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Quinoa (Chenopodium quinoa Willd.) is an Andean grain with a perfect nutritional composition that, by diversifying its transformation, becomes an attractive alternative for consumers looking for a high-quality, healthy diet with a source of vegetable proteins. The objective of this work was to elaborate and evaluate the technological and textural properties of quinoa paste in its entirety through the Star-Shaped Composite Central Design (CCD) of 5 process variables: Water Temperature (°C), Water Quality (ml), Mixing Time (min), Drying Temperature (°C), and Drying Time (min), with 5 levels each. At the same time, the yield and good cooking quality were studied to optimize the process. In the model of the equation for the cooking time response, a negative and significant influence of drying temperature was shown. On the other hand, for cooking loss, dough gain, a* and b* values, and texture had high values if the drying time was increased. On the contrary, the L-value decreases, which is positively significant. Meanwhile, the swelling index was only significantly positive within the technological properties. In addition, it was found that the optimal conditions for producing quality pasta were 25 °C: 1150 ml: 30 min: 70 °C and 80 min, respectively, with a desirability of 0.883. When the pasta was prepared with quinoa, the cooking time was 7 min, the cooking loss was 2.46 g/g, the mass gain was 23.6 g/g, the cooking yield was 7.99%, the swelling index was 2.9%, water absorption was 135%, and protein was 12.71 g and 0. 21 Pa in texture, these results being consistent with cited research. Likewise, the whiteness was 51.97 for the values a* 2.41 and b* 12.45; all this analysis is reflected in the final yield of the process at 78%. In conclusion, the results indicated that, by optimizing the conditions in the production of gluten-free quinoa pasta, it is possible to obtain a gluten-free product with high added value, excellent cooking quality, adequate technological properties, texture, and color acceptable to the consumer.

Modifying starch allows for improvements in its properties to enable improved uses in food matrices, bioplastics, and encapsulating agents. In this research, four varieties of native potato starch were modified by acid treatment, enzymatic treatment, and ethanol precipitation, and their physicochemical, structural, thermal, and techno-functional characteristics were analyzed. According to FT-IR analysis, no influence of the modified starches on the chemical groups was observed, and by scanning electron microscopy (SEM), spherical and oval shapes were observed in the acid and enzymatic treatments, with particle sizes between 27 and 36 μm. In particular, the ethanolic precipitation treatment yielded a different morphology with a particle size between 10.9 and 476.3 nm, resulting in a significant decrease in gelatinization temperature (DSC) and more pronounced crystallites (XRD). On the other hand, the enzymatic treatment showed higher values for z-potential (ζ), and the acid treatment showed lower mass loss (TGA). Acid and ethanolic treatments affected the dough properties compared to native starches. The techno-functional properties showed a decrease in the water absorption index, an increase in the water solubility index, and varied swelling power behaviors. In conclusion, the modification of potato starches through acid, enzymatic, and ethanolic precipitation treatments alters their physicochemical properties, such as swelling capacity, viscosity, and thermal stability. This in turn affects their molecular structure, modifying morphology and the ability to form gels, which expands their applications in the food industry to improve textures, stabilize emulsions, and thicken products. Furthermore, these modifications also open new opportunities for the development of bioplastics by improving the biodegradability and mechanical properties of starch-based plastic materials.

Chocolate is a widely consumed product, due to the contribution of fats and antioxidant compounds; the addition of other components makes it possible to increase the content of polyunsaturated fatty acids, although they can affect its rheological properties. The influence of the partial addition of peanut paste and Sacha Inchi on the rheological and functional properties of dark chocolate was evaluated. Cocoa beans, peanuts, and Sacha Inchi were refined in order to obtain the cocoa paste (PC), peanut paste (PM), and Sacha Inchi paste (PSI). Then, mixtures between 0 to 20% of PM and PSI were formulated, and the rheological properties were evaluated at 30, 40, and 50 °C; these were adjusted to mathematical models. Functional groups were identified by FTIR in ATR mode, and it was observed that the partial addition of PM and PSI did not show significant changes in the shear stress and apparent viscosity of the mixture, although they did show dependence on temperature. The Herschel–Bulkley model showed a better adjustment (R2 > 0.999), reporting behavior index values, n < 1.0, and indicating pseudo-plastic behavior for pastes and formulations. The yield limit τy and the consistency index kH increased significantly with the addition of PM and PSI, but they decreased with increasing temperature. The activation energy show values between 13.98 to 18.74 kJ/mol, and it increased significantly with the addition of PM and PSI. Infrared analysis evidenced the presence of polyunsaturated fatty acids, coming mainly from PSI and PM. The addition of PM and PSI does not influence the rheological properties and allows for an increase in the content of polyunsaturated fatty acids.

