pH Affects the Thermal Inactivation Parameters of R-Phycoerythrin from Porphyra yezoensis |
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| Authors: | A Orta-Ramirez JE Merrill DM Smith |
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| Affiliation: | Authors Orta-Ramirez and Smith are affiliated with the Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824-1224. Author Merrill is affiliated with the Department of Microbiology, Michigan State University, East Lansing, MI 48824-1101. Direct inquiries to: . |
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| Abstract: | ABSTRACT: R-phycoerythrin (PE), a protein that fluoresces in the visible range, was purified from Porphyra yezoensis. PE had a molecular mass of 292 kDa and an isoelectric point of 4.1 to 4.2. Thermal inactivation parameters of PE, calculated on the basis of fluorescence loss, were determined under different pH conditions. PE was more thermostable between pH 5.0 and 8.0, and became more heat sensitive at pH 4.0 and 10.0. PE at pH 6.0 had the highest D value (12258.7 min) at 70 °C. The z values of PE increased from 4.58 °C at pH 5.0 to 9.15 °C at pH 9.0. PE could be used as a time-temperature integrator by adjusting the inactivation kinetics of PE to match those of target microorganisms in a thermal process. |
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| Keywords: | R-phycoerythrin pH thermal inactivation D value z value |
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