Eunice Valduga

Produção de carotenoides: microrganismos como fonte de pigmentos naturais

Carotenoids are natural dyes synthesized by plants, algae and microorganisms. Application in many sectors can be found, as food dyeing and supplementation, pharmaceuticals, cosmetics and animal feed. Recent investigations have shown their ability to reduce the risks for many degenerative diseases like cancer, heart diseases, cataract and macular degeneration. An advantage of microbial carotenoids is the fact that the cultivation in controlled conditions is not dependent of climate, season or soil composition. In this review the advances in bio-production of carotenoids are presented, discussing the main factors that influence the microbial production of these dyes in different systems.

Pré-tratamentos de melaço de cana-de-açúcar e água de maceração de milho para a bioprodução de carotenóides

This work studied the pretreatment of sugarcane molasses (CM) and corn steep liquor (CS) for the production of carotenoids by Sporidiobolus salmonicolor (CBS 2636). The acid pretreatment removed less micronutrients than that with activated carbon and led to high removals of Cu and Mn. Reduction in optical density of the prepared medium and removal of glucose from it were 22% and 7% for CM and 95% and 38% for CS, respectively. Total carotenoids obtained with substrates pretreated with acids (541 mg/L) were higher than the results obtained when the medium was treated with activated carbon (208 mg/L).

Screening of microorganisms for production of carotenoids Selección de microorganismos para la producción de carotenoides

This work aimed at screening microorganisms capable of producing carotenoids. Microorganisms were isolated from soil, leaves, fruits, flowers, agro-industrial wastes, and processed product in decomposition and then grown in an orbital shaker, using 10% (w/v) of inoculum (25 °C, 180 rpm for 48 h) and incubated for 120 h in a dark room. A total of 116 microorganisms were isolated and screened: 16 yeasts, 65 bacteria, and 35 fungi. Three yeasts demonstrated great potential to produce red carotenoids, with a total carotenoid content of 707–818 μg L−1 (99–263 μg g−1). One filamentous fungus and two bacteria produced mostly yellow pigments in a final concentration ranging from 1063 to 2563 μg L−1 (239–2310 μg g−1). From 116 isolated microorganisms, several of them showed potential for production of carotenoid-synthesizing activity. RAPD analysis was used to check the genetic differences between the screened strains, showing that all microorganisms were from different species. El objetivo de este trabajo fue examinar los microorganismos capaces de producir carotenoides. Microorganismos de tierra, hojas, frutos, flores, residuos agro-industriales y producto procesado en descomposición se aislaron y se cultivaron en un agitador orbital, usando 10% (w/v) de inóculo (25 °C, 180 rpm durante 48 horas) e incubados durante 120 h en una habitación oscura. Se aislaron y examinaron un total de 116 microorganismos, 16 levaduras, 65 bacterias y 35 hongos. Tres levaduras demostraron un gran potencial para producir carotenoides rojos, con un contenido total de carotenoides de entre 707 a 818 μg L−1 (de 99 a 263 μg g−1). Un hongo filamentoso y dos bacterias produjeron en su mayoría pigmentos amarillos en una concentración final de entre 1063 a 2563 μg L−1 (239 a 2310 μg g−1). De 116 microorganismos aislados, varios de ellos mostraron potencial para la producción de actividad sintetizadora de carotenoides. Se usó el análisis RAPD para revisar las diferencias genéticas entre las cepas examinadas, mostrando que todos los microorganismos eran de diferentes especies.

Formulação de bebida láctea fermentada sabor pêssego utilizando substratos alternativos e cultura probiótica

Nowadays, new food products are launched in the market, and the main focus of the dairy industry is on functional products. Thus, the first objective of this work was to develop a fermented dairy drink with probiotic characteristics. Furthermore, milk serum and soy hidrosoluble extract were used as substrates increasing the value of low cost raw materials that have functional features, as reported in the literature. Based on these aspects, an experimental design was used to investigate the formulation of a peach- flavored dairy drink using milk serum, cow milk and soy hidrosoluble extracts. The formulation with 30% of soy hidrosoluble extract, 36.6% of cow milk and 33.3% of milk serum was found as ideal in terms of sensorial analysis and cell growth evaluation. Organoleptical, physicochemical, and microbiological analyses determined the shelf life of the product. During the storage period, the peach- flavored dairy drink presented viable cells according to the Legislation (1 x 106 UFC.mL-1) for 22 days. The physicochemical quality changed slightly since the acidity presented high values after the 22nd day. The sensorial quality defined the shelf life as 14 days without the addition conservants due to the high acidity value of the fermented dairy drink determined.

