ABSTRACT Cryopreservation is a technique used to preserve genetic material at ultra-low temperatures in cryogenic germplasm banks. In order to enable the cryopreservation of a seed, it is necessary to study its appropriate freezing temperature and its water content, because seeds reach maximum physiological quality with high water contents, and they tolerate drying when they are orthodox seeds, but they may not tolerate cryopreservation. Therefore, the objective of this study was to analyze the influence of initial water content (50 to 10% wet basis) on the kinetic behavior of the lima bean seed at the temperature of −150 °C, in addition to determining changes in its physiological quality (germination and vigor) when cryopreserved (−150 °C) for 30 days with the variation of initial water contents (50 to 10% wet basis). For this purpose, changes in lima bean size (length, width, and thickness), sphere-equivalent radius and volume, and kinetics of seed cryopreservation as a function of its water content. The Fourier model and the Cavalcanti-Mata & Duarte models I and II were used for cryopreservation modeling, in addition to proposing a new model for cryopreservation kinetics in which water content determines the kinetic behavior. The conclusion was that the water content of 10% wb should be used for the lima bean seed cryopreservation since its physiological quality was not affected by cryopreservation at −150 °C. The model that best represents the experimental data is Cavalcanti Mata & Duarte Model II.

ABSTRACT Based on mass and energy balance equations and data collected in specialized bibliographies, it was proposed a methodology for modeling of an ice bank for thermal storage of energy at low temperature to be used in milk cooling. The data obtained by the equations arrangement were used in the design and installation of a real system, which was tested to collect data and to compare it with the estimated. The data obtained in terms of prediction of ice formation, temperature of the ice bank, water and capacity of the selected refrigeration system prove the adequacy of the equations arrangement, showing that it can be used as a tool for sizing solid ice bank in smooth pipe coils, with good approximation.

O objetivo neste trabalho foi obter as curvas de congelamento do feijão, cultivar 'gordo', nas temperaturas de -25, -50, -170 e -196 ºC e determinar sua difusividade térmica efetiva. Com vista à obtenção das curvas de congelamento das sementes nas temperaturas de -25 e -50 ºC utilizou-se um freezer criogênico horizontal; para a temperatura de -170 ºC, o vapor de nitrogênio e, para a temperatura de -196 ºC, as sementes foram submersas no nitrogênio líquido. Afim de expressar o comportamento cinético do congelamento das sementes de feijão, foi usado o modelo de Fourier levando-se em consideração o primeiro termo da série, além dos Modelos I e II de Cavalcanti-Mata & Duarte. Os resultados obtidos indicam que os três modelos representam satisfatoriamente os dados experimentais da cinética de congelamento; apesar disto, com o Modelo II de Cavalcanti-Mata & Duarte se obtém o maior coeficiente de determinação. Constata-se também que, para congelar as sementes de feijão até atingir o equilíbrio térmico na temperatura de -25 ºC, o tempo necessário foi de 1200 min; em temperatura de -50 ºC o equilíbrio foi atingido com 480 min; a -170 ºC o equilíbrio se deu em 180 min e, a -196 ºC, em 30 min.

The objective of this study was to obtain the freezing curves of beans, variety 'gordo' at temperatures of -25, -50, -170 and -196 ºC, and determine their effective thermal diffusivity. For the curves of freezing beans seeds at temperatures of -25 and -50 ºC a cryogenic horizontal freezer was used, for temperature of -170 ºC, nitrogen vapor was used and at temperature of -196 ºC seeds were submerged in liquid nitrogen. To express the kinetic behavior of the freezing of bean seeds, the Fourier model was used taking into account the first term of the series and; Cavalcanti-Mata & Duarte model I and II. The results indicate that the three models satisfactorily represent the experimental data of the kinetics of freezing, though with Model II of Cavalcanti-Mata & Duarte highest coefficient of determination were obtained. It is concluded that time necessary to freeze the seeds of beans at temperature of -25 ºC was of 1200 min; at temperature of -50 ºC the equilibrium was reached with 480 min; at -170 ºC the time was 180 min and at -196 ºC it was 30 min.

