Cassava Starch Films with Anthocyanins and Betalains from Agroindustrial by-Products: Their Use for Intelligent Label Development.

The development of biodegradable packaging materials has become a widely addressed topic in recent years. Microparticles generated from Brassica oleracea var. capitata f. rubra (red cabbage, RC) and Beta vulgaris L. var. conditiva (beetroot, BR) which contained anthocyanins or betalains, were included in the formulation of edible films based on cassava starch (CS) giving origin to films CSRC, CSBR, or CSBC (mixture of both particles). The inclusion of the filler determined an increase in the stress at rupture from 0.8 MPa (CS) to 1.2 MPa (CSRC) or 1.0 MPa (CSBC), of the contact angle from 2.6° to 13.8° (CSBR) or 19.6° (CSBC). The use of these films for developing a smart label for hake packaging and the study of the TBV-N content, the microbiological characteristics of the muscle, and the color changes of the label with time, allowed us to conclude that the films CSRC and CSBC would be suitable for sensing the deterioration of packaged and chilled hake and that the color change of the label CSBC was completely consistent with fish muscle deterioration. As the microparticles can be obtained from by-products of the production and industrialization of plant tissues, the composite films and the smart labels developed can contribute not only to the development of safe food but also to the addition of value to those residues and to environmental protection.

Solubilization of lipolysis products in mixed micelles is enhanced in presence of bile salts and Tween 80 as revealed by a model study (oleic acid) and emulsified chia-oil.

In the last few decades, there has been a growing interest in understanding the mechanisms involved in lipid digestion with the purpose of developing strategies to control this complex physiological process. Bile salts (BS) are natural bio-surfactants that play crucial functions in this process and may represent a key strategy to modulate the lipolysis. One of the main functions is the removal of lipolysis products present at the interface of lipid droplets by solubilizing them in BS micelles, thus avoiding the reaction inhibition. However, there are few studies that analyzed the effects that could have the emulsion components on the solubilization capacity of BS micelles. Thus, the main purpose of the present work was to evaluate the impact of a typical food emulsifier (Tween 80) on the fatty acid (FA) solubilization capacity of BS micelles by using a method recently developed, involving a combination of turbidity and dynamic light scattering (DLS) determinations. As FA solubilization into BS micelles may strongly affect the kinetics of lipolysis, the lipolysis of T80-stabilized oil-in-water (O/W) emulsions was also studied. The results showed that a higher concentration of the emulsifier in the duodenal medium causes the lipolysis rate to be maximum for a longer time. The mechanism involved could be the contribution of T80 to increase the solubilization of FA (and possibly other products of the lipolysis) in the duodenal medium, consequently affecting the potential bioavailability of fatty acids.

A new methodology to assess the solubility of fatty acids: Impact of food emulsifiers.

In food formulations, lipids are normally incorporated as emulsions stabilized by different types of emulsifiers. The emulsifiers can affect fatty acid (FA) solubilization as they can interact with FA. The main purpose of the present work is the development of a methodology to evaluate the FA solubilization in an aqueous medium in the absence and presence of exogenous emulsifiers. To this end, a combination of turbidimetry, oiling off and dynamic light scattering (DLS) was used. The FA solubility, as well as its supramolecular assemblies, were determined by analyzing the changes in the turbidity profile and the corresponding size of particles obtained by DLS. Oleic acid (OA) was used as a model FA and a simulated intestinal fluid (SIF) as the aqueous phase. Emulsifiers of low (Tween 80) and high (protein and polysaccharide) molecular weight were tested. Tween 80 was the only emulsifier that improved OA solubilization, whereas the macromolecules only affected the supramolecular structure that OA adopted, being the structure of these assemblies governed by the emulsifier nature.

Studies on the interactions between bile salts and food emulsifiers under in vitro duodenal digestion conditions to evaluate their bile salt binding potential.

During the last decade a special interest has been focused on studying the relationship between the composition and structure of emulsions and the extent of lipolysis, driven by the necessity of modulate lipid digestion to decrease or delay fats absorption or increase healthy fat nutrients bioavailability. Because bile salts (BS) play a crucial role in lipids metabolism, understanding how typical food emulsifiers affect the structures of BS under duodenal conditions, can aid to further understand how to control lipids digestion. In the present work the BS-binding capacity of three emulsifiers (Lecithin, Tween 80 and ß-lactoglobulin) was studied under duodenal conditions. The combination of several techniques (DLS, TEM, ζ-potential and conductivity) allowed the characterization of molecular assemblies resulting from the interactions, as modulated by the relative amounts of BS and emulsifiers in solution.

Modification of foaming properties of soy protein isolate by high ultrasound intensity: Particle size effect.

The effect of high intensity ultrasound (HIUS) may produce structural modifications on proteins through a friendly environmental process. Thus, it can be possible to obtain aggregates with a determined particle size, and altering a defined functional property at the same time. The objective of this work was to explore the impact of HIUS on the functionality of a denatured soy protein isolate (SPI) on foaming and interfacial properties. SPI solutions at pH 6.9 were treated with HIUS for 20 min, in an ultrasonic processor at room temperature, at 75, 80 and 85°C. The operating conditions were: 20 kHz, 4.27 ± 0.71 W and 20% of amplitude. It was determined the size of the protein particles, before and after the HIUS treatment, by dynamic light scattering. It was also analyzed the interfacial behavior of the different systems as well as their foaming properties, by applying the whipping method. The HIUS treatment and HIUS with temperature improved the foaming capacity by alteration of particle size whereas stability was not modified significantly. The temperature of HIUS treatment (80 and 85°C) showed a synergistic effect on foaming capacity. It was found that the reduction of particle size was related to the increase of foaming capacity of SPI. On the other hand, the invariable elasticity of the interfacial films could explain the stability of foams over time.

Interfacial and foaming interactions between casein glycomacropeptide (CMP) and propylene glycol alginate.

Proteins and polysaccharides are widely used in food formulation. While most of the proteins are surface active, only few polysaccharides can adsorb at the air-water interface; this is the case of propylene glycol alginates (PGA). It is known that casein glycomacropeptide (CMP), a bioactive polypeptide derived from κ-casein by the action of chymosin, presents a great foaming capacity but provides unstable foams. So, the objective of this work was to analyze the impact of mixing CMP and a commercial variety of PGA, Kelcoloid O (KO), on the interfacial and foaming properties at pH 7.0. It was determined the surface pressure isotherm, the dynamics of adsorption and the foaming properties for CMP, KO and the mixed system CMP-KO. CMP dominated the surface pressure of CMP-KO mixed system. The presence of KO synergistically improved the viscoelastic properties of surface film. The foaming capacity of CMP was altered by KO. KO foam presented a higher stability than CMP foam and it controlled the stability against drainage and the initial collapse in the mixed foam.