Abstract: The effect of two different preparation methods, namely HCl/KOH and rapid visco analyzer (RVA), on thermal properties and digestibility properties of wheat starch-oleic acid inclusion complexes was studied by differential scanning calorimetry, thermogravimetric analyzer and X-ray diffraction. The results indicated that different preparation methods affected thermal properties and digestibility properties of wheat starch-oleic acid inclusion complexes. The crystal types of wheat starch-oleic acid inclusion complexes prepared by both methods were type-V. Wheat starch-oleic acid inclusion complexes prepared by RVA method revealed an increase in complex index, glass transition temperature, thermal decomposition stability, ordered degree of short-range structure of particle surface, and the contents of slowly digestive starch and resistant starch and a decrease in relative crystallinity, onset temperature, gelatinization enthalpy, the content of rapidly digestive starch, hydrolysis degree, relative digestibility and predicted glycemic index compared with those prepared by HCl/KOH method. These two samples had a medium glycemic index.

Key words: HCl/KOH method, RVA method, wheat starch-oleic acid complex, thermal properties, digestibility