Conclusion
A comparative study was undertaken to examine the effect of different saccharides on the gelatinization of corn starch by employing with a new method, IOD method and the MRDCC was applied to analyze the results. The increase of the sucrose concentration (0–20%) inhibited the gelatinization of starch. The multiple hydroxyl groups contained in the sucrose structure interacted with the molecular chains in starch hindered the water swelling of starch, and the increasing of sucrose concentration reduced the water content and the water activity. All of the saccharides proposed in our research showed protection effect on starch crystalline structure during gelatinization. Among monosaccharides, the gelatinization inhibition effect was in the order glucose > fructose > ribose; among disaccharides, the effect was in the order trehalose ≥ sucrose > lactose > maltose. By analyzing the oligosaccharides, trisaccharide and tetrasaccharide were more effective in inhibiting the gelatinization process than disaccharide; and the protection effect of disaccharides on starch was bigger than that of monosaccharide during gelatinization. The gelatinization inhibition effect had good relationship with nDHN, the increase of the e−(OH) group number of saccharides might increase the inhibition effect on starch gelatinization. However, we also found out that some disaccharides (like maltose and lactose) acted like monosaccharide in term of protection effect on starch gelatinization and were less effective than other disaccharides, which meant that beside the e−(OH) groups, the combination ability of sugar with water molecules might be also related to the size of the sugar molecules and their three-dimensional structure. We believed that owing to the helical structure which formed through hydrogen bonds, tetrasaccharide tended to decrease the hydration ability of saccharide and destabilize the water structure, thus the inhibitory effect of stachyose was almost the same as raffinose.