive<br />pattern accompanied with attributes of<br />functional food can be made, while Fibrex is<br />adversly contributing to crumb colour contrary<br />to inulin HPX and GR.</p>

X-ray computed tomography presents and ultimate for non-destructive investigation of objects. Under normal circumstances is the object placed on stage and the temperature of the object is defined by ambient air. However there are also cases when observation at freezing or high temperatures is needed to reveal thermal stability of observed object. Naturally the size of used tomography equipment and the object just like form of cooling or heating are subjected to final design. This work provides a summary of used methods for temperature controlled tomography. Furthermore handles about design of cooling chamber capable to reach -40°C by preserving relative high X-ray transparency. As an addition that showed up as a response to additional requirements is here presented a heating chamber, in which the object can be maintained at 80°C . All test and scans were carried out on GE phoenix v|tome|x L240 industrial computed tomography scanner.

Orientador: Eunice Oba / Resumo: A congelação de sêmen é uma ferramenta de grande importância na reprodução de animais domésticos, auxiliando na difusão do do material genético, preservando-o por tempo indeterminado, além do maior aproveitamento do uso de reprodutores com genética superior comprovada. Para que a congelação de sêmen seja eficiente e alcance resultados satisfatórios com a inseminação, utiliza-se no processo o emprego de diluentes, que tem como função proteger a célula contra o choque térmico e manter o espermatozoide viável até o momento da inseminação. O uso de frações de leite como meio diluidor tem se tornado muito conhecida e de grande importância no processo, usando, por exemplo, as micelas de caseína que conferem função de proteção da membrana plasmática e manutenção da viabilidade espermática. Levando em conta essas informações, este trabalho teve como objetivo avaliar a ação do caseinato de sódio nas características seminais pós descongelação do sêmen utilizando diluentes a base de gema de ovo (BB) e o mesmo diluente acrescido de caseinato de sódio 2% (BC).No experimento I, foram colhidos 3 ejaculados de 8 animais (n=24) por eletroejaculação, este sêmen foi divido em duas alíquotas, uma era diluída em meio comercial a base de gema de ovo e a outra alíquota diluída no mesmo meio mas acrescido de 2% de caseinato de sódio, em seguida foram envasadas em palhetas francesas com volume de 0,25 ml e refrigerado 4 horas á 5 °C em seguida congelado em nitrogênio líquido. Após a congelação as amo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The reproduction of domestic animals, helping in the diffusion of the genetic material, preserving it indefinitely, in addition to the greater use of reproducers with proven superior genetics. In order for semen freezing to be efficient and achieve satisfactory results with insemination, the use of diluents is used in the process, which has the function of protecting the cell against thermal shock and keeping the sperm viable until the time of insemination. The use of milk fractions as a diluting medium has become very well known and of great importance in the process, using, for example, the casein micelles that provide a protective function of the plasma membrane and maintenance of sperm viability. Taking this information into account, this study aimed to evaluate the action of sodium caseinate on semen characteristics after semen thawed using egg yolk (BB) diluents and the same diluent plus 2% sodium caseinate (BC) In experiment I, 3 ejaculates were collected from 8 animals (n = 24) by electroejaculation, this semen was divided into two aliquots, one was diluted in commercial medium based on egg yolk and the other diluted in the same medium but added of 2% sodium caseinate, then they were packaged in French straws with a volume of 0.25 ml and refrigerated 4 hours at 5 ° C then frozen in liquid nitrogen. After freezing, the samples were evaluated by computerized analysis of sperm movement (CASA), integrity of plasma and acrosomal membranes and generation of superoxide anion... (Complete abstract click electronic access below) / Mestre

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21138号 / 農博第2264号 / 新制||農||1057(附属図書館) / 学位論文||H30||N5112(農学部図書室) / 京都大学大学院農学研究科食品生物科学専攻 / (主査)教授 谷 史人, 教授 保川 清, 教授 橋本 渉 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

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Muscle foods/meat enhances bioavailability of non-heme iron form the diet. This effect is generally thought to be due to production of peptides, by gastro-intestinal digestion, which reduces/chelate the iron in upper intestine. Dialyzable iron is widely used as an in-vitro indicator of iron bioavailability, and with few exceptions, correlates well with human studies. Human studies have used cooked meat to test the effect on iron, but little attention has been given to the effects of cooking. We studied the effect of heating chicken muscle on the production of dialyzable iron. Chicken breast muscle was homogenized and heated to the temperatures in the range of 130-195oF. The concentration of amino acid binding residues was determined in the heated samples. The samples were then mixed with ferric iron and digested with pepsin and pancreatin. Heating chicken muscle caused a large drop in sulfhydryl (-SH) content and a lesser but significant loss in histidine content, both of which increased progressively with temperature. At 165oF, considered a safe cooking temperature, the loss in –SH and histidine was 75% and 37%, respectively. Changes in dialyzable iron and dialyzable ferrous iron (often considered the best indicator of bioavailability) paralleled the drop in amino acid. Raw uncooked chicken muscle produced about 11 times as much dialyzable iron and 17 times as much dialyzable iron as the control but heating to 165oF reduced the values by 47% and 74% respectively. Heating to 195oF reduced caused a further drop in dialyzable iron values. Our result showed that cooking chicken muscle caused a large decrease in the production of dialyzable iron forms-especially in the ferrous form- and this is correlated with the loss in critical iron binding amino acids.

