Navegando por Autor "Dias, Sandra de Cássia"

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Characterization, techno-functional properties, and encapsulation efficiency of self-assembled β-lactoglobulin nanostructures.
(2021) Couto, Brunna D’Onofre; Costa, Rayla Novaes da; Laurindo, Wilquer Castro; Silva, Heriveltom Moraes da; Silva, Cinthia Rocha da; Coimbra, Jane Sélia dos Reis; Mageste, Aparecida Barbosa; Dias, Sandra de Cássia; Santos, Igor José Boggione
Whey is a cheese co-product with high protein content used in the food industry due to its techno-functional properties and nutritive value. This study aims to optimize the production of β-lactoglobulin (β-lg) nano structures, to characterize their techno-functional properties and stability, and to apply them as a carrier of bioactive molecules. Box-Behnken planning was applied to determine the best conditions to obtain the β-lg nanostructure, which consists in treatment at 100 ◦C in NaCl 50 mmol⋅L-1 for 60 min. TEM analysis showed a fibril structure in the observed nanostructures. The nanostructured systems formed foam and emulsion with higher stability than the systems composed of the native protein. The results for encapsulation efficiency of bioactive compounds were 96.50%, 89.04%, 67.78%, and 36.39% for quercetin, rutin, naringin, and vitamin B2, respectively. Thus, β-lg nanostructure’s great capacity to encapsulate hydrophobic molecules was verified.
Manganese (ii) removal from aqueous solutions by Bacillus cereus: an optimization study using experimental design and response surface methodology.
(2017) Gonzaga, Flávia Donária Reis; Candido, Giselle Cristina; Oliveira, Ludmila Fagundes de; Dias, Sandra de Cássia; Leão, Versiane Albis
The present study was carried out in order to investigate the removal of soluble Mn2+ from an aqueous solution using Bacillus cereus. A manganese aqueous solution at 50 mg L−1 was treated, and the product was less than 1 mg L−1 of residual concentration, which complied with environmental regulations. Before the optimization, B. cereus was able to remove Mn2+ ions from an aqueous solution; however, the residual content was around 2.5 mg L−1. Screening experiments aiming at defining the effects of the growth medium composition indicated that both casamino acid-peptone and yeast extract contributed to manganese removal. These experiments also showed the interaction between these two components of the culture media, nevertheless the use of glucose did not prove significant. Considering these observations, the Doehlert design was used to generate a response surface. The model was significant with the p value lower than 0.05 and the lack-of-fit not significant (p > 0.05). The optimized composition of the growth medium was defined as 0.5 g L−1 of casamino acid-peptone and 0.25 g L−1 of yeast extract, whereas glucose could be removed from the original growth medium. When the optimized condition of the growth medium was used, the time required for manganese removal was reduced from 21 to 8 days. After optimization, B. cereus was capable of producing high manganese removal, reducing the residual concentration to levels below 1.0 mg L−1.