Ultrasound-assisted extraction of d-pinitol from carob pods using Response Surface Methodology

• Ultrasonication was used for the extraction of d-pinitol from carob pod.
• The extraction conditions were optimized using Response Surface Methodology.
• The highest d-pinitol concentration was in 50 °C, 1:4 dilution rate, and 75 min.
• d-Pinitol concentration of 11.98 g/L was obtained in the carob extract.
• Ultrasonication was found more successful than conventional hot water extraction.

This study reports on the optimization of the conditions of extraction of d-pinitol compound from carob pods by using ultrasonication. For this purpose, the Box–Behnken design, which is a widely used form of Response Surface Methodology, was used to investigate the effects of parameters on the ultrasound-assisted extraction. Four independent variables, temperature (°C), ultrasonic power (W), dilution rate (material:water ratio) and time (min), were studied. The results showed that the highest d-pinitol concentration of 11.98 g/L was obtained with an extraction temperature of 50 °C, ultrasonic power of 207 W, a dilution rate of 1:4 and an extraction time of 120 min. It was found that the d-pinitol concentration of carob extract increased with the effect of ultrasonication during the extraction process. Therefore, ultrasound-assisted extraction could be used as an alternative to conventional hot water extraction with respect to the recovery of d-pinitol from carob pods with the advantages of lower extraction temperatures, shorter extraction time and reduced energy consumption.