Calor de sorbición y cambio en energía libre en pulpa de piña liofilizada

Two thermodynamic properties, the heat of sorption (Qs) and the Gibbs free energy change (∆G) were evaluated at several temperatures (5, 25, 30, 35 and 55°C) on freeze-dried pineapple pulp. It was found that 1) the heat of sorption follows the Clauslus-Clapeyron relationship; 2) the shape of the heat of sorption vs. the equilibrium moisture content curve was sigmoid; 3) the heat of sorption from adsorption data gave higher values than those from desorption data; and 4) the free energy change (∆G) is linearly related to the equilibrium moisture content. These two parameters are very important in dealing with food stability because it is possible to predict the water activity at any given temperature of either of these values is known.Dos propiedades termodinámicas, el calor de sorción (Qs) y el cambio en energía libre de Gibbs (∆G) fueron evaluadas a diferentes temperaturas (5, 25, 30, 35 y 55°C) en pulpa de piña liofilizada. Se encontró que: 1) el calor de sorbición sigue la relación de Clausius-Clapeyron; 2) la forma de la curva que representa la relación de calor contra humedad es sigmoide; 3) los calores de sorbición obtenidos de los datos de adsorción son más altos que los obtenidos de los datos de desorción; 4) los cambios en energía libre están linealmente relacionados con el contenido de humedad en equilibrio. Estos dos parámetros son muy importantes cuando se estudia la estabilidad de un alimento, ya que conociendo el valor de cualquiera de ellos es posible predecir la actividad de agua a cualquier temperatura

Rodajas de piña preservadas por métodos combinados

Pineapple slices were treated by two combined methods, packaged and stored at room temperature. The first preservation method consisted of blanching pineapple slices at 100° C for two minutes followed by a cooling period of 1.5 minutes at room temperature. The slices were then immersed in a 50% sucrose solution with 1,000 ppm of potassium sorbate and 150 ppm of sodium bisulfite. The osmotic treatment was done at room temperature (28.5 ± 1.5° C) for 24 hours. The treated slices were removed from the osmotic solution, the excess syrup from the slices was removed, and the product was later packaged in sealed plastic bags. The final water activity values ranged between 0.95 and 0.97 for the packaged product. For the second preservation method, the pineapple slices were blanched in saturated steam for 12 minutes and stored at 12° C until processing by combined methods. Sucrose solutions (55 and 60° Brix) with four different concentrations of potassium sorbate (100, 200, 300, or 500 ppm) were used as osmotic solutions. The water activity was 0.91 after the osmotic process and 0.88 after hot air drying. A shelf life of at least 30 days was observed for product prepared with both preservation techniques, and the sensory characteristics noted were similar to those in a commercially canned product (Del Monte canned slices). The inhibitory effect of potassium sorbate on yeast and mold growth was significant for concentrations above 300 ppm.Se trataron rebanadas de pina con dos métodos combinados y se almacenaron a temperatura ambiente para evaluar su vida útil. El primer método de preservación consistió en escaldar la fruta a 100° C por dos minutos y luego enfriarla a temperatura ambiente (28.5 ± 1.5° C) por 1.5 minutos. Tras el enfriamiento se procedió a colocar las rodajas en almíbar al 50% de sacarosa con 1,000 ppm de sorbato de potasio y 150 ppm de bisulfito de sodio. El tratamiento osmótico se hizo a temperatura ambiente por 24 horas. Las rodajas se sacaron del almíbar y se empacaron en bolsas plásticas luego de escurrir la mayor parte del almíbar. La actividad de agua del producto empacado fluctuó entre 0.95 y 0.97. En el segundo método de preservación, las rebanadas de piña se escaldaron en vapor saturado por 12 minutos y se almacenaron en refrigeración (12° C) hasta su tratamiento por métodos combinados. Se usaron soluciones de sacarosa de 66 y 60° Brix con cuatro niveles de sorbato de potasio (100, 200, 300, 500 ppm) para la deshidratación osmótica de las rebanadas. Una vez en equilibrio, se removieron las rebanadas de la solución de sacarosa y se secaron parcialmente con aire caliente por una hora. El valor de actividad de agua fuego del tratamiento osmótico fue de 0.91 y bajó a 0.88 luego del secado parcial con aire caliente. Para ambos métodos de preservación se observó un período no menor a 30 días durante el cual las características sensoriales del producto compararon favorablemente con las de productos comerciales de piña enlatada (Del Monte). El efecto inhibidor de sorbato de potasio sobre los hongos y las levaduras fue evidente a concentraciones mayores de 300 ppm

Root-retained overdentures as the first choice in the rehabilitation of partially edentulous patients: case report / Sobredentadura sobre raízes como primeira escolha na reabilitação de pacientes parcialmente edêntulos: relato de caso

