Is very complicated keep intact for a long time antioxidants, but can use amber containers, and add ascorbic acid, and preferably stored at low temperatures, these general recommendation could help preserve for a longer time bioactive compounds. Another strategy is to encapsulate the bioactive compounds. 

May be u can use the natural preservatives such as grape seed extract, vitamin E and so on. u can use high-temperature sterilization but limit the duration of exposure. the industrial foods or drinks enriched with spirulina platensis should be kept in freezer to preserve antioxidants and bioactive substances...

Hi

thanks Francisco & Puganeswary

 I need  methods  for formulation of drinks and foods . phycocyanins and antioxidans of spirulina are sensitive to PH , heat and light.