OPTIMIZATION OF SPIRULINA MAXIMA CULTIVATION AND SPRAY-DRYING MICROENCAPSULATION OF THE BIOMASS FOR VEGAN BISCUITS PRODUCTION

Spirulina maxima is a cyanobacteria with several applications in the food industry due to its high protein content. However, this biomass has a characteristic green color and an unpleasant flavor and aroma. The objective of the present work was to optimize the cultivation of S. maxima in terms of protein content and to apply technological processes to mask or attenuate its color and aroma. Central composite design (CCD) was employed to evaluate optimum culture conditions (temperature, light irradiance and agitation) to enhance biomass and protein content of S. maxima. According to experimental results, the predicted maximum biomass and protein content after 7 days of cultivation was 1.01 g/L and 69.97g/100g, respectively, under optimized conditions (temperature of 30 ± 2 ºC, light irradiance of 100 μmol photons m−2 s−1 and agitation of 136 rpm). Then, the biomass produced at the optimized conditions was processed to disguise its green color and aroma. Firstly, the biomass was dried at 200 ºC or 105 ºC for 90 minutes, neither of which was effective as protein degradation was observed. Freeze-drying and Soxhlet extraction were also ineffective methods, as green color and aroma were not attenuated. Biomass microencapsulation by spray-drying with octenyl succinate modified starch (Capsul®) showed positive results, by masking S. maxima aroma and color. Capsul surface activity, low viscosity and film forming capability probably contributed to retention of volatiles. Henceforth, vegan biscuits will be prepared using microencapsulated S. maxima biomass in four different formulations: control and by substitution of wheat flour with 20%, 25%, and 30% of biomass. Finally, biscuits will be characterized in terms of chemical, technological and sensorial quality. Microencapsulation of S. maxima biomass proved to be an effective method in mask its unpleasant flavor, making the biscuits more attractive to the consumer.