L.A. Garcia-Zapateiro

Rheological properties of oil-in-water emulsions prepared with oil and protein isolates from sesame (Sesamum Indicum)

In this study, food emulsions of oil in water from sesame (Sesamum indicum) protein isolates and their oil were formulated and standardised. The effect of the concentrations of sesame (Sesamum indicum) protein isolates and base oil and the speed of the emulsification process for the food emulsion stability was studied. The protein isolates were achieved from the defatted sesame flour (DSF), obtaining a percentage of 80% ± 0.05% of protein. Emulsions were formulated through a factorial design 23. The rheological behaviour of sesame (Sesamum indicum) protein isolates-stabilised emulsions and microstructural composition were investigated. Stable emulsions with suitable rheological properties and microstructure were formulated at a concentration of 10% sesame oil and different concentrations of protein isolates, between 1.5% and 2.5%, with the best droplet distribution characteristics being shown for the 2.5% sesame protein isolates. The emulsions showed a non-Newtonian fluid behaviour, adjusting the Sisko model.

PHYSICO-CHEMICAL AND BROMATOLOGICAL CHARACTERISTICS OF ARENCA AND RHEOLOGICAL PROPERTIES OF OIL-IN-WATER EMULSIONS CONTAINING ISOLATED PROTEIN

The design, formulation and development of a new product or the improvement of a traditional product are dependent on the knowledge of the physicochemical, bromatological and rheological characteristics of that product. An important aspect of the study of food is complex dispersions such as emulsions. For preparation and formulation of emulsions, surfactants like protein are used to constitute a molecular barrier that helps emulsions to form and stabilizes dispersions. The aim of this work was to standardize an oil in water (O/W) food emulsion with Arencas (Triportheus magdalenae) isolated protein. For this procedure, a physicochemical and bromatological characterization of fish muscle has been done, in which a protein percentage of 17.85±0.12 has been achieved. This has allowed for the recovery of 72-90% of isolated protein to be used in food products such as salad dressing, mayonnaise, spreads, dressings and other products. Stable emulsions with adequate rheological and microstructural characteristics were prepared using 40% w/w palm oil and different concentrates of isolated protein from Arenca, between 2.5 and 3.5% w/w. Therefore, we have obtained an oil in water (O/W) food emulsion with isolated proteins from Arenca that presented non-Newtonian fluid type pseudoplasticity and homogeneous distribution of droplets.

Steady and shear dynamic rheological properties of squash (Cucurbita moschata) pulp

Squash (Cucurbita moschata) is being progressively utilized for the manufacture of different products and the design of different processing methods requires information about its rheological properties of the pulp. The present work has evaluated the rheological properties of the pulp as function of temperature (20 – 100 °C). The rheological properties of natural pulp were evaluated as a function of the temperature. The product flow behavior is well described by the Carreau-Yasuda model (R > 0.9712). The product has shown a weak gel behavior, with storage modulus higher than loss modulus in the evaluated frequency range. The Cox-Merz rule was found to not be applicable to the pulp. The results obtained are potentially useful for future studies on the new products, for the extraction of microcomponents with technological functionality and process design.

Effect of lyophilization on the rheological properties of squash (Cucurbita moschata) and sesame (Sesamun indicum) cream

Several factors affecting rheological properties such as temperature, concentration, Ph and enzyme addition during processing; the knowledge on changes of these properties for research and engineering applications is essential in the design of systems in the development of new products. The aim of this work was formulated and standardize reconstituted creams of squash (Cucurbita moschata) and sesame (Sesamun indicum) using lyophilization. The influence of physicochemical and rheological properties on the pasteurization process of pulp, the percentage of sesame flour and the amount water on standardization was studied. Creams present a Non-Newtonian flow behavior type shear thinning. The rheological parameters were fitted to Power law model. So, on the subsequent rehydration, the power presented the same behavior although a decrease on consistency index (ks) and index (n) due to lyophilization process. The preservation of the bromatological and rheological properties of the final product can be evidenced after being subjected to the effect of the lyophilization process

Viscous characterization of soursop (Annona muricata) jam with blend of hydrocolloids

Jam is one of the most popular fruit preserves, prepared by boiling fruit pulp with sugar and hydrocolloid. In the formulation the effect the blend of different hydrocolloids (carrageenan, guar and xanthan guar) and the concentration of sugar (45, 55 and 55 %wt) on the standardization of soursop (Annona muricata) jam and viscous properties were investigated. The samples tested by steady shear flow tests were carried out to characterize the viscous behavior of jam. All samples presented a non-Newtonian behavior type with shear thinning and flow curves that could be described by the Cross model. The interaction of mixtures of hydrocolloids with different concentrations of sugar in the interface plays a decisive role for the process of gelling and stability of the jams. The use of soursop (Annona muricata) in the formulation of products such as jams are an alternative for its exploitation and exploitation at an industrial level.

Propiedades reológicas de la pulpa de papaya (Carica papaya)

espanolEl objetivo de este trabajo fue analizar el efecto de la temperatura sobre el comportamiento reologico de la pulpa de papaya (Carica papaya). Se realizaron curvas de flujo viscoso en estado estacionario a 5, 15, 25, 40, 60 y 80°C evaluando la influencia de la temperatura en los parametros reologicos. Los ensayos mostraron que las pulpas presentaron comportamiento de fluidos no Newtoniano tipo reofluidificante (s hear thining) y los datos se ajustaron al modelo de Carreau-Yasuda. La influencia de la temperatura sobre la viscosidad de la pulpa se modelo a partir de una ecuacion tipo Arrhenius, evidenciando una disminucion de la viscosidad con el incremento de la temperatura. Los resultados obtenidos aportan informacion sobre el comportamiento reologico de la pulpa de papaya para su aplicacion en el diseno de procesos para la elaboracion de productos a partir de esta materia prima. EnglishThe objective of this work was the analysis of the temperature effect on the rheological behavior of papaya pulp (Carica papaya). Viscous flow curves at steady state were experimentally determined at 5, 15, 25, 40, 60 and 80°C evaluating the influence of temperatures on the rheological parameters. The tests show the pulps presented non-Newtonian shear thinning behavior, adjusted to the Carreau-Yasuda model. The influence of temperature on the viscosity of the pulp was modeled using an Arrhenius type equation, showing a decrease in viscosity with increasing temperature. The results contribute new information for on the rheological behavior of papaya pulp for the application in the design of processes to manufacture of foods products from this raw material.

Efecto de la Adición de Goma Gelana sobre las Propiedades de Barrera y Físico Mecánicas de Biopelículas Binarias

El objetivo del presente estudio fue caracterizar las propiedades físico mecánicas y de barrera al vapor de agua de biopelículas (BP) a base de carboximetilcelulosa (CMC) y goma xantana (GX) formuladas con varias concentraciones de goma gelana de bajo acilo (GBA). Las BP fueron elaboradas por el método de casting y posteriormente fueron determinadas la permeabilidad al vapor de agua (PVA), elongación al quiebre (EQ), resistencia a la tensión (RT), humedad y transparencia. Los resultados obtenidos indicaron que las BP con menores concentraciones de GBA mostraron propiedades más deseables con respecto a las demás formulaciones, ya que se producen BP con baja humedad y PVA. Además presentan elevados valores de EQ y son más transparentes. Estos resultados son realmente prometedores y sugieren la posibilidad de utilizar combinaciones terciarias de CMC, GX y GBA como una fuente de empaque biodegradable para aplicaciones alimentarias.