Determinação de compostos bioativos, atividade antioxidante e antimicrobiana do extrato da fibra da manga (Mangifera indica l. cv. Tommy Aktins) / Determination of bioactive compounds, antioxidant and antimicrobial activity from mango (Mangifera indica l. cv. Tommy Aktins) fiber extract

Tendo em vista que a manga é um dos principais frutos da economia brasileira, a presente pesquisa teve o objetivo de analisar o teor de carotenoides, compostos fenólicos e a capacidade antioxidante e antimicrobiana da fibra, resíduo da polpa deste fruto. Deste modo foi elaborado um extrato etanólico 80% (v/v) com a fibra desidratada e pelos resultados obtidos, pode-se concluir que esse resíduo não é rico em nenhum dos compostos bioativos analisados, bem como não possui boa capacidade antioxidante ou atividade antimicrobiana.

Antimicrobial profile of Arthrobacter kerguelensis VL-RK_09 isolated from Mango orchards

Abstract An actinobacterial strain VL-RK_09 having potential antimicrobial activities was isolated from a mango orchard in Krishna District, Andhra Pradesh (India) and was identified as Arthrobacter kerguelensis. The strain A. kerguelensis VL-RK_09 exhibited a broad spectrum of in vitro antimicrobial activity against bacteria and fungi. Production of bioactive metabolites by the strain was the highest in modified yeast extract malt extract dextrose broth, as compared to other media tested. Lactose (1%) and peptone (0.5%) were found to be the most suitable carbon and nitrogen sources, respectively, for the optimum production of the bioactive metabolites. The maximum production of the bioactive metabolites was detected in the culture medium with an initial pH of 7, in which the strain was incubated for five days at 30 °C under shaking conditions. Screening of secondary metabolites obtained from the culture broth led to the isolation of a compound active against a wide variety of Gram-positive and negative bacteria and fungi. The structure of the first active fraction was elucidated using Fourier transform infrared spectroscopy, electrospray ionization mass spectrometry, 1H and 13C nuclear magnetic resonance spectroscopy. The compound was identified as S,S-dipropyl carbonodithioate. This study is the first report of the occurrence of this compound in the genus Arthrobacter.

Qualidade de polpas de frutas congeladas comercializadas na cidade de Salvador - BA / Quality of frozen fruit pulp marketed in Salvador - BA

Nesta pesquisa foram analisadas nove amostras de polpas de frutas congeladas, no sabor manga, obtidas em dois hipermercados e três minimercados de Salvador - BA. As amostras foram analisadas em triplicata, realizando-se a determinação de coliformes totais e termotolerantes, além de bolores e leveduras. As amostras apresentaram 100% de contaminação por bolores e leveduras, sendo que as contagens variaram de < 1 até 2,5 x 105 UFC/g. As bactérias termotolerantes apresentaram o total de 11,1% de contaminação acima do padrão microbiológico vigente, porém as bactérias totais, por não terem padrão estabelecido, não podem ser reportadas como contaminadas. Conclui-se que as polpas de frutas comercializadas na cidade de Salvador - BA não estão nas condições higienicossanitárias adequadas de acordo com a legislação vigente.

In this research were analyzed nine samples of frozen fruit pulps in manga flavor, chosen because the pH is 3.3 to 4.5, (Embrapa 2000) and obtained in two hypermarkets and three minimarkets in Salvador, Bahia. The samples were analyzed in triplicate by performing the determination of thermotolerant coliforms in addition to yeasts and molds. Samples showed 100% contamination by molds and yeasts, and counts ranged from <1 to 2,5 x 105 CFU/g. The thermotolerant bacteria showed a total of 11,1% of contamination above the current microbiological standard, but the total bacteria by not having standard established, may not be reported as contaminated. It concludes that the fruit pulp sold in the city of Salvador-BA are not in the proper sanitary conditions in accordance with current legislation.

Low doses of gamma radiation in the management of postharvest Lasiodiplodia theobromae in mangos

The postharvest life of mango is limited by the development of pathogens, especially fungi that cause rot, among which stands out the Lasiodiplodia theobromae. Several control methods have been employed to minimize the damages caused by this fungus, chemical control can leave residues to man and nature; physical control by the use of gamma radiation in combination with modified atmosphere and cold storage. The use of gamma radiation helps to reduce the severity of the pathogen assist in the ripening process of fruits, even at low doses (0.25, 0.35 and 0.45 kGy) chemical properties such as pH, soluble solids, acid ascorbic, titratable acidity and also the quality parameters of the pulp showed no damage that are ideal for trade and consumption of mangoes. This treatment can be extended for use in the management of diseases such as natural infections for penducular rot complex that has as one of L. theobroma pathogens involved.

