Dextran—low-molecular saccharide sweetener interactions in aqueous solutions Jo ´zef Mazurkiewicz, Krzysztof Re ˛bilas, Piotr Tomasik * Department of Chemistry, University of Agriculture, The Hugon Kollatay, Mickiewicz Ave., 21, 31 120 Cracow, Poland Received 7 September 2004; accepted 2 February 2005 Abstract Viscosity of aqueous solutions of dextrans of M w 19,500, 71,400, and 282,000 is fairly insensitive to admixed L-arabinose, lactose, rhamnose, sorbitol, and xylitol. These results, together with results of polarimetric studies, suggested that a subtle increase in the viscosity of solutions, accompanied with increase in concentration of the additive was induced by changes in water activity rather than direct interactions between dextrans and additives. q 2005 Elsevier Ltd. All rights reserved. Keywords: Dextran; Viscosity; Water activity 1. Introduction Low-calorie diet is commonly followed. One of several approaches to the reduction of the energetic value of foodstuffs involves limits put on the use of sucrose—a most common sweetener. In food technology, sucrose plays a role of sweetener and a texturising agent. Therefore, reduction of its level produces several complications in designing a proper foodstuff quality. There are several examples that a significant increase in the viscosity and adhesiveness of fairly diluted saccharide solutions could be noted when another, thoroughly selected saccharide, was admixed to such solution. Our former studies Mazurkiewicz and Nowotny-Ro ´zan ´ska (1998) demonstrated that interactions between mono- and di-saccharides even in concentrated solutions did not provide any substantial increase in viscosity. However, when at least one of the components was either a higher oligosaccharide or polysaccharide a significant increase in viscosity was achieved Mazurkiewicz, Zaleska, and Zaplotny (1993). The use of the interactions between various polysaccharides in con- trolling texture of foodstuffs and non-nutritional pre- parations is widely studied but there are very limited number of studies on such interactions between poly- saccharides on one hand and mono- and di-saccharides on the other. Published results contradict one another. They depend on (i) a processes under study, for instance, sorption, retrogradation, mutaratation, (ii) saccharides investigated, and (iii) botanical origin of starch Tomasik and Schilling (1998). Perhaps, fairly subtle interactions Tomasik, Wang, and Jane (1995) do not provide results which would be particularly promising for practical controlling texture of foodstuffs. At the present state of knowledge, one is not sure whether observed effects are controlled by such kind of interactions. Therefore, in this paper, interactions in aqueous solutions between three dextrans of M w 19,500, 71,400, and 282,000, respectively, on one hand and either rhamnose, arabinose xylitol, sorbitol or lactose, on the other are examined. Considerations involve effects of molecular weight of dextrans at the concentration maintained constant throughout experiments, the variable concentration of low-molecular partners, water activity, and rate of mutar- otation recorded polarimetrically. 2. Materials and methods 2.1. Materials Dextrans M w Z19,500, 71,400 and 282,000, arabinose, lactose, rhamnose, sorbitol, and xylitol of 98–100% purity Food Hydrocolloids 20 (2006) 21–23 www.elsevier.com/locate/foodhyd 0268-005X/$ - see front matter q 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodhyd.2005.02.006 * Corresponding author. Tel./fax: C48 12 662 4335. E-mail address: rrtomasi@cyf-kr.edu.pl (P. Tomasik).