Correlation between morphology, hydration kinetics and mathematical models on Andean lupin (Lupinus mutabilis Sweet) grains
Introduction
The Andean lupin, also called Chocho or Tarwi (NRC-US, 1989) is a legume from the Andean region, of South America, which is widely used by the local population as food and natural medicine (Jacobsen & Mujica, 2006). It is known by its high nutritional value, with a high content of proteins (44.3 g/100 g) and unsaturated fatty acids (40.4 g/100 g of omega-9, 37.1 g/100 g of omega-6 and 2.9 g/100 g of omega-3, with respect to the total fat content – 16.5 g/100 g) (Jacobsen & Mujica, 2006). It is used mainly as a protein source in human and animal nutrition in various parts of the world, and its consumption has increased in recent years (Güémes-Vera, Peña-Bautista, Jiménez-Martínez, Dávila-Ortiz, & Calderón-Domínguez, 2008). This grain is being considered an internationally promising crop, especially in Peru, where its production is growing since it started to be incentivized (Brigas Céspedes, 2014, Mohme Seminario, 2014).
The hydration process in grains is a prior step to different processes such as cooking, extraction, germination and wet milling, since it prepares the grains for processing. In most cases, this stage is a batch unit operation, with a long duration (between 4 and 18 h on average). Many studies have already been conducted about the hydration of different grains, such as adzuki beans (Oliveira et al., 2013), chickpeas (Gowen et al., 2007, Ibarz et al., 2004, Yildirim et al., 2011), white lupin (Solomon, 2009), red kidney beans (Abu-Ghannam and McKenna, 1997a, Abu-Ghannam and McKenna, 1997b), sesame seeds (Khazaei & Mohammadi, 2009), and so on. However, most of these works just evaluated the grain hydration using simple kinetics models, neglecting the initial lag phase that some grains have. The few studies that considered sigmoidal hydration kinetics for grains neither ensure the cause of lag phase nor explain the process morphologically giving only suppositions. Further, there is not any work in the literature studying the hydration kinetics of Andean lupin (Lupinus mutabilis Sweet), despite that it is an important stage because it increases the water content of the grain and enhances the alkaloids extraction in the subsequent stages (Carvajal-Larenas, Nout, van Boekel, Koziol, & Linnemann, 2013).
The present work correlated the morphology, hydration behavior and mathematical models in order to explain and predict the hydration kinetics of Andean lupin (L. mutabilis Sweet) grains.
Section snippets
Water uptake behavior
Andean lupin grains (L. mutabilis Sweet) (9.08 ± 1.44 g/100 g d.b moisture, 9.98 ± 0.64 mm length, 8.39 ± 0.41 mm width and 6.02 ± 0.35 mm thick) were purchased in a local market of Trujillo – Perú. The Andean lupin used was breed in the north Andean region of Perú (La Libertad ∼3200 masl (meters above the sea level)). After harvest, the grains were stored for 2 months before being sold. The grains were selected by eliminating those that were not intact and stained. The grains were stored in a
Andean lupin hydration kinetics
The effect of temperature on the moisture content of Andean lupin grains is shown in Fig. 1. The moisture increased with the duration of soaking and a lag phase at the first part of the curve can be clearly seen, where the water uptake rate was low at all evaluated temperatures. Thus, the grain hydration can be described by a sigmoidal behavior, with an initial lag phase followed by a higher absorption rate phase and, finally, by a stationary phase.
This behavior is similar to different grains
Conclusions
The Andean lupin grains (L. mutabilis Sweet) hydration follows a sigmoidal behavior, which was proven to be due to the seed coat and the first distribution of water into it. Since seed coat has the function of controlling water intake in the grain by waterproofing, it reduces the water absorption rate almost six times and allows higher water holding capacity. Besides, it was demonstrated that the water entrance into the grain is carried out both by capillarity through the hilar fissure, and
Acknowledgments
The authors thank the “Ministerio de Educación del Perú” for the A.C. Miano scholarship granted by the program “Programa Nacional de Becas y Crédito Educativo” (PRONABEC). The authors are grateful to the “Núcleo de Apoio à Pesquisa em Microscopia Eletrônica Aplicada à Pesquisa Agropecuária” (NAP/MEPA-ESALQ/USP) for the support and facilities of Electronic Microscopy.
Nomenclature
- a
- Linear model parameter (slope) (Equation (3)) [Different unit]
- b
- Linear model parameter (ordinate axis intercept) (Equation (3)) [Different unit]
- kIA
- Ibarz–Augusto's kinetics parameter related to the lag phase and water absorption rate (Equations (5), (9))) [g/100 g d.b.−1 min−1]
- kK
- Kaptso et al. kinetics parameter related to water absorption rate (Equations (4), (8))) [g/100 g d.b.−1]
- Meq
- Equilibrium moisture content (Equations (4), (5), (6), (7)) [g/100 g d.b.]
- Mexperimental
- Experimental moisture
References (37)
Modelling textural changes during the hydration process of red beans
Journal of Food Engineering
(1998)- et al.
The application of Peleg's equation to model water absorption during the soaking of red kidney beans (Phaseolus vulgaris L.)
Journal of Food Engineering
(1997) - et al.
Factors affecting water uptake of rice grain during soaking
LWT – Food Science and Technology
(2004) - et al.
Modelling of the aqueous debittering process of Lupinus mutabilis Sweet
LWT – Food Science and Technology
(2013) - et al.
Modelling the water absorption process in chickpeas (Cicer arietinum L.)—The effect of blanching pre-treatment on water intake and texture kinetics
Journal of Food Engineering
(2007) - et al.
Kinetic models for water adsorption and cooking time in chickpea soaked and treated by high pressure
Journal of Food Engineering
(2004) - et al.
Modeling of water absorption of Botswana bambara varieties using Peleg's equation
Journal of Food Engineering
(2009) - et al.
Physical properties and rehydration kinetics of two varieties of cowpea (Vigna unguiculata) and bambara groundnuts (Voandzeia subterranea) seeds
Journal of Food Engineering
(2008) - et al.
Effect of temperature on hydration kinetics of sesame seeds (Sesamum indicum L.)
Journal of Food Engineering
(2009) - et al.
The seed coats of cowpeas and other grain legumes: structure in relation to function
Field Crops Research
(1980)
Effect of maturation and processing on water uptake characteristics of wheat
Journal of Food Engineering
Modelling the effect of temperature on the hydration kinetic of adzuki beans (Vigna angularis)
Journal of Food Engineering
Fitting Fick's model to analyze water diffusion into chickpeas during soaking with ultrasound treatment
Journal of Food Engineering
Hydration kinetics of red kidney beans (Phaseolus vulgaris L.)
Journal of Food Science
Official methods of analysis
The encyclopedia of seeds: Science, technology and uses
Germinação: Do básico ao aplicado
Cadenas productivas de tarwi y quinua fortalecerá la región
Cited by (49)
Modeling and thermodynamic analysis of the hydration and germination of triticale seeds
2023, Journal of Cereal ScienceInnovations in legume processing: Ultrasound-based strategies for enhanced legume hydration and processing
2023, Trends in Food Science and TechnologyHard-to-cook phenomenon in common legumes: Chemistry, mechanisms and utilisation
2023, Food Chemistry