کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10278764 | 464582 | 2005 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Kinetics and inactivation of carrot peroxidase by heat treatment
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
مهندسی شیمی (عمومی)
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چکیده انگلیسی
The activity and kinetics of carrot peroxidase were determined by using pyrogallol, guaiacol and o-dianisidine as hydrogen donors and peroxidase inactivation was studied by thermal and microwave heating. The kinetics of peroxidase showed characteristics which were dependent upon the identity and concentration of the hydrogen donor used. With pyrogallol and guaiacol, the true Km was found to be 0.34 and 1.4 mM for hydrogen peroxide, respectively, whereas the apparent Km with o-dianisidine was 7.7 Ã 10â3 mM. The lowest Km and highest Vmax/Km with o-dianisidine exhibited the greater tendency of the enzyme toward hydrogen peroxide and the specificity of the competing substrate, o-dianisidine. Thermal treatment of carrot peroxidase was done in the range of 35-75 °C for 0.5-180 min. Inactivation kinetics of peroxidase showed a biphasic first-order model, while at 75 °C, peroxidase showed monophasic first-order behaviour. Kinetic parameters, k and Ea, were determined for heat labile and heat resistant fractions of peroxidase. Biphasic behaviour of enzyme inactivation was observed for the microwave treatment at 70 and 210 W, whereas at 350 and 700 W microwave powers enzyme inactivation was monophasic. Microwave heating was found to be more effective for inactivating the enzyme than thermal treatment and additionally vitamin C retention was higher in microwave treated samples compared to heat treatment.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Food Engineering - Volume 68, Issue 3, June 2005, Pages 349-356
Journal: Journal of Food Engineering - Volume 68, Issue 3, June 2005, Pages 349-356
نویسندگان
ÃigËdem Soysal, Zerrin Söylemez,