Abstract

BARAZARTE, Humberto et al. Evaluation of two colorimetric methods for quantification of pectic substances in passion fruit (Passiflora edulis). Bioagro [online]. 2010, vol.22, n.2, pp.163-166. ISSN 1316-3361.

The routine analysis of pectins in vegetal products requires fast and precise quantitative techniques. By such a reason, the accuracy and precision of the carbazole and m-hydroxydiphenyl methods for quantification of pectin content in passion fruit rind was evaluated. The galacturonic acid (GA) recovery was determined in dehydrated samples with addition of varying amounts of commercial pectin, and the rind GA content was quantified using the mentioned methods. With the carbazole method, recovery from 90.74 to 102.18 % and coefficient of variation (CV) from 0.80 to 3.44 % was obtained, while with the m-hydroxydiphenyl method the recovery was from 85.01 to 107.9 % and CV from 2.74 to 5.98 %, reflecting low dispersion and little effect of interfering substances. In passion fruit rind from 15.81 to 17. 0 % of GA on a dry matter basis was obtained. Based on simplicity, reproducibility and minimal effect of interfering compounds, the carbazole and m-hydroxydiphenyl methods are useful for determination of pectic substances in fruits, like passion fruit.

Keywords : Carbazole; m-hydroxydiphenyl; galacturonic acid; pectin.