Pectinases: aplicações industriais e perspectivas

Pectic substances are structural heteropolysaccharides that occur in the middle lamellae and primary cell walls of higher plants. They are composed of partially methyl-esterified galacturonic acid residues linked by alpha-1, 4-glycosidic bonds. Pectinolytic enzymes are complex enzymes that degrade pectic polymers and there are several classes of enzymes, which include pectin esterases, pectin and pectate lyases and polygalacturonases. Plants, filamentous fungi, bacteria and yeasts are able to produce pectinases. In the industrial world, pectinases are used in fruit juice clarification, in the production of wine, in the extraction of olive oil, fiber degumming and fermentation of tea, coffee and cocoa.

Fundamentos e aplicações ambientais dos processos fenton e foto-fenton

Wastewater and soil treatment processes based on Fenton's reagent have gained great attention in recent years due to its high oxidation power. This review describes the fundaments of the Fenton and photo-Fenton processes and discusses the main aspects related to the degradation of organic contaminants in water such as the complexation of iron, the use of solar light as the source of irradiation and the most important reactor types used. An overview of the main applications of the process to a variety of industrial wastewater and soil remediations is presented.

Surfactina: propriedades químicas, tecnológicas e funcionais para aplicações em alimentos

Surfactin, a lipopeptide produced by strains of Bacillus subtilis, has been proved to be a suitable biosurfactant in several applications. For many years, it has been investigated mainly for oil recovery and environmental usage. Its chemical, technological and functional characteristics turn surfactin into an attractive compound for several utilizations. In this review we emphasize some aspects of surfactin as a new food ingredient and its potential pharmaceutical and health applications.

Carotenóides: propriedades, aplicações e biotransformação para formação de compostos de aroma

Carotenoids are widely distributed in nature, providing yellow, orange or red color in a great number of vegetables, microorganisms and in some animals. Carotenoids act as biological antioxidants and seem to play an important role in human health by protecting cells and tissues from the damaging effects of free radicals and singlet oxygen. Several authors describe the oxidative cleavage of carotenoids in flavor compounds as occuring through chemical or photochemical degradations or through biotechnological processes. Biotransformation of carotenoids seems to be a reasonable alternative to produce flavor compounds since these compounds are considered 'natural' ingredients. In this work we describe the properties of some carotenoids, as well as biotechnological approaches to obtain its oxyfunctionalized derivatives.

Mecanismo e aplicações da reação de fenton assistida por compostos fenólicos redutores de ferro

The mechanism and applications of the Fenton reaction assisted by iron-reducing phenolic compounds (IRPC) is reviewed. The presence of IRPC leads to the formation of a larger number of free radicals. The relationship between the redox potential and the IRPC structure is discussed. The effect of humic substances in the degradation of xenobiotics is also included, since these substances are able to reduce metallic ions. The natural occurrence of Fe3+/H2O2/IRPC in wood biodegradation processes, as well as their application is also discussed. The review concludes with the advantages of the Fe3+/H2O2/IRPC systems and some considerations for further process optimization and their applications at industrial levels.

Transformação de triglicerídeos em combustíveis, materiais poliméricos e insumos químicos: algumas aplicações da catálise na oleoquímica

The use of biomass as raw-material for obtaining chemicals, polymers and fuels is emerging as a clever alternative solution for the increasing energy demand, environmental awareness and petroleum shortage. In this work, some attempts in order to develop catalytic systems suitable for triglyceride transformation into fuels, polymers and intermediates are reviewed.

Preparações e aplicações sintéticas recentes de enaminonas

Enaminones are beta-enamino carbonylic compounds bearing the conjugated system N-C=C-C=O, which makes them versatile ambident synthetic building blocks, particularly in synthesis of heterocycles. This review covers the last three years of the literature concerning the preparation and synthetic applications of enaminones.

Microssistemas de análises químicas: introdução, tecnologias de fabricação, instrumentação e aplicações

The amazing world of micro total analysis systems has provided a true revolution in analytical chemistry in recent years. The application of the microfluidic devices for chemical and biochemical processing has attracted considerable interest due to its advantages such as reduced sample and reagent consumption, processing time, energy, waste, cost, and portability. The aim of the present report is to disseminate the state of the art related to the miniaturization science in Analytical Chemistry. Historical progress, microfabrication technologies, required instrumentation and applications of the mTAS are presented in the current article, with special attention to the Brazilian contributions.

