Vilásia Guimarães Martins

Rheology of Surimi-Based Products from Fatty Fish Underutilized by the Industry

Abstract Different products, like emulsified sausages, can be made from surimi from Argentine croaker (Umbrina canosai). This fish is caught in large amounts in the Southern Brazil coast, but is underutilized and has a low commercial value. The objective of the present work was to evaluate the influence of soy protein, potato starch and heating temperature on the texture of an emulsified sausage processed from this surimi. For this, a factorial design was carried out with gel strength and cohesiveness being the measured processing parameters. It could be concluded that cohesiveness diminishes with the increase in soy protein or increase in potato starch. The heating temperature was the parameter that most affected the gel strength. When the soy protein or potato starch concentrations were increased the gel strength decreased.

Impact of acid hydrolysis and esterification process in rice and potato starch properties

The modification of the starches aims to change the properties of these polymers making them more suitable for specific applications. Therefore, the objective of this study was to modify potato and rice starch using the hydrolysis process with hydrochloric acid (HCl) and the esterification process with citric acid (CA), both acids at different concentrations and reaction time. To verify if the modifications were effective, the physicochemical changes (solubility, swelling power, gel strength and amylose content), thermal, morphological and pasting properties were evaluated. The applied modifications reduced the swelling power, solubility and amylose content of starches. The strength of the gel was reduced with the modifications for the rice starch and increased for the potato starch. Regarding the pasting properties, modified starch RS1 (modified rice starch using 0.1 M HCl) and PS3 (modified potato starch using 2% CA) showed a tendency to reduce retrogradation. Structurally, X-ray evaluation indicated reduced crystallinity. Thermal analyses showed that gelatinization temperatures were increased for all treatments, while gelatinization enthalpies were reduced indicating greater thermal stability of the modified starches. Therefore, modified starches have distinct characteristics that can be used for specific processes that requiring starches with different properties from the conventional ones.

Chapter 16 – Solid-State Fermentation for the Production of Biosurfactants and Their Applications

Abstract Biosurfactants are active compounds that are produced at the microbial cell surface or excreted, and reduce surface and interfacial tension. Microbial surfactants offer several advantages over synthetic ones, such as low toxicity and high biodegradability, and remain active at extreme pH and salinity. Biosurfactants are produced by bacteria, yeasts, and filamentous fungi. The composition and yield of biosurfactants depends on bioreactor characteristics, pH of the medium, nutrient composition, agitation, oxygen availability, and temperature. Solid-state fermentation conditions allow the use of alternative substrates such as industrial or agricultural by-products to reduce costs. Thus, there is industrial interest in developing large-scale production processes for these compounds. The largest market for biosurfactants is the oil industry; however, the applications are distributed among the various industrial sectors, such as agriculture, cosmetics, and food industries. Based on this, the current chapter reports the processes involved in biosurfactant production.