Cgl-SLT2 is required for appressorium formation, sporulation and pathogenicity in Colletotrichum gloeosporioide

The mitogen-activated protein (MAP) kinase pathways has been implicated in the pathogenicity of various pathogenic fungi and plays important roles in regulating pathogenicity-related morphogenesis. This work describes the isolation and characterization of MAP kinase gene, Cgl-SLT2, from Colletotrichum gloeosporioides. A DNA sequence, including 1,633 bp of Cgl-SLT2 open-reading frame and its promoter and terminator regions, was isolated via DNA walking and cloned. To analyze gene function, a gene disruption cassette containing hygromycin-resistant gene was constructed, and Cgl-SLT2 was inactivated via gene deletion. Analysis on Cgl-slt2 mutant revealed a defect in vegetative growth and sporulation as compared to the wild-type strain. When grown under nutrient-limiting conditions, hyperbranched hyphal morphology was observed in the mutant. Conidia induction for germination on rubber wax-coated hard surfaces revealed no differences in the percentage of conidial germination between the wild-type and Cgl-slt2 mutant. However, the percentage of appressorium formation in the mutant was greatly reduced. Bipolar germination in the mutant was higher than in the wild-type at 8-h post-induction. A pathogenicity assay revealed that the mutant was unable to infect either wounded or unwounded mangoes. These results suggest that the Cgl-SLT2 MAP kinase is required for C. gloeosporioides conidiation, polarized growth, appressorium formation and pathogenicity.

Análisis de la calidad microbiológica y potencial presencia de Listeria monocytogenes en pulpas de guanábana (Annona muricata), mango (Mangifera indica) y maracuyá (Passiflora edulis) costarricenses / Analysis of the microbiological quality and potential presence of Listeria monocytogenes in custard apple (Annona muricata), mango (Mangifera indica) and passion fruit (Passiflora edulis) pulps from Costa Rica

El objetivo del presente trabajo fue el determinar algunos de los indicadores de vida útil, higiene y condiciones del proceso y almacenamiento, la asociación entre la pulpa de la fruta y microorganismos patógenos de pulpas de guanábana, mango y maracuyá provenientes de las principales cadenas de supermercados de la gran área metropolitana (GAM) de San José, Costa Rica, así como examinar la potencial presencia de Listeria monocytogenes en ellas. Se analizó un total de 60 muestras, a las cuales se les determinó su pH así como su recuento total aerobio, recuento de mohos y levaduras, bacterias lácticas, número más probable de coliformes totales y fecales y la presencia o ausencia de Listeria monocytogenes en 25 g del producto. Los rangos de pH encontrados en las pulpas variaron entre 3,1 y 3,9 y los recuentos obtenidos fueron relativamente bajos a excepción de los provenientes de una industria. Ninguna de las muestras analizadas presentó coliformes totales ni fecales. Se confirmó la presencia de Listeria monocytogenes en tres muestras, todas provenientes de la industria C. Los bajos recuentos obtenidos pueden deberse a la adición de sustancias preservantes pero también porque son productos pasteurizados; la falta de estos dos elementos puede significar la presencia de bacterias tan peligrosas como Listeria monocytogenes.

The objective of this work was to determine some of the indicators associated to shelf life, hygiene, process and storage conditions for some of custard apple, mango and passion fruit pulps distributed by the main supermarket chains of the Metropolitan Area of San José, Costa Rica, as well as to examine the potential presence of Listeria monocytogenes in them. Sixty fruit pulp samples were analyzed. Tests included pH determination, total aerobic plate count, yeasts and mold count, lactic bacteria count, total and fecal most probable number and the presence/absence of Listeria monocytogenes in 25 g of the product. Fruit pulp’s pH ranged between 3,1 and 3,9, and the microbiological counts obtained were relatively low except for one industry. None of the samples analyzed presented total or fecal coliforms. The presence of Listeria monocytogenes was confirmed in three samples, all of them coming from industry C. Low microbiological counts obtained may be due to the addition of preserving substances and to the pasteurization of some of the products; lack of these two elements may allow the presence of dangerous bacteria such as Listeria monocytogenes.

Processamento de frutas tropicais por desidratação osmótica seguida de fritura: estudo de caso da manga e do melão / Processing of tropical fruits by osmotic dehydration followed by frying: a case study of the mango and melon

Manga e melão foram processados por desidratação osmótica em xarope de sacarose, seguida de fritura em gordura vegetal hidrogenada. Em cada etapa do processamento foram avaliados o rendimento e as características físico-químicas dos frutos. Nos produtos finais também avaliaram-se as características microbiológicas (aeróbios mesófilos, coliformes totais e fecais, Escherichia coli, bolores e leveduras, Salmonella sp. e Staphylococcus coagulase positiva) e a aceitação sensorial. O rendimento total do processo ficou em torno de 11 por cento para ambos os frutos. A etapa de fritura foi a que mais contribuiu para redução da atividade de água e a etapa de osmose para a redução do pH e incorporação de sólidos (sacarose). Os produtos finais obtidos se caracterizam por apresentar baixa atividade de água (0,675 para manga e 0,446 para melão) e umidade (16,01 por cento para manga e 5,70 por cento para melão), alto teor de sólidos solúveis totais (76,60ºbrix para manga e 81,07ºbrix para o melão) e baixo pH (3,87 para manga e 4,12 para o melão). As análises microbiológicas demonstram a boa qualidade dos produtos. As médias de aceitação sensorial (6,9 para manga e 6,8 para melão, em escala de 9,0) foram próximas de gostei moderadamente para ambos os frutos.