Cério: propriedades catalíticas, aplicações tecnológicas e ambientais

Cerium based-compounds have great importance in a wide range of technological applications, such as: fuel cell devices development; metallurgic processes, petroleum refining; glass and ceramic production. Recently, its catalytic properties have been also explored for environmental applications, especially those to prevent or to control atmospheric and water pollution. Subjects covered in this work include a brief description of the fundaments of cerium catalytic properties and some relevant technological applications. Special attention is given to its photocatalytic activity and its ability to degrade pollutants. Recent results and future prospect about these applications are also evaluated.

Propriedades e aplicações recentes das ciclodextrinas

Cyclodextrins (CDs) are cyclic oligosaccharides comprised of six or more glucose units connected by alpha-1,4 bonds. They have hydrophobic cavities with a hydrophilic exterior, and are versatile receptors for a variety of substrates. This ability allows them to be applied in many fields, as distinct as supramolecular chemistry, nanotechnology, pharmaceuticals, green chemistry, agrochemicals, analytical chemistry, toiletries, foods, and cosmetics. This review summarizes several aspects related to the physico-chemical properties of CDs and discusses their potential applications illustrated by recent examples. The prospects for their use in several areas are also described.

Análise dinâmico-mecânica: aplicações em filmes comestíveis

Edible films are thin materials based on biopolymers and food additives. The aim of this work is a review on the application of dynamic mechanical analysis in edible film technology. After a brief review of the linear visco-elasticity theory, a description of some practical aspects related to dynamic mechanical analysis, such as sample fixation and sample dehydration during analysis and types and modes of tests are presented. Thus, the use of temperature scanning analysis for glass transition and for plasticizer-biopolymer compatibility studies and frequency scanning tests, less common in edible film technology, are critically reviewed.

Microextração em fase líquida (LPME): fundamentos da técnica e aplicações na análise de fármacos em fluidos biológicos

The analysis of drugs and metabolites in biological fluids usually requires extraction procedures to achieve sample clean-up and analyte preconcentration. Commonly, extraction procedures are performed using liquid-liquid extraction or solid-phase extraction. Nevertheless, these extraction techniques are considered to be time-consuming and require a large amount of organic solvents. On this basis, microextraction techniques have been developed. Among them, liquid-phase microextraction has been standing out. This review describes the liquid-phase microextraction technique based on hollow fibers as a novel and promising alternative in sample preparation prior to chromatographic or electrophoretic analysis. The basic concepts related to this technique and its applicability in extraction of drugs are discussed.

Catalisadores contendo carbenos n-heterocíclicos como ligantes: propriedades, sínteses, aplicações e comparação com outros ligantes

N-heterocyclic carbenes (NHCs) have become of considerable importance in modern organometallic chemistry and homogeneous catalysis. There are several advantages in the use NHCs over their phosphorus analogues, which explains the enormous development of NHC ligands in the field of organometallic catalysis in the past few years. In this article, we present an overview of the importance of the catalysts containing NHC ligands, their synthesis, some pertinent synthetic applications, and a brief comparison with other catalysts.

Monoglicerídeos: produção por via enzimática e algumas aplicações

Monoglycerides (MAG) are non-ionic surfactants, widely used in the pharmaceutical, food and cosmetic industries. Although MAGs are manufactured on an industrial scale by chemical glycerolysis of oils and fats, new developments in lipase catalyzed synthesis have been studied as an alternative to the classical method seeking to use clean technology and green chemistry. In this work, different methods such as glycerolysis, selective hydrolysis of fats and oils, and esterification of fatty acids or transesterification of esters with glycerol are presented. The properties and applications of the monoglycerides are also included in this review.

Principais aplicações das microondas na produção e refino de petróleo

Microwave irradiation offers a clean, inexpensive, and convenient method of heating, which is an alternative way of introducing energy into chemical systems. In particular, applications of microwave irradiation technology for petroleum processing have been developed in the last twenty years. The main objective of this paper is to review the use of microwave irradiation technology as an alternative technique applied during petroleum refining and primary processing of petroleum fluids, presenting and discussing successful applications of this technology as a tool for petroleum emulsion separation and catalytic reactions normally found at hydrorefining plants.