کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
675814 887734 2006 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Kinetics of thermal degradation applied to starches from different botanical origins by non-isothermal procedures
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Kinetics of thermal degradation applied to starches from different botanical origins by non-isothermal procedures
چکیده انگلیسی

Amylose content, crystallinity, morphology and the kinetic of thermal degradation to starches from different botanical origins are described based on XRD, SEM, DSC and TG/DTG curves. Applying the non-isothermal isoconversional Wall–Flynn–Ozawa method on the TG/DTG curves average activation energy (0.10 ≤ α ≤ 0.70) E = 144.1 ± 9.8, 171.6 ± 14.6, 158.3 ± 7.4 and 159.4 ± 15 kJ mol−1 could be obtained for thermal degradation of corn, rice, potato and cassava starches, respectively. From E values and the generalized time θ, the Sesták–Berggren (SB) in which f(α) = αm(1 − α)n seems to be most suitable kinetic model in describing physicogeometrically the thermal degradation for the samples regardless of its botanical origins. The determination of the kinetic exponents m and n allows to obtain the pre-exponential factor (0.2 ≤ α ≤ 0.8) ln A = 8.8, 10.4, 9.2 and 8.9 min−1 for corn, rice, potato and cassava starches, respectively. There were not significant differences between values of the kinetic triplet of the starches, indicating that, despite structural differences, these had little influence on the thermal degradation process of the starches.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Thermochimica Acta - Volume 447, Issue 2, 15 August 2006, Pages 190–196
نویسندگان
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