This case report aimed to describe the oral rehabilitation after the loss of multiple dental elements due to chronic periodontal involvement, with complaints of aesthetics, and loss of masticatory function. The patient, CRT, to 55 years old, presented, in maxillary, dental elements 13 and 23, horizontal bone loss and 1/3 of the roots' bone insertion. In the lower arch, the dental elements presents were 45, 44, 31, 32, 33, 34, and 35. Among these, the teeth 44, 33, 34, and 35 showing no loss of protective and support tissue, while teeth 45, 31, and 32 had more than half of the lost support bone and dental extrusion. Therefore, a complete upper denture and an overdenture were made with additional retention utilizing spherical retainers (o'rings) installed in the dental roots. The treatment involved a multidisciplinary approach with indication the support periodontal, endodontic, oral and maxillofacial surgery, and prosthesis. Despite the lack of support tissue, the patient reported excellent retention and stability of new dentures. Mandibular overdenture with additional retention on roots provide greater retention to the complete dentures, returning aesthetics, function, and comfort to the patient, and should be considered as the first rehabilitation option in several clinical cases, especially when there are clinical, individual, and socioeconomic conditions related to patients who cannot install osseointegrated implants

Procesamiento no térmico de alimentos

Conventional approaches to process foods have proven to offer very safe products but, in some cases, the quality of the final product is significantly lower to the original one. Nonthermal processing of foods has emerged as a viable alternative to those conventional processing by offering safe products of excellent quality and at very reasonable cost. These emerging technologies utilize nonthermal microbial stress factors as the main inactivation mechanism. In some cases, external sources of heat or self-generated heat are utilized to supplement the main inactivation mechanism. This combination becomes very relevant in the case of the sterilization of low-acid foods by pressure assisted thermal processing (PATP). This article presents some of the most relevant nonthermal technologies where some of them are already in use by the food industry and others will be adopted in the very near future. It is the case; these nonthermal technologies could be used in combination among themselves or with other preservation approaches seeking synergistic effects in order to have shorter processes and very good quality food products.Los procesos comúnmente utilizados por la industria de alimentos ofrecen productos seguros pero, en muchos casos, la calidad de los mismos es significativamente peor a los productos no procesados. En forma reciente, se ha empezado a investigar en forma sistemática y desde un punto de vista científico, tecnológico y práctico, las llamadas tecnologías “no térmicas”. Las mismas utilizan como factores principales de inactivación microbiana estrategias que no utilizan el calor. El mismo puede utilizarse como suplemento o puede ser autogenerado por la tecnología utilizada, y a veces puede jugar un papel importante en el proceso como por ejemplo en la esterilización de alimentos de baja acidez utilizando altas presiones. En este trabajo se describen algunas tecnologías “no térmicas” que han adquirido mucha relevancia y que han sido incorporadas a las líneas de proceso en algunas industrias o que, eventualmente, serán incorporadas en un futuro muy cercano. Todas estas tecnologías tienen ventajas y desventajas, y ninguna de ellas es capaz de procesar todos los alimentos, sin embargo debido a la seguridad que ofrecen, la calidad del producto final y los costos involucrados en el uso de las mismas, las hacen una opción muy atractiva a los métodos convencionales, generalmente centrados en el uso del calor. Es del caso señalar que las tecnologías no térmicas pueden ser utilizadas en combinación entre ellas o con otras, buscando efectos sinérgicos lo cual redundará en procesos más cortos y la obtención de productos de mejor calidad

Study of strawberry flavored milk under pulsed electric field processing

Few studies exist on flavored milk processed by pulsed electric fields (PEF). The main concern is product stability. This study aimed to analyze the degradation of coloring agent Allura Red in strawberry milk under PEF. Four systems were tested containing Allura Red: two commercial milks and two model systems. PEF conditions were 40 kV/cm, 48 pulses (2.5 μs), and 55 °C; coloring agent was quantified via RP-HPLC. After processing, only minor changes were observed in color, Allura Red concentration, and pH. During storage (32 d) at refrigerated conditions (4 °C) commercial samples maintained pH above 6. Model systems dropped below pH 6 after 10 days of storage. Color of samples showed important decrease in a⁎; hue angle and chroma changed during storage. HPLC analysis reported a bi-phasic effect in Allura Red concentrations versus time. Concentration changed, reaching a maximum value during the middle of storage, possibly attributed to microbial growth, pH reduction, or interaction of proteins. However, PEF affected the stability of Allura Red in milk when additional ingredients were not added to the product

Study of strawberry flavored milk under pulsed electric field processing

Few studies exist on flavored milk processed by pulsed electric fields (PEF). The main concern is product stability. This study aimed to analyze the degradation of coloring agent Allura Red in strawberry milk under PEF. Four systems were tested containing Allura Red: two commercial milks and two model systems. PEF conditions were 40 kV/cm, 48 pulses (2.5 μs), and 55 °C; coloring agent was quantified via RP-HPLC. After processing, only minor changes were observed in color, Allura Red concentration, and pH. During storage (32 d) at refrigerated conditions (4 °C) commercial samples maintained pH above 6. Model systems dropped below pH 6 after 10 days of storage. Color of samples showed important decrease in a⁎; hue angle and chroma changed during storage. HPLC analysis reported a bi-phasic effect in Allura Red concentrations versus time. Concentration changed, reaching a maximum value during the middle of storage, possibly attributed to microbial growth, pH reduction, or interaction of proteins. However, PEF affected the stability of Allura Red in milk when additional ingredients were not added to the product

