PRODUÇÃO DE XILANASE POR Aspergillus casielus COM DIFERENTES FONTES DE CARBONO

Neste trabalho foi avaliada a produção de xilanase por Aspergillus casielus, utilizando diversas fontes de carbono (resíduo ou bagaço de cevada, bagaço de cana, casca de amendoim, resíduo fibroso da mandioca, germe de trigo, bagaço de milho verde e casca de laranja). Dentre as fontes de carbono testadas na produção de xilanase pelo fungo A. casielus em condições de fermentação semi-sólida, os melhores indutores foram o bagaço de cevada seguido pela casca de amendoim com atividade especifica de 9,22 U/mg de proteína e 4,55 U/mg, respectivamente. Obeteve-se produção máxima de xilanase livre de celulase no 3º dia (72 horas) com atividade específica de 7,88 U/mg proteína. O pH ótimo e a temperatura ótima de atividade xilanásica foram 6,5 e 50ºC, respectivamente. A estabilidade térmica da xilanase na temperatura de 45ºC mostrouse praticamente constante, com perda de apenas 18% da atividade xilanolítica inicial em 90 minutos de reação. No entanto, nas temperaturas de 50ºC e 55ºC a enzima mostrou meia-vida de 50 e 17 minutos, respectivamente. Na análise dos produtos de hidrólise do xilano pela xilanase produzida por A. casielus verificou-se a formação de vários xilooligossacarídeos (xilose, xilobiose, xilotriose) indicando a ação de provável endoxilanase

A natural food ingredient based on ergosterol: Optimization of the extraction from: Agaricus blazei, evaluation of bioactive properties and incorporation in yogurts

In recent years, mycosterols have emerged as potential functional ingredients for the development of sterol-enriched food products and dietary supplements. Agaricus blazei is a mushroom rich in bioactive compounds. For commercial purposes, their fruiting bodies must obey rigid morphological criteria. Those not conforming to these criteria are usually discarded, although this does not mean impairment of their content in bioactives. The aim of the present work was to propose the use of commercially discarded A. blazei fruiting bodies for obtaining an extract rich in ergosterol as a fortifier ingredient for yogurts. For extraction, the Soxhlet technology was used and the highest ergosterol yield (around 12%) was achieved in the 5th cycle, yielding 58.53 ± 1.72 μg of ergosterol per 100 g of mushroom (dry weight). The ergosterol rich extract presented notable antioxidant and antimicrobial properties, besides showing no hepatotoxicity. When added to the yogurts it significantly enhanced their antioxidant properties. Furthermore, it did not significantly alter the nutritional or the individual fatty acid profiles of the final dairy products. Thus, A. blazei fruiting bodies that do not conform to the commercial requirements of the market and are normally discarded could be exploited for obtaining a natural high added-value food additive, following the circular bioeconomy concept.R. C. G. Correa thanks the CAPES Foundation, Ministry of Education, Brazil (CAPES fellow, process number 88881.120010/2016-01), for the financial support provided for her postdoctoral research in the Polytechnic Institute of Bragança. The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and the FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/ 00690/2013), L. Barros contract and A. Fernandes grant (SFRH/ BPD/114753/2016). This work was also funded by the European Structural and Investment Funds (FEEI) through the Regional Operational Program North 2020, within the scope of Project Mobilizador ValorNatural®. Rosane Marina Peralta and Adelar Bracht are recipients of scientific productivity research grants from CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil), grants numbers 307944/2015- 8 and 304090/2016-6, respectively. M. Sokovic is grateful for financial support to the Ministry of Education, Science and Technological Development of Republic of Serbia, Grant No. 173032.info:eu-repo/semantics/publishedVersio

Laccases in food processing: Current status, bottlenecks and perspectives

Background: Laccases (benzenediol:oxygen oxidoreductases, EC 1.10.3.2) catalyze the oxidation of a wide variety of organic and inorganic substrates, typically p-diphenols with a concomitant reduction of oxygen (O2) to water. Several molecules naturally occurring in foods and beverages (e.g., phenols, carbohydrates, unsatured fatty acids and thiol-containing proteins) can be modified by laccases. Hence, the interaction between laccase and these molecules can and has been widely explored by the food industry for various technological purposes. Scope and approach: The present work aims at providing a critical review on the current uses of laccases in food processing, at discussing the main bottlenecks for its popularization, and at presenting future perspectives. Both scientific reports and patents, covering preferably the last five years, were considered. Key findings and conclusions: Several traditional uses of laccases in food processing including baking, beverage, and dairy industries were detailed. Special efforts were developed, however, in analyzing future perspectives. The latter includes the application of laccases in the synthesis of new compounds with functional properties, such as antioxidant and antimicrobial activities. No less attention was devoted to the recent developments in the field of crosslinking of polymers, such as proteins and polysaccharides. Scaling up of the production of the laccase itself and especially of the novel products derived from its applications in the food sector will be essential for cost reduction and, consequently, for market expansion.This work was supported by the National Council of Scientific and Technological Development (CNPq, Proc. 404898/2016-5). R.C.G. Corrêa is a research grant recipient of Cesumar Institute of Science Technology and Innovation (ICETI). C.G. Kato (Proc. 151189/2019-6), E. Backes (Proc. 304406/2019-8), R.M. Peralta, R.A. Peralta, R.F. Peralta Muniz Moreira and A. Bracht are research grant recipients from CNPq.info:eu-repo/semantics/publishedVersio

Antioxidant and antimicrobial activities of a purified polysaccharide from yerba mate (Ilex paraguariensis)

