Navegando por Autor "Silva, Daison Olzany"
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Item Control of lactose crystallization in "dulce de leche" by Beta-D-Galactosidase activity from permeabilized Kluyveromyces lactis cells.(1984) Sabioni, José Geraldo; Pinheiro, Adão José Rezende; Silva, Daison Olzany; Chaves, José Benício Paes; Borges, Arnaldo ChaerFeasibility of controlling lactose crystallization in "dulce de leche" by permeabilized Kluyveromyces lactis cells was studied. Optimum temperature for lactase activity was 45°C. Stability of the enzyme system remained practically unaltered during storage at room temperature or below for up to 7 mo. Degree of lactose hydrolysis in milk was determined as a function of the content of permeabilized cells. Addition of 400 or 800 rag/liter of permeabilized cells to milk used to make "dulce", followed by 2.5 or 3.5 h incubation at 35°C, resulted in hydrolysis of 45.02 and 69.13% of the lactose. There was no lactose crystallization after 120 days storage in products treated by permeabilized cells. The sensory qualities of the "dulces" were similar to those of the control.Item Control of lactose crystallization in "Dulce de Leche" by Kluyveromyces lactis fermentation.(1984) Sabioni, José Geraldo; Silva, Daison Olzany; Pinheiro, Adão José Rezende; Borges, Arnaldo Chaer; Chaves, José Benício PaesKluyveromyces lactis was an inoculums in milk to hydrolyze lactose. Five mixtures of lactose-hydrolyzed: normal milk were prepared (0:1, 1:2, 1:1.5, 1:1, and 1.5:1) for comparisons of lactose crystallization in "dulce de leche". "Dulce de leche" was produced, stored at room temperature, and tested by sensory evaluation for lactose crystallization and preference immediately and after 30, 60, 90, and 120 days storage. Statistical analysis of sensory evaluation showed no significant differences among treatments. There was no crystallization in any treatment after 120 days storage, except for the "dulce" produced with the standard (0:1, control) milk.Item Cyclic AMP and low molecular weight effector(s) present in yeast extract are involved in pectin lyase production by Penicillium griseoroseum cultured on glucose.(1999) Pereira, Maria Cristina Baracat; Coelho, Jorge Luiz Cavalcante; Minussi, Rosana Cristina; Alves, Virgínia Maria Chaves; Brandão, Rogélio Lopes; Silva, Daison OlzanyPectin lyase (PL) induction by organic and inorganic components of yeast extract (YE) was evaluated in Penicillium griseoroseum, cultured in a mineral medium containing sucrose, by determining PL activity (A235) and mycelial growth (mycelial dry weight). The lowest YE concentration that promoted significant PL induction without acting as a carbon source for the fungus corresponded to 0.0075%. Neither calcined YE nor a nutrient solution containing micronutrients induced PL production, indicating that the inducer was an organic compound. Vitamins, phospholipid components, amino acids, and nitrogenous bases were tested in place of YE and promoted no significant PL induction. A PL inducer compound was found to be soluble in the nucleotide fraction obtained during extraction of YE. The inducer was shown to be a thermostable polar substance dialyzable at 2000 Daltons, hydrolyzable by HCl, and activated by boiling for up to 60 min. Cyclic AMP (cAMP) exogenously added to the culture medium at 5 and 10 mM was capable of inducing PL in P. griseoroseum grown on sucrose, suggesting that at least one compound may be present in YE acting in a cooperative fashion for the maintenance of high levels of cAMP into the cell. PL activity and the level of cAMP inside the fungal cells increased after the addition of YE to the culture medium, suggesting the participation of this messenger in this enzyme’s synthesis.