The present invention relates to a recombinant nucleic acid encoding a hybrid polypeptide which comprises a transit peptide for the translocation of the polypeptide into an appropriate organelles such as plastids, a starch-encapsulating region from maize starch synthase and a payload polypeptide, wherein said payload polypeptide can be either N- or C-terminal to the starch encapsulating region. The invention also relates to the expression vectors comprising said nucleic acid, and hosts comprising the said vector. Also, the invention encompasses methods of producing the hybrid polypeptide thereof from starch and particularly from starch granules, and industrial uses of the payload polypeptide recombinantly produced in said hybrid polypeptide wherein said payload polypeptide is a biologically active molecule.