O objetivo do trabalho foi determinar a difusividade térmica aparente de sementes de cajá avaliando o efeito da variação do teor de água e da temperatura e ajustar diferentes modelos matemáticos aos valores experimentais. Sementes com a faixa de teor de água de 6,05 a 61,84% (b.u.) foram submetidas a secagem e à temperatura de 40 ºC. A redução do teor de água ao longo da secagem foi acompanhada pelo método gravimétrico (perda de massa) enquanto a difusividade térmica aparente da semente de cajá foi determinada pelo método de Dickerson. Concluiu-se que a difusividade térmica aparente, em temperatura acima do congelamento e em ultrabaixas temperaturas em função do teor de água (b.u), podem ser representados satisfatoriamente por um modelo de regressão linear e que o valor da difusividade térmica aparente aumenta exponencialmente com o aumento da temperatura.

The aim of this study was to determine experimentally the apparent thermal diffusivity caja seeds, evaluating the effect of variation of water content and temperature and adjust different mathematical models to experimental values. Seeds with the range of water content from 6.05 to 61.84% (wb) subjected to drying at a temperature of 40 ºC were studied. The reduction of water content during drying was monitored by gravimetric method (weight loss). The apparent thermal diffusivity of caja seed was determined by the method of Dickerson. It was concluded that the apparent thermal diffusivity in temperature above freezing and ultralow temperatures as a function of water content (wb), can be satisfactorily represented by a linear regression model and that value of the apparent thermal diffusivity increases exponentially with increasing temperature.

Os métodos atualmente utilizados para realização de análise sensorial têm deixado muito a desejar por não traduzir satisfatoriamente os resultados. Diante deste problema, analisou-se a possibilidade de introdução de um fator que medisse o índice de concordância dos provadores sobre determinado aspecto analisado. Para validação deste coeficiente, foi avaliada a concordância entre julgadores na análise sensorial para três diferentes amostras de suco de pinha (Annona squamosa L.): uma constituída apenas do suco de pinha sem leite e duas com diferentes concentrações pinha/leite. Utilizou-se a Análise de Componentes Principais (ACP) e também a nova metodologia proposta pelos autores, com base na definição do desvio-padrão, aplicada às frequências absolutas das notas dos julgadores, para cada propriedade sensorial estudada. Com esta metodologia, definiu-se uma relação para o cálculo de uma medida de concordância entre os julgadores, denominada de coeficiente de concordância, a qual pode assumir valores de 0 a 100% e também permite comparações que não são possíveis, utilizando-se da ACP. Por fim, concluiu-se que tal metodologia é mais indicada que a ACP, na avaliação da concordância entre os julgadores na análise sensorial.

The methods now used, for accomplishment of sensorial analysis, do not translate the results satisfactorily. Because of this problem, it was analyzed the possibility of introducing a factor that measures the agreement index of the tasters on a particular aspect analyzed. To validate this coefficient, the agreement coefficient among the sensory analysis tasters had been evaluated using three different annona samples; one consisting only of the annona juice (without milk) and the other with different concentrations of juice / milk (mass percentage). This evaluation was accomplished by the Analysis of Main Components (ACP) and by the new methodology also proposed by the authors, with base in the definition of the standard deviation, applied to the absolute frequencies of the tasters' notes, for each studied sensorial property. With this methodology it was defined a relation for calculation of an agreement measure among the tasters, denominated of agreement coefficient, which can assume values from 0 to 100%. Finally, it was concluded that such methodology is more suitable than ACP, in the evaluation of the agreement among the tasters in the sensorial analysis, since that methodology results in a measure of the agreement degree and it allows comparisons that are not possible being used ACP.

