Name: Thiago Teixeira Costa
Type: MSc dissertation
Publication date: 03/11/2022
Advisor:
Name |
Role |
|---|---|
| Hildegardo Seibert França | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| Hildegardo Seibert França | Advisor * |
| JOSINEI RODRIGUES FILHO | External Alternate * |
| Maria do Carmo Pimentel Batitucci | Internal Examiner * |
| Sara Dousseau Arantes | Internal Alternate * |
| Thiago de Melo Costa Pereira | External Examiner * |
Summary: Pereskia aculeata is an unconventional food plant of the Cactaceae family, originally from the American continent, with wide distribution. Despite its notorious nutritional value, this species, popularly known as Ora pro nobis, is rarely consumed as food. This work aimed to produce a protein concentrate with the potential to be used in food, by cheap techniques and easy reproduction. The comparison was made for two techniques, saline extraction (ES) and alkaline extraction. In saline extractions, two salts were used (NaCl and Na2CO3) at different concentrations (0,1M, 0,5M e 1M). Alkaline extraction (EA) was performed alone and combined with ultrasound (EA+Ultra). The precipitates, recovered by the isoelectric point of the proteins, were
submitted to the Bradford method and it was established that the most efficient treatments were EA and EA+Ultra. In a second moment, the efficiency in the extraction of proteins in the EA and EA+Ultra treatments were compared in two dilutions (1:10 and 1:20 (p:v)). Re-extraction of residues from EA and EA+Ultra treatments at the same dilutions were also tested. An alternative protein product was proposed, the lyophilized aqueous extract (EAL). All treatments (except EAL) underwent isoelectric precipitation at different pH followed by centrifugation and the proteins of these precipitates and EAL were quantified by Bradford. In addition, the purity of the recovered protein products was established and the characterization of the molecular weight of the proteins was performed on a 12% polyacrylamide gel.
Finally, the antioxidant activity of the lyophilized aqueous extract (EAL) was
measured by the DPPH method. The results showed that the EA+Ultra 1:20
treatment was the best in the extraction of proteins and in the purity of the
precipitate. The positive effects of the higher dilution, the combination of the EA method with ultrasound were evident. The isoelectric point of the proteins from the leaves of Pereskia aculeata, which was at pH 4. The results of the electrophoresis gel showed two main bands of 68 kDa and 168 kDa, which may be related respectively to a globulin (β-conglycinin 7S) and carbonic anhydrase, a protein related to Rubisco that plays a fundamental role in photosynthesis. Keywords: Antioxidant; leafy cactus; Ora pro nobis; PANC; supplement.
