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首页> 外文学位 >Inverse methods to estimate anthocyanin degradation kinetic parameters in cherry pomace during non-isothermal heating.
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Inverse methods to estimate anthocyanin degradation kinetic parameters in cherry pomace during non-isothermal heating.

机译：估计非等温加热过程中樱桃果渣中花色苷降解动力学参数的逆方法。

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摘要

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 (> 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°C. Tart cherry pomace was equilibrated to other lower moisture contents (MC) and heated in sealed 54 x 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°C, and ranged from 60 to 40 % for 100 and 125 min heating, respectively at 105°C. The total color difference (ΔE) 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°C (k1) and 125°C (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 k115.8°C = 0.0129 ± 0.0013 min-1 and 75.7 ± 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°C, where ACY degrade.
机译：水果和蔬菜是许多生物活性化合物的丰富来源，可从中生产增值性保健食品。花青素（ACY）在高温（> 70°）下不稳定，是最丰富的类黄酮化合物，用作天然着色剂。 ACY对健康有益，可以从廉价的副产品（例如樱桃果渣）中获取。使用副产物的最常见方法是将其作为成分添加到热处理食品中。要设计这些过程，必须将ACY降解动力学视为时间，温度和水分含量的函数。因此，这项工作的目的是估计在不同恒定水分含量下樱桃果渣中的颜色动力学参数和花青素降解参数。为此，必须首先估计果渣的热性能。通过将樱桃果渣密封在罐中，使水分含量保持恒定。在两个re锅温度105和126.7°C加热期间，研究了ACY在果渣中的保留。将酸樱桃果渣平衡至其他较低的水分含量（MC），并在密封的54 x 73 mm罐中加热不同的时间。 70 MC湿基（wb）樱桃果渣的ACY保留率随加热时间而降低，分别在126.7°C下25和90分钟加热时为76％至10％，加热100和125分钟时则为60％至40％，分别在105°C下总色差（ΔE）随着加热时间的增加而增加，而褐变指数（BI）则呈现相反的趋势。 ACY与红色之间的相关性在樱桃果渣的较高水分含量（70 MC，wb）下显示线性关系。氧自由基吸收能力（ORAC）方法在加热过程中的不同时间显示出稳定性。差示扫描量热法（DSC）用于测量比热。在25°C时，25、41和70 MC（wb）的比热分别为1671、2111和2943 J kg-1 K -1。使用普通最小二乘法和顺序估计方法估计热和动力学参数。热导率（W m-1 K-1）被估计为25°C（k1）和125°C（k2）时温度的线性函数。 70％，41％和25％MC（wb）的估计k1和k2值以及标准误为0.49 +/- 0.00047和0.55 +/- 0.00058、0.20 +/- 0.0015和0.39 +/- 0.0012和0.15 +/-分别为0.0034和0.28 +/- 0.0037 W m-1 K-1。 70％MC果渣的速率常数和活化能分别估计为k115.8°C = 0.0129±0.0013 min-1和75.7±10.7 kJ / mol。该模型拟合良好，如三个MC的RMSE约为初始ACY浓度的9％（约65 mg / kg db），相对误差小于％24 .;水分含量对反应速率没有显着影响不变。建立了ACY降解与红色，热性质和动力学参数的经验相关性。这些结果对于希望使用樱桃果渣在高温下生产增值副产品的加工商很有用。例如挤出的零食和早餐谷物，干燥和粉状产品（例如饮料混合物）和烘焙食品（例如面包，糖果和糖果）。这些产品均在高于100°C的温度下加热，此时ACY会降解。

著录项

  • 作者

    Greiby, Ibrahim.;

  • 作者单位

    Michigan State University.;

  • 授予单位 Michigan State University.;
  • 学科 Agriculture Food Science and Technology.;Engineering Agricultural.
  • 学位 Ph.D.
  • 年度 2013
  • 页码 231 p.
  • 总页数 231
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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