Neste trabalho se objetivou avaliar a crioconservação de sementes de algodão. Inicialmente se determinou o teor de água limite para a crioconservação (TALC); para esta determinação as sementes foram imersas em nitrogênio líquido durante cinco dias e, após este período, foram descongeladas e submetidas ao teste de germinação e vigor. O delineamento estatístico empregado foi o inteiramente casualizado com arranjo fatorial. Utilizou-se um lote de sementes com teor de água limite previamente determinado para as diferentes cultivares, a partir do qual se procedeu ao seu armazenamento em nitrogênio líquido e no vapor do nitrogênio. O delineamento experimental usado nesta etapa foi o inteiramente casualizado, em parcela subdividida no tempo. Em cada período de armazenamento as sementes foram submetidas a testes de germinação e vigor e de acordo com os resultados obtidos, concluiu-se que: o TALC, durante 5 dias para a crioconservação das quatro cultivares, considerando-se a germinação dessas cultivares, encontra-se entre 6 e 8% e, quanto ao vigor das sementes, o TALC foi de 6%; sementes das diferentes cultivares podem ser crioconservadas em banco de germoplasma, nas duas temperaturas; a crioconservação aumenta o percentual de germinação e vigor das sementes de algodão, em virtude dessa temperatura promover quebra de dormência pela ação do frio.

The objective of this work was to evaluate the crioconservation of cotton seed. At first, the water limit content for the crioconservation (TALC) was determined. For this determination, the seeds were immerse in liquid nitrogen during five days and after this period they were unfrozen and submitted to germination and vigor test. The statistical design used was completely randomized with the factorial. A portion of seeds was used with water limit content previously determinated for the different cultivars, since this has proceeded the storage in liquid nitrogen and in nitrogen vapor. The experimental design used in this stage was completely randomized in subdivided plots over time. In each period of storage the seeds were submitted to germination and vigor tests. According to the obtained results, it was concluded that: (a) the water content limit for crioconservation (TALC), during 5 days, for the conservation of four cultivars, considering the germination of these cultivars, is between 6 and 8% and, as to the seed vigor, the TALC was 6%; (b) the seeds of the different cultivars can be crioconserved in germoplasma bank at two temperatures; (c) the crioconservation increases the percentage of germination and the vigor of the cotton seeds, due to this temperature promoting termination of dormancy by the action of cold.

A micropropagação in vitro tem-se apresentado como técnica que possibilita várias metodologias que, por sua vez, contribuem com a redução no tempo, para a obtenção de novas cultivares. Objetivou-se com esse trabalho avaliar o comportamento dos genótipos BRS-Verde, BRS-200-Marrom, 6M-Mocó-Branco e BRs(-1)87 8H Branco na indução do superbrotamento em diferentes combinações de reguladores de crescimento. As sementes, para obtenção do material de partida, foram desinfectadas em solução de hipoclorito de sódio a 1% de cloro ativo por 20 min. Os brotos foram induzidos, a partir de explante de nós cotiledonares em meio básico MS, suplementado com 6-benzylaminopurine (BAP), Cinetina ( KIN) e Tiadiazuron (TDZ), isolados ou associados em diferentes concentrações. O material foi mantido por 40 dias em sala de crescimento, sob condições ambientais controladas. Utilizou-se 10 tubos de ensaio por tratamento com um explante por frasco, em um delineamento inteiramente casualizado, com arranjo fatorial de 4 x 17 (quatro genótipos x dezessete meios). Observou-se que o meio MS suplementado com BAP (2,0 mg L-1) isolado ou associado com KIN (1,0 mg L-1), promoveu maior capacidade de regeneração e altura de brotos; o meio MS suplementado com BAP (2,5 mg L-1) estimulou maior altura de brotos e o meio MS suplementado com TDZ (1,0, 0,50 e 0,25 mg L-1) afetou a capacidade de regeneração de brotos, observando-se maior formação de calos.

