Adjustment Of Sorption Isotherms For Seeds Of Phaseolus Vulgaris Cultivars [ajuste De Isotermas De Sorção De Sementes De Cultivares De Feijoeiro]

It is feasible to establish a relationship between free water and seed conservation, through seed water and pure water vapour pressures, at the same temperature. A sorption isotherm describes the equilibrium of an amount of water sorbed by seed components and the vapour pressure or relative humidity, at a specific temperature. The main aim of this work was to analyze sorption isotherms for two Phaseolus vulgaris cultivar seeds. Seed moisture contents were adjusted, prior to storage, either by dehydration in desiccators over silica gel or rehydration over water. Seed sub sample weights were recorded periodically to control the amounts of removed or sorbed water. When corresponding weights to the desired seed moisture contents had been achieved, the process was over. Seed moisture content and water activityr determinations were carried out and different empirical equation models were used aiming at correlating experimental data of sorption isotherms of the seed samples. The best fit of the sorption isotherms was achieved through the Oswin 2-parameter model the and Peleg 4-parameter model for seeds of the Tibatã and Una cultivars, respectively.2913539AQUALAB. Analisador de atividade de água Decagon. Brasil: ABRASEQ, 1997. 21p. (Manual, 01)BAKER, R.J., NELDER, J.A., The GLIM system (1978) Release 3, , Oxford: Numerical Algorithms GroupBENEDETTI, B.C., JORGE, J.T., Curvas de umidade de equilíbrio de vários grãos (1987) Ciência e Tecnologia de Alimentos, 7, pp. 172-188. , Campinas, vBRASIL. Ministério da Agricultura e Reforma Agrária. Regras para análise de sementes. Brasília: SNDA/DNDV/CLAV, 1992. 365pBROOKER, D.B., BAKKER-ARKEMA, F.W.HALL, C.W. Grain equilibrium moisture content. In: BROOKER, D.B., BAKKER-ARKEMA, F.W.HALL, C.W. Drying and storage of grains and oilseeds, New York: Van Nostrand Reinhold Company, 1992, p.67-86CHINNAN, M.S., BEAUCHAT, L.R., Sorption isotherms of whole cowpeas and flours (1985) Lebensmittel-Wissenschaft und Technologie, 18, pp. 83-88. , London, vCHUNG, D.S.PFOST, H.B. Adsorption and desorption of water vapor by cereal grains and their products. Part II. Development of the general isotherm equation. Transactions of the American Society Agricultural Engineers, St Joseph, v.10, p.551-554, 1967COMPANHIA NACIONAL DE ABASTECIMENTO. Disponível em: 〈http://www.conab.gov.br〉. Acesso em 2005DICKIE, J.B.SMITH, R.D. Observations on the survival of seeds of Agathis sp. stored at low moisture contents and temperature. Seed Science Research, Wallingford, v.5, p.5-14, 1995ELLIS, R.H., HONG, T.D., ROBERTS, E.H., A low-moisture-content limit to logarithmic relations between seed moisture content and longevity (1988) Annals of Botany, 61, pp. 405-408. , London, vHONG, T.D., ELLIS, R.H., The survival of germinating orthodox seeds after desiccation and hermetic storage (1992) Journal of Experimental Botany, 43, pp. 239-247. , London, vLANGMUIR, I., Adsorption of gases on glass, mica and platinum (1918) Journal of the American, 46, pp. 1361-1403. , Chemical Society, Washington, vNELLIST, M.E., HUGUES, M., Physical and biological processes in the drying of seed (1973) Seed Science and Technology, 1 (3), pp. 613-643. , Zürich, vPARK, K.J., NOGUEIRA, R.I., Modelos de ajuste de isotermas de sorção de alimentos (1992) Engenharia Rural, 3, pp. 81-86. , Piracicaba, vPELEG, M., Assessment of a semi-empirical four parameter general model for sigmoid moisture sorption isotherms (1993) Journal of Food Processing Engineering, 16, pp. 21-37. , Connecticut, vROA, G., ROSSI, S.J., Determinação experimental de curvas de teor de umidade de equilíbrio mediante a medição da umidade relativa de equilíbrio (1977) Revista Brasileira de Armazenamento, 2, pp. 17-22. , Viçosa, vVALENTINI, S.R.T. Efeito da secagem de sementes de perobarosa (Apidosperma polyneuron M. Arg.). 1992. 70f. Dissertação (Mestrado em Engenharia Agrícola), Faculdade de Engenharia Agrícola, Universidade de Campinas, Campinas, 1992VAN DER BERG, C., Description of water activity of foods for engineering purposes by means of the GAB model of sorption (1984) Engineering and Food, 1, pp. 311-321. , MCKENNA, B.M, Ed, London: Elsevier Applied ScienceWANG, X.F., JING, X.M., ZHENG, G.H., Effect of seed moisture content on seed storage longevity (2001) Journal of Integrative Plant Biology, 43, pp. 551-557. , Beijing,