Optimization of release process of lycopene microcapsules made by whey protein and maltodextrin using Response Surface Methodology

Lycopene is a useful carotenoid pigment for human health but is very sensitive to environmental conditions. A useful method to control lycopene degradation is microencapsulation by biopolymers. This technology can control release progress of active materials and protect them in different conditions by covering and releasing them in proper place and time. In this investigation, whey protein concentrate (WPC) and maltodextrin were used to encapsulate lycopene. In order to do that, an emulsion of oily lycopene 5% with whey protein concentrate and maltodextrin was prepared. Percentage of solid materials and lycopene were 37.04% and 18.66% respectively and homogenizer speed was set on 18000 rpm. Then emulsion was dried in a spray dryer with inlet air temperature of 150 °C and air pressure of 2 bar at entrance of nuzzle funnel. In order to find the best conditions of releasing of capsules in water, response surface methodology and central composite design were used. Independent variables were pH (3, 7, and 11), water temperature (24, 62 and 100 °C) and percentage of sodium chloride (0.5, 1 and 1.5%). Results showed that alkaline pH resulted to higher rate of rehydration and release of core materials; also the highest rate of release was achieved at water temperature of 62 °C and salt concentration of 0.5%, but higher and lower temperatures and higher levels of salt resulted to a significant decrease of rehydration and rate of core release.