Impact of processing on the production of a carotenoid-rich Cucurbita maxima cv. Hokkaido pumpkin juice.

Pumpkin juice with high carotenoid content can be attractive natural alternative for artificial food colourants. We evaluated the impact of processing treatments on aqueous carotenoid extraction from pumpkins, aiming to enhance carotenoid transfer into the juice fraction. Crushed whole pumpkins were processed by high pressure homogenization (HPH) for mechanical cell disruption, by enzymatic treatment for cell wall polysaccharide degradation or by a pulsed electric field (PEF) treatment for cell membrane electroporation. Processed purees were separated into juice and pomace and carotenoids were quantified by HPLC-DAD. Whereas only 54-60% of the carotenoids in non-processed puree was transferred into the juice, HPH- and enzyme-assisted processing of purees significantly increased juice yields and total soluble solids, and consequently, carotenoid concentrations in these juices up to 90-98% and 72-90%, respectively. No significant improvement was observed for PEF-treated samples. Results obtained can be industrially useful in producing natural colouring plant concentrates as clean-label ingredients.