Chapters authored
Calorimetric Study of Inulin as Cryo- and Lyoprotector of Bovine Plasma Proteins
Part of the book: Applications of Calorimetry in a Wide Context
Chitosan from Marine Crustaceans: Production, Characterization and Applications
Chitosan is a very useful marine polysaccharide that forms structural components in the exoskeleton of crustaceans. In this chapter, the production of chitosan (CH) and chitosan reticulated micro/nanoparticles (CHM) is described. Three case studies corresponding to different effective applications of chitosan are discussed: (i) the performance of CH to destabilize oil/water emulsion waste for water clarification. It was observed that as long as colloidal charge was maintained around zero, turbidity also showed low values and water clarification was achieved. However, when the applied doses were higher than the optimum, colloidal charge and turbidity both increased, showing emulsion restabilization. Emulsions treated with the optimum chitosan doses were clarified in very short periods; (ii) CH and CHM were used as effective antibacterial agents against three different pathogenic microorganisms that are problematic for aquaculture: Vibrio alginolyticus and parahaemolyticus, and Lactococcus garvieae and the minimum bactericidal concentrations were determined; and (iii) the removal of hexavalent chromium and the comparative performance of CH versus CHM. Results showed that at pH < 2, the adsorption capacity of CHM was higher because CH is unstable. Additionally, Cr(VI) was adsorbed on CH without further reduction; in contrast, Cr(VI) adsorbed on CHM was reduced to nontoxic Cr(III).
Part of the book: Biological Activities and Application of Marine Polysaccharides
Performance of Anoxic-Oxic Sequencing Batch Reactor for Nitrification and Aerobic Denitrification
The biological nitrogen removal (BNR) involves two processes: nitrification and denitrification. Denitrification occurs almost exclusively under facultative anaerobic or microaerophilic conditions; however, aerobic denitrification can occur in aerated reactors. In this chapter, the feasibility of achieving nitrogen removal using a lab-scale biological sequencing batch reactor (SBR) exposed to anoxic/oxic (AN/OX) phases is described in order to attain aerobic denitrification. The SBR was fed with acetate and ammonium sulfate. Nitrite generation was controlled in order to avoid the N2O production by nitrifier denitrification. Experiments under four different operating conditions were carried out: low and high aeration, each one with low and high organic loads. For all the tested conditions, a complete COD removal was achieved. The highest inorganic N removal close to 80% was obtained at pH = 7.5, high organic load (880 mg COD/(L day)) and high aeration given by 12 h cycle, AN/OX ratio = 0.5:1.0, and dissolved oxygen concentration higher than 4.0 mg O2/L. Nitrification followed by high-rate aerobic denitrification took place during the aerobic phase. Denitrification took place mainly from the intracellular reserves of polyhydroxyalkanoates (PHA) during the aerobic phase. The proposed AN/OX system constitutes a simple and potentially eco-friendly process for biological nitrogen removal, providing N2 as the end product and decreasing the formation of N2O, a powerful greenhouse gas.
Part of the book: Biotechnology and Bioengineering
Development of Functional Cheeses with Fructooligosaccharides
Cheese is a food of great consumption in the world; however, some aspects related to its fat content and the possibility of incorporating fiber represent interesting challenges for the dairy industry. In this sense, fructooligosaccharides (FOS), as inulin and agave fructans, exhibit valuable nutritional and functional attributes that can be used as supplements as soluble fiber or as macronutrient substitutes. In this chapter, the study of the development of soft and cream cheeses was performed to determine the operating conditions that allow obtaining products with beneficial health properties taking advantage of the characteristics of this carbohydrate. The skim milk was produced by ultrafiltration, and all the products were characterized physicochemically, including determinations of color, texture, and sensory analysis. The cheeses obtained were of high moisture, >45% (w/w), and reduced fat content (10–25% w/w), including a high protein concentration. The presence of fructans did not significantly modify the texture and appearance of the developed products, but its retention in the matrix was maximal in the case of spreadable cream cheeses containing inulin. Considering the health benefits of fructans and their abundance, this development could represent an innovation for dairy industry.
Part of the book: Current Issues and Challenges in the Dairy Industry