| 摘要: |
| 为了获取较优的种子干燥工艺，并在确保种子活力的前提下提高干燥速率，以黄豆种子为例，将超声波与热泵联合，探究不同干燥温度(28、32、36、40 ℃)及不同超声波功率(0、50、100、150、200 W)对种子干燥动力学特性、理化特性和发芽特性的影响。理化特性包括超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性以及丙二醛(MDA)的含量，发芽特性包括发芽率、平均发芽时间和发芽指数。结果表明:提高干燥温度和增大超声波功率都可以加快种子干燥速率，显著缩短干燥时间(P<0.05)，并且将有效水分扩散系数Deff从3.035×10-11 m2/s提高至11.394×10-11 m2/s；而SOD的活性随干燥温度的升高而降低，随超声波功率的提高先增大后降低，POD与CAT的活性都是随温度和超声功率的提高先增大后减少；SOD、POD和CAT活性最大值对应的干燥条件分别为28 ℃+100 W、36 ℃+100 W和36 ℃+150 W；有毒物质MDA的含量随温度的升高会显著增加(P<0.05)，而在较高的温度下应用超声波能够显著降低其含量；种子的发芽能力随温度的升高会逐渐降低，而随超声波功率的增大先提高后降低，并且其发芽指标参数最优值所对应的干燥条件为28 ℃+100 W。 |
| 关键词: 黄豆种子 干燥动力学 超声波 理化特性 发芽特性 |
| DOI：10.11841/j.issn.1007-4333.2020.08.14 |
| 投稿时间：2019-12-18 |
| 基金项目:天津市自然科学基金重点项目(16JCZDJC33900) |
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| Characteristics of heat pump combined with ultrasound for drying soybean seed |
|
YU Fei,YANG Zhao,YANG Zongyu
|
| (College of Mechanical Engineering, Tianjin University, Tianjin 300350, China) |
| Abstract: |
| In order to explore the optimal seed drying technique and improve the drying efficiency while insure the vigor of seed, heat pump combined with ultrasound and soybean seeds was taken as study case. The effects of drying at different temperatures(28, 32, 36 and 40 ℃)and ultrasonic powers(0, 50, 100, 150 and 200 W)on the drying kinetics, physicochemical properties and germination performance were investigated. The physicochemical properties included the activities of superoxide dismutase(SOD), peroxidase(POD)and catalase(CAT), and the content of malondialdehyde(MDA). The germination performance included germination percentage, mean germination time and germination index. The results showed that the increase of drying temperature and ultrasonic power accelerated the seed drying rate, shortened the drying time significantly(P<0. 05), and increased the effective moisture diffusion coefficient Deff from 3. 035×10-11 m2/s to 11. 394×10-11 m2/s. The activity of antioxidant enzyme SOD decreased with the increase of temperature, and increased as the ultrasonic power increased initially and decreases afterwards. The activities of POD and CAT increased first and then decreased with both drying temperature and ultrasonic power. The optimum drying conditions of SOD, POD and CAT activity were 28 ℃+100 W, 36 ℃+100 W and 36 ℃+150 W, respectively. The content of MDA increased significantly with an increase in temperature(P<0. 05), and decreased with the application of ultrasound at high temperature. The ability of seed germination decreased with an increase in drying temperature, while increased first and then decreased with the increase of the ultrasonic power. In conclusion, the optimum drying condition of the germination index was 28 ℃+100 W. |
| Key words: soybean seed drying kinetics ultrasonic physicochemical properties germination performance |
