Effects of