Effect of Encapsulation Process on Technological Functionality and Stability of Spirulina Platensis Extract

The limited stability of Spirulina protein extract towards environmental factors limits its application in food formulations. This study evaluates the characteristics and efficacy of different delivery systems composed of pure trehalose and trehalose-maltodextrin mixtures at different ratios (50:50; 20:80) to encapsulate Spirulina extract. The delivery systems were obtained through conventional amorphization techniques as freeze- and spray-drying and novel ones such as co-milling. Among the studied techniques, freeze-dried samples, regardless of the matrix composition, exhibited the highest carrying capacity with a residual amount of phycocyanin >89% after encapsulation. The use of ball co-milling for encapsulation caused a complete degradation of the core compound when applied using processing times applied of 6 h and 12 h. The glass transition temperature of the different samples, determined by differential scanning calorimetry, was affected by the carrier composition, increasing with increasing amounts of maltodextrin present in the matrix. When samples were exposed to high temperature during storage the delivery systems containing maltodextrin were more effective in preventing thermal degradation of the Spirulina extract and preserving its colouring ability.