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The objective of this research was to assess the sensory acceptance and shelf life of a fresh cheese employing dry bromelain extract as a coagulating agent. Dry bromelain extract was used in three concentrations (5%, 10% and 15% w / w) and the milk utilized was both raw and pasteurized, for a total of six treatments being studied according to a factorial model 3 * 2. A sensorial analysis was conducted and the shelf life (sensorial, physicochemical and microbiological) of the treatment, with the greatest acceptance, was determined. The results showed that the cheeses obtained with the greatest sensorial acceptance were those made with 5% w / w of dry bromelain extract regardless of the type of milk used (raw or pasteurized). The shelf life of the selected product (T2), at the physicochemical level is 26 days; however, sensorially and microbiologically the quality of the product is good up to day 14. Therefore, the use of dry bromelain extract as a vegetable coagulant showed a great potential as a substitute for traditional rennet, El objetivo de esta investigación fue evaluar la aceptación sensorial y la vida útil de un queso fresco utilizando extracto de bromelina seca como agente coagulante. El extracto seco de bromelina se usó en tres concentraciones (5%, 10% y 15% p / p) y la leche se usó de forma cruda y pasteurizada, para un total de seis tratamientos en estudio bajo un modelo factorial 3*2. Se realizó un análisis sensorial y se determinó la vida útil (sensorial, físicoquímica y microbiológica) del tratamiento con mayor aceptación. Los resultados mostraron que los quesos obtenidos con mayor aceptación sensorial fueron los elaborados con un 5% p / p de extracto seco de bromelina, independientemente del tipo de leche utilizada (cruda o pasteurizada). La vida útil del producto seleccionado (T2) a nivel fisicoquímico es de 26 días, sin embargo, sensorial y microbiológicamente, el producto es de buena calidad hasta el día 14. Por lo tanto, el uso de extracto seco de bromelina como coagulante vegetal mostró un gran potencial como Sustituto del cuajo tradicional.

Lipid compounds are gaining increasing attention due to a wide range of applications in the food industry. Particularly, supercritical carbon dioxide (SCCO2) is being successfully employed as a green solvent in the extraction and fractionation of nonpolar lipids. Knowledge of the solubility of pure lipid-type substances and their mixtures in SCCO2 is essential for evaluating the viability of supercritical separation processes and for their subsequent design. Hence, both solubility measurements and thermodynamic modeling are of interest to researchers and process engineers and are receiving considerable attention in the literature. Solubility data of pure mono-, di- or triglycerides in SCCO2 are to a certain extent reported in the literature. However, the information regarding solubility of complex multicomponent glyceride mixtures is relatively scarce. In this work, we report the solubility of a commercial glyceride mixture (51.9 % wt monoglycerides, 34.0 % wt diglycerides and 14.1 % wt triglycerides) in SC-CO2, measured in a variable-volume equilibrium cell at T = (313 and 323) K and pressures in the range of (10-35) MPa. Additionally, we apply two different equation of state based models, to represent the solubility data reported. The thermodynamic modeling is based on an appropriate selection of model substances to represent the glyceride mixture composition, which was determined by HPLCELSD and GC analysis, and an accurate estimation of the pure compounds properties required for the modeling.

Chrastil (1982) established that the solubility of a substance in a supercritical fluid can be correlated with the density of the pure supercritical gas. Recently, the solubility of supercritical fluids in different organic liquids was successfully correlated as a function solely of the supercritical fluid density, since we demonstrated that the supercritical fluid density also defines the solubility of the gas in the liquid phase. In this work, the solubility of supercritical carbon dioxide in high-molecular weight substances, such as high-molecular weight paraffins, alcohols, fatty acids, fatty acid methyl and ethyl esters, has been correlated and constants provided. More than 20 binary systems comprising around 1000 solubility data points were correlated, obtaining regression coefficients greater than 0.96 and confirming the goodness of the density-dependent equation previously reported.

Rosmarinusofficinalis (rosemary) extracts were obtained in a supercriticalpilot-scale plant. Based on experimental information available in the literature for analytical or low-scale processes, extraction temperature and pressure were selected to be 313 K and 30 MPa. At these extraction conditions, the kinetic behavior of the pilot-scale overall extraction curve were determined with respect to yield, antioxidant activity and carnosic acid content. The overall extraction curve was represented using Sovova's model; the average deviation between measured and calculated yields was lower than 2%. Mass transfer coefficients in the fluid and solid phases were determined and were compared with previous data reported in the literature for low-scalerosemarysupercriticalextraction. A two-stage depressurization procedure was accomplished and the effect of both on-line fractionation and extraction time on the antioxidant activity of the samples collected was studied. The antioxidant activity of the different fractions could be straight correlated with the carnosic acid content with a regression coefficient of 0.92.

