The present invention relates to a compound of formula (I) wherein: i is 0 or 1; j is 0 or 1; k is 0 or 1; R1 and R2 are in particular H, (C1-C12)alkyl, or a group of formula C(O)R; R is a, linear or branched, alkyl radical, comprising at least 19 carbon atoms; R3 is H and k=0 when j=1; or, when j=0, R3 is —C(O)R or -L-C(O)R; L, U and L″ are linkers; wherein, when j=0, at least one of the groups R1; R2 and R3 comprises a radical R.