|QU, WENJUAN - University Of California|
|MA, HAILE - Jiangsu University|
|ATUNGULU, GRIFFITHS - University Of California|
Submitted to: Ultrasonics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/2011
Publication Date: 1/20/2011
Publication URL: http://dx.doi.org/10.1016/j.ultsonch.2011.01.005
Citation: Pan, Z., Qu, W., Ma, H., Atungulu, G.G., Mc Hugh, T.H. 2011. Continuous and pulsed ultrasound-assisted extractions of antioxidants from pomegranate peel. Ultrasonics. doi: 10.1016/j.ultsonch.2011.01.005.
Interpretive Summary: This research discovered that using pulsed ultrasound-assisted extraction can extract antioxidants from pomegranate marc with significant energy savings.
Technical Abstract: 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 ºC 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/cm2, and the 5 and 5 s 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%. By considering the energy saving of 50% compared to CUAE, PUAE was better and had the 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 dry peel of pomegranate marc.