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Photodegradation kinetics of curcumin in ethanol solution and encapsulated in alginate-pectin hydrogel

Gielink, Celene
http://rave.ohiolink.edu/etdc/view?acc_num=osu1587044962123771

Abstract Details

2020, Master of Science, Ohio State University, Food, Agricultural and Biological Engineering.
Curcumin, a polyphenol derived from the turmeric root (Curcuma longa), is a natural food colorant with potential benefits as an antioxidant, and an anti-inflammatory agent. Curcumin use is limited by its low water solubility and susceptibility to light, heat, and alkaline degradation, resulting in color loss. Curcumin degrades to form multiple compounds such as 4-vinyl-guiacol, vanillin, ferulic aldehyde, ferulic acid, and vanillic acid. Encapsulation has been used to protect curcumin against light degradation. In this study, the effect of light treatment on the kinetics of curcumin degradation and its antioxidant capacity were characterized for curcumin in ethanol solution and encapsulated in alginate-pectin hydrogel particles at 10, 20 and 35 °C. Light treatment was conducted using visible light (380-740 nm). Degradation was studied by measuring the absorbance of curcumin solution as a function of time with a spectrophotometer. For encapsulation studies, after light treatment of hydrogel particles, curcumin was extracted from the hydrogel with ethanol and the absorbance was measured. The antioxidant activity of the light-treated and control curcumin samples was evaluated by using the Ferric Thiocyanate (FTC) and DPPH radical scavenging assays. Photodegradation of curcumin in ethanol solution and in hydrogel particles followed first order kinetics at all temperatures investigated. The degradation of curcumin ethanol solution rate constant increased with temperature from 0.3 day-1 at 10 °C to 0.62 day -1 at 35 °C, with an activation energy, Ea, of 21.22 kJ/mol. For encapsulated curcumin, the rate constants changed from 2.4 day-1 at 10 °C to 4.818 day-1 at 35 °C, with an Ea of 16.62 kJ/mol. Rate constants for antioxidant capacity of curcumin in ethanol solution were approximately ten times slower than curcumin degradation rate constants, based on DPPH assay data which increased from 0.0216 day-1 at 10 °C to 0.0864 day -1 at 35 °C, with an E¬¬a of 40.8 kJ/mol. Kinetic analysis of FTC assay data revealed an even slower antioxidant capacity change than the DPPH assay data. The results may indicate degradation products of curcumin have similar antioxidant activity as the parent molecule, curcumin, and are less dependent on temperature. Ultra-High Pressure Liquid Chromatography (UHPLC) and Quadrupole-Time-of-Flight (QTOF) mass spectroscopy analyses of pre- and post-light treated curcumin indicated a significant decrease of the principal curcuminoids and an increase in degradation products, such as 1,3-benzothiazole.
Gonul Kaletunc, Dr. (Advisor)
Rachel Kopec, Dr. (Committee Member)
Sudhir Sastry , Dr. (Committee Member)
150 p.
Engineering
curcumin; hydrogel; light exposure; encapsulation; kinetics

Recommended Citations

Citations

  • Gielink, C. (2020). Photodegradation kinetics of curcumin in ethanol solution and encapsulated in alginate-pectin hydrogel [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587044962123771

    APA Style (7th edition)

  • Gielink, Celene. Photodegradation kinetics of curcumin in ethanol solution and encapsulated in alginate-pectin hydrogel. 2020. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1587044962123771.

    MLA Style (8th edition)

  • Gielink, Celene. "Photodegradation kinetics of curcumin in ethanol solution and encapsulated in alginate-pectin hydrogel." Master's thesis, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587044962123771

    Chicago Manual of Style (17th edition)

osu1587044962123771
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This open access ETD is published by The Ohio State University and OhioLINK.