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| Author(s): |
Priscilla Siqueira Melo
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2010-09-10 |
| Examining board members: |
Severino Matias de Alencar;
Solange Teresinha Carpes;
Masaharu Ikegaki
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| Advisor: | Severino Matias de Alencar |
| Abstract | |
The agricultural industry has expanded to meet the growing population demand for food. Within this context, Brazil with its economy heavily based on agribusiness contributes to the generation of large amounts of industrial residues resulting from processing activities. These residues represent a serious problem because are discarded directly into the environment. Many of them are rich in bioactive compounds, widely recognized for its health-promoting properties and technological applications, such as antioxidants and antimicrobials, thus representing potential sources of these natural substances. In this study, we analyzed 15 residues collected in Bento Gonçalves, RS, Petrolina, PE, Jacareí and Monte Alto, SP. They are: grape pomace - Pinot Noir, Petit Verdot, Cabernet Sauvignon, Isabel (red), Moscato, Verdejo (white), stems of grape - Cabernet Sauvignon, Syrah (red), Moscato, Verdejo (white), wine lees red and white, tomato pomace, guava pomace and malt pomace. The samples were extracted with solvents of different polarities (hexane, chloroform, ethyl acetate, ethanol:water (80:20, v/v) and water) and the extracts analyzed for the content of total phenolics and antioxidant activity (DPPH) . The best solvents and samples selected on the basis of these two parameters followed for the other tests of antioxidant activity (EC50, ABTS, auto-oxidation of beta-carotene/linoleic acid and Rancimat), antimicrobial activity and chemical composition by GC-MS. Stems white Moscato and Pinot Noir pomace showed the highest levels of total phenolics, 48.61 and 40.79 mg GAE/g in the ethanol extracts, respectively. The ethanol extract of Pinot Noir pomace showed high antioxidant activity in all tests. Besides him, extracts of white stem (EC50, ABTS), Petit Verdot pomace (ABTS, auto-oxidation of beta-carotene), red stems (EC50, auto-oxidation of beta-carotene) and bagasse Cabernet Sauvignon (Rancimat) presented the best results of these tests, and many of them comparable to the synthetic antioxidant BHT. None of the samples showed antimicrobial activity to the concentration of 32 mg/mL against S. aureus, S. mutans and A. naeslundii by agar diffusion method. The chemical profile of the samples revealed that epicatechin is the major compound both in aqueous and ethanol extracts in all waste wine analyzed. In tomato and guava pomaces, quercetin is the predominant phenolic. Other compounds such as gallic acid, ferulic, caffeic, vanillic, sinapic, resveratrol, syringic were also identified. Based on these results we conclude that the samples analyzed, particularly the waste wine, are rich in bioactive compounds with high antioxidant power and have great potential application in the food industry. (AU) | |