Formulation and characterization of nano-curcumin fortified milk cream powder through microfluidization and spray drying.

In the present investigation, novel nano-curcumin enriched milk cream powder (CP) was formulated using microfluidization (at 100 MPa/2 passes) followed by spray drying (at three different temperatures: 150, 170 and 190 °C) with sodium caseinate (N) and gum arabic (G) as encapsulating materials. The effect of processing and encapsulating materials on the powder functionalities, particle size, encapsulation efficiency, morphology, fluorescence properties, bioaccessibility and cytotoxicity were studied. Results showed that NCP (spray dried at 190 °C) had significantly higher yield (68 %), encapsulation efficiency (EE) (93 %), and lower particle size (724 nm) than that of GCP. Fluorescence spectra of the powders revealed characteristic 'blue shift' phenomenon indicating better encapsulation and protection of the nano-curcumin corroborating EE results. SEM images showed distinctive features of NCP and GCP; wherein, NCP had shrivelled and irregular surface as compared to the GCP which exhibited round shape and smooth surface. TEM results confirmed that curcumin particles were in the nano-scale (50-250 nm) for both NCP and GCP. In vitro simulated digestion showed significantly high (88.48 %) curcumin bioaccessibility of NCP plus remarkable inhibition of HepG2 cells; whereas, no cytotoxicity was observed in Caco-2 cells by MTT assay. Formulation's applicability was shown by reconstituting powders as a 'cream spread' wherein high sensory acceptability observed. Sodium caseinate was found to be an excellent delivery vehicle for the fortification of nano-curcumin in the cream powder. To our knowledge, this is the first report of formulating a novel nano-curcumin fortified cream powder which has tremendous potential as a functional food ingredient.