School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China.
Department of Food Science and Nutrition, King Saud University, Riyadh, Saudi Arabia.
J Sci Food Agric. 2021 Aug 15;101(10):4361-4372. doi: 10.1002/jsfa.11076. Epub 2021 Jan 28.
Ultrasonic pretreatment is a novel physical method that can be used in the extraction process of okra pectin. Real-time online monitoring technologies were introduced in time and frequency domains when okra was pretreated. Preparation time of dried okra and yield of okra pectin were studied; and physicochemical properties of okra pectin were analyzed at the optimum ultrasonic parameter.
Results showed that ultrasonic intensity of sweeping-frequency ultrasonic (SFU) pretreatment was stronger than that of fixed-frequency ultrasonic pretreatment (FFU). SFU pretreatment (60 ± 1 kHz) at 30 min had a strong ultrasonic voltage peak of 0.05387 V and signal power peak of -6.62 dBm. The preparation time of dried okra was 160 ± 14.14 min in the pretreated group, 44.83% lower than control without SFU pretreatment. The intercellular space was 56.03% higher than control. Water diffusion coefficient increased from 1.41 × 10 to 2.14 × 10 m s . Monobasic quadratic equations were developed for the monitored ultrasonic intensity and pectin yield. Compared to control, extraction yield (16.70%), pectin content (0.564 mg mg ), solubility (0.8187 g g ) and gel strength (30.91 g) were improved in the pretreated group. Viscosity decreased, and values of G' and G″ crossing at 63 rad s revealed the viscoelastic behavior and the beginning of viscous behavior with a sol state.
Decrement of dried preparation time and increment of yield were achieved by ultrasonic pretreatment during the extraction process of okra pectin, and the relationship of ultrasonic intensity monitored by real-time online technologies and yield was given. © 2021 Society of Chemical Industry.
超声预处理是一种新型物理方法，可用于黄秋葵果胶的提取过程。在黄秋葵预处理时，引入了实时在线监测技术的时域和频域。研究了干黄秋葵的制备时间和黄秋葵果胶的产率；并在最佳超声参数下分析了黄秋葵果胶的理化性质。
结果表明，扫频超声（SFU）预处理的超声强度强于固定频率超声预处理（FFU）。SFU 预处理（60±1kHz）30min 时，超声电压峰值为 0.05387V，信号功率峰值为-6.62dBm。预处理组干黄秋葵的制备时间为 160±14.14min，比无 SFU 预处理的对照组低 44.83%。细胞间空间比对照组高 56.03%。水扩散系数从 1.41×10 增加到 2.14×10 m s 。建立了监测超声强度和果胶产率的一元二次方程。与对照组相比，提取产率（16.70%）、果胶含量（0.564mg/mg）、溶解度（0.8187gg）和凝胶强度（30.91g）均有所提高。预处理组的粘度降低，63rads 时 G'和 G″交叉值表明了粘弹性行为和溶胶状态粘性行为的开始。
在黄秋葵果胶提取过程中，通过超声预处理缩短了干制备时间并提高了产率，并给出了实时在线监测技术监测的超声强度与产率的关系。© 2021 化学工业协会。
