Gabriel Lorenzo

Mechanical and optical characterization of gelled matrices during storage.

The effect of composition and storage time on the rheological and optical attributes of multi-component gels containing locust bean gum (LBG), low acyl (LAG) and high acyl (HAG) gellan gums, was determined using three-component mixture design. The generalized Maxwell model was used to fit experimental rheological data. Mechanical and relaxation spectra of gelled systems were determined by the type of gellan gum used, except LBG alone which behaved as a diluted gum dispersion. Storage time dependence of the gels was analyzed using the rubber elasticity theory and to determine changes in network mesh size the equivalent network approach was applied. Destabilization kinetic was obtained from light scattering results; increasing LAG content improved the long-term stability of the matrices. Almost every formulation exhibited an increment in both moduli during the first 10 days remaining practically constant thereafter or until they broke (binary mixtures with LBG); gels with HAG/LBG mixtures were the least stable.

Alternative Proteins and Pseudocereals in the Development of Gluten-Free Pasta

Abstract Most gluten-free products on the market are based on starch; however, gluten-free food manufacturers are investing in the use of whole grains, corn, sorghum, amaranth, and quinoa, as these products are excellent sources of fiber, iron, and vitamin B. Quinoa in particular demonstrates high protein content and a balanced amino acid profile. In addition, mixtures of maize prolamin (zein), starch, and water can form dough with properties similar to wheat dough, which could be used to mimic gluten. This chapter will provide an overview on how to replace gluten functionality in gluten-free pasta using quinoa flour, zein, and other biopolymers. Partially, replacing corn with quinoa flour increases the protein content of the dough, which greatly influences both viscoelastic characteristics and the drying process kinetics. The cooking quality of the final product could be explained in terms of the rheological characteristics and microstructural attributes using mathematical models that relate dough composition to structural parameters.

Food grade microemulsion systems: Sunflower oil/castor oil derivative-ethanol/water. Rheological and physicochemical analysis

Microemulsions are thermodynamically stable systems that have attracted considerable attention in the food industry as delivery systems for many hydrophobic nutrients. These spontaneous systems are highly dependent on ingredients and composition. In this work phase diagrams were constructed using two surfactants (Kolliphor RH40 and ELP), water, sunflower oil, and ethanol as cosurfactant, evaluating their physicochemical properties. Stability of the systems was studied at 25 and 60 °C, monitoring turbidity at 550 nm for over a month to identify the microemulsion region. Conductivity was measured to classify between water-in-oil and oil-in-water microemulsions. The phase diagram constructed with Kolliphor RH40 exhibited a larger microemulsion area than that formulated with Kolliphor ELP. All formulations showed a monomodal droplet size distribution with low polydispersity index (<0.30) and a mean droplet size below 20 nm. Systems with higher water content presented a Newtonian behavior; increasing the dispersed phase content produced a weak gel-like structure with pseudoplastic behavior under flow conditions that was satisfactorily modeled to obtain structural parameters.

Influence of quinoa and zein content on the structural, rheological, and textural properties of gluten-free pasta

This work analyzed the effect of quinoa flour and zein protein on the rheological, structural, and physicochemical characteristics of gluten-free pasta throughout the production process. Supplementing corn flour with quinoa increased dough protein content and greatly decreased the elastic behavior of the dough. Water diffusivity in the dough matrix during the drying process decreased in the presence of quinoa and was related to the smooth homogeneous surface of the dough. Cooking quality of the final product was explained in terms of the rheological and microstructural characteristics using mathematical models that related dough composition with structural parameters. The presence of zein seemed to weaken the protein network; microstructure was more crumbly with starch granules not completely embedded in the carbohydrate–protein matrix. These structural features explained the lower cooking time, higher breakability, and low cohesiveness of cooked zein-containing pasta. The addition of zein negatively altered the structure of pasta, whereas quinoa flour resulted in a cooked product with good textural properties and higher protein content.

Response Surface Methodology to Assay the Effect of the Addition of Proteins and Hydrocolloids on the Water Mobility of Gluten-Free Pasta Formulations

In gluten-free pasta formulation (suitable for those suffering from celiac disease), the influence of each constituent has a major importance on the final product quality, especially water and hydrocolloid contents used to replace the gluten matrix. Gluten-free doughs are mixed dispersed systems; the dispersion medium contains several types of dispersed particles, with two main construction materials—polysaccharides and proteins. Four levels of structural hierarchy in dispersed food systems can be distinguished: submolecular, molecular, supermolecular, and macroscopic. Structural functions of a biopolymer depend upon its place in the structural hierarchy of the product (Tolstoguzov 2000).