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This study evaluated rheological behavior of the pig waste biotransformation process to produce Lactic Acid (LA) and biomass with Lactobacillus acidophilus in a stirred reactor. Also, cell growth, carbohydrate consumption, and LA production at three different agitation speeds, 100, 150, and 200 rpm at 37°C, with a reaction time of 52 h. During the development of the process, the kinetic and rheological parameters were obtained using the logistic, Gompertz, and generalized Gompertz, Ostwald de Waele, and Herschel-Bulkley mathematical models, respectively. The substrate used was pig manure, to which molasses was added at 12% v/v to increase the concentration of carbohydrates. The results suggest that mass exchange is favorable at low agitation speeds. Still, the presence of molasses rich in carbohydrates as a carbon source modi es the characteristics of the uid, dilatant (n > 1) at the beginning of the process to end up as pseudoplastic (n < 1) due to the addition of exopolysaccharides and the modi cation of the physical structure of the substrate. This effect was con rmed by the Herschel-Bulkley model, which presented a better t to the data obtained, in addition to nding a direct relationship between viscosity and pH that can be used as variables for the control of bioconversion processes of pig manure into biomass rich in Lactobacillus acidophilus.

The cob is the residue generated from the separation of the grain from the cob, and due to its components, it is considered a lignocellulosic material, so its use is limited, which favors the burning of the cob and its spreading, thus generating a problem of environmental pollution. Probiotics are live microorganisms that, when supplied in adequate amounts, provide a beneficial effect to the host, reducing the carbohydrate content in lignocellulosic materials through fermentation, obtaining a product rich in nutrients. Therefore, this research aimed to determine the kinetic parameters of biotransformation of corn residues through the fermentative action of the probiotic bacteria Lactobacillus acidophilus. Anaerobic fermentation kinetics were performed using the bacterium Lactobacillus acidophilus at different concentrations (10 and 15% v/v) to obtain kinetic parameters of microbial growth and substrate consumption for the biotransformation of white corn (Zea MaysL.) residues. The kinetic parameters indicate that when using 15% inoculum, the bacteria adapt to a greater extent to the substrate since the Ks value was 0.5693 g/L and the adaptation time was 18.25 h, thus allowing the growth of Lactobacillus acidophilus and therefore the process of biotransformation of corn residues. While for the consumption of substrate, it was identified that the use of 10% inoculum was better since it presented a value of k of 0.2534 that is higher than the value obtained when 15% is used because the rate of substrate consumption is faster. Therefore, the dose of 15% inoculum seems to be the most suitable for the adaptation of the bacteria in the shortest time and therefore the biotransformation process is carried out.

This study evaluated rheological behavior of the pig waste biotransformation process to produce Lactic Acid (LA) and biomass with Lactobacillus acidophilus in a stirred reactor. Also, cell growth, carbohydrate consumption, and LA production at three different agitation speeds, 100, 150, and 200 rpm at 37°C, with a reaction time of 52 h. During the development of the process, the kinetic and rheological parameters were obtained using the logistic, Gompertz, and generalized Gompertz, Ostwald de Waele, and Herschel-Bulkley mathematical models, respectively. The substrate used was pig manure, to which molasses was added at 12% v/v to increase the concentration of carbohydrates. The results suggest that mass exchange is favorable at low agitation speeds. Still, the presence of molasses rich in carbohydrates as a carbon source modifies the characteristics of the fluid, dilatant (n > 1) at the beginning of the process to end up as pseudoplastic (n < 1) due to the addition of exopolysaccharides and the modification of the physical structure of the substrate. This effect was confirmed by the Herschel-Bulkley model, which presented a better fit to the data obtained, in addition to finding a direct relationship between viscosity and pH that can be used as variables for the control of bioconversion processes of pig manure into biomass rich in Lactobacillus acidophilus.

SUMMARY:This paper presents the concept of the fat quality index (FQI), which is based and established in pursuancet of the current food regulations. It is a numerical value representing the correlated information of all parameters that provide the definition of fat according to the international guidelines. With the implementation of this index, it is possible to compare different types of fats using a single numerical value, which facilitates the elucidation of the effects of treatment processes or origins of fats. The FQI includes all the parameters considered in the regulations by incorporating a sub-index for each parameter and using the minimum and maximum limit values to model and adjust an equation describing the quality of fat according to the standard. Finally, the procedure is used to obtain indices based on other experimental works that assessed the quality of fat samples produced under different operating conditions, treatment, origin or processes, allowing for better comparison and evaluation. Therefore, this index is an excellent analytical tool for assessing the quality of fats from different origins for human consumption. KEYWORDS:Butter; Fat Quality Index; FQI; Margarine; Standard regulations; Vegetable RESUMEN: Propuesta de un índice de calidad de grasas (ICG). En este artículo se presenta el concepto de índice de calidad de una grasa (ICG), que se basa y se establece en virtud de los reglamentos alimentarios actuales. Es un valor numérico que representa la información correlacionada de todos los parámetros que proporcionan la definición de la grasa de acuerdo con las directrices internacionales. Con la implementación de este índice es posible comparar los diferentes tipos de grasas usando un único valor numérico, lo que facilita la elucidación de los efectos de los procesos de tratamiento u orígenes de las grasas. El ICG incluye todos los parámetros considerados en la normativa mediante la incorporación de un sub-índice para cada parámetro y utilizando el valor límite máximo y mínimo para componer y ajustar una ecuación que describe la calidad de la grasa de acuerdo con la norma. Por último, el procedimiento se utiliza para obtener los índices en base a otros trabajos experimentales que evaluaron la calidad de las muestras de las grasas producidas bajo diferentes condiciones operacionales, tratamientos, orígenes o procesos, permitiendo una mejor comparación y evaluación. Por lo tanto, este índice es una herramienta analítica excelente para evaluar la calidad de las grasas de diferentes orí-genes para el consumo humano.