Se ha evaluado el efecto de diferentes niveles de tiempo y temperatura del plasma frio sobre la eliminación de microorganismos patógenos y los cambios fisicoquímicos y organolépticos en la carne de cerdo. Se ha determinado el efecto de diferentes niveles de tiempo y temperatura del plasma frío sobre la eliminación de microorganismos patógenos, sobre los cambios fisicoquímicos y sobre los atributos organolépticos en carne de cerdo. El estudio mostró que, respecto a la eliminación de microorganismos patógenos, los valores de las tablas 7 y 8 (para 25 °C) y, 9 y 10 (para 30°C), presentan diferencia significativa entre los tiempos y temperaturas de exposición. Así mismo, respecto a los cambios fisicoquímicos, presentados en las tablas 12, 13, 14 y 15(para 25 °C); y en las tablas 16, 17, 18 y 19 (para 30 °C), muestran que no existe, estadísticamente, diferencia significati...

The study describes the biotechnological process, a product of the hydrolyzed starch's fermentation using Saccharomyces cerevisiae Meyen ex E.C. Hansen as an enzyme agent. The behavior and speeds of the three intervening components (consumed substrate [Sc], product [P], and enzymatic agent [E]) were evaluated and was formulated the corresponding logistic models, independently, for each of the components and their subsequent application and analysis. Also, the saturation constant of the substrate [Km] was determined. The maximumconcentration for the enzyme reached a value of 9.80 g·L-1, and the reaction rate constants were 0.27 h-1, 0.20 h-1, and 0.22 h-1, for the concentrations of E, Sc, and P, respectively. The maximum speeds (and the optimal times) for the enzyme, substrate consumed, and product were 0.66 gL-1h-1 (6.80 h), 6.68 gL-1h-1 (11.50h), and 3,15 gL-1h-1 (11.40h), respectively...

The Bessel expression is an ordinary diff erential equation of second order (EDOPO), whose solutions are spherical and can be solved by Frobenius' methods, indeterminate series, and coeffi cients; whose values can be used very well and easily in food engineering and technology. Their solutions are specifi ed in four parts, of which those of the type are those that have an application in the present study. The Bessel EDOPO was solved in its four possibilities, in which the values and behaviors are given in tables and graphs in detail. Th e corresponding values were used in the temperature distribution for cylindrical containers of known dimensions using the equations of heat transfer by conduction, preferably, coming from the Fourier theory, facilitating the improvement, modifi cation, and design of new processes. The results of the temperature distribution were calculated by the respecti...

The rheological properties of different liquid foods and especially of fruit-based syrups depend on different aspects, among which are composition and temperature. One of the most influential aspects is the water content of the syrup and, in general, when the moisture content increases, the viscosity of the fruit syrup decreases. The objective of this work was to determine the physicochemical rheology of the fruit syrup (honey) for the Peruvian nougat "Doña pepa", to obtain the best percentage of synergism of the xanthan and tara gums, and the most suitable formulation for the fruit syrup. Six concentrations of 0.60 %, 0.80 %, 1.00 %, 1.20 %, 1.20 %, 1.40 % and 1.60 % were determined for the two gums. At each of these percentages the apparent viscosity was determined, thus characterizing the flow behavior of the product. The results of pH, soluble solids, and dynamic viscosity of the co...

The study describes the biotechnological process, a product of the hydrolyzed starch's fermentation using Saccharomyces cerevisiae Meyen ex E.C. Hansen as an enzyme agent. The behavior and speeds of the three intervening components (consumed substrate [Sc], product [P], and enzymatic agent [E]) were evaluated and was formulated the corresponding logistic models, independently, for each of the components and their subsequent application and analysis. Also, the saturation constant of the substrate [Km] was determined. The maximumconcentration for the enzyme reached a value of 9.80 g·L-1, and the reaction rate constants were 0.27 h-1, 0.20 h-1, and 0.22 h-1, for the concentrations of E, Sc, and P, respectively. The maximum speeds (and the optimal times) for the enzyme, substrate consumed, and product were 0.66 gL-1h-1 (6.80 h), 6.68 gL-1h-1 (11.50h), and 3,15 gL-1h-1 (11.40h), respectively...

