30F-5 |
A comparison of two models for describing cooking kinetics of chickpeas |
M. T. JIMÉNEZ-MUNGUIA1, M. R. Arce-Garcia, A. López-Malo, E. Palou, and A. Ibarz5. (1) Departamento de Ingeniería Química y Alimentos, Universidad de las Américas-Puebla, Sta. Catarina Martir, Cholula, Puebla, 72820, Mexico, (2) Departament de Tecnologia d'Aliments, Universitat de Lleida, Rovira Roure, 177, Lleida, 25198, Spain
Legumes are often soaked before cooking in order to be soft enough to be eaten and reduce cooking time. Cooking kinetics follow a sigmoid shape curve that can be described by selected mathematical models to predict cooking time.
The effect of soaking time (30, 105 or 180 min) and NaHCO3 concentration in the soaking solution (0, 2.5 or 5.0 %) on the cooking kinetics of chickpeas was evaluated. This study presents a comparison of two kinetic models applied for describing cooking kinetics of chickpeas subjected to soaking pre-treatments.
Previous to cooking, chickpeas were soaked in NaHCO3 solutions. Soaked chickpeas were cooked in a multiple test (needle) texturemeter using fresh water at 92-93°C. An edible texture of 80g was selected. The time needed for each needle to puncture a chickpea was registered.
The behavior was modeled using two model equations. The Fermi's function and one proposed in this study: C=(G0/(1+G0 exp(-G0 k (t - t0)))), where C is the number of cooked chickpeas, G0 initial raw chickpeas, t time to cook each legume, t0 is delay time to cook the first chickpea, and k is a constant.
For both models, the cooking time was defined as the time needed to puncture 50% of the chickpeas. In the Fermi's function the cooking rate was defined as the skewness of the cooking kinetics curve. Cooking time decreased with long soaking times and when using NaHCO3 on the soaking water. The lowest cooking time was 34.5 min obtained when the chickpeas were soaked for 180 min in a 5% NaHCO3 solution before cooking.
Chickpeas cooking time can be reduced using soaking pre-treatments. The Fermi function parameters, as well as the proposed model constants can be used to compare and describe legume cooking kinetics, establishing the effect of soaking pre-treatments on cooking rate. The proposed equations predicted cooking time and cooking rate of chickpeas in a suitable way.
Session 30F, Food Engineering: Transport processes and kinetics
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