[6)-β-D-fructofuranosyl-(2→]_(n) α-D-glucopyranoside + sucrose --> [6)-β-D-fructofuranosyl-(2→]_(n+1) α-D-glucopyranoside + D-glucose (according to UniProt)

Sucrose (6)-beta-D-fructofuranosyl-(2)(n) alpha-D-glucopyranoside = glucose (6)-beta-D-fructofuranosyl-(2)(n 1) alpha-D-glucopyranoside (according to Swiss-Prot)