Experimental and modeling studies of the liquid-liquid equilibria at ambient pressure of three model systems-squalene + ethyl lactate, olive oil + ethyl lactate, and squalene + olive oil + ethyl lactate-were performed with the view to explore the potential application of an agrochemical solvent, namely, ethyl lactate, to recover squalene from pretreated olive oil deodorizer distillate. The favorable separation factors obtained reveal the strength and potential of ethyl lactate as a green solvent for the recovery of squalene from squalene + triglyceride mixtures. © 2011 American Chemical Society.

[ES]: En este trabajo se presentan los resultados obtenidos del estudio (experimental y teórico) del equilibrio entre fases de compuestos alimentarios y solventes verdes, aportando nuevos resultados a los fundamentos de los procesos de separación por contacto en equilibrio de la tecnología de alimentos. Se obtuvieron nuevos datos de equilibrio entre fases, aplicando métodos experimentales a altas presiones (equilibrio líquido – fluido supercrítico, para el disolvente dióxido de carbono) y a bajas presiones (equilibrio líquido – líquido, para el disolvente lactato de etilo). Se desarrollaron metodologías apropiadas para medir experimentalmente tanto sistemas binarios simples, como en el caso de Escualeno + CO2 y Escualeno + Lactato de Etilo, hasta sistemas pseudo-cuaternarios, como es el caso de una mezcla comercial de mono-, di- y triglicéridos con CO2. Los resultados experimentales obtenidos en este trabajo se representaron utilizando un modelo termodinámico basado en contribuciones grupales. Para esto se ajustaron y revisaron algunos parámetros de interacción energética, creando una tabla de parámetros confiable para ser aplicada a la simulación de procesos de extracción supercrítica en el campo de los lípidos y de las bebidas alcohólicas. Por último, los estudios teóricos desarrollados durante el trabajo de modelización permitieron observar la gran influencia de la densidad del solvente supercrítico sobre las composiciones de las fases (líquida y supercrítica) en equilibrio. Este concepto, presentado por Chrastil en 1982 para calcular la solubilidad de un soluto en un fluido supercrítico en función de la densidad del solvente supercrítico, se extiende en esta tesis para correlacionar la solubilidad de un fluido supercrítico en un líquido orgánico, desarrollando nuevas ecuaciones semi-empíricas dependientes de la densidad., [EN]: This work describes the experimental and theoretical results obtained concerning phase equilibria in mixtures of food-related compounds and green solvents. These results represent a singular contribution related to food technology, and particularly connected to the development of equilibrium-based separation process. New experimental liquid – supercritical fluid phase equilibria data were obtained at high pressures (being carbon dioxide the green solvent) and liquid –liquid phase equilibria data were obtained at ambient pressure (being ethyl lactate the agrochemical-green solvent). Appropriate experimental methods were developed to consider binary simple systems, such as Squalene + CO2 and Squalene + Ethyl Lactate, and pseudo-quaternary mixtures such as a commercial mono-, di- and triglyceride mixture + CO2. Additionally, the experimental data obtained in this work were correlated using a thermodynamic group contribution based model. Energy interaction parameters were adjusted and revised and thus, a consistent parameter table was developed to be applied in the simulation of supercritical processing of food-type substances (lipids and alcoholic beverages). The theoretical modeling carried out in this work has demonstrated the relevance of the supercritical solvent density on the composition of the equilibrium phases. This concept was firstly reported by Chrastil in 1982 to calculate the solubility of a solute in a supercritical fluid as a function of the supercritical solvent density. In this work, this idea was successfully extended to correlate the solubility of CO2 in organic liquids by developing new density-dependent semi-empirical equations.

The supercritical removal of ethanol from alcoholic beverages (brandy, wine, and cider) was studied using the GC-EoS model to represent the phase equilibria behavior of the CO2 + beverage mixture. Each alcoholic drink was represented as the ethanol + water mixture with the corresponding ethanol concentration (35 wt% for brandy, 9-12 wt% for different wines and 6 wt% for cider). The thermodynamic modeling was based on an accurate representation of the CO2 + ethanol and CO2 + water binary mixtures, and the CO2 + ethanol + water ternary mixture. The GC-EoS model was employed to simulate the countercurrent supercritical CO2 dealcoholization of the referred beverages; the results obtained compared good with experimental data from the literature. Thus, the model was used to estimate process conditions to achieve an ethanol content reduction from ca. 10 wt% to values lower than 1 wt%. The model results were tested by carrying out several extraction assays using wine, in a 3 m height packed column at 308 K, pressures in the range of 9-18 MPa and solvent to wine ratio between 9 and 30 kg/kg. © 2010 Elsevier B.V. All rights reserved.