Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.5/2881
Título: Myrosinase stability in broccoli (Brassica oleracea var. italica). Influence of temperature and water activity
Autor: Castelo-Branco, João Diogo Cristovão Pinto
Orientador: Martins, Margarida Moldão
Palavras-chave: broccoli
brassica oleracea var. italica
myrosinase
water activity
temperature
kinetics
mirosinase
actividade da água
temperatura
Data de Defesa: 2010
Editora: ISA
Citação: Castelo-Branco, João Diogo Cristovão Pinto - Myrosinase stability in broccoli (Brassica oleracea var. italica). Influence of temperature and water activity. Lisboa, Instituto Superior de Agronomia, 2010, 90 p.
Resumo: Epidemiological studies have shown that a diet rich in Brassica vegetables is associated with a decreasing risk of incidence of some types of cancer. These health promoting effects are most likely due to the breakdown products of glucosinolates formed by the action of myrosinase which catalyzes the hydrolysis of glucosinolates, found in Brassica plants. Industrial processing of food can affect the content, composition, activity and bioavailability of glucosinolates breakdown products, due to cell lysis or glucosinolates and myrosinase degradation. The aim of this thesis is to investigate the combined effect of moisture content (water activity) and temperature on myrosinase stability. The study was conducted in batches of freeze dried broccoli with different moisture contents. These batches of broccoli were then heated at different time/temperature combinations and myrosinase activity was analysed, the obtained results from these measurements were kinetically modeled. Myrosinase was shown to be much less thermo stable in higher moisture content samples than in the driest samples. Thermal stability (30-80 ºC) of myrosinase was described by a first order kinetic model. Besides showing higher myrosinase thermal stability, driest samples show lower activation energies, i.e, lower increase of degradation rate when temperature increases.
Descrição: Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia
URI: http://hdl.handle.net/10400.5/2881
Aparece nas colecções:BISA - Dissertações de Mestrado / Master Thesis

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