The micropropagation in vitro has been presented as a technique that allows various methodologies which, for in turn, contribute to a reduction in the time to obtain new cultivares. The objective of this work was to evaluate the behavior of the genotypes BRS-Verde, BRS-200-Marrom, 6M-Mocó-white and BRs(-1)87-8H- white, in the induction of the multiple shoots in different combinations of growth regulators. The seeds, to obtain the initial material, were placed in a solution of 1% sodium hypochlorite of active chlorine for 20 min. The shoot had been induced, in the explant of cotiledonary nodes in MS medium basic, supplemented with 6-benzylaminopurine (BAP), Cinetina (KIN) and Tiadiazuron (TDZ), isolated or associated in different concentrations. The material was kept for 40 days in growth chamber, under controlled ambient conditions. 10 mL of medium was used for treatment with a explant for culture tube, in an entirely randomized design, with factorial arrangement of 4 x 17 (four genotypes x seventeen medium). It was observed that the MS medium supplemented with BAP (2.0 mg L-1) isolated or associated with KIN (1.0 mg L-1), promoted greater capacity of regeneration and height of sprouts; MS medium supplemented with BAP (2.5 mg L-1) stimulated greater height of sprouts and the MS medium supplemented with TDZ (1.0, 0.50 and 0.25 mg L-1) affected the capacity of regeneration of sprouts, a larger formation of calluses was observed.

A polpa de cajá tem sido exportada da região Nordeste para todo o Brasil, e uma das maneiras de conservá-la é processando-a e armazenado-a na forma congelada. Durante o processamento, existem dois fatores que favorecem a qualidade do produto a ser armazenado: a rapidez com que o produto é congelado e a adição de açúcar como forma de dificultar a ação microbiológica. Na linha de processo, algumas propriedades termofísicas, como o calor específico e a densidade, se alteram com as temperaturas negativas e com o teor de sólidos solúveis totais; dessa forma, para o dimensionamento adequado de máquinas e equipamentos, torna-se necessário conhecer essas propriedades, principalmente quando se operam equipamentos criogênicos, onde as temperaturas podem chegar a -196 ºC. Neste trabalho, determinaram-se a densidade e o calor específico da polpa do cajá com quatro diferentes níveis de sólidos solúveis totais (natural da polpa; 20; 40 e 60%) e temperaturas entre -196 ºC e -18 ºC. A densidade foi obtida pela razão entre a massa da polpa e o seu volume. O volume foi determinado pelo método do deslocamento de massa (água) e o calor específico por meio de balanço de calor entre a massa da polpa, a massa do cilindro que contém a polpa e a massa do gelo. Conclui-se que a densidade da polpa de cajá aumenta em função da redução da temperatura e do aumento do teor de sólidos solúveis totais de 9 para 60 °Brix e que o calor específico da polpa diminui com a diminuição de temperatura e aumenta com a concentração de sólidos solúveis totais.

The cajá pulp has been exported from the Northeast area to all parts of Brazil, and one of the ways of conserving it is processing and storing it in the frozen form. During the processing, there are two factors that favor the quality of the product to be stored; the speed that the product is frozen and the addition of sugar as a form of hindering the microbiologic action. In the process line, some thermo-physics properties like the specific heat and the density change themselves according to the negative temperatures and the total soluble solids content. Then, it's necessary to know those properties mainly when cryogenic equipments are operated, where the temperatures can be -196 ºC to have the appropriate dimension of machines and equipment. Therefore, in this work, it was determined the cajá pulp density and the specific heat for 4 different levels of total soluble solids (natural of the pulp; 20; 40 and 60%) and temperatures from -196 to -18 ºC. The density was obtained by the rate between mass of the pulp and its volume. The volume was determined by the displacement of mass (water) and the specific heat was determined by the balance of heating among the mass of the pulp, the mass of the cylinder that contains the pulp and the mass of the ice. The results allow to conclude that: a) the cajá pulp density increases in function of the variation of the temperature from -18 to -196 °C, and also as a function of the increase of the total soluble solids content from 9 to 60 °Brix; b) the cajá pulp specific heat decreases according to the decrease of the temperature and it increases according to the concentration of total soluble solids.