Microbiological analysis of critical points in the chicken industry

O objetivo deste trabalho foi identificar a contaminacao microbiana no processo de escaldagem, assepsia e resfriamento do frango (chiller), e em linguicas de frango produzidas a partir destes. As amostras foram coletadas em um frigorifico de aves, em sete datas e analisadas em triplicata. A presenca de Salmonella foi detectada em duas amostras da agua de escaldagem nao estando mais presente na agua do chiller e nem no produto final. Isto se deve a reducao de temperatura da agua e adicao de cloro. O NMP de coliformes fecais variou entre < 1 a 11/ml na agua de escaldagem e < 1 a 64/ml na agua do chiller, que embora em padroes aceitaveis, mostram tendencia de acrescimo no chiller, devido principalmente ao processo de evisceracao. As contagens de Aeromonas variaram de 5 a 3,5x101UFC/ml na agua de escaldagem e 9 a 3,7x102UFC/ml na agua do chiller. Este acrescimo se deve, provavelmente, por Aeromonas ser psicrofila e tambem devido a retirada das viceras. As analises de linguica de frango mostraram acrescimo nas contagens de Aeromonas, apresentando ate 2,5x103UFC/g. Esta tendencia de aumento de crescimento no produto final, aliado a capacidade de causar infeccoes de Aeromonas demonstram a necessidade de incluir a analise destas nas avaliacoes microbiologicas de alimentos.

Oxidative stability of fermented Italian-type sausages using mate leaves (Ilex paraguariensis St. Hil) extract as natural antioxidant

The objective of this work is to evaluate the effects of the addition of dried extract from mate leaves on the oxidative stability (lipid and protein), microbiological characteristics (lactic and Micrococcaceae bacteria) and sensory attributes of formulations of Italian-type sausages. The different Italian-type sausages formulations tested in this work were in agreement with the legislation in terms of chemical and microbiological parameters. During storage, the formulation with 0.4 wt% of mate leaves extract presented lower thiobarbituric acid reactive substances and carbonyl values compared with the control, proving the antioxidant action of the extract. The sensory characteristics of flavour, texture and global acceptation were not affected by the addition of mate extract compared with the formulation with artificial antioxidant.

Decontamination of Pig Carcasses Using Water Pressure and Lactic Acid

The objective of this work was to evaluate the effect of different water pressures and concentrations of lactic acid on microbial counts (mesophilic bacteria, enterobacteria and Salmonella) on pig carcasses without contamination and contaminated carcasses, before and after the last shower and before being cooled. The tests were carried out using 4, 3 and 2 bar water pressure, and 2, 1 and 0% lactic acid concentration. In general, both the pressure in the shower and lactic acid had a positive effect by reducing the microbial count. The interaction between the pressure and lactic acid caused the largest reduction in carcasses surface count for mesophiles. With regard to enterobacteria on contaminated carcasses, the most important variable was the lactic acid concentration and in uncontaminated carcasses, it was water pressure. The use of 8 bar pressure of the wash water without lactic acid caused a reduction in mesophilic bacteria and enterobacteria, for both the contaminated and uncontaminated carcasses, with results statistically equal to each other, and significantly lower than the initial counts. The water pressure at 8 bar reduced the percentage of carcasses with Salmonella in contaminated carcasses.

