Due to the technological, energetic and economic impact of spray drying in the production of acetylated gelatinized starch from native starch of Manihot esculenta Crantz (Cassava), the objective of this work is to optimize the dynamic profitability indicators considering as optimization criteria the production capacity and the drying air temperature, and establishing the detailed design of the installation under optimum conditions.  A composite central experimental design was generated for the indicators Net Present Value (NPV), Internal Rate of Return (IRR) and Discounted Payback Period (DRP).  The regression models of the profitability indicators were optimized by ridgeline analysis through the Response Surface Methodology. For the evaluation of the indicators, the economic indexes of the process were determined, after technological selection, material and energy balances and technological design. The optimum economic variant has an NPV of USD 2 862 010, an IRR of 45,51 % and DRP of 3 years and is reached when 3454,45 tcassava/y are processed and the air feed temperature to the spray dryer is 184 °C, but the energy index is not favorable. An option that adequately combines energy, environmental and technical-economic results can be used by processing 3150 tcassava/y with 130 °C in the air feed to the dryer, reaching favorable economic results with NPV of USD 2 767 166, IRR of 37,99 % and DRP of 3,45 years and drastically reducing fuel consumption, although increasing the size of the spray dryer.

Para efectuar la modelación de un reactor es necesario obtener el mayor conocimiento de las propiedades termodinámicas, físicas y químicas del sistema,la cinética de las reacciones, las características térmicas y otras específicas. El objetivo de este trabajo fue abordar metodológicamente la modelación de procesos químicos y biológicos, para estudiar etapas con reacciones químicas mediante modelos matemáticos. Se han presentado métodos analítico-matemáticos para el análisis cinético y el tratamiento estadístico de datos experimentales de la industria. Varias situaciones reales han sido resueltas aplicando los modelos globales presentados. Se expresó el tratamiento estadístico de datos industriales para complementar modelos con reacciones químicas.Se presentó un diagrama heurístico diseñado para la modelación de un reactor químico o fermentativo.

Cow manure is an abundant residue and poses a problem regarding recycling. Intensive animal farming produces manure, which, if not properly managed, can contaminate nearby water bodies and soils with nutrient excess. There are 1.9 billion cattle worldwide, with a calculated capacity to produce 7.6 billion tons per year. Feeding of these cows is carried out mainly with cellulosic material. Therefore, cow manure contains an important fraction of lignocellulose. Cow manure can be valorized using such lignocellulosic fractions as the raw material of several fermentative processes. This fraction can be transformed into sugar, which can, in turn, be used to feed lactic acid bacteria (LAB). LAB produces lactic acid (LA), which can later be polymerized to poly(lactic acid) (PLA), a bioplastic with promising market forecasts. This review describes the most updated processes for all of the necessary steps to produce lactic acid from lignocellulosic biomass with LAB. Key process parameters to obtain PLA from lignocellulose are reviewed and analyzed herein, including lignocellulosic fraction extraction, sugar transformation, pretreatment, hydrolysis, fermentation, purification, and polymerization. This review highlights the potentiality to obtain lignocellulose from cow manure, as well as its use to obtain PLA.

Se determinan las potencialidades técnico-económicas para la producción mecanizada de casabe en Cuba aplicando asimilación tecnológica y considerando la incertidumbre en la demanda del producto. El análisis se efectúa para variedades de yuca cubanas cosechadas con fines industriales. Se propone el esquema tecnológico para el proceso mecanizado, garantizando los requerimientos de seguridad y calidad. Se modelan los balances de materiales y energía, se determina el punto de equilibrio del proyecto y se efectúa un análisis de sensibilidad al comportamiento de los precios y al tamaño de planta. Los ingresos superaron los costos a partir de una capacidad de 1 traíces/d. Para generar pequeñas producciones que permitan incentivar el consumo y consolidar los mercados se propone la combinación de los surtidos casabe, harina y almidón. Cuando los mercados estén consolidados pueden lograrse producciones que alcanzan períodos de recuperación menores de cuatro años cuando el tamaño del proyecto es mayor a 2,25 traíces/d, obteniendo producciones superiores a las 0,92 tcasabe/d. El proyecto alcanza resultados similares a capacidad de 1,4 traíces/d y escenarios de precios del casabe 15 % más favorables que los actuales.

Considering the technological, energetic and environmental advantages of precolloidal starch production compared to other types of starches modified by physical and chemical means and the potential uses of precolloidal starch as a food stabilizer, the objective of this work is to carry out the functional evaluation of precolloidal starch compared to native starch and the sensory evaluation of ice cream made using precolloidal starch from Manihot esculenta Crantz as a partial substitute for the stabilizing agents in its formulation. The comparative functional evaluation showed a significantly higher performance for precolloidal starch with respect to native starch for the criteria water absorption index, water solubility index and swelling power.  Through the preparation of milk ice cream, in discontinuous operation at pilot scale, it was shown that the sensory evaluation is satisfactory for the substitution of between 20 and 30 % of a commercial stabilizer by precolloidal starch, reaching adequate industrial yield indexes. Additionally, it was evidenced that the production of ice cream of cream typology, in continuous operation at industrial scale, reaches satisfactory sensory evaluation when 20 % of commercial stabilizer is replaced by precolloidal starch and similar industrial yield levels, with respect to the experience without starch.