Evaluating Some Empirical Models for Predicting Water Absorption in African Breadfruit (Treculia Africana) Seeds

Abstract

Water absorption process during soaking of African breadfruit (ABF) seeds was studied at five typical soaking temperatures, ranging between 30 and 70 C. The progress of water absorption by the seeds followed an exponential increase with increase in temperature. The experimental data were fitted to three empirical equations. All the equations were able to explain over 90% of the experimental data. The predicted water absorption capacity (M e), which ranged between 68 and 92/100 g dry solid were not significantly affected by temperature changes (p > 0.05) while the time to achieve maximum water absorption capacity ranged between 9 and 140 h. The water absorption rate constant in Singh-Kulshrestha's model was more sensitive to temperature changes than from the others. By applying Arrhenius equation, it was shown that water absorption at 30-70 C was the predominant process responsible for the changes in mass of ABF seeds. The differences in the experimental and predicted data from the three models were compared to evaluate their goodness of fit. The chi-square and the

Modelling the Water Absorption Characteristics of Different Maize (Zea Mays L.) Types during Soaking

“…The water absorption rate increased with increase in soaking temperature as this is due to increased water diffusion rate. Similar observations have been reported (Sopade and Obekpa, 1990;Lu et al, 1994;Sanni et al, 2003;Shittu et al, 2004;Addo et al, 2006;Addo and Bart-Plange, 2009;Tunde-Akintunde, 2010;Agu et al, 2013;Udoro et al, 2014). However, the rates of increment between the initial and final soaking temperatures were not the same for the different maize types.…”

“…This could be as a result of the difference in nutritional composition of the maize types considered. Addo et al (2006) made similar observation when they studied the water absorption characteristics of maize (Obatanpa and Mamaba) as well as Shittu et al (2004), and Ali et al (1974) when they studied the water absorption characteristics of rice. The soaking water temperature and concentration of starch in food material determines starch behaviour in water (Addo et al, 2006;Tunde-Akintunde, 2010).…”

“…1(a -f). The maize samples exhibited the typical water absorption characteristic as previously described for other food materials (Shittu et al, 2004;Addo et al, 2006;Peleg, 1988;Sopade et al, 1992;Hung et al, 1993;Maharaj and Sankat, 2000). There is an initial very rapid rate of water absorption which was later followed by a slower rate in the later stages as the saturation moisture content (SMC) was approached at all four temperatures.…”

“…An equation was developed by Peleg (1988) to model the mode of water absorption by food materials. It is a two-way parameter, non-exponential, empirical equation which has been reported to describe the water uptake in food materials especially that of soaked cereals and leguminous food grains accurately (Shittu et al, 2004;Sopade and Obekpa, 1990;Sopade et al, 1992;Hung et al, 1993;Maharaj and Sankat, 2004;Sanni et al, 2003) K is the Peleg capacity constant (% -1 ). In Eq.…”

“…The extent of water absorption or the amount of water absorbed into the food material during soaking depends primarily on the soaking water temperature, time, initial moisture content, variety of the seeds, soaking duration, acidity level of the water and physicochemical properties (such as seed structure, size etc) of the food material ( Singh and Kulshrestha, 1987;Karapantsios et al, 2002;Shittu et al, 2004;Laria et al, 2005;Tunde-Akintunde, 2010.…”