Carboxymethyl cellulose with tailored degree of substitution obtained from bacterial cellulose

A. CASABURI; U. MONTOYA ROJO; P. CERRUTTI; A. VAZQUEZ; M.L. FORESTI

FOOD HYDROCOLLOIDS

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2018 vol. 75C p. 147 - 156

0268-005X

Among the multiple industrial applications of carboxymethyl cellulose (CMC), those related to food andbeverages industries (e.g. as thickener, stabilizer, emulsifier, binding agent), involve one fourth of theglobal CMC consumption. In the last years, a number of abundant and underutilized vegetable cellulosesources have been assayed as raw material for CMC production, as alternatives to cotton linters or cellulosefeedstocks obtained from bleached pulps derived from wood. Alternatively, cellulose of microbialorigin appears as a very promising highly pure raw material for CMC production.Together with molecular weight and substituents distribution, it is well established that the degree ofsubstitution (DS) of CMC plays a key role in most food and beverages applications. In the currentcontribution, highly pure cellulose of bacterial origin was used to produce CMC with tailored DS in a twostageprocess consisting of alkalinization with sodium hydroxide, followed by etherification with sodiummonochloroacetate. Aiming to get insight into how the carboxymethylation extent conferred to BC canbe easily tuned within the DS interval allowed for food uses (i.e. 0.2e1.5), the effects of NaOH concentration,molar NaOH/anhydroglucose unit ratio, molar etherifying reagent/anhydroglucose unit ratio, andetherification time, were systematically analyzed. By proper control of those variables, CMC samples withtailored DS within the 0.60e1.52 interval could be successfully obtained. Samples with varying DS werefurther characterized by means of FTIR, solid state 13C NMR, XRD and TGA. The suitability of using TGA data for estimating the carboxymethylation extent achieved is proposed