Processed Foods Research Unit, USDA-ARS West Regional Research Center, Albany, CA 94710, USA.
Ultrason Sonochem. 2011 Sep;18(5):1249-57. doi: 10.1016/j.ultsonch.2011.01.005. Epub 2011 Jan 20.
There is a great demand for developing efficient extraction methods in order to reduce extraction time and increase the yield and activity of functional antioxidants. The yields, activities, and extraction kinetics of antioxidants from dry peel of pomegranate marc were studied using ultrasound-assisted extraction in continuous and pulsed modes and the results were compared with conventional extraction (CE) at a temperature of 25±2°C and water/peel ratio of 50/1, w/w. The studied factors were intensity level and treatment time for continuous ultrasound-assisted extraction (CUAE), and intensity level, number of pulse repetition, and pulse duration and interval for pulsed ultrasound-assisted extraction (PUAE). The results showed that all factors significantly affected the antioxidant yield, but only treatment time had a significant effect on the antioxidant activity. Compared to CE, PUAE at intensity level of 59.2 W/cm(2), and the 5 and 5s of pulse duration and interval increased the antioxidant yield by 22% and reduced the extraction time by 87%. Similarly, CUAE at the same intensity level increased the antioxidant yield by 24% and reduced the extraction time by 90%. Since PUAE had 50% energy saving compared to CUAE, we recommend using PUAE for the extraction with antioxidant yield of 14.5% and DPPH scavenging activity of 5.8 g/g. A second-order kinetic model was successfully developed for describing the mechanism of ultrasound-assisted extractions under PUAE and CUAE. This research clearly demonstrated the superiority of PUAE for producing antioxidants from peel of pomegranate marc.
为了减少提取时间、提高功能抗氧化剂的产率和活性，人们对开发高效提取方法的需求很大。本文研究了连续和脉冲模式下超声辅助提取对石榴皮干渣中抗氧化剂的提取率、活性和提取动力学的影响，并与 25±2°C 下、料液比为 50/1（w/w）的常规提取（CE）进行了比较。研究的因素包括连续超声辅助提取（CUAE）的强度水平和处理时间，以及脉冲超声辅助提取（PUAE）的强度水平、脉冲重复次数、脉冲持续时间和间隔。结果表明，所有因素都显著影响抗氧化剂的产率，但只有处理时间对抗氧化剂的活性有显著影响。与 CE 相比，强度水平为 59.2 W/cm(2)、脉冲持续时间和间隔分别为 5s 和 5s 的 PUAE 使抗氧化剂的产率提高了 22%，提取时间缩短了 87%。同样，相同强度水平的 CUAE 使抗氧化剂的产率提高了 24%，提取时间缩短了 90%。由于与 CUAE 相比，PUAE 节省了 50%的能量，因此我们推荐使用 PUAE 来提取产率为 14.5%、DPPH 清除活性为 5.8 g/g 的抗氧化剂。本文成功地建立了描述 PUAE 和 CUAE 下超声辅助提取机制的二阶动力学模型。该研究清楚地表明了 PUAE 在从石榴皮中提取抗氧化剂方面的优越性。
