Inverse methods to estimate anthocyanin degradation kinetic parameters in cherry pomace during non-isothermal heating

Fruit and vegetables are a rich source of many bio-active compounds from which value-added nutraceuticals can be produced. Anthocyanins (ACY), which are unstable at high temperature (>¡ÆC 70), are the most abundant flavonoid compound and are used as a natural colorant. ACY have health benefits and can be sourced from inexpensive byproducts, such as cherry pomace. The most common method of using the byproduct is to add it as an ingredient to foods that are thermally processed. To design these processes, the kinetics of ACY degradation must be known as a function of time, temperature, and moisture content. Therefore, the purpose of this work was to estimate color kinetic parameters, and anthocyanin degradation parameters in cherry pomace at different constant moisture contents. To do this, the thermal properties of the pomace had to be estimated first. The moisture content was kept constant by sealing the cherry pomace in cans. The retention of ACY in the pomace was investigated during heating at two retort temperatures 105 and 126.7¡ÆC. Tart cherry pomace was equilibrated to other lower moisture contents (MC) and heated in sealed 54 ¡¿ 73 mm cans for different times. ACY retention of 70 MC wet basis (wb) cherry pomace decreased with heating time and ranged from 76 to 10% for 25 and 90 min heating, respectively at 126.7¡ÆC, and ranged from 60 to 40 % for 100 and 125 min heating, respectively at 105¡ÆC. The total color difference (¥ÄE) increased with increasing heating time, whereas Browning Index (BI) exhibited an inverse trend. Correlation between ACY and red color showed a linear relationship at higher moisture content (70 MC, wb) of cherry pomace. Oxygen radical absorbance capacity (ORAC) method showed stability during heating at different times.Differential scanning calorimetery (DSC) was used to measure the specific heat. At ̈¬C 25, the measured specific heat was 1671, 2111 and 2943 J kg-1 K-1 for 25, 41and 70 MC (wb), respectively. Ordinary least squares and sequential estimation methods were used to estimate the thermal and kinetic parameters. Thermal conductivity (W m-1 K-1) was estimated as a linear function of temperature at 25¡ÆC (k1) and 125¡ÆC (k2). The estimated k1 and k2 values and standard errors for 70, 41 and 25% MC (wb) were 0.49 +/- 0.00047 and 0.55 +/- 0.00058, 0.20 +/- 0.0015 and 0.39 +/- 0.0012, and 0.15 +/- 0.0034 and 0.28 +/- 0.0037 W m-1 K-1, respectively. The rate constant and activation energy for 70% MC pomace were estimated as k 115.8 ¡ÆC = 0.0129 ¡3⁄4 0.0013 min-1 and 75.7 ¡3⁄4 10.7 kJ/mol, respectively. The model fit well as shown by a RMSE of approximately 9% of initial ACY concentration (about 65 mg/kg db) and relative error less than %24 for the three MCs.There was no significant effect of moisture content on the reaction rate constant. Empirical correlations for ACY degradation with red color, thermal properties and kinetic parameters were established. These results can be useful for processors desiring to use cherry pomace to make value-added by-products at elevated temperatures. Examples include extruded snacks and breakfast cereals, dried and powdered products such as drink mixes, and baked goods such as breads, confectionaries, and candies. These products are all heated at temperatures above 100¡ÆC, where ACY degrade.

Author dc:creator

• Greiby, Ibrahim

Contributors dc:contributor

• Dolan, Kirk Dolan
• Marks, Bradley
• Bennink, Maurice R.
• Steffe, James

• Anthocyanins
• Cherry industry

Statement dc:rights

• In Copyright

Language dc:language

English

Identifier

etd:1061
isbn:9781303010132
isbn:1303010135
oclc:931731651
umi:3557598
local:GREIBY_grad.msu_0128D_11869

OAI identifier oai:identifier

oai:d.lib.msu.edu:etd_1061