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| 脂肪酸含量对植物油介电特性的影响 |
| Effect of fatty acid content on dielectric property of vegetable oil |
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| DOI： |
| 中文关键词: 介电特性 植物油 脂肪酸 橄榄油 氧化反应 |
| 英文关键词:dielectric property vegetable oil fatty acid olive oil oxidation reaction |
| 基金项目: |
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| 中文摘要: |
| 为了提供植物油在微波和射频等介电加热技术和通电加热技术中的应用基础数据，考察脂肪酸含量对植物油介电特性的影响，分别利用LCR阻抗测试仪和网络分析仪（同轴探针法）测量了4种植物油（橄榄油、自制橄榄油、橄榄调和油、大豆油）和5种脂肪酸（棕榈酸、硬脂酸、油酸、亚油酸、亚麻酸）在低频段（1 000 Hz～2 MHz）和高频段（300～10 000 MHz）的介电特性。结果表明：低频下，植物油的介电常数比较稳定，其均值为（1.56±0.02），介电损耗随着频率的增加而下降，其中0.7 MHz时橄榄油具有最大的介电常数（1.67±0.00）和介电损耗（7.31±0.02）;高频下，植物油的介电特性随着频率的上升而缓慢下降，4种植物油之间的介电特性的差异不显著（p>0.05);低频下，在植物油中加入油酸后，植物油的介电常数和介电损耗呈现先上升后下降的趋势，而添加亚油酸呈现相反的趋势。添加脂肪酸会加快油脂的氧化反应。 |
| 英文摘要: |
| In order to provide the essential data of vegetable oils being applied in dielectric heating technology such as microwave and radio frequency, and ohmic heating technology and investigate the effect of fatty acid content on dielectric property of vegetable oil, the dielectric properties of four kinds of vegetable oils (olive oil, self-made olive oil, olive blend oil, soybean oil) and five kinds of fatty acids (palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid) were measured at low frequency (1 000 Hz-2 MHz) and high frequency (300-10 000 MHz) by LCR impedance instrument and the network analyzer (open-ended coaxial probe technology) respectively. The results indicated that the dielectric constant of vegetable oils at low frequency was stable and the mean was (1.56±0.02), while the dielectric loss decreased with the increase of frequency. Among them, olive oil had the maximal dielectric constant (1.67±0.00) and dielectric loss (7.31±0.02)at 0.7 MHz. At high frequency, dielectric property of vegetable oil decreased gradually with the increase of frequency and the difference of dielectric property among the four kinds of vegetable oils was insignificant (p>0.05). At low frequency, the dielectric constant and dielectric loss of vegetable oils increased first and then decreased after adding oleic acid to vegetable oils. On the contrary, the dielectric constant and dielectric loss of vegetable oils decreased first and then increased after adding linoleic acid to vegetable oils. Meanwhile, adding fatty acid could speed up the oxidation reaction of vegetable oils. |
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