[关键词]
[摘要]
试验研究了桃渣在60 ℃、70 ℃和80 ℃条件下热风干燥和中短波红外干燥的干燥特性、有效水分扩散系数和活化能,建立了桃渣干燥的数学模型,并比较了桃渣在不同干燥条件下多酚的含量。结果表明,对文中所建立的5种干燥模型进行对比可以发现,Midilli et al.模型最适合描述桃渣在所有干燥条件下的干燥特性(R2>0.9996);桃渣热风干燥的有效水分扩散系数为(1.1652~1.7393)×10-9 m2/s,红外干燥的为(1.6718~2.4993)×10-9 m2/s;利用阿伦尼乌斯方程计算桃渣两种干燥方式的活化能分别为19.56及19.68 kJ/mol。此外,相同干燥温度下红外干燥样品中的总酚保留率较高,分别为68.22%、75.42%及82.63%。与热风干燥相比,桃渣中短波红外干燥速率较大,多酚保留率较高,且多酚含量随干燥温度的升高而增大,80 ℃红外干燥对桃渣的多酚含量影响最小。本试验为桃渣不同干燥条件下的干燥特性以及多酚的利用提供了理论基础。
[Key word]
[Abstract]
The drying characteristics, effective moisture diffusivity (Deff) and activation energy (Ea) of peach pomace under hot-air drying (HAD) as well as short- and medium-wave infrared radiation drying (IRD) at 60 ℃, 70 ℃ and 80 ℃ were investigated. The mathematical models of peach pomace under different drying processes were established and the total polyphenol contents of peach pomace under different drying conditions were tested. The results showed that the Midilli et al. model was the best model to describe the drying process of peach pomace under all drying conditions (R2>0.9996) as compared with the five drying models established in this study. The values of effective moisture diffusivity varied from 1.1652×10-9 to 1.7393×10-9 m2/s for HAD and from 1.6718×10-9 to 2.4993×10-9 m2/s for IRD. The activation energies of HAD and IRD methods for peach residue calculated by Arrhenius equation were 19.56 kJ/mol and 19.68 kJ/mol, respectively. In addition, the total polyphenol retention in the IRD samples were 68.22%, 75.42% and 82.63%, which were higher than that in HAD samples at the same drying temperature. In conclusion: the drying rate and polyphenol content of peach pomace under IRD were higher than those under HAD, and the content of polyphenol increased with the increasing drying temperature. The IRD process at 80 ℃ had the minimal effect on the polyphenol content of peach pomace. This study provided the theoretical basis for the drying characteristics of peach pomace under different drying conditions and the usage of polyphenol in the future.
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[基金项目]
国家现代农业产业技术体系(CARS-31);公益性行业(农业)科研专项(201503142)