Francesca R. Lupi

Olive oil/policosanol organogels for nutraceutical and drug delivery purposes

Low molecular weight organogels are semisolid systems structured by the assembly of molecules that crystallise under suitable process conditions. The inner microstructure of organogels is made up of a 3-D network, in which both an organic liquid solvent and other dispersed particles can be entrapped. In this work, olive oil organogels, structured from policosanol (a nutraceutical mixture of fatty alcohols), were studied in order to obtain the best formulation for producing a support for delivery of lipophilic agents (namely ferulic Acid) via oral administration. A rheological optimisation of the olive oil-policosanol organogel was first of all performed with Step Shear Rate Temperature Ramp tests. This provided important information on the policosanol fraction to be added to the system and on the onset of crystallisation temperature, an indirect measurement of the system melting point. It was found that a policosanol weight percentage of 0.03 was suitable to obtain contemporary semisolid organogels, consistent enough and thermally stable for human ingestion. In vitro tests on organogels loaded with ferulic acid were also carried out in order to simulate the oral intake of the nutraceutical compound. This evidenced a release mechanism determined by both erosion and diffusion; a good performance of gels and their ability to control the release rate through the degree of structuration were also observed.

The effects of intermolecular interactions on the physical properties of organogels in edible oils

The microstructure of organogels based on monoglycerides of fatty acids (MAGs) and policosanol and on different edible oils was investigated by using different techniques (calorimetry, nuclear magnetic resonance, infrared spectroscopy, rheology, polarized light microscopy) towards a better understanding and control of the oil gelation phenomena. Dynamic moduli were related via a fractal model to microstructural information such as solid content and fractal dimension. Infrared spectroscopy evidenced that network structure in MAGs gel is mainly due to hydrogen bonding, whereas in policosanol system is mainly given by van der Waals interactions. Because of the different relative contribution of molecular interactions, the investigated organogelators exhibit a distinguished macroscopic behavior. MAGs are sensitive to the utilized oil and structuration occurs quickly, even though at a temperature lower than policosanol. Policosanol organogels exhibit a behavior independent of the used oil and a slower gelation rate, as a result of the weaker van der Waals interactions. Nevertheless, at lower concentration a stronger final gel is obtained, probably due to of the large number of interactions arising among the long alkyl chains of the fatty alcohols. Obtained results evidenced that policosanol is very effective in gelation of different oils and seems promising for potential commercial uses.

Olive oil and hyperthermal water bigels for cosmetic uses.

Bigels are biphasic systems produced with an organogel (or oleogel) and a hydrogel mixed together at high shear rates. These systems are promising for different uses, among them the formulation of new cosmetic matrices for cosmetic agents delivery is under investigation. In the present paper, a common cosmetic formulation for skin care was enriched with increasing fractions of monoglycerides of fatty acids/olive oil organogels, in order to understand the rheology and the microstructure of these systems. Small amplitude oscillation tests, NMR-self diffusion analysis, contrast phase microscopy and electric conductivity confirmed that the addition of the organogel caused a microstructural change of the starting material, which turned from O/W to a more complex system where, probably, a matrix-in-matrix structure is present at the highest fractions of added organogel.

Rheological investigation of pectin-based emulsion gels for pharmaceutical and cosmetic uses

Emulsion gels are structured emulsions suitable for different uses for their specific behaviour, which is strongly dependent on the characteristics of the gelled dispersing phase. Therefore, it is important to adopt the specific gelling agent to tune the final emulsion rheological behaviour properly. Pectin is extremely interesting among potential hydrophilic gelling agents owing to its specific characteristics. In the present work, four different low-methoxyl pectins were adopted to prepare gels to be used as the dispersing phase in cosmetic or pharmaceutical emulsion gels. The rheological characterisation of pectin gels, prepared at room temperature to avoid the damage to potential thermolabile components, was carried out with small amplitude oscillations. The obtained gels were used, together with a common non-ionic surfactant (Tween 60), to prepare olive oil emulsion gels suitable to design new cosmetic products. A simple empirical model, proposed to relate the emulsion complex modulus to the oil fraction and properties of the dispersing phase, has shown itself to be a potentially useful tool to design formulations with desired properties.

