Valéria Dal Prá

Evaluation of activity of a commercial amylase under ultrasound-assisted irradiation

The main objective of this work was to evaluate the effects of ultrasound irradiation on the activity of a commercial amylase. A central composite design was carried out to assess the effects of temperature and pH on the enzyme activity in the presence and absence of ultrasound irradiation. The activation energy, the influence of treatment time as well as the substrate concentration on enzyme activity were also determined in the presence and absence of ultrasound irradiation. The results demonstrated that the effect of temperature was less pronounced in the presence of ultrasound, resulting in a decreasing of about 80% in the activation energy in comparison with the value obtained in the absence. The enzyme showed activities about 3 times higher for temperatures up to 40 °C in the presence of ultrasound. The pH negatively affected the activity in the presence of ultrasound, whereas in the absence a positive effect was verified. The ultrasound irradiation is a promising technology to be used in enzymatic reaction due to its positive effects on enzyme activity.

Supercritical CO2 extraction, chemical characterisation and antioxidant potential of Brassica oleracea var capitata against HO, O2·- and ROO

In this work were extracted bioactive compounds from Brassica oleracea var capitata using supercritical CO2 and evaluated the antioxidant potential of the extracts. Five extractions were accomplished to investigate the influence of pressure (10-25 MPa) and temperature (20-60 °C) in the extraction yield, chemical composition and antioxidant potential towards peroxyl, superoxide and hydroxyl radicals. The highest extraction yield was obtained at 60 °C and 25 MPa, which was 0.47 wt% (run 2). In the characterisation of the extracts obtained was possible the identification of sulforaphane and iberin nitrile that present known biological properties. The extracts of all runs presented antioxidant activities towards the three radicals, but the highest activities for all radicals were using the extracts obtained in the run 2. The use of supercritical CO2 extraction to obtain bioactive compounds of B. oleracea var capitata showed to be a promising alternative to conventional extraction methods, since allowed the extraction of compounds with scientific and industrial interest.

Hybrid modeling of xanthan gum bioproduction in batch bioreactor

This work is focused on hybrid modeling of xanthan gum bioproduction process by Xanthomonas campestris pv. mangiferaeindicae. Experiments were carried out to evaluate the effects of stirred speed and superficial gas velocity on the kinetics of cell growth, lactose consumption and xanthan gum production in a batch bioreactor using cheese whey as substrate. A hybrid model was employed to simulate the bio-process making use of an artificial neural network (ANN) as a kinetic parameter estimator for the phenomenological model. The hybrid modeling of the process provided a satisfactory fitting quality of the experimental data, since this approach makes possible the incorporation of the effects of operational variables on model parameters. The applicability of the validated model was investigated, using the model as a process simulator to evaluate the effects of initial cell and lactose concentration in the xanthan gum production.

Investigation of phenolic antioxidants as chemical markers in extracts of Connarus perrottetii var. Angustifolius Radlk by capillary zone electrophoresis

ABSTRACT Plant roots, leaves, barks, seeds berries, or flowers can be used to promote health and treat diseases and also have compounds that provide information about the best quality of raw materials. A medicinal plant native to the Amazonia region (Brazil) was investigated in this work. For this purpose, a new analytical approach was developed by capillary zone electrophoresis (CZE) with UV detection for the separation of 14 phenolic compounds extracted from the plant extracts. The method enabled simultaneous determination of 3-acetylcoumarin, resveratrol, 6-hydroxycoumarin, catechin, rutin, ferulic acid, quercitrin, kaempferol, fisetin, myricetin, quercetin, caffeic acid, gallic acid, and 4-hydroxycinnamic acid using borate buffer (20 mM, pH 9.2) containing 15% methanol (v/v) as working electrolyte, separation potential of −20 kV, separation temperature of 25°C and hydrodynamic injection by gravity (20 cm for 60 s). The developed method was validated, obtaining repeatability and inter-day precision values lower than 7% and 6%, respectively. Recovery was performed and ranged from 84% to 118%. The method permitted the quantification of catechin and rutin in Connarus perrottetii var. angustifolius aqueous infusions, ethanolic extracts, and butanolic extracts (both obtained after maceration). The radical scavenging activity of the extracts toward free radicals is also described. GRAPHICAL ABSTRACT

Cellulases for Food Applications

Abstract Enzymes are important additives in the food industry with a wide range of applications. Cellulases are used in different food processing units, thus presenting a fundamental role in improving the extraction and clarification of fruit and vegetable juices; improving cloud stability and texture, and decreasing viscosity of nectars and purees from tropical fruits; improving extraction of olive oil; and altering the texture, flavor, and other sensory properties such as aroma and volatile characteristics of fruits and vegetables. In this way, this chapter presents the state-of-the-art of the applications of cellulase in the food industry, focusing on the mentioned topics.

