Water Behavior of Aerogels Obtained from Chemically Modified Potato Starches during Hydration.

Joanna Le Thanh-Blicharz,Zuzanna Małyszek,Jacek Lewandowicz,Katarzyna Walkowiak,Hanna Maria Baranowska,Przemysław Łukasz Kowalczewski,Łukasz Masewicz

doi:10.3390/foods10112724

Abstract

Aerogels are highly porous materials that are prepared by removing water held within a hydrogel in a manner that maintains the three-dimensional structure of the gel. Recently, there has been much interest in the preparation of aerogels from biopolymers, including starch. The applicability of native starches in the food industry is partially limited; therefore, the functional properties of starch are often improved by means of physical and/or chemical modification. The aim of the work was the analysis of molecular dynamics and the transport of water in aerogels obtained from native and chemically modified potato starches of the normal and waxy variety. Chemical modification with OSA (E 1450) as well as cross-linking with adipic anhydrite and acetylation (E 1422) had no significant impact on the hydration of potato starch aerogels as well as equilibrium water activity. The introduction of chemical moieties into starch macromolecules led to the improved binding of water by the biopolymer matrix; this was especially evident in the case of waxy starch derivatives. A increase in the amylopectin-to-amylose ratio of starch used for production of aerogels resulted in a decrease of equilibrium water activity along with spin-lattice relaxation time.

Highlights

The first aerogel was produced by Kistler in 1931 [1], using silica, gelatin, albumin, cellulose and agar
The type of chemical modification of starch performed did not affect the ar of aerogels, regardless of the relative humidity in which they were conditioned
The observed phenomena should be linked with the presence of amylose, but the physics behind that process cannot be solely explained by the ar analysis

Summary

Introduction

The first aerogel was produced by Kistler in 1931 [1], using silica, gelatin, albumin, cellulose and agar. Ultralight materials that are prepared by removing water held within a hydrogel in a manner that maintains the three-dimensional structure of the gel [2]. The drying step of wet polysaccharide gel is crucial to maintain the integrity of the original three-dimensional structure. One of the most important polysaccharides used in various industries is starch, which is commonly used in the food industry, and in the chemical and electrochemical industries [4,5,6]. One of the advantages of bio-aerogels over inorganic aerogels is their ability to undergo a functionalization by modification of hydroxyl groups of polysaccharide chains, which is especially effortless in the case of starch [7,8]

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