Publicação
Effect of ionic strength, pH and temperature on the behaviour of re-dispersed BC:CMC - A comparative study with xanthan gum
| Resumo: | The rheological performance of bacterial cellulose and carboxymethyl cellulose (BC:CMC) dry formulations with mass ratios of 1:1, 1:0.75 and 1:0.5 was compared with that of a commercial xanthan gum. The zero-shear viscosity and the yield stress of these hydrocolloids, at concentrations ranging from 0.001% to 0.5% (w/w), were determined by fitting the Cross and Herschel-Bulkley models to the flow curves. Only BC:CMC formulations presented a measurable yield stress, the highest value (1.54±0.17Pa) being obtained for the 1:0.5 ratio at a concentration of 0.5%. This formulation also presented the highest values of dynamic moduli, namely G, indicating a stronger solid-like character. Contrarily to xanthan gum, BC:CMC formulations' viscosity profile in aqueous solution was not considerably affected by the pH (in the range from 2.8 to 10.4), the ionic strength (NaCl from 0mM to 350mM) or the temperature (680°C). Food grade sunflower oil-in-water emulsions (20% oil) were prepared with 0.3% of the test hydrocolloids, with 150mM NaCl and pH 3.5. Emulsions with BC:CMC in the ratios of 1:0.75 and 1:0.5 had smaller droplets, stronger solid-like behaviour and resisted centrifugation with little phase separation. These results confirm the high performance of the dry BC:CMC formulations in the stabilization of colloidal systems. |
|---|---|
| Autores principais: | Martins, Daniela Sofia Rodrigues |
| Outros Autores: | Dourado, Fernando; Gama, F. M. |
| Assunto: | Bacterial cellulose Xanthan gum Food stabilizers Rheology Oil-in-water emulsions |
| Ano: | 2023 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | The rheological performance of bacterial cellulose and carboxymethyl cellulose (BC:CMC) dry formulations with mass ratios of 1:1, 1:0.75 and 1:0.5 was compared with that of a commercial xanthan gum. The zero-shear viscosity and the yield stress of these hydrocolloids, at concentrations ranging from 0.001% to 0.5% (w/w), were determined by fitting the Cross and Herschel-Bulkley models to the flow curves. Only BC:CMC formulations presented a measurable yield stress, the highest value (1.54±0.17Pa) being obtained for the 1:0.5 ratio at a concentration of 0.5%. This formulation also presented the highest values of dynamic moduli, namely G, indicating a stronger solid-like character. Contrarily to xanthan gum, BC:CMC formulations' viscosity profile in aqueous solution was not considerably affected by the pH (in the range from 2.8 to 10.4), the ionic strength (NaCl from 0mM to 350mM) or the temperature (680°C). Food grade sunflower oil-in-water emulsions (20% oil) were prepared with 0.3% of the test hydrocolloids, with 150mM NaCl and pH 3.5. Emulsions with BC:CMC in the ratios of 1:0.75 and 1:0.5 had smaller droplets, stronger solid-like behaviour and resisted centrifugation with little phase separation. These results confirm the high performance of the dry BC:CMC formulations in the stabilization of colloidal systems. |
|---|