Method of preparing a composition (C 2), where 100% of its mass comprises: - From 1% to 70% by mass of a polyol of formula (A 1): HO-CH 2 -(CHOH) n- CH 2 -OH (A 1) wherein n is an integer equal to 2, 3 or 4; - From 25% to 98.9% by mass of a composition (C 1), represented by formula: HO-CH 2 -(CHOH) n -CH 2 -O- x -H, wherein G represents the residue of a sugar-reducing agent, selected from among the residues of glucose, xylose and arabinose, n is an integer equal to 2, 3 or 4 and x, which indicates the average level of polymerisation of said residue G, and represents a decimal number greater than 1 and less than or equal to 5; - From 0.1% to 5% by mass of a compound or a mixture of compounds, selected from among: - the compound of formula (B 11): - the compound of formula (B 12): - the compound of formula (B 13): - the compound of formula (B 14): said method comprising at least a stage a) reaction of a polyol of formula (A 1): HO-CH 2 -(CHOH) n -CH 2 -OH (A 1), wherein n is an integer equal to 2, 3 or 4, with a sugar-reducing agent of formula: HO-G-H wherein G represents the residue of a sugar-reducing agent, in the presence of an acid catalyst (C a), characterised in that said acid catalyst (C a) is selected from among hypophosphorous acid, phosphoric acid and polyphosphoric acid, in that the molar ratio, sugar-reducing agent of formula on polyol of formula (A 1), is greater than or equal to 1/6, and less than or equal to 4/1, and in that the proportion by mass of acid catalyst (C a) used is greater than or equal to 0.05%, and less than or equal to 2%, for 100% of the total of sugar-reducing agents of formula and polyol of formula (A 1). - From 1% to 70% by mass of a polyol of formula (A 1): HO-CH 2 -(CHOH) n- CH 2 -OH (A 1) wherein n is an integer equal to 2, 3 or 4; - From 25% to 98.9% by mass of a composition (C 1), represented by formula: HO-CH 2 -(CHOH) n -CH 2 -O- x -H, wherein G represents the residue of a sugar-reducing agent, selected from among the residues of glucose, xylose and arabinose, n is an integer equal to 2, 3 or 4 and x, which indicates the average level of polymerisation of said residue G, and represents a decimal number greater than 1 and less than or equal to 5; - From 0.1% to 5% by mass of a compound or a mixture of compounds, selected from among: - the compound of formula (B 11): - the compound of formula (B 12): - the compound of formula (B 13): - the compound of formula (B 14): said method comprising at least a stage a) reaction of a polyol of formula (A 1): HO-CH 2 -(CHOH) n -CH 2 -OH (A 1), wherein n is an integer equal to 2, 3 or 4, with a sugar-reducing agent of formula: HO-G-H wherein G represents the residue of a sugar-reducing agent, in the presence of an acid catalyst (C a), characterised in that said acid catalyst (C a) is selected from among hypophosphorous acid, phosphoric acid and polyphosphoric acid, in that the molar ratio, sugar-reducing agent of formula on polyol of formula (A 1), is greater than or equal to 1/6, and less than or equal to 4/1, and in that the proportion by mass of acid catalyst (C a) used is greater than or equal to 0.05%, and less than or equal to 2%, for 100% of the total of sugar-reducing agents of formula and polyol of formula (A 1). - the compound of formula (B 11): - the compound of formula (B 12): - the compound of formula (B 13): - the compound of formula (B 14):