Study of physicochemical and flow behavior properties of pectins extracted from the tomato industry

MATIAS MIGUEL ALANCAY; MANUEL OSCAR LOBO; LAURA BEATRIZ ITURRIAGA

Villa Carlos Paz, Córdoba

Otro; XLII Reunión Anual de la Sociedad Argentina de Biofisica; 2013

Sociedad Argentina de Biofisica

Pectin is responsible of the texture of fruit and plants due to its ability cementing. The Food industry uses pectin as a gelling forming and/or thickening agent. The by-product from the tomatoes industry (BTI) represents an alternative source for commercial pectins. The objective was to determine in pectins extracted from BTI (PBTI) by acid hydrolysis, high methoxyl (HM) and low methoxyl amidated (LMA) commercial pectins: a) intrinsic viscosity [η] of dispersed samples in NaCl 50 mM; b) pectin solubility at pH 4,5 and 6,5, c) degree of esterification (DE%) and flow properties of aqueous solutions of pectins at pH 4,5;6,5 and natural pH. [n] showed the following increasing order: HM, PBTI and LMA. Solubility at pH 4,5 and 6,5 were higher than 70 (g/100g) in both cases and for all pectins. The DE% at natural pH and pH 6,5 were 76,8, 58,3 and 55,9% and 21,22, 27,89 and 22,52% for HM, PBTI and LMA respectively, reflecting the effect of pH. Intermediate values were obtained at pH 4,5. The flow behavior of the samples to different pH was fitted to Ostwald-de Weale model. The consistency coefficient (K) was higher for PBTI, it didn´t show changes for LMA, decreased with the increase of pH in the HM and PBTI and would be associated with the change of DE% of pectins at different pH. Values of flow behavior index (n) showed that PBTI at pH 4,5 and 6,5, were more pseudoplastic than HM and LMA. The results present physicochemical and flow promising properties for PBTI under the conditions of this study.