Characterization of nutritional and functional properties of "Blanco Sinaloa" chickpea (Cicer arietinum L.) variety, and study of the rheological behavior of hummus pastes.

In this work the preparation of a hummus pastes from a Mexican variety of chickpea (Blanco Sinaloa, BS) was investigated. With this purpose, the nutritional and functional properties of the raw chickpea were evaluated, which revealed a content of protein, fiber and lipids of 19, 1.6 and 10.3%, respectively. Meanwhile the values of hydration capacity, water absorption index, water solubility index, emulsifying activity and foam capability were 0.65 g/seed, 2.26 g/g, 22.3%, 40.7% and 29.2%, respectively. Based on these results this variety of chickpea was considered suitable for the target application. The preparation of the paste was done by further sterilization of the paste promoted a decreased on the activity of lipoxygenase (68%) and starch content (40%). The rheological characterization of the hummus paste showed that the sterilization induced the formation of a tridimensional structure, due to the gelatinization of the starch and protein denaturation. Moreover, the linear viscoelastic zone shifted to higher values of strain (%γ), whereas the storage modulus (G') increased in about two orders of magnitude. The results of frequency sweeps showed that the paste exhibits a solid-like behavior (weak gel). Measurements of shear rate of the paste (unsterilized and sterilized) revealed that the shear viscosity exhibited a shear thickening behavior and a thixotropic behavior.

Physicochemical, morphological and rheological properties of canned bean pastes "negro Queretaro" variety (Phaseolus vulgaris L.).

Proximate, thermal, morphological and rheological properties of canned "negro Querétaro" bean pastes, as a function of fat content (0, 2 and 3 %) and temperature (60, 70 and 85 °C), were evaluated. Raw and precooked bean pastes were characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Well-defined starch granules in the raw bean pastes were observed, whereas a gelatinized starch paste was observed for the canned bean pastes. The DSC analysis showed that the raw bean pastes had lower onset peak temperatures (79 °C, 79.1 °C) and gelatinization enthalpy (1.940 J/g), compared to that precooked bean pastes (70.4 °C, 75.7 °C and 1.314 J/g, respectively) thermal characteristics. Moreover, the dynamic rheological results showed a gel-like behavior for the canned bean pastes, where the storage modulus (G') was frequency independent and was higher than the loss modulus (G″). The non-linear rheological results exhibited a shear-thinning flow behavior, where the steady shear-viscosity was temperature and fat content dependent. For canned bean pastes, the shear-viscosity data followed a power law equation, where the power law index (n) decreased when the temperature and the fat content increased. The temperature effect on the shear-viscosity was described by an Arrhenius equation, where the activation energy (Ea) was in the range from 19.04 to 36.81 KJ/mol. This rheological behavior was caused by gelatinization of the starch during the cooking and sterilization processes, where starch-lipids and starch-proteins complex were formed.