Effect of hypotonic and hypertonic solutions on impregnation of curcuminoids in coconut slices

The immersion of solid foods into the surrounding hypotonic or hypertonic solution was explored as a method to infuse curcuminoids in coconut slices without altering its matrix. The rate of mass transfer of moisture, solid and curcuminoid with or without application of ultrasound was studied for the surrounding solutions of sucrose (12.5%) and/or sodium chloride (2.5 and 5.0%) consisting of curcuminoids. The highest diffusion coefficient of curcuminoids (1.78 × 10− 10 m2/s) was found to be in a situation, when curcuminoids were dissolved in 2.5% sodium chloride solution, which was further enhanced by the application of ultrasound to 1.81 × 10− 10 m2/s. The direction of moisture and solute mass transfer was dependent on the osmotic pressure of the surrounding solution as well as the osmotic pressure in the coconut slices. The extent and rate of mass transfer can be varied by varying the type and concentration of solutes in the surrounding solution.Industrial relevance: The knowledge provided by this work may be useful for impregnation of bioactive compounds in solid foods without altering their natural matrix. The extent and rate of infusion of bioactive compounds can be changed by varying the type of surrounding solution from hypotonic to hypertonic solution. Further, the application of external field such as ultrasound can result in enhanced mass transfer of bioactive compounds. This technique may be helpful in producing foods with enriched bioactive compounds, besides providing diversified products in terms of taste and nutrition.

► Effect of hypotonic and hypertonic solutions on infusion of curcuminoids in foods
► Mass transfers was studied in binary and ternary solutions.
► Ultrasound was used for possible enhancement in mass transfer.
► Direction mass transfer was found to be dependent on osmotic pressure gradient.