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BACKGROUND: Biosurfactants are biomolecules that have the potential to be applied in food formulations due to their low toxicity and ability to improve sensory parameters. Considering the ability of yeasts to produce biosurfactants with food-friendly properties, the aim of the present study was to apply a biosurfactant produced by Candida utilis in the formulation of cookies. RESULTS: The biosurfactant was obtained with a yield of 24.22 ± 0.23 g/L. The characterization analysis revealed that the structure of a metabolized fatty acid with high oleic acid content (68.63 ± 0.61%), and the thermogravimetric analysis demonstrated good stability at temperatures lower than 200°C, potential for food applications. The biosurfactant also exhibited satisfactory antioxidant activity at concentrations evaluated, without cytotoxic potential for cell strains, L929 and RAW 264.7, according to the (3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The incorporation of the surfactant into the dough of a standard cookie formulation to replace animal fat was carried out, achieving a softer, spongier product without significantly altering the physical and physicochemical properties or energy value. CONCLUSION: The thermal stability and antioxidant activity of the biosurfactant produced by C. utilis were verified, besides the positive contribution in the texture analysis of the cookies. Therefore, this biomolecule presents itself as a potential ingredient in flour-based sweet food formulations.

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The aim of this study was to assess the effect of selenium-enriched Candida utilis with high contents of organic selenium (Se) and glutathione (GSH) on growth performance, antioxidant capacity and immune function of broiler chickens. A total of 100 healthy 7-day-old male broiler chickens were randomly divided into 5 groups, and fed diets supplemented with (a) Na2SeO3, (b) C. utilis, (c) Se-enriched Saccharomyces cerevisiae, (d) Se-enriched C. utilis, and (e) the control without any supplements. The experiment lasted for 6 weeks and parameters were recorded on day 42. No significant differences in average daily gain were found among the 5 groups. However, Se-enriched C. utilis supplemented in the diet increased activities of glutathione peroxidase in the whole blood (p 0.01), catalase in the serum (p 0.01) and breast meat (p 0.01), and superoxide dismutase in the breast meat (p 0.01), as well as decreased contents of malondialdehyde in the serum (p 0.01), liver (p 0.01) and breast meat (p 0.05). Also, Se-enriched C. utilis improved titers of IgG (p 0.01), IgM (p 0.01), and IgA (p 0.01) in the serum, as compared to the control. All these results indicated that Se-enriched C. utilis was a good candidate of dietary supplement to improve the antioxidant capacity and immune function of broiler chickens.(AU)

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The aim of this study was to assess the effect of selenium-enriched Candida utilis with high contents of organic selenium (Se) and glutathione (GSH) on growth performance, antioxidant capacity and immune function of broiler chickens. A total of 100 healthy 7-day-old male broiler chickens were randomly divided into 5 groups, and fed diets supplemented with (a) Na2SeO3, (b) C. utilis, (c) Se-enriched Saccharomyces cerevisiae, (d) Se-enriched C. utilis, and (e) the control without any supplements. The experiment lasted for 6 weeks and parameters were recorded on day 42. No significant differences in average daily gain were found among the 5 groups. However, Se-enriched C. utilis supplemented in the diet increased activities of glutathione peroxidase in the whole blood (p 0.01), catalase in the serum (p 0.01) and breast meat (p 0.01), and superoxide dismutase in the breast meat (p 0.01), as well as decreased contents of malondialdehyde in the serum (p 0.01), liver (p 0.01) and breast meat (p 0.05). Also, Se-enriched C. utilis improved titers of IgG (p 0.01), IgM (p 0.01), and IgA (p 0.01) in the serum, as compared to the control. All these results indicated that Se-enriched C. utilis was a good candidate of dietary supplement to improve the antioxidant capacity and immune function of broiler chickens.

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One of the main challenges in the food industry is to design strategies for the successful incorporation of natural sources of bioactive compounds. Recently, yogurts and other fermented dairy beverages have been proposed as ideal carriers of such bioactive compounds such as fatty acids and antioxidants that could improve consumers' health. However, the incorporation of new ingredients causes functional and structural modifications that may affect the consumers' preferences. In this work, a dairy beverage model supplemented with oleic acid has been designed by partial substitution of milk by Candida utilis single-cell protein extract. The changes in the structural properties of this new beverage were evaluated by following the fermentation process, pH, aggregate size, microstructure, and changes in rheological properties. Furthermore, molecular dynamics simulations were carried out to analyze the interaction between its main components. Our data revealed that samples with a percentage of milk substitution of 30% showed a higher viscosity as compared with the other percentages and less viscosity than the control (no substitution). These samples were then selected for fortification by incorporating oleic acid microcapsules. A concentration of 1.5 g/100 g was shown to be the optimal quantity of microcapsules for oleic acid supplementation. Molecular dynamic simulations revealed glutathione as an important component of the micro-gel structure. The present study forms the basis for novel studies where Candida utilis single-cell protein and microencapsulated essential oils could be used to design innovative bioproducts.

