Recovery of bioactive volatiles from byproduct of curcumin manufacture by membrane processing.

Curcumin-removed-turmeric-oleoresin (CRTO) contains volatile oil and leftover curcuminoids but remains as an
underutilised byproduct. Nanofiltration technique is being proposed for the separation of volatile oil, and concentration of turmerones in the hexane-extracted CRTO-turmeric oil. The nanofiltration membranes exhibited
high selectivity for volatile oils, increasing the content from 75.0% to 97.8%. Correspondingly, the ar-turmerone
content increased from 16.4% to 19.4%. The colour value and viscosity of membrane-processed turmeric oil were
comparable with hydro-distilled turmeric oil. The degradation of turmerones upon storage (90 d) followed a firstorder kinetic model. The rate constants obtained from the degradation kinetics revealed that the membraneprocessed turmeric oil possessed higher stability of turmerones than hydro-distilled turmeric oil owing to its
higher total phenolic content. The results demonstrated that the nanofiltration technique offered a non-thermal
route to separate the volatile constituents to produce a premium quality turmeric oil with the higher stability of
turmerones from CRTO-turmeric oil