The isosteric heats of sorption of two varieties of quinoa (Chenopodium quinoaWilld.) grain were determined by the static gravimetric method at four temperatures (40, 50, 60 and 70 °C) andin relative humidity environments provided by six saturated salt solutions. Six mathematical equations were used to model the experimental data: GAB, Oswin, Henderson, Peleg, Smith and Halsey. The isosteric heat of sorption was determined using the parameters of the GAB model. All the equations were shown to be appropriate by the coefficients of determination (R2) and the mean absolute error (MA%E). The influence of temperature was observed because the adsorption of water by the grains was lower at highertemperatures. The equilibrium moisture contents for security of storage, for long periods of time at water activity lower than 0.65, were 12 -13%. The effect of temperature on the parameters of the GAB model was analysed using the exponential Arrhenius equation. The isosteric heats of sorption were determined by applying the Clausius-Clapeyron equation as a function of humidity. The isosteric heat at 5% moisture for grains of the Blanca de Juli variety was 3663 kJ/kg and for the Pasankalla variety it was 3393 kJ/kg. The experimental data for isosteric heat as a function of humidity were satisfactorily modelled using three mathematical equations.

A quinoa possui mais de 60% de amido, sendo uma alternativa de extração e comercialização. Para isto é necessário conhecer o comportamento do amido frente à temperatura e umidade relativa do ar. O objetivo desta pesquisa foi avaliar as isotermas de adsorção do amido de quinoa em cinco temperaturas (20, 30, 40, 50 e 60ºC) e dez atividades de água (0,036 a 0,907). Os pontos experimentais foram ajustados aos modelos matemáticos GAB, Oswin, Henderson, Peleg e Ferro-Foltan. Foram determinadas as energias de ativação da adsorção da água pelas constantes do modelo GAB e o calor isostérico pelo modelo de Peleg. As isotermas mostraram ser do tipo II na classificação de Brunauer. Os teores de água da monocamada (Xm) determinados pelo modelo de GAB variaram de 7,90% a 10,38% base seca (b.s.) para temperaturas de 60 e 20°C e as energias de ativação obtidas pelas constantes Xm, C e K do modelo de GAB foram de 300; 160 e 6 kJ/kg, respectivamente. O calor isostérico de adsorção foi de 3732 kJ/kg para umidade de equilíbrio de 0,5% b.s. e diminuiu com o aumento da umidade até valor próximo ao calor latente de vaporização da água pura a 36% b.s. As propriedades determinadas são características de amidos com elevado teor de amilopectina.

The effect of time, temperature and varieties were analyzed during kinetics hydration of quinoa grains and some physical properties were determined. Quinoa grain varieties Kancolla, Salcedo Inia, Blanca de Juli and Pasankalla were used in the study. The hydration was performed in triplicate with 25 g of grain immersed into a solution with 0.55% lactic acid and 0.2% SO2, three temperatures (30, 40 and 50°C) at seven time intervals from 0 to 6 hours were considered to determine moisture of the grains. Moisture data were adjusted to empiric model of Peleg and to the diffusion model based on the Fick’s second law. Effective diffusivity as well as activation energy of the water absorption was also determined. The data were submitted to analyses of variance (ANOVA) and Tukey’s means difference test at 5% probability. Models adjustments were evaluated through determination coefficient (R2) and mean quadratic error (RMSE). Physical properties of Pasankalla variety shown different values compared with white varieties. Peleg’s model constants K1 ranged from 28 to 65.8 (s/%) and K2 from 0.004 to 0.008 (1/%). The effective diffusivity ranged from 2.594 x 10-11 to 8.180 x 10-11 m2.s-1 and activation energy from 210.5 to 1648.5 kJ.k- Para citar este artículo Pumacahua, A., Limaylla, K., Telis, J. y Lopes, J. (2016). Hydration kinetics of four quinoa (Chenopodium quinoa Willd.) varieties. Rev. Colomb. Investig. Agroindustriales, 3(1), 23-33. DOI: http://dx.doi.org/10.23850/24220582.348