Extração da fração proteica do farelo de arroz por tratamento ultrassônico e enzimático e caracterização das propriedades funcionais
New techniques for protein extraction from rice bran have been studied to increase the process yield by reducing the extraction time, volume of organic solvents, reducing costs and environmental pollution. The use of ultrasound has been tested for the extraction of proteins from vegetables due to th...
| Autor principal: | Carmo, Edianez Umbelina Ferrazzo do |
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| Formato: | Dissertação |
| Idioma: | Português |
| Publicado em: |
Universidade Tecnológica Federal do Paraná
2021
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| Assuntos: | |
| Acesso em linha: |
http://repositorio.utfpr.edu.br/jspui/handle/1/25745 |
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| Resumo: |
New techniques for protein extraction from rice bran have been studied to increase the process yield by reducing the extraction time, volume of organic solvents, reducing costs and environmental pollution. The use of ultrasound has been tested for the extraction of proteins from vegetables due to the mechanical and thermal effect of cavitation. The isolation of proteins through enzymatic removal can be carried out with several enzymes, including pancreatin, alkaline, fungal or bacterial proteases, together or not with the action of amylases and carboidrases. In order to obtain a Rice Bran Protein Concentrate (RBPC) and a Rice Bran Protein Hydrolyzate (RBPH) with high yield and adequate technological properties, the main objective of this work was to evaluate the protein extraction from Defatted Rice Bran (DRB) by ultrasonic probe treatment and by enzymatic route. A sequential strategy of experimental design was applied, consisting of a Fractional Factorial Design (FFD) followed by a Central Composite Rotatable Design (CCRD) to determine the variables of influence on the processes and to optimize the extraction methods. The protein yield of the ultrasonic probe extraction process was 6.01%, and the RBPC presented 76.01% of proteins. The protein yield of the enzymatic extraction process was 4.63%, and the RBPH presented 71.19% of proteins. The RBPH showed a solubility of 96.06%, while the RBPC was 95.34%, both at pH 9. The RBPH had a water absorption capacity of 5.08 gg-1, being higher than that of the RBPC (3.21 gg -1) and did not differ significantly in the oil absorption capacity (11.56 gg-1 and 11.38 gg-1, respectively), values higher than those of the reference Serum Bovine Albumin (SBA). The greatest foaming occurred at pH 8 (RBPC: 46.66%; RBPH: 36.00%), and the stability of the foams formed was low at all pHs; in both cases, the SBA showed superior sparkling characteristics. The emulsion formation capacity of RBPC showed no significant difference when compared to that of SBA at pH 6 (76.27% and 75.46%), as well as the stability of the emulsion, which was 56.60% (RBPC) and 58.40% (SBA) at pH 8. The thermal analyzes showed that the extraction methods influenced the thermal stability and the structures of the proteins, the protein extracted by ultrasonic probe showed secondary structures of the α-helix type, which favor the emulsions formation. The proteins extracted by the enzymatic method showed greater sensitivity to thermal degradation. The treatments showed to have an acceptable protein extraction yield. The functional properties demonstrated that RBPC and RBPH have potential for application as an ingredient, with important functional attributes to food industry. |
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