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Chemical changes in Brazil nuts and co-products: characterisation and strategies of control and monitoring

Sartori, Alan Giovanini De Oliveira

Biblioteca Digital de Teses e Dissertações da USP; Universidade de São Paulo; Escola Superior de Agricultura Luiz de Queiroz 2017-11-30

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  • Título:
    Chemical changes in Brazil nuts and co-products: characterisation and strategies of control and monitoring
  • Autor: Sartori, Alan Giovanini De Oliveira
  • Orientador: Bastos, Deborah Helena Markowicz; d'Arce, Marisa Aparecida Bismara Regitano; Skibsted, Leif Horsfelt
  • Assuntos: Vida Útil; Oxidação Lipídica; Óleo De Castanha Do Brasil; Farinha De Castanha Do Brasil; Espectroscopia De Ressonância De Spin Eletrônico; Bertholletia Excelsa; Electron Spin Resonance Spectroscopy; Brazil Nut Oil; Lipid Oxidation; Brazil Nut Flour; Shelf Life; Bertholletia Excels
  • Notas: Tese (Doutorado)
  • Descrição: Brazil nuts (Bertholletia excelsa, H.B.K.) are seeds of high nutritional value collected from South American rainforests and its productive chain is one of the most important non-timber economic activities in Brazilian amazon. The main objectives of this research were: 1) characterize the occurrence of chemical changes in Brazil nut kernels (BNK), cold-pressed Brazil nut oil (BNO) and Brazil nut flour obtained by water extraction (BNF); and 2) investigate strategies of control and monitoring these changes during storage. For this, consolidated techniques, such as spectrophotometry and chromatography, and a relatively new analytical technique, the electron spin resonance (ESR) spectroscopy, were employed. As major results, it was found that different combinations of storage temperatures and atmosphere packages have differently affected the tendency of radical formation and off-flavor volatile aroma compounds generation in BNK, and that the combination of refrigeration with vacuum packing was able to keep BNK at their best. It was demonstrated that a spin-trapping ESR spectroscopy method would be suitable to monitor oxidative changes in BNO with known history stored either in clear or in brown glass bottles under retail conditions. For BNF, it was demonstrated that minor variations on water activity (aw) might significantly affect the rates of both lipid oxidation and nonenzymatic browning reactions during storage. There was indication that for BNF with initial aw of 0.196, but not for BNF with initial aw of 0.101, under the studied conditions, secondary products from lipid oxidation might be substrates for nonenzymatic browning products formation. As a conclusion, these results may help to better understand chemical deteriorative processes in BNK and its co-products, according to the storage conditions, and that the use of less sample-demanding, fast and solvent-free analytical method to monitor these changes in BNO is feasible.
  • DOI: 10.11606/T.11.2018.tde-22032018-151230
  • Editor: Biblioteca Digital de Teses e Dissertações da USP; Universidade de São Paulo; Escola Superior de Agricultura Luiz de Queiroz
  • Data de criação/publicação: 2017-11-30
  • Formato: Adobe PDF
  • Idioma: Inglês
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  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

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