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This study aimed at characterizing a biosurfactant from Candida utilis, and use it in the preparation of salad dressings. The biosurfactant was produced in mineral medium supplemented with 6% glucose and 6% waste frying canola oil. The crude biosurfactant was then tested for stability in different conditions of pH, salt concentration, heating time and temperature. The critical micelle dilution, chemical composition, and structural analysis were determined. The compound was resistant to extreme conditions and presented stable surface tension and emulsification activity in alkaline pH and was characterized as a carbohydrate-lipid-protein complex showing the best formulation and consistency at 0.7% (w/v) with guar gum indicating potential applicability in food emulsions.

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Background: Candida utilis is widely used in bioindustry, and its cell mass needs to be produced in a cost effective way. Process optimization based on the experimental results is the major way to reduce the production cost. However, this process is expensive, time consuming and labor intensive. Mathematical modeling is a useful tool for process analysis and optimization. Furthermore, sufficient information can be obtained with fewer experiments by using the mathematical modeling, and some results can be predicted even without doing experiments. Results: In the present study, we performed the mathematical modeling and simulation for the cell mass production of Candida utilis based on limited batch and repeated fedbatch experiments. The model parameters were optimized using genetic algorithm (GA), and the processes were analyzed. Conclusions: Taken together, this newly developed method is efficient, labor saving and cost effective.

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Los avances en biotecnología industrial ofrecen oportunidades potenciales para la utilización económica de residuos agro-industriales tales como la pulpa de café, material mucilaginoso, fibroso (producto secundario) obtenido durante el proceso húmedo o seco del beneficio de las cerezas de café. El propósito de este trabajo fue utilizar los residuos de la pulpa de café, rico en materia orgánica, como sustrato para la producción de biomasa de levaduras por procesos de fermentación aeróbica. Los residuos de café se sometieron a hidrólisis con una solución de ácido sulfúrico al 2%, en una relación 10:1 (líquido:sólido), con un tamaño de partícula ≤ 2 mm., operando a presión atmosférica, ebullición a reflujo, durante 4 horas. El extracto ácido se filtró y se ajustó a pH 4,5 y luego se esterilizó a 120 ºC por 15 minutos. La fermentación se realizó con Saccharomyces cerevisiae y Candida utilis, medio de producción extracto de café enriquecido con sales nutritivas. Se formularon diferentes medios de producción (1,2,3 y 4), siendo el N°3, enriquecido con extracto de café hidrolizado, 1L; urea, 3g/L; fosfato ácido de potasio, 2g/L; extracto de malta, 1,3g/L y melaza, 30g/L, el cual aportó los mejores resultados. El tiempo total de fermentación fue de 8 horas. Se obtuvo 10g/L de biomasa con un incremento proteico de 7,39 a 42,5%. Se puede concluir que la pulpa de café constituye un sustrato adecuado para obtener biomasa o proteína unicelular, que podría ser destinada como suplemento en formulaciones para alimentación animal.

The advances in industrial biotechnology offer potential opportunities for the economic use of agro-industrial remainders such as the coffee pulp, mucilagenous, fibrous material (secondary product) obtained during the humid or dry process of the benefit of the coffee cherries. The intention of this work was to use the remainders of the pulp of coffee, rich in organic matter, like substrate for the production of biomass of leavenings by processes of aerobic fermentation. The coffee remainders were put under hydrolysis with a sulfuric acid solution to 2%, in a 10:1 relation (liquid: solid), with a size of particle ≤ 2 mm, operating to atmospheric pressure, boiling to ebb tide, during 4 hours. The acid extract filtered and it adjusted to pH 4,5 and then it sterilize to 120 ºC by 15 minutes. The fermentation was made with Saccharomyces cerevisiae and Candida utilis, the production means: extract of coffee enriched with nutritious salts. Different means from production were formulated (1,2,3 and 4), being the N°3, enriched with extract of hydrolyzed coffee, 1L; urea, 3g/L; acid potassium phosphate, 2g/L; extract of Malta, 1,3g/L and molasses, 30g/L, which contributed the best results. The total time of fermentation was of 8 hours. 10g/L of biomass with a protein increase from 7.39 to 42.5% was obtained. It is possible to be concluded that the coffee pulp constitutes an suitable substrate to obtain biomass or unicellular protein, that could be destined like supplement in formulations for feeding animal.

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Se identificò a Candida tropicalis como el agente causal de una severa contaminaciòn detectada en la producciòn de levadura forrajera en una fàbrica de la regiòn oriental de Cuba. Posteriormente a un detallado diagnòstico en las materia primas y diferentes secciones de la fàbrica con el objetivo de identifcar el foco y aislar el microorganismo contaminante se procediò a su identificaciòn mediante comparaiòn de sustancias nucleòtidas de las regiones adyacentes no codificadas...(AU)

Candida tropicalis was identified as the etiologic agent of a severe contamination detected on an industrial fodder yeast production at the Cuban eastern region. After a detailed diagnostic task on raw material carried out on different factory sections, protocols to identify the contamination source and to isolate the microorganism were proposed...(AU)

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