Production of resistant starches via citric acid modification: Effects of reaction conditions on chemical structure and final properties

• Published in: International journal of biological macromolecules Vol. 278; no. Pt 3; p. 134922
• Main Authors: Cavallo, Ema, Tupa Valencia, Maribel Victoria, Rossi, Ezequiel, Errea, María Inés, Foresti, María Laura
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-10-2024
• Subjects: Citric acid; Crosslinking; Esterification; Resistant starch; Starch; Crosslinking; Resistant starch; Starch; Citric acid; Esterification
• ISSN: 0141-8130; 1879-0003; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.134922

Aiming to contribute to the current knowledge on the impact of reaction conditions on the chemical structure and target properties of starch citrates, in the current contribution different corn starch citrates were prepared by manipulation of reaction time, temperature and citric acid concentration. Modified starches were characterized in terms of chemical structure, morphology, crystallinity, swelling power and resistant starch content. For the first time, total substitution, crosslinking and monosubstitution degrees were quantitatively determined; and the relationship among final chemical structure, reaction conditions and target starch citrates properties was comprehensively analyzed. Products with total substitution values in the range of 0.075–0.24, crosslinking degrees in the 0.005–0.11 interval, and monosubstitution extents within the 0.05–0.12 range, were produced. By proper selection of reaction conditions products with almost 100 % of resistant starch were obtained. Results evidenced that starch citrates properties (mainly swelling power and RS content) depend on both chemical structure and the reaction conditions employed. Actually, the reaction temperature set (120 °C or 150 °C) proved to play a determinant role in the final products properties as evidenced from starch citrates with similar chemical structure and substantially different swelling and digestibility properties.
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•Corn starch citrates with varying properties were prepared by manipulation of reaction conditions.•Total substitution, crosslinking and monosubstitution degrees attained were quantified.•Products with almost 100 % of resistant starch were obtained.•Swelling power and RS content did not only depend on the final chemical structure of starch.•Reaction temperature set proved to play a determinant role on starch citrated properties.