Head Space Solid Phase Micro-Extraction (HS - SPME) of volatile organic compounds produced by Sporidiobolus salmonicolor (CBS 2636)

O objetivo do presente estudo foi avaliar os compostos orgânicos volateis produzidos por Sporidiobolus salmonicolor (CBS 2636) utilizando metil e etil ricinoleato, acido ricinoleico e oleo de mamona como precursores. A analise dos compostos volateis produzidos foi conduzida por Micro-Extracao em Fase Solida (MEFS). A tecnica de planejamento experimental foi utilizada na avaliacao das condicoes de extracao, na qual se avaliaram a agitacao (0-400 rpm), a temperatura (25-60 oC), o tempo de extracao (10-30 minutos) e o volume da amostra (2-3 mL). A identificacao dos compostos foi realizada por Cromatografia a Gas com deteccao por Espectrometria de Massas (CG/EM). As condicoes que resultaram na maxima extracao foram: 60 oC, 10 minutos de extracao, sem agitacao, volume de amostra de 2,0 mL e adicao de solucao de KCl saturada (1:10 v/v). Na bioproducao dos compostos volateis, o efeito da agitacao (120-200 rpm), da temperatura (23-33 oC), do pH (4,0-8,0), da concentracao do precursor (0,02 a 0,1%), da concentracao de manitol (0 a 6%) e de asparagina (0 a 0,2%) foi avaliado. Na condicao de 28 oC, 160 rpm, pH 6,0 e com a adicao de 0,02% de acido ricinoleico ao meio, foi atingida a maxima producao dos compostos volateis, identificados como: 1,4-butanodiol, 1,2,2-trimetilciclopropilamina, beta-ionona; 2,3-butanodiona, pentanal, tetradecano, 2-isononenal, 4-octen-3-ona, acido propanoico e octadecano.

Experimental Design Applied to the Optimization and Partial Characterization of Pectin Liase from a Newly Isolated Penicillium brasilianum

Penicillium brasilianum was previously isolated from tea and identified by molecular biology technique. A Plackett-Burman design, followed by a complete second order design was used for the screening of most important factors and to maximize the pectin liase (PMGL) activity, respectively. The maximum PMGL activity by P. brasilianum achieved was 9.0 U/mL after 48 h of cultivation in a medium containing pectin (33.0 g/L), yeast extract (30.0 g/L) and potassium phosphate (2.0 g/L) at 30oC, with a stirring rate of 180 rpm, initial pH 5.5 and 5x106spores/mL inoculum size. The kinetic evaluation in terms of substrate consumption demonstrated that the maximum production of PMGL was at 72 h, and 40% of the total organic carbon, 25% of the nitrogen, 88% of the magnesium, 13% of the potassium and 66% of the iron were consumed. The pH remained almost stable during the whole period of production (5.33 to 4.9). The partial characterization of the crude PMGL enzyme extract showed optimal pH and temperature of 5.5 and 37°C, respectively.

Comparative evaluation of liquid and traditional smoke on oxidative stability, color and sensory properties of Brazilian calabrese sausage Evaluación comparativa del ahumado tradicional y líquido en la estabilidad oxidativa, propiedades de color y sensoriales de la salchicha calabresa brasileña

The objective of this work was to evaluate the cooked Brazilian calabrese sausage stability submitted to conventional and liquid smoke treatments. Product stability was accomplished by analyses of lipid and protein oxidation, instrumental color, and sensory evaluation. The different evaluated treatments presented a similar behavior related to lipid oxidation, increasing until 40 days of storage, showing a relationship with sensory analysis. The product was characterized as moderately rancid, with TBARS values from 0.44 to 0.56 mg MA kg−1. Treatment with liquid smoke led to lower tonality of yellow coloration and luminosity, indicating that this conducted to a darker aspect for the product obtained using liquid smoke compared to the use of traditional one. In addition, liquid smoke reduced the processing time in about 37.5%, leading to a significant reduction in the costs related to the productive process. El objetivo de este trabajo fue evaluar la estabilidad de la salchicha calabresa brasileña cocida sometida a tratamientos de ahumado convencional y líquido. La estabilidad del producto se estableció a través de análisis de oxidación de lípidos y proteínas, color instrumental y evaluación sensorial. Los diferentes tratamientos evaluados presentaron un comportamiento similar en cuanto a la oxidación de lípidos, aumentando hasta 40 días de almacenamiento, mostrando una relación con el análisis sensorial. El producto se caracterizó como moderadamente rancio, con valores TBARS entre 0,44 y 0,56 mg MA kg−1. El tratamiento con humo líquido ofreció una menor coloración amarilla y luminosidad, lo que indica que este método conduce a un aspecto más oscuro del producto obtenido si se compara con el método tradicional. Además, el humo líquido reduce el tiempo de procesado en un 37.5%, lo que conlleva una reducción significante del coste del proceso productivo.