Effect of ultra-fine friction grinding on the physical and chemical properties of curcuma (Curcuma longa L.) suspensions.

Curcuma longa is a rhizome used for the extraction of curcumin, a yellow colorant that only represents 3 wt% of the dried rhizome. To increase the possibility of using the entire rhizome as a food colorant, in the present investigation, the effect of ultra-fine friction grinding (supermasscolloider) to obtain turmeric suspensions was evaluated. To achieve this goal, two distances between the grinding stones or Gap were evaluated (G of -1 and -1.5), and the obtained suspensions were characterized by infrared spectroscopy and through the determination of curcumin content, color, particle size, sedimentation index, serum cloudiness, and microstructure. The results establish that a lower G contributes to an increase in the release of curcumin in the suspension up to 21%, which is related to a greater tendency for yellow coloration, observed in the increase of the * b coordinate of color (from 61.588 to 66.497). Additionally, it was found that a lower G generates smaller particle sizes, which is related to a lower turbidity. PRACTICAL APPLICATION: This research shows that ultra-fine friction grinding (UFFG) has great potential for the development of turmeric suspensions. The results have applications in the food industry sector, because UFFG could be used to produce different types of vegetable suspensions.