Perfil Cromatográfico e Atividade Antioxidante Frente aos Radicais Peroxila (roo•), Superóxido (o2•-) e DPPH da folha, flor, ramo e inflorescência da Plectranthus Barbatus

Este trabalho teve como objetivo avaliar a atividade antioxidante (ROO · , O 2 · - e DPPH) e o perfil cromatografico de compostos fenolicos da folha, flor, ramo e inflorescencia da Plectranthus barbatus. Os extratos etanolicos das diferentes partes da planta obtidos atraves de extracao por ultrassom foram caracterizados por cromatografia liquida acoplada a um detector UV-HPLC-UV. Alem disso, avaliou-se a atividade antioxidante frente aos radicais DPPH, superoxido e peroxil. Como resultado, a maioria dos extratos apresentaram atividade antioxidante frente aos radicais investigados, alem de que foram identificados os compostos quercetina, quercetrina, flavona, acido cafeico e canferol nas partes investigadas da planta. Por fim, o estudo demonstrou que e de extrema importância se saber qual parte da planta esta sendo avaliada, visto que estas apresentam diferencas na atividade antioxidante e na composicao quimica.

ATIVIDADE ANTIOXIDANTE (ROO•, O2•- E DPPH) E COMPOSTOS FENÓLICOS MAJORITÁRIOS PARA FOLHA, FLOR, RAMO E INFLORESCÊNCIA DA ACHILLEA MILLEFOLIUM

Este trabalho teve como objetivo avaliar a atividade antioxidante (ROO · , O 2 · - e DPPH) e o perfil cromatografico de compostos fenolicos da folha, flor, ramo e inflorescencia da Achilea millefolium. Os extratos etanolicos das diferentes partes da planta obtidos atraves de extracao por ultrassom foram caracterizados por cromatografia liquida acoplada a um detector UV-HPLC-UV. Alem disso, avaliou-se a atividade antioxidante frente aos radicais DPPH, superoxido e peroxil. Como resultado, a maioria dos extratos apresentaram atividade antioxidante frente aos radicais investigados, alem de que foram identificados os compostos quercetina, quercetrina, flavona, acido cafeico e canferol nas partes investigadas da planta. Por fim, o estudo demonstrou que e de extrema importância se saber qual parte da planta esta sendo avaliada, visto que estas apresentam diferencas na atividade antioxidante e na composicao quimica.

ASPECTOS QUÍMICOS E ATIVIDADE ANTIBACTERIANA DE PIPTADENIAGONOACANTHA (FABACEAE)

This study aimed to evaluate the antibacterial and phytochemical aspects of Piptadeniagonoacantha . First, there was a standardization of extracts from the leaves of P. gonoacantha and its phytochemical characterization were analyzed, where the main variables were: extraction method (maceration and ultrasound bath), solvent (water, alcohol and water-alcohol mixtures), extraction temperature (30, 40 and 50°C) and influence pH (2 to 12) on the extinction coefficient (absorbance) of the same. Moreover, a phytochemical screening and quantification of total polyphenols in the sample was performed. An evaluation of the antibacterial activity in vitro was performed by adapting the method of diffusion in solid media with perforation of agar against Staphylococcus aureus and Escherichia coli. Through chemical evaluation identified the most effective way to promote the extraction of constituents should be performed with ultrasound at 40°C using 80% ethanol (v/v). The pH promoted structural modification (Deprotonation/protonation) of chemical constituents in extracts with pH values above 8. Furthermore, quantification of total phenols indicated that a significant proportion of the extracts is constituted by compounds within this class is confirmed by phytochemical which could be evidenced the presence of flavonoids , tannins, coumarinsandanthraquinones. The extract of this species showed antibacterial activity, especially with 80% ethanol (v/v ), and efficient ability to inhibit the growth of bacteria S. aureus . The data suggest that the species P. gonoacantha has promising compounds as their source of new drugs to combat resistant microorganisms.

ATIVIDADE ANTIBACTERIANA DE Brassica oleracea var. capitata EM MODELOS EXPERIMENTAIS IN VITRO

The ability of microorganisms, especially bacteria become resistant, has been widely discussed in various publications, and plants are one source to search for new drugs that each day has become more necessary. This work aimed to evaluate different ways of preparing extracts of Brassica oleracea var. capitata and test them fronts strain of Staphylococcus aureus using the test on solid medium by diffusion in agar and in liquid medium in the ELISA plate. Tests revealed that extracts obtained by solvent extraction and decoction hydroalcoholic acid have greater appeal to the search for new drugs with activity against S. aureus, and the latter fractions obtained by liquidliquid partition relating to solvents ethyl acetate, dichloromethane and hydroalcoholic remaining fraction showed more efficient. As for the solid medium, there was a lack of antibacterial activity of hydroalcoholic extract. However, a strong antibacterial activity was observed when analyzed in the same extracts in liquid medium. Ethanolic extracts with concentrations of 50 and 70% showed better results when evaluated for 8 h of incubation. Different results were observed when the period was bent where the concentrations became more expressive of the 70 and 80%. The results demonstrate that the species is a potential source of antibacterial agents. However, the choice of solvent, the extraction method and the bacterial growth medium should be considered. The data shown here motivates further studies for the isolation and identification of the active principles responsible for the antibacterial activity that can be used in the pharmaceutical industry, because of the large number of resistance to existing antibacterial drugs. Key-words: Anti-Bacterial Agents, Plants Medicinal, Medicine Traditional, Phytotherapy, Brassica.