SIVAKUMAR , V and RAVI VERMA , V and RAO , P G and SWAMINATHAN, G
(2007)
Studies on the use of power ultrasound in solid-liquid myrobalan extraction process.
Journal of Cleaner Production, 15 (18).
pp. 1813-1818.
Abstract
Focus on eco-friendly processing techniques makes vegetable tanning a viable option in leather processing and establishes the subsequent
need for the more efficient methods of extraction in tannin manufacture. Application of ultrasound has been tried in the extraction of tannins
from myrobalan nuts in order to improve the extraction efficiency, to perform the extraction under milder process conditions and to reduce the
processtime.Theinfluenceofprocessparameterssuchasultrasonicoutputpower,timeandtemperaturehasbeenstudied.Scale-uptrialsandthe
use of ultrasound in pulse mode have also been attempted. The results show that a three- to fivefold improvement is possible with ultrasonic
output from 20 to 100 W. Extraction efficiency has been calculated from the maximum extractable materials from myrobalan nuts. Extraction
efficiencyisfoundtobe90%forultrasound,100Wwithoutexternalheatingascomparedto77%forcontrolprocessat70 Cfor4 h.Therefore,
ultrasound could be employed even dispensing with provision for temperature controls. The use of ultrasound in pulse mode offered 70%
extraction efficiencyof continuous mode. Scale-up trials indicate that there exists an optimum ultrasonic output power depending on the amount
ofnutsused, toachievebetter extraction efficiency.Theeffectivenessofultrasonicallyextractedtanninsolutionhasalsobeentestedinthetanning
process for its applicability. The degree of tanning efficacy has been assessed by shrinkage temperature measurement. The results indicate
that ultrasonically extracted tannin solution is suitable for tanning process. Therefore, application of ultrasound in tannin extract manufacture
is a viable option with added advantages.
2006 Elsevier Ltd. All rights reserved.
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