Interfacial Rheological Study of ß-Casein/Pectin Mixtures at the Air/Water Interface.

Colloidal food products, such as emulsions, foams, gels, and dispersions, are complex systems that need the presence of stabilizing agents to enable their formation and provide stability. Proteins are often used for food foams and emulsions because of their ability to lower interfacial tension and make viscoelastic interfaces. Generally, to improve the resistance against rupture, polysaccharides are used in association with the proteins. Pectin is a complex polysaccharide that can help to stabilize foams or emulsions. This work aims at studying the mechanical resistance of the interface formed by mixtures of ß-casein and pectin at high and low methoxylation degrees at the air/water interface using dilatational and shear kinematics. Frequency sweep tests, in the linear region, were performed in shear at different aging times and in dilatational mode, and the rheological data were analyzed. The transient data of the surface tension were analyzed by kinetic models to obtain the characteristic rates of the interfacial phenomena. The kinetic mechanisms of the protein/pectin mixed systems are controlled by protein and show a weak gel behavior for short aging times. The interfaces obtained with both pectins in a mixture with ß-casein evolved with time, gelling and showing a solid-like behavior at concentrations of 1 and 10 g/L and after 3.5 h of aging time. The interfacial shear trend obtained suggests a good stabilizing effect of the pectins from citrus with long aging times.

Oil Extraction from Hemp Plant as a Potential Source of Cannabidiol for Healthy Protein Foods.

In recent years, the increasing demand for alternative foods has shifted research toward new sources enriched with nutraceutical molecules. It is well known that many diseases are caused by oxidative stress; thus, the supplementation of antioxidants has been proposed to reduce it. Cannabis sativa L. is an interesting species that could provide an alternative source of antioxidants. This work aimed to investigate the possibility of optimizing the yield of cannabidiol (CBD) and recovering it from residual biomass (stalks), valorizing the residual biomass, and using this for protein bar preparation. Different extraction methods were used, and High-Pressure Liquid Chromatography (HPLC) analysis was used to analyze the extracts. Antioxidant power was investigated using the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. The best results in terms of CBD yield were obtained via dynamic maceration after decarboxylation with a quantity of 26.7 ± 2 mgCBD/graw material from inflorescences. The extract also shows good antioxidant power with an IC50 value of 38.1 ± 1.1 µg/mL measured using the DPPH assay. The CBD extract was added to the hemp oil to obtain dough for protein bars. The doughs were studied by taking rheological and technological measurements, and it was found that the protein bars could provide an excellent means for the consumption of products enriched with antioxidants because their CBD anti-inflammatory activity is preserved after cooking.

Formulation Study on Edible Film from Waste Grape and Red Cabbage.

(1) Background: Recent research on the valorization of agro-industrial waste has attempted to obtain new products. Grape residue is a waste product used in the grape wine industry that is rich in anthocyanins, as well as leaves and waste parts from red cabbage processing. Anthocyanins, thanks to their various functionalities, can be recovered and used as active and intelligent agents in food packaging. Anthocyanins have antioxidant properties that help to prevent cardiovascular disease. (2) Methods: In this study, the process of extracting waste was studied using solvent and supercritical CO2 extraction. The obtained anthocyanins were used in starch-based food film formulations. Several formulations were studied using rheometric techniques and the effect of adding anthocyanins on optimal film formulation was investigated. (3) Results: Solvent extractions resulted in a maximum extraction yield. The extracts obtained were used for the preparation of coating and edible films, optimized in the formulation. (4) Conclusions: The addition of anthocyanins to films resulted in increased sample structuring and mechanical properties that are valid for applications, like dipping using coverage methods. The packaging is also attractive and pH-sensitive.

Key characteristics and modelling of bigels systems: A review.

Bigels are interesting semisolid formulations with better properties for different applications such as cosmetics and pharmaceutical systems. Due to the mixing of two phases of different nature (polar and apolar), bigels possess some interesting features like ability to deliver hydrophilic and hydrophobic drugs, better spreadability and water washability, improved permeability of drugs, enhanced hydration of stratum corneum and ability to manipulate the drug release rate. The main objective of this review article is to provide a thorough insight into the important characteristics of bigels together with the discussion on modelling of bigel systems to relate their properties with individual constituents and different parameters. Moreover, some important applications of bigels are also discussed by considering some examples from the literature.

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.

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/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.