Efeitos do tratamento térmico em separado da polpa e do suco sobre a qualidade físico-química, microbiológica, enzimática e sensorial do suco de laranja mantido sob refrigeração

Detalhes bibliográficos
Ano de defesa: 2013
Autor(a) principal: Silva, Felipe Rodrigues Nogueira [UNESP]
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Dissertação
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Estadual Paulista (Unesp)
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://hdl.handle.net/11449/110510
Resumo: Pasteurization is a common technique used to increase shelf life of fruit juices, followed by refrigeration, by destroying pathogenic microorganisms employing the appropriate thermal treatment that minimizes losses of sensory attributes and nutritional quality. Pectinesterase is an enzyme present in almost all parts of the orange fruit, mainly in the flavedo, albedo, seeds and membranes, and when the juice vesicles are ruptured, requiring inactivation to maintain important quality attributes such as turbidity. Accordingly, the heat treatment of orange juice must inactivate this enzyme; however, it requires relatively high temperatures, which may interfere with sensory attributes such as flavor and aroma. The aim of this study was to evaluate the quality and stability under refrigeration of the juice, containing different amounts of pulp, thermally treated separately and by different conditions the pulp (94°C/15 s) and the juice (80°C/15 s), and compared with the conventionally pasteurized juice (94°C/15 s), by physical-chemistry, enzymatic and microbiological methods, and by sensory acceptance of orange juice. A team of 69 untrained panelists evaluated during 21 days the different types of orange juice for appearance, global acceptance, aroma, flavor and texture, and also regarding the amount of pulp. The physical-chemical, microbiological (Salmonella sp., Fecal coliforms, total mesophilic and fungi and yeast), and enzyme activity of the different types of orange juice were evaluated for 28 days. The results for the physical-chemical parameters of soluble solids, titratable acidity, pH, sinking and floating pulp had few changes during cold storage. The Orange juice treated in the conventional way had the highest vitamin C degradation among all juices. For the remaining juices treated separately, the juice with low pulp content suffered less degradation of vitamin C. The heat treatment of the juice and the pulp separately proved to be ...