The rheological properties of different liquid foods and especially of fruit-based syrups depend on different aspects, among which are composition and temperature. One of the most influential aspects is the water content of the syrup and, in general, when the moisture content increases, the viscosity of the fruit syrup decreases. The objective of this work was to determine the physicochemical rheology of the fruit syrup (honey) for the Peruvian nougat "Doña pepa", to obtain the best percentage of synergism of the xanthan and tara gums, and the most suitable formulation for the fruit syrup. Six concentrations of 0.60 %, 0.80 %, 1.00 %, 1.20 %, 1.20 %, 1.40 % and 1.60 % were determined for the two gums. At each of these percentages the apparent viscosity was determined, thus characterizing the flow behavior of the product. The results of pH, soluble solids, and dynamic viscosity of the co...

The effects of concentration and temperature on the thermo-physical properties of apple juice were studied, in which density and viscosity were measured at different temperature and concentration conditions, varying from 20°C to 80°C and from 12 to 70° Brix, respectively. Density was determined by the pycnometer method and viscosity by Hooke's falling sphere method, based on Stokes' law. The density results were correlated several times, arriving, by the least squares method, at a multiple linear regression model, of three terms; while the viscosity results proved to be more difficult to correlate, which, by the least squares method, arrived at a multiple linear regression model, of six terms.  The experimental mathematical models can be used to obtain the density and viscosity data within the temperature and concentration conditions indicated in the study. Key words: density –...

The use of citrus by-products was evaluated through the fermentation of the orange peel by means of Aspergillus niger van Tieghem strain, 1867, which was obtained by inoculation in a petri dish, at a temperature of 35°C and a pH of 4,3. The crushed orange peel was used as a substrate, partially dehydrated, spread on trays, dried in cardboard trays and without heat pretreatment, adding only components and mineral nutrients, and A. niger was cultivated at different fermentation temperatures between 8°C and 40 °C. Upon completion of the fermentation process of the pretreated orange peel, maximum percentages of transformation of mineral nitrogen to organic nitrogen of 34.5% were obtained, for a value of the thermal integral between 0°C and 320°C per day, obtaining for a kg of dry matter, 6.6% protein for 600 g of product (feed) with 18% protein. Finally, the variation of the pH of the s...

The effects of concentration and temperature on the thermo-physical properties of apple juice were studied, in which density and viscosity were measured at different temperature and concentration conditions, varying from 20°C to 80°C and from 12 to 70° Brix, respectively. Density was determined by the pycnometer method and viscosity by Hooke's falling sphere method, based on Stokes' law. The density results were correlated several times, arriving, by the least squares method, at a multiple linear regression model, of three terms; while the viscosity results proved to be more difficult to correlate, which, by the least squares method, arrived at a multiple linear regression model, of six terms.  The experimental mathematical models can be used to obtain the density and viscosity data within the temperature and concentration conditions indicated in the study. Key words: density –...

The Bessel expression is an ordinary diff erential equation of second order (EDOPO), whose solutions are spherical and can be solved by Frobenius' methods, indeterminate series, and coeffi cients; whose values can be used very well and easily in food engineering and technology. Their solutions are specifi ed in four parts, of which those of the type are those that have an application in the present study. The Bessel EDOPO was solved in its four possibilities, in which the values and behaviors are given in tables and graphs in detail. Th e corresponding values were used in the temperature distribution for cylindrical containers of known dimensions using the equations of heat transfer by conduction, preferably, coming from the Fourier theory, facilitating the improvement, modifi cation, and design of new processes. The results of the temperature distribution were calculated by the respecti...

