Provided is a compound represented by Formula (1) or a salt thereof (in the formula, R 1 and R 2 each independently represent a hydrogen atom or a linear or branched acyl group having 11 to 30 carbon atoms, a hydrocarbon group bonded to a carbonyl carbon of the acyl group is a saturated or unsaturated hydrocarbon group, and at least one of R 1 and R 2 represents the acyl group).