Evaluación de la concentración de metales pesados (Pb, Hg, Cd) y As en pescados expendidos en los mercados de la ciudad del Cusco, Perú

En la ciudad del Cusco, los pescados constituyen una fuente principal de nutrientes de la dieta familiar de la población, sin embargo, la contaminación ambiental por efecto antropogénico repercute en su inocuidad muchas veces afectada por la presencia de metales pesados por lo que el objetivo principal de esta investigación fue evaluar la concentración de Mercurio (Hg), Plomo (Pb), Cadmio (Cd) y Arsénico (As) en tejidos de cabeza, piel, hueso y músculo donde posiblemente exista bioacumulación de estos metales en pescados comercializados en los principales centros de abastos (Vinocanchon, Wanchaq, General Buendía). Se utilizo el método de espectrometría de Emisión Óptica por plasma de acoplamiento inductivo ICP-OES para cuantificar la presencia de plomo (Pb), Cadmio (Cd) y Arsénico (As), y el método de espectrofotometría de Absorción Atómica con vapor frío para el mercurio (Hg). Los resultados obtenidos indican que la trucha (Oncorhynchus mykiss) y el jurel (Trachurus murphyi) son los más consumidos. En la cabeza de jurel de Vinocanchón la concentración de Cd fue 0,2 mg/kg y en el músculo se detectó 0,09 mg/kg de Hg, valores que se encuentran dentro de los límites máximos permisibles. Las concentraciones de Pb, Cd y As encontradas en el músculo del jurel ytrucha están por debajo de los niveles de concentración permisibles indicados por los organismos internacionales, mientras que la concentración de Hg, se encuentra dentro del límite máximo permisible, concluyéndose que la especie de menor riesgo para el consumo es la trucha

Study of the pollution by surfactants in a river of a high Andean micro basin

The surfactants linear alkylbenzene sulfonate (LAS), is used in large quantities in modern society, and wastewater containing it can contaminate groundwaters through runoff and sewers. The study aimed to determine the level of LAS in the Huatanay river; in Cusco city, Peru. Water samples were taken from nine points along the river, in the rainy and dry season in 2018. LAS surfactants were determined spectrometrically using methylene blue as indicator; dissolved oxygen (DO) and conductivity were also determined; both were correlated through Pearson coefficient at 5% significance, and analyzed in triplicate. The concentration of LAS in the dry season varied between 0.01 to 23.17 mg/L and in rains from 0.09 to 1.47 mg/L; the DO level shows values between 0.11 to 5.04 mg O2/L, and the conductivity varied from 777.7 to 2688.9 µS/cm. In conclusion, high levels of LAS considerably decrease the DO and increase the conductivit

Rheological and functional properties of dark chocolate with partial substitution of peanuts and sacha inchi

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 ty 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

Determinación de contaminantes tensioactivos tipo ácido dodecilbenceno sulfónico lineal en aguas del Río Huatanay - Cusco

TesisLos detergentes de sulfonato de alquilbenceno lineal (LAS) son utilizados en grandes cantidades en la sociedad moderna, industrias y hogares pasan a las aguas superficiales a través de escorrentías y desbordamientos combinados de alcantarillas, entre otras fuentes, sin embargo se desconoce su destino final. El rio Huatanay que atraviesa la ciudad del Cusco está altamente contaminada por efecto del vertido de aguas servidas directamente al río, uno de los contaminantes presentes es el tensioactivo aniónico tipo ácido dodecil benceno sulfónico lineal (LAS) cuya presencia de determinó utilizando un método estándar de análisis SMEWW-APHA-AWWA-WEF Anionic Surfactants as MBAS. Se tomaron 40 muestras de diferentes tributarios del rio seleccionados de acuerdo al Protocolo Nacional-ANA, en dos estaciones del año, seco y lluvioso. Los resultados indican que las concentraciones de detergente en promedio para el período seco y lluvioso fueron respectivamente 0.2429 mg/L y 8.5301 mg/L superiores a los permitidos por el MINAN de 0.2 mg/L para agua de riego y 0.5 mg/L para bebida de animales, lo que podría indicar un efecto potencial en la salud y en el ambiente aún desconocido. Se hizo la caracterización física química del agua demostrándose que no cumple con la: dureza, fosfatos, amoniaco, cloruros, resultado del efecto de la presencia de los detergentes y materia orgánica. Se evaluó una muestra de suelo regada con agua natural el que presentó características adecuadas para el desarrollo de la planta y otra muestra con riego de agua de río Huatanay cuyas características impiden el crecimiento adecuado de la planta

