Investigations on d-pinitol extraction from carob (Ceratonia siliqua L.) pod

D-pinitol, an insulinomimetic compound which has a potential use for curing of diseases associated with insulin metabolism, is one of the promising functional compounds. Hence, scientific studies intended for enhancement and purification of Dpinitol, have become popular. Manufacturers, producing D-pinitol as a dietary supplement, extract this compound mainly with suitable purification techniques from the rich food matrixes and obtain high-purity D-pinitol. At present, the most favourite techniques are ion exchange resins, active charcoal chromatography and solvent extraction. However, due to the high cost and difficulties in applicability, manufacturers have had to look for new techniques that can be used for this purpose. In recent years, many researches have been made about obtaining D-pinitol from carob (Ceratonia siliqua L.) fruit, which has a rich content (5-7 %) for it. In this study, techniques such as enzyme treatment, hot clarification, CaO treatment, ultrafitration, ethanol fermentation and crystallization were performed to enhance the D-pinitol content of the carob extract. Besides, some other techniques (fractional ultrafiltration, nanofiltration and solvent extraction), which were not within the project, were also investigated for the aim of enhancing the D-pinitol. According to the results; especially invertase enzyme treatment before the ethanol fermentation stage increased the metabolic activity of Saccharomyces cerevisiae yeast. Therefore, the concentrations of the free Dpinitol molecules in the carob extract increased depending on this metabolic activity. On the other hand, enhancement application which was combined with fractional ultrafiltration and solvent extraction with ethanol was found to be more successful than other applications mentioned in this study and an approximate increase of 3.5 - fold in Dpinitol concentration of carob extract was observed when compared to the initial concentration. It has also been demonstrated by a small test that nanofiltration rather than ultrafiltration was more effective in enrichment of D-pinitol in this matrix. Thus, the permeat (21.69 g/L) and retentate (22.35 g/L) compositions in respect to D-pinitol were not significantly different from each other when the membrane filter with a 5 kDamolecular weight cut-off (MWCO) was used. But, when the membrane filter with a 2 kDa-MWCO was used, most of the D-pinitol molecules couldn't pass the membrane therefore the D-pinitol concentration of the retentate (17.69 g/L) was higher than the permeat (5.79 g/L). Consequently, a concentration increment in the range of 2-3.5-folds i occurred by using the enhancement techniques stated in this study and other techniques added later on to the study.