Osmotic treatment for the impregnation of anthocyanin in candies from Indian gooseberry (Emblica officinalis)

• Osmotic treatment was used for the impregnation of anthocyanin in candies from Indian gooseberry.
• Bioactive compounds were infused in solid food matrix while candy making.
• Diffusion coefficients for anthocyanin infusion and candy making process were calculated.
• Total time was reduced from 120 h to 24 h including 4 h of anthocyanin infusion and 20 h for candy making process.

Bioactive compound like anthocyanin can be infused into the solid food matrix like Indian gooseberry or amla (Emblica officinalis) through osmotic treatment. When the surrounding solution concentration was minimum (0 °Brix) the infusion of anthocyanin was higher (3.15 mg/100 g). The values of moisture, solids and anthocyanins diffusion coefficients during infusion process were found to decrease with increase in concentration from 0 °Brix to 20 °Brix from 2.71 × 10−9 to 1.06 × 10−9 m2/s, from 0.73 × 10−9 to 0.28 × 10−9 m2/s and from 1.14 × 10−9 to 0.71 × 10−9 m2/s, respectively. The infused amla pieces were further subjected to higher osmotic solution concentration (30–70 °Brix) for candy making. The diffusion coefficients for moisture and solid contents increased from 0.33 × 10−9 to 2.30 × 10−9 m2/s and 0.68 × 10−9 to 1.25 × 10−9 m2/s respectively. With an increase in the concentration of surrounding solution, the time required to reach moisture and solid equilibrium was reduced. The entire process for anthocyanin infused amla candy could be achieved in 24 h of immersion time compared to conventional method of candy making 120 h (5 days). The resulting product had higher retention of nutrients like vitamin C, with softer texture, reduced lightness and high anthocyanin content as a result of infusion. The product was highly acceptable with higher sensory attributes compared to control sample. The present study concluded that osmotic treatment could be a feasible technology for impregnation of bioactive compounds for candy making without significantly altering the cellular integrity of the solid food matrix.