Se ha desarrollado un modelo matemático que permita analizar el comportamiento de la mortalidad en la República Popular de China ocasionado por COVID-2019. Se aplicó el modelo logístico para los datos reportados entre 11 de enero y el 12 de abril del 2020. El modelo formulado fue linealizado y planteado en dos formas. La primera, evaluando el factor de corrección B, que hace las veces de cantidad máxima de fallecidos. Se determinaron los parámetros A, k y r, obteniendo el modelo (Ecuación 7), con un coeficiente de correlación r=-0,9660 y el coeficiente de determinación r^2×100=93,31 %. La segunda forma, con el mismo valor de B, introduciendo un factor de corrección para la variable independiente, t, que hace las veces de “periodo”. Se determinaron los parámetros A, k y r, obteniendo el modelo (Ecuación 10), con un coeficiente de correlación r=-0,9668 y el coeficiente d...

The objective of the work was to develop a mathematical model to analyze the behavior of mortality in the People’s Republic of China caused by COVID-2019. The logistic model was applied to the data reported in Table 1, between January 11 and April 12, 2020. The model formulated was linearized and presented in two forms, which, with the same value of B, introducing a correction factor for the independent variable, t, which serves as “period” and applying the method of minimum squares, the parameters A, k and r were determined, obtaining the respective model (Equation 10), which was analyzed with Pearson’s correlation coefficient, obtaining the correlation coefficient r=-0.9668 and the determination coefficient r^2×100=93.48 %; deducing the best estimate of the model to the process in modeling (Equation 10) to analyze the mortality phenomenon. Likewise, the mortality rate was eval...

While it is true that vaccines generate immunity with a high degree of effectiveness and that in Peru, a certain time was spent initiating the COVID-19 disease, a vaccination process that was developed logistically. The objective was to obtain the mathematical model of the COVID-19 vaccination process in Peru, to estimate the number of people vaccinated, the critical time for which the estimated rate of vaccinated people has been the highest value, and to specify the date on which the highest number of people vaccinated has occurred. The methodology was based on determining the form of dispersion of the vaccination process, this being a logistic distribution and considering that a mathematical model is a mathematical description, by means of a function of a real-world phenomenon, such as the number of people vaccinated against the COVID-19 disease. The model presented a correlation coeff...

Describe the COVID-19 pandemic in Peru, carry out mathematical statistical modeling, determine the critical time, the speed with which the pandemic developed and validate the estimated data; have characterized this research; whose objective has been to model and analyze COVID-19 infections in Peru, and compare infected people and estimated infected people; assess the critical time in which the maximum speed of estimated infected people occurs and statistically validate the model. The data on COVID-19 infections until February 24, 2023 has been taken into account; determining that they describe a sigmoidal logistic dispersion; event that was mathematically modeled using the expression , which is a predictive logistic equation. With the predictive mathematical model, the number of people infected and their behavior of COVID-19 in Peru was estimated. Likewise, the speed of people infected w...

The calculation of Bernoulli numbers is because there are numerous mathematical expressions and environmental engineering phenomena in which they can be applied. Although it is true that, with the aid of the computer and the use of programs, there are a great number of them; in the current references they are published in a reduced number and, therefore, when using them, unsatisfactory approximations are made. The purpose was to calculate the first 20 Bernoulli numbers, apply them to mathematics (∫ ln(cosx)dx) and environmental engineering, quantifying the alkalinity of natural water in the form of calcium carbonate (CaCO3)(mg/l ), measuring carbon dioxide (CO2). There is a great variety of relations containing Bernoulli numbers presented in several practical applications of mathematics. The best relationships used here are binomial developments. Employing the appropriate equations, th...

Monkeypox (mpox) is a virus of the same family as human smallpox, detected in tropical forest regions in May 2022 in the United Kingdom and subsequently in Latin America. The objective of the present investigation was to study, by means of mathematical models, the infectivity of Monkeypox in North America in epidemiological comparison with South America. Data on monkeypox infectivity in both North and South America between the beginning of June 2022 and the end of February 2023 have been taken into account. By performing the pandemic dispersion, it was determined that the mathematical model of estimation is: ; with which the number of people infected with monkeypox in both North and South America was estimated. The mathematical model for estimating the rate of infection with monkeypox in both North and South America was determined: . At the 5% significance level, the variances of the con...