Adsorption isotherms and thermodynamics properties of water yam flour

Main Article Content

H.O. Owo
A.A. Adebowale
O.P. Sobukola
A.O. Obadina
O.E. Kajihausa
M.O. Adegunwa
L.O. Sanni
K. Tomlins

Keywords

water yam flour, water activity, differential enthalpy, differential entropy, compensation theory

Abstract

Adsorption isotherms of water yam flour were determined by static gravimetric method of saturated salt solutions in the range of water activities between 0.11 and 0.96 and at temperatures of 25, 35 and 45 °C. The experimental sorption data was fitted to five models: Guggenheim-Anderson-De Boer (GAB), Peleg, Iglesias-Chirife, Exponential and Oswin and the differential enthalpy and entropies were determined. Equilibrium moisture contents decreased with increase in temperature at all the water activities studied. Peleg model gave the best fit for the sorption isotherm of water yam flour. Monolayer moisture content values estimated from the GAB-model were found to decrease with increases in temperature. The differential enthalpy and entropy decreased with increases in moisture content. The isokinetic temperature was 371.32 K and the compensation theory was satisfied

Abstract 42 | PDF Downloads 29

References

Adebowale, A.A., Sanni, L., Awonorin, S., Daniel, I. and Kuye, A., 2007. Effect of cassava varieties on the sorption isotherm of tapioca grits. International Journal of Food Science and Technology 42: 448-452.
Afoakwa, E.O. and Sefa-Dedeh, S., 2001. Chemical composition and quality changes occurring in Dioscorea dumetorum pax tubers after harvest. Food Chemistry 75: 85-91.
Ahmed, J., Ranaswamy, H.S. and Khan, A.R., 2005. Effect of water activity on glass transitions of date pastes. Journal of Food Engineering 66: 253-258.
Al-Muhtaseb, A.H., McMinn, W.A.M. and Magee, T.R.A., 2004. Water sorption isotherms of starch powders, part 1: mathematical description of experimental data. Journal of Food Engineering 61: 297-307.
Anderson, R.H., 1946. Modification of the BET equation. Journal of American Chemical Society 68: 689-691.
Brunauer, S., Emmet, P.H. and Teller, E., 1938. Adsorption of gases in multi-molecular layers. Journal of American Chemical Society60: 309-319.
De Boer, J.H., 1953. The dynamic character of adsorption (2nd Ed.). Clarendon Press, Oxford, UK.
Ekwu, F.C., Ozo, N.O. and Ikegwu, O.J., 2005. Quality of fufu flour from white yam varieties (Dioscorea spp.). Nigeria Food Journal 23: 107-113.
Fasina, O.O., 2006. Thermodynamics properties of sweet potato.Journal of Food Engineering 75: 149-155.
Guggenheim, E.A., 1966. Applications of statistical mechanics. Clarendon Press, Oxford, UK.
Iglesias, H.A. and Chirife, J., 1978. An empirical equation for fitting water sorption isotherms of fruits and related products. Canadian Institute of Food Science and Technology Journal 11: 12-18.
Krug, R.R., Hunter, W.G. and Grieger, R.A., 1976. Enthalpy entropy compensation. Separation of the chemical from the statistical effect. Journal of Physical Chemistry 80: 2341-2346.
Kuye, A. and Ariri, I., 2005. Modeling the equilibrium moisture sorption data for some Nigerian foods. International Journal of Food Properties 8: 1-13.
Lazarides, H.N., 1990. Sorption isotherm characteristics of an intermediate meat product. LWT-Food Science Technology 23: 418-421.
Leffer, J.E. and Grunwald, E., 1963. Rates and equilibria of organic reactions. Wiley, New York, NY, USA.
McMinn, W.A.M., Al-Muhtaseb, A.H. and Magee, T.R.A., 2005. Enthalpy-entropy compensation in sorption phenomena of starch materials. Food Research International 38: 505-510.
Moreira, R., Chenlo, F., Torres, M.D. and Valejo, N., 2008. Thermodynamic analysis of experimental sorption isotherms of loquat and quince fruits. Journal of Food Engineering 88: 514-521.
Olayemi, F.F., Adegbola, J.A., Bamishaiye, E.I. and Awagu, E.F., 2012. Assessment of post harvest losses of some selected crops in eight local government areas of River State, Nigeria. Asian Journal of Rural Development 2: 13-23.
Onayemi, O. and Oluwamukomi, M.O., 1987. Moisture equilibria of some dehydrated cassava and yam products. Journal of Food Process Engineering 9: 191-200.
Osagie, A.U., 1992. The yam in storage. AMBIK Press, Post Harvest Research Unit, University of Benin, Benin City, Nigeria, pp. 22-24.
Osunde, Z.D., 2008. Minimizing postharvest losses in yam (Dioscorea spp.): treatments and techniques. In: Robertson, G.L. and Lupien, J.R. (eds.) Using food science and technology to improve nutrition and promote national development. International Union of Food Science and Technology, Ontario, Canada, pp. 1-12.
Oswin, C.R., 1946. The kinetics of packaging life III: the isotherm. Journal of Chemical Industry 65: 419-423.
Oyelade, O.J., Tunde-Akintunde, T.Y. and Igbeka, J.C., 2008. Predictive equilibrium moisture content equations for yam (Dioscorea rotundata, Poir) flour and hysteresis phenomena under practical storage conditions. Journal of Food Engineering 87: 229-235.
Pawar, V.S., Pawar, D.K., Rodge, V.D., Surve, V.D. and More, D.R., 1992. Moisture adsorption isotherms of ground turmeric at different temperature. Journal of Food Science and Technology 29: 170-173.
Peleg, M., 1993. Assessment of a semi-empirical four parameter general model for sigmoid moisture sorption isotherms. Journal of Food Process Engineering 16: 21-37.
Quirijns, E.J., Van Boxtel, A.J.B., Van Loon, W.K.P. and Van Straten, G., 2005. Sorption isotherms, GAB parameters and isosteric heat of sorption. Science of Food and Agriculture 85: 1805-1814.
Sanni, L.O., Atere, C. and Kuye, A., 1997. Moisture sorption isotherms of fufu and tapioca at different temperatures. Journal of Food Engineering 34: 203-212.
Simal, S., Femenia, A., Castell-Palou, A. and Rossello, C., 2007. Water desorption thermodynamic properties of pineapple. Journal of Food Engineering 80: 1293-1301.
Tsami, E., 1991. Net isosteric heat of sorption in dried fruits. Journal of Food Engineering 14: 327-335.
Wahab, B.A., Adebowale, A.A., Sanni, S.A., Sobukola, O.P., Obadina, A.O., Kajihausa, O.E., Adegunwa, M.O., Sanni, L.O. and Keith, T., 2015. Effect of species, pretreatments, and drying methods on the functional and pasting properties of high-quality yam flour. Food Science and Nutrition 4: 50-58.