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|Type:||Artigo de periódico|
|Title:||Thermal inactivation of pectinesterase in papaya pulp (pH 3.8)|
|Abstract:||In order to establish the thermal process required by acified papaya pulp (pH 3.8) var ''formosa'', a study was carried out on the kinetics of thermal inactivation of the heat resistant enzymes present in the pulp. Since no peroxidase activity was detected, the study was focused on pectinesterase. The heat inactivation curves at 75, 77 and 80C showed a change in slope indicating the presence of two different portions of the enzyme, one heat labile and the other hear resistant. The decimal reduction limes (D value) of pectinesterase were 0.8, 0.3 and 0.2 min for the heat labile portion and for the heat resistant portion 16.7, 7.2 and 3.7 min, respectively. The temperature-dependency factor for the heat labile portion was 9.2C and 7.8C for the thermostable portion, while the activation energies were 258.3 and 304.4 Kj/mol. These values were within the range of 167.5-418.7 Kj/mol reported in the literature for the thermal inactivation of enzymes. Thermal destruction studies with Clostridium pasteurianum, conducted at the same temperatures used for the inactivation of the enzyme, showed that the heat resistant portion of pectinesterase presented greater thermal resistance and should be used as target for the establishment of the required process.|
|Editor:||Food Nutrition Press Inc|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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