SPECTROPHOTOMETRIC METHOD OF STABILITY ESTIMATION OF STARCH INCLUSION COMPLEXES WITH LOW-MOLECULAR LIGANDS

N. D. Lukin¹, A. Y. Vinokurov², A. A. Vodyashkin³, Y. S. Hapilina^2
1All-Russian Research Institute of Starch Products – the branch of the V. M. Gorbatov Federal Science Center of Food Systems of the RAS, ul. Nekrasova, 11, pos. Kraskovo, Lyuberetskii r-n, Moskovskaya obl., 140051, Russian Federation
²I.S. Turgenev Oryol State University, ul. Komsomol’skaya, 95, Orel, 302026, Russian Federation
³Saint Petersburg State National Research University of Information Technologies, Mechanics and Optics, Kronverkskii prosp., 9, Sankt-Peterburg, 197101, Russian Federation

Abstract. Starch polysaccharides, which have a number of advantages (high prevalence, biodegradability, biocompatibility, relatively low cost, availability for modification of the chemical and spatial structure due to physical, mechanical, chemical, biochemical or combined effects), are increasingly used in the development of drug delivery systems, a new generation of food additives, tissue engineering and other areas, many of which are related to nanobiotechnology. Often it is due to the ability of amylose and amylopectin to form inclusion complexes with various ligand substances, which are usually hydrophobic in nature. A wider introduction of complexing in practice can be possible after the using of the proposed method of quantitative evaluation of complexes at the research stage. It is based on the study of the effect of the ligand on the color intensity of the starch complex with iodine. With the expressed ability of the ligand to incorporate polysaccharides into the structure of the molecules, iodine is displaced, which leads to a decrease in the optical density of the solutions studied. Moreover, the higher affinity of the ligand for starch leads to a more abrupt drop in the optical density. The use of the developed algorithm of the data processing makes it possible to calculate the value of the stability constant of the complexes. This method was used to assess the stability of corn starch complexes with a number of aliphatic monohydric alcohols. A quantitative confirmation of theoretical ideas on the role of the hydrophobicity of ligands in the formation of inclusion compounds is found. Thus, in the homologous series of normal alcohols with the elongation of the carbon skeleton, the stability constant of the complex increased (from 2.1 L/micromol for ethanol to 30.0 L/micromol for pentanol-1). The ability to complexing in alcohols with a branched carbon skeleton is lower than that of isomeric normal alcohols (the stability constant in the case of 2-methylbutanol-1 was 13.5 L/micromol, which is more than 2 times lower than in pentanol-1). The advantage of this method is the use of common analytical equipment for absorption spectrophotometry.

Keywords: starch; amylose; amylopectin; inclusion connections; method of assessment of complex stability; interaction of starch with alcohols.

Author Details: N. D. Lukin, D. Sc. (Tech.), director (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); A. Y. Vinokurov, Cand. Sc. (Tech.), assoc. prof. (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); A. A. Vodyashkin, research fellow; Yu. S. Hapilina, research fellow.

For citation: Spectrophotometric Method of Stability Estimation of Starch Inclusion Complexes with Low-Molecular Ligands / N. D. Lukin, A. Y. Vinokurov, A. A. Vodyashkin, Y. S. Hapilina // Dostizheniya nauki i tekhniki APK. 2018. Vol. 32. No. 4. Pp. 77-80 (in Russ.). DOI: 10.24411/0235-2451-2018-10419.