Comparison of the volatile antioxidant contents in the aqueous and methanolic extracts of a set of commercial spices and condiments

Spices are of great interest because their aromatic properties and to preserve food, with no or low nutritional value, and also as components of a healthy diet. The composition of the methanolic and aqueous extracts of commercial samples of Basil, Cinnamon powder, Cinnamon sticks, Clove, Cumin, Turmeric, Ginger, Nutmeg, Oregano, Rosemary and Thyme was studied as a first step in the relation of their antioxidant activities with the composition. Methods used were Gas Chromatography coupled with Mass Spectrometry (GC-MS) and High Performance Liquid Chromatography (HPLC). Extracts were prepared with an amount of the sample suspended in ultrapure water preheated at 100 oC or methanol at 60 ºC, stirring at room temperature and filtering; for GC-MS the extracts were dried and re-dissolved in methanol. To solve the problem in GC-MS with the flash-points of some compounds, both techniques have been combined. The contents in antioxidants of the different species are compared finding spices having much higher antioxidant contents in the methanolic extract than in water, other with aqueous extracts much rich in antioxidants than the alcoholic extracts, and spices with low antioxidant content in both extracts. For Clove, Turmeric, Ginger, Cinnamon, Rosemary and Cumin, it is recommended the use of lipid and/or alcoholic fractions for the food preparation. For Basil, Oregano, Thyme and Nutmeg, to extract most of their antioxidant content only water must be used. Knowledge of the composition in antioxidants can aid the food industry in the design of healthy foods and food preparations

Biosorption of Metals and Metalloids

Industrial activities such as mining operations, refining of ores and combustion of fuel oils play a relevant role in environmental pollution since their wastes contain high concentrations of toxic metals that can add significant contamination to natural water and other water sources if no decontamination is previously applied. As toxic metals and metalloids, including arsenic, cadmium, lead, mercury, thallium, vanadium, among others, are not biodegradable and tend to accumulate in living organisms, it is necessary to treat the contaminated industrial wastewaters prior to their discharge into the water bodies. There are different remediation techniques that have been developed to solve elemental pollution, but biosorption has arisen as a promising clean-up and low-cost biotechnology. Biosorption is one of the pillars of bioremediation and is governed by a variety of mechanisms, including chemical binding, ion exchange,physisorption, precipitation, and oxide-reduction. This involves operations(e.g. biosorbent reuse, immobilization, direct analysis of sample without destruction) that can be designed to minimize or avoid the use or generation of hazardous substances that have a negative impact on the environment and biota, thus following the concepts of "green chemistry" and promoting the environmental care. Furthermore, it has to be specially considered that the design of a biosorption process and the quality of a biosorbent are normally evaluated from the equilibrium, thermodynamic, and kinetic viewpoints.Therefore, a successful biosorption process can be only developed based on multidisciplinary knowledge that includes physical chemistry, biochemistryand technology, among other fields.In this chapter, we explain in detail all the aforementioned aspects. State of the art applications of biosorbents for metals and metalloids removal are carefully revised based on a complete analysis of the literature. Thus, it is evidenced in this chapter that the main points to consider regarding biosorption are the type of biomaterial (e.g. bacteria, fungi, algae, plant?derivatives and agricultural wastes, chitin/chitosan based materials) and the presence of a broad set of functional groups on their surface that are effective for the removal of different toxic metals and metalloids. In fact, removal percentages as high as 70-100% can be found in most works reported in the literature, which is demonstrating the excellent performance obtained with biosorbents. Also, biosorbents have evolved with the help of nanotechnology to modern bio-nano-hybrids materials having superlative sorption properties due to their high surface area coming from the nano-materials structures and multifunctional capacity incorporated from the several types of chemical groups of biomaterials. These, as well as other important aspects linked to biosorption are fully covered in the present chapter.Fil: Escudero, Leticia Belén. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Quintas, Pamela Yanina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Wuilloud, Rodolfo German. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Dotto, Guilherme L.. Universidade Federal de Santa Maria; Brasi