Two studies were conducted to examine the effects of lactose hydrolysis on freezing point and dipping characteristics of ice cream. The overall research objective was to determine changes in freezing point, texture and ease of dipping ice cream as a result of lactose hydrolysis. It was also the goal of this research to relate observations from the sensory dippability study with hardness and yield stress data to determine if the latter methods could be used as an alternative to human testing of dippability. In the first experiment, ice cream mixes were treated with lactase (EC 3.2.1.23) to cause 0 to 83% lactose hydrolysis. Lactose hydrolysis decreased the freezing point from -1.63oC in the control (0% hydrolysis) to -1.74oC in the 83% hydrolyzed sample (p < 0.05). Firmness decreased from 0.35 J in the control sample to 0.08 J in the 83% hydrolyzed sample. Lactose hydrolyzed samples melted at a faster rate than the control. There was a difference (p < 0.05) in ease of dipping between samples treated with lactase and the control. There were no perceived differences in sweetness and coldness. In the second study, ice cream mixes were treated with lactase (EC 3.2.1.23) from the microbial sources Kluyveromyces lactis and Aspergillus oryzae to cause 0 to 100% lactose hydrolysis. Compression measurements and yield stress as measured by the vane method were both affected by the temperature of the samples. R2 values for compression measurements as related to lactose hydrolysis were higher then those obtained for yield stress measurements. Human evaluation determined a difference (p < 0.05) between the control samples (0% hydrolyzed) and the treatment groups (80% and 100% hydrolyzed). This research demonstrated a relationship between lactose hydrolysis and ease of dipping ice cream. The results implied that the effect of lactose hydrolysis on the dipping characteristics could be evaluated successfully by three different methods: the vane method, compression measurements, and human evaluation. Changes in freezing point due to lactose hydrolysis were minimal, implying that monitoring freezing point is not enough to determine textural characteristics. / Master of Science

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Several thousand coastal perennially ice-covered oligotrophic lakes and ponds have been identified on the Antarctic continent. To date, most hydrochemical studies on Antarctica’s ice-covered lakes have been undertaken in the McMurdo Dry Valleys (more than 20 lakes/ponds studied since 1957) because of their proximity to the McMurdo research station and the New Zealand station Scott Base. Yet, little attention has been given to coastal ice-covered lakes situated in Antarctica’s central Queen Maud Land region, and more specifically in the Untersee Oasis: a polar Oasis that encompasses two large perennially ice-covered lakes (Lake Untersee & Lake Obersee), and numerous small ice-covered morainic ponds. Consequently, this PhD research project aims to describe and understand the distribution, ice cover phenology, and contemporary hydrochemistry of perennially ice-covered lakes and ponds located in the Untersee Oasis and their effect on the activity of the benthic microbial ecosystem. Lake Untersee, the largest freshwater coastal lake in central Queen Maud Land, was the main focus of this study. Its energy and water mass balance was initially investigated to understand its current equilibrium and how this perennially well-sealed ice-covered lake may evolve under changing climate conditions. Results suggest that Lake Untersee’s mass balance was in equilibrium between the late 1990s and 2018, and the lake is mainly fed by subglacial meltwater (55-60%) and by subaqueous melting of glacier ice (40-45%). A recursive stable water isotope (δD-δ18O) evolution model for well-sealed perennial ice-covered lakes that takes into account the effect of changing chemistry in residual waters on δD-δ18O values was then developed and determined that Lake Untersee is in isotopic steady-state. Modeling results also showed that Untersee most likely did not receive additional inputs from surface streams during the last 300–500 years at the time of sampling, in November-December 2017. However, in mid-January 2019, Untersee experienced a glacial lake outburst flood (GLOF) that increased the water level by 2 m (contributing 1.75×107 m3 of water), modifying its water chemistry and inorganic carbon load. High-resolution grain size and carbon isotope analyses of the benthic microbial mats suggest that GLOFs occurred periodically over the Holocene and that those events sporadically increased the primary productivity of its benthic microbial ecosystem. Finally, ice-covered ponds in the Oasis were identified and sampled to compare their morphometric properties, hydrochemical properties, and microbial mat activity with Lake Untersee. It was discovered that the Untersee Oasis ponds offer the full spectrum of ice cover types (i.e., perennial well-sealed, perennial and moat forming, and seasonally ice-covered) and that their hydrochemical properties depend on ice cover type. Empirical pond data was used to determine how Lake Untersee and the ponds themselves will evolve as they transition under a warming climate from well-sealed to moat forming and from moat forming to seasonally ice-covered.

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