Optimization model for ultrasonic-assisted and scale-up extraction of anthocyanins from Pyrus communis 'Starkrimson' fruit peel

Ultrasonic effect on extraction of cyanidin-3-galactoside (Cy3-gal) from pear fruit peel was investigated and compared with conventional extraction (CE) method. Different process factors were tested to determine the optimum conditions for ultrasonic-assisted extraction (UAE). Results revealed that under optimized UAE conditions (ultrasonic power = 162 W, temperature = 71 degrees C, trifluoroacetic acid = 3%, ethanol = 57%, ultra-sonication time = 11 min, and sample to solvent ratio = 1: 30 g/ml), Cy3-gal yield was significantly higher (0.34 3 +/- 0.005 mg/g) than from CE (0.266 +/- 0.004 mg/g), whereas the extract viscosity during UAE showed a negative impact. UPLC-Triple-TOF/MS analysis detected a total number of 13 anthocyanin compounds, out of which 8 were identified and that mainly consisted of cyanidin, delphinidin and petunidin compounds. Higher yield of Cy3-gal under UAE compared to CE was also justified by higher deformations in the cell structure. The possible mechanism of ultrasonication effect during the extraction process is also proposed in the present study. During scale-up UAE process, the extraction yield of Cy3-gal was recorded higher under batch scale-up compared to continuous operation. The present study is an attempt to optimize UAE of valuable anthocyanins from Pyrus communis 'Starkrimson' fruit peel and further scaled-up for higher volume extraction which can be utilized for industrial applications.