This study investigated the antioxidant, antimicrobial and cytotoxic properties of a purified yerba mate polysaccharide. The yerba mate polysaccharide showed a prominent antioxidant activity as evaluated by 2,2-diphenyl-1- picrylhydrazyl (DPPH•)-radical scavenging activity (IC50 = 1.25 ± 0.10 mg/mL), 3-ethyl benzothiazoline-6- sulphonic acid (ABTS•+)-radical scavenging activity (IC50 = 0.41 ± 0.05 mg/mL), and hydroxyl scavenging activity (IC50= 3.36 ± 0.31 mg/mL). The antioxidant activity evaluated as the ferric ion reduction power (FRAP) and oxygen radical absorbance radical assay (ORAC), expressed as trolox equivalents,were 20.84±1.61 μMTE/- mg and 556.30± 12.83 μM TE/mg, respectively. The purified yerbamate polysaccharide presented high antimicrobial activity against several bacterial and fungal strains; however, no cytotoxicity against all four tumor human cell lines assessed.The authors thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Proc. 3079/2015-8) for funding this study. Author V.G. Correa thanks Coordenação de Aperfeiçoamento do Pessoal do Ensino Superior (CAPES) for the financial support provided for their post-graduate studies in Universidade Estadual de Maringá. R.C.G. Corrêa thanks CAPES Foundation,Ministry of Education, Brazil (process number 88881.120010/2016–01) for funding her postdoctoral internship in Polytechnic Institute of Bragança. A. Bracht, R.A. Peralta and R.M. Peralta are research grant recipients of CNPq.info:eu-repo/semantics/publishedVersio

Xylanase from Fusarium heterosporum: Properties and influence of thiol compounds on xylanase activity

The properties of xylanase purified from Fusarium heterosporum that was grown in barley-brewing residue under solid-state fermentation and the effects of thiol compounds on the reactivation of the metal ion-inhibited xylanase were investigated. Xylanase was purified to homogeneity by ion exchange chromatography, and its molecular mass was estimated to be 19.5 kDa by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH for the xylanase was 5.0, and it was stable in acidic pH (4.5 to 5.5), where it retained more than 87% of its activity after 24 h. The optimum temperature was 50°C, and it had a half-life of 53 min at 45°C. The apparent Km and Vmax values for the xylanase were 5.63 mg/ml and 800 μmol/mg/min, respectively. Ba2+, Ca2+, Mg2+ and the thiol compounds β-mercaptoethanol and dithiothreitol (DTT) enhanced xylanase activity, while Hg2+, Pb2+ and Zn2+ strongly inhibited enzyme activity. Furthermore, this xylanase had an alternative mode of regulation in the presence of thiol compounds because the enzyme was able to recover its catalytic activity after inhibition by heavy metal ions.Keywords: Hemicellulase, fungus, solid-state fermentation, barley brewing residue, thiol compoundsAfrican Journal of Biotechnology, Vol. 13(9), pp. 1047-1055, 26 February, 201

Bioactive formulations prepared from fruiting bodies and submerged culture mycelia of the Brazilian edible mushroom Pleurotus ostreatoroseus Singer

Pleurotus ostreatoroseus is a Brazilian edible mushroom whose chemical characterization and bioactivity still remain underexplored. In this study, the hydrophilic and lipophilic compounds as well as the antioxidant, anti-inflammatory and antimicrobial activities of formulations (ethanol extracts) prepared with its fruiting bodies and submerged culture mycelia were compared. The bioactive formulations contain at least five free sugars, four organic acids, four phenolic compounds and two tocopherols. The fruiting body-based formulation revealed higher reducing power, DPPH scavenging activity, β-carotene bleaching inhibition and lipid peroxidation inhibition in brain homogenates than the mycelium-based preparation, as well as higher anti-inflammatory and antimicrobial activities. The absence of hepatotoxicity was confirmed in porcine liver primary cells. These functional responses can be related to the levels of bioactive components including phenolic acids, organic acids and tocopherols.The authors are grateful to Foundation for Science and Technology (FTC, Portugal) for financial support to CIMO (Pest-OE/AGR/UI0690/2014), L. Barros research contract (“Compromisso para a Ciência”) and R.C. Calhelha grant (SFRH/BPD/68344/2010), and to the Serbian Ministry of Education, Science and Technological Development for the Grant No 173032. R.C.G. Correa thanks CAPES Foundation, Ministry of Education of Brazil (CAPES fellow, process number BEX 3974/14-6). R.M. Peralta and A. Bracht are Research Fellows of CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico). The authors also thank to A. Fernandes for all the support in some of the laboratorial work

Chestnut and lemon balm based ingredients as natural preserving agents of the nutritional profile in matured “Serra da Estrela” cheese

Chestnut flowers, lemon balm plants and their decoctions were incorporated into "Serra da Estrela" cheese, to assess their potential to preserve its nutritional properties and provide new foodstuffs. The analyses were carried out after the normal ripening period of 1month and after 6months of storage. The most abundant nutrients were proteins and fats. The most abundant minerals were Ca and Na, while C16:0 and C18:1 were the main fatty acids. Saturated fatty acids were the most abundant, followed by the monounsaturated. Moisture seemed to be lower in the samples with the plants incorporated. The dried plants, when incorporated, seemed to be more efficient as preservers then the decoctions, although these better preserved the proteins. These plants can be regarded as promising natural preservers in foodstuffs cheese, given the preservation of key parameters and the slight impact on the nutritional value.The authors are grateful to Queijos Casa Matias, Lda and Mais Ervas, Lda. For providing the cheese and M. officinalis samples, respectively. The authors also acknowledge PRODER project No. 46577-PlantLact, the Foundation for Science and Technology (FCT, Portugal) for financial support to the CIMO research centre (Pest-OE/AGR/UI0690/2014) and ALIMNOVA research group (UCM-951505/2012), J.C.M. Barreira acknowledges the FCT for his post-doctoral grant (BPD/72802/2010)