Sustainable Consumption Behaviour in Colombia: An Exploratory Analysis

Sustainable consumption has positioned itself as an alternative for economic growth and social development because of its ability to deal with the future scarcity of natural resources and the prevention and mitigation of climate change, among other things. In this sense, the role of the consumer is preponderant, due to the fact their consumption behaviour has a direct effect on the environment; hence the importance of analysing their habits from different perspectives and social realities. Accordingly, the aim of this work is to explore the low-impact sustainable consumption behaviour in Colombia and the convergence and divergence of this type of consumer behaviour in the country. To achieve this, an exploratory, quantitative, and transversal methodology was used. The latter was based on a sample of 393 consumers to whom a self-report scale was applied in order to evaluate behaviours linked to quality of life, care for the environment, and resources for future generations. With the data collected, the following step to follow was to identify how consumers are grouped (hierarchical cluster analysis), what the differences are (single-factor ANOVA), the behaviours (descriptive statistics), as well as the relationship among them (Pearson correlation statistics). Results show that there are two consumer profiles with different levels of awareness of sustainable consumption behaviour. The principal outcome of the study was that Colombian consumers have embraced the behaviour of quality of life and resources for future generations; however, those consumers related to environmental care have been less involved, especially due to the influence of economic variables as such the cost of products and speculation in the prices of environmentally friendly products

High-pressure Processing: Kinetic Models for Microbial and Enzyme Inactivation

High pressure processing (HPP) has become the most widely accepted nonthermal food preservation technology. The pressure range for commercial processes is typically around 100-600 MPa, whereas moderate temperature (up to 65°C) may be used to increase microbial and enzymatic inactivation levels. However, these industrial processing conditions are insufficient to achieve sterilization since much higher pressure levels (>1000 MPa) would be required to inactivate bacterial endospores and enzymes of importance in food preservation. The next generation of commercial pressure processing units will operate at about 90-120°C and 600-800 MPa for treatments defined as Pressure Assisted Thermal Processing (PATP), or Pressure Assisted Thermal Sterilization (PATS) if the commercial food sterilization level required is achieved. Most published HPP kinetic studies have focused only on pressure effects on the microbial load and enzyme activity in foods and model systems. Published work on primary and secondary models to predict simultaneously the effect of pressure and temperature on microbial and enzymatic inactivation kinetics is still incomplete. Moreover, few references provide a detailed and complete analysis of theoretical, empirical, and semi-empirical basis for the kinetic models proposed to predict the level of microbial and enzyme inactivation achieved. This review organizes these published kinetic models according to the approach used, and then presents an in-depth and critical revision to define the modeling research needed to provide commercial users with the computational tools needed to develop and optimize pasteurization and sterilization pressure treatments.Keywords: Primary and Secondary Models, High Pressure Processing, Kinetics, Microbial Inactivation, Pressure Assisted Thermal Processing, Enzyme Inactivatio

Modeling and optimization of sensory changes and shelf-life in vacuum-packaged cooked ham treated by E-beam irradiation

[EN] The E-beam irradiation of vacuum-packaged RTE cooked ham was carried out to establish the dose required to achieve the food safety objective (FSO) and to minimize changes in selected sensory attributes. Cooked ham was irradiated with doses ranging 1-4 kGy. After the treatment, the microbial inactivation of Listeria monocytogenes, the shelf-life of the product and some sensory attributes (appearance, odor, and flavor) were determined. The inactivation of L monocytogenes was satisfactorily described by a first-order kinetics equation (R2=0.99). The influence of the irradiation dose on appearance, odor, and flavor was modeled through Gompertz (R2=0.99, for appearance) and Activation/Inactivation (R2=0.99, for odor and flavor) equations. A model was also developed to determine the shelf-life of irradiated cooked ham depending on the irradiation dose (R2 > 0.91). The dose that maximized the scores of the sensory attributes was 0.96 kGy resulting in an acceptable sensory quality for 80 days. It is possible to apply up to 2 kGy to ensure microbial safety, while provoking no significant changes in the above mentioned sensory attributes. (C) 2010 Elsevier Ltd. All rights reserved.The authors acknowledge the financial support from the Project CSD2007-00016 (CONSOLIDER-INGENIO 2010) funded by the Spanish Ministry of Science and Innovation.Benedito Fort, JJ.; Cambero, MI.; Ortuño Cases, C.; Cabeza, MC.; Ordoñez, JA.; De La Hoz, L. (2011). Modeling and optimization of sensory changes and shelf-life in vacuum-packaged cooked ham treated by E-beam irradiation. Radiation Physics and Chemistry. 80(3):505-513. https://doi.org/10.1016/j.radphyschem.2010.11.001S50551380