Influence of the addition of hydrocolloids on the thermal, pasting and structural properties of starch from common vetch seeds (Vicia sativa sp)

Abstract

Belonging to the leguminous family, the common vetch seeds are a non-conventional starch source that can be exploited to attend the growing demand of the food industry. Thus, the aim of this study was to evaluate the influence of addition of hydrocolloids (5% of: carrageenan, carboxymethylcellulose (CMC), guar, jatahy, xanthan and pectin) on the thermal, pasting and structural properties of starch from common vetch (Vicia sativa) seeds. The interaction with the hydrocolloids was analysed by thermogravimetry and derivative thermogravimetry, differential scanning calorimetry (DSC), viscoamylographic analysis (RVA) and X-ray powder diffraction (DRX). From the thermogravimetry, a similar behaviour was observed for all the studied samples, with three well-defined mass losses and a thermal stability plateau. The addition of guar gum promoted an increase in its thermal stability, unlike the sample added of CMC. From the DSC analysis, it was possible to observe a decrease in onset temperatures with the addition of hydrocolloids, which can be correlated with the decrease in pasting temperatures obtained by RVA, except for the carrageenan gum, which increased these temperatures. By RVA an increase in peak viscosities was achieved, highlighting the addition of CMC, pectin and xanthan. Small variations in the degree of relative crystallinity were noted, but no changes in the diffraction pattern occurred for the samples from the XRD analysis. Although native starch has some limitations, the synergistic effect produced by the addition of gums can optimise its technological properties expanding the industrial use.