A rheological and microstructural characterisation of bigels for cosmetic and pharmaceutical uses

Bigels are biphasic systems formed by water-based hydrogels and oil-based organogels, mainly studied, in the last few years, for pharmaceutical and cosmetic application focused on the controlled delivery of both lipophilic and hydrophilic active agents. The rheological properties of bigels depend on both the amount and the rheological characteristics of single structured phases. Moreover, it can be expected that, at large fractions of one of the starting gels, systems more complex than oil-in-water or water-in-oil can be obtained, yielding bicontinuous or matrix-in-matrix arrangement. Model bigels were investigated from a microstructural (i.e. microscopy and electrical conductivity tests) and rheological point of view. The hydrogel was prepared by using a low-methoxyl pectin whereas the organogel was prepared by using olive oil and, as gelator, a mixture of glyceryl stearate and policosanol. Model bigels were obtained by increasing the amount of organogel mixed with the hydrogel, and microstructural characterisation evidenced an organogel-in-hydrogel behaviour for all investigated samples, even though at the highest organogel content a more complex structure seems to arise. A semi-empirical model, based on theoretical equations developed for suspensions of elastic spheres in elastic media, was proposed to relate bigel rheological properties to single phase properties and fractions.

Saturated fat reduction in pastry

Abstract: Pastries are baked goods mainly produced to complement the flavor of the fillings and to provide them with a casing. The main kinds of pastry, short and puff, are produced with hard fats hydrogenated with catalytic processes in order to match the rheological properties of the dough. Unfortunately, these processes lead to the formation of trans fats dangerous for consumers’ health. Therefore, the use of hydrogenated fats is nowadays reduced in favor of natural added fat sources. This chapter gives an overview of pastry characteristics, also looking at the new frontiers in healthy food production based on rheological modeling.

Pectin: Properties Determination and Uses

Pectin is a high-molecular-weight heteropolysaccharide present in plant cell walls where it contributes to the firmness and structure of the vegetal tissue. Pectin is widely used as food ingredient owing, mainly, to its ability to impart texture and firmness to food products (hydrogels), even though recent interesting uses are also related to other pectin properties, such as interfacial activity. A general overview of pectin and pectin gels is presented, including the most recent experimental techniques used to characterize pectin properties and the texture–structure relationships in pectin hydrogels.

Rheological Study of O/W Concentrated Model Emulsions for Heavy Crude Oil Transportation

Abstract The oil-in-water emulsion is increasing in popularity as a cost-reducing method for “heavy” crude oil transportation. In order to analyze the effect of oil-in-water ratio and emulsifier amount on the viscosity of the final emulsion, concentrated model-emulsion of oil-in-water were rheologically characterized. Two emulsification methods were investigated: batch and “in-flow” in a lab scale plant. Comparison revealed the effect of the emulsifier amount both on the viscosity decay during time and on the final emulsion viscosity. Qualitative microscopy results revealed a rather wide drop size distribution for systems exhibiting a lower viscosity value.

Olive Oil Based Emulsions in Frozen Puff Pastry Production

Puff pastry is an interesting food product having different industrial applications. It is obtained by laminating layers of dough and fats, mainly shortenings or margarine, having specific properties which provides required spreading characteristic and able to retain moisture into dough. To obtain these characteristics, pastry shortenings are usually saturated fats, however the current trend in food industry is mainly oriented towards unsatured fats such as olive oil, which are thought to be safer for human health. In the present work, a new product, based on olive oil, was studied as shortening replacer in puff pastry production. To ensure the desired consistency, for the rheological matching between fat and dough, a water‐in‐oil emulsion was produced based on olive oil, emulsifier and a hydrophilic thickener agent able to increase material structure. Obtained materials were characterized by rheological dynamic tests in linear viscoelastic conditions, aiming to setup process and material consistency, and...

Bigels: A unique class of materials for drug delivery applications

ABSTRACT Bigels, combination of organogel and hydrogel, are unique solid-like formulations with improved properties for food, cosmetics, and pharmaceutical applications. Bigel possesses merits of both phases, aqueous and oily, and displays better properties than either of the single gel. The uniqueness of bigels comes from their ability to deliver both hydrophilic and lipophilic active agents, enrichment of hydration of stratum corneum, easily spreadable, and so on. The main objective of this review article is to provide a thorough insight into the classification of bigels on the basis of synthesis method and morphology and also to demonstrate the detailed analysis of bigel formulations by considering different characterization techniques. Moreover, a special focus is given on the applications of bigels as drug delivery vehicles by transdermal route.