Rheological and Functional Properties of Dark Chocolate with Partial Substitution of Peanuts and Sacha Inchi

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 &deg;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&ndash;Bulkley model showed a better adjustment (R2 &gt; 0.999), reporting behavior index values, n &lt; 1.0, and indicating pseudo-plastic behavior for pastes and formulations. The yield limit &tau;y 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

Rheological and Functional Properties of Dark Chocolate with Partial Substitution of Peanuts and Sacha Inchi

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 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

Formulation of Novel Composite (Activated Nanoclay/Hydrocolloid of Nostoc sphaericum) and Its Application in the Removal of Heavy Metals from Wastewater

The removal of heavy metals from wastewater is an environmental challenge which demands the use of environmentally friendly materials that promote a circular economy. This study aimed to apply a novel composite of an activated nanoclay/hydrocolloid in the removal of heavy metals from wastewater. A composite blended under pressure was prepared with spray-dried hydrocolloid derived from Nostoc sphaericum algae and activated nanoclay in an acid medium and 1M NaCl. The composite and components were analyzed through infrared (IR), X-ray (XR), &zeta; potential, cation exchange capacity (CEC), particle size, and SEM images. The composite was subjected to the adsorption of heavy metals (Pb, As, Zn, and Cd) at pH 4.5 and the removal percentage, kinetics, and adsorption isotherms were evaluated. It was observed that the activated nanoclay and the composite that presented a particle size of around 400 nm significantly increased (p-value &lt; 0.05) the CEC, &zeta; potential, the functional groups, and chelating components, removing heavy metals above 99% for Pb, As 33%, Cd 15%, and Zn 10%. Adsorption kinetics was adjusted to the pseudo second-order model (R2 &gt; 0.98), and the Langmuir and Freundlich models better represented the sorption isotherm at 20 &deg;C. The formulated composite presents a good ability to remove heavy metals in wastewater

Effect of the Application of a Coating Native Potato Starch/Nopal Mucilage/Pectin on Physicochemical and Physiological Properties during Storage of Fuerte and Hass Avocado (Persea americana)

The avocado fruit is an agro-industrial product with high export demand in Peru due to its sensory and nutritional qualities, which can be affected during storage. The study aimed to evaluate the effect of the application of a coating formulated with potato starch (Solanum tuberosum ssp andigena), nopal mucilage (Opuntia ficus indica), and pectin on the physicochemical and physiological properties during the storage of Fuerte and Hass avocados. Samples were taken in their harvest state from the plantation in &ldquo;Occobamba&rdquo;, which is cultivated by the Avocado Producers Association in Chincheros, Apur&iacute;mac, Peru. Physicochemical properties (titratable acidity, pH, total soluble solids) and physiological properties (weight loss, firmness, and color L* a* b*) were determined during 20 days of storage at 20 &deg;C. The elaborated films present high transparency and low aw values. In the coated avocado of the Hass and Fuerte varieties, acidity and total soluble solids decreased significantly (p-value &lt; 0.05) during the storage time. Weight loss and firmness of coated fruits decrease to a lesser extent. Luminosity L*, color index, and color variation showed better attributes for the coated samples. The use of coatings made with potato starch, nopal mucilage, and pectin allows the physicochemical and physiological properties of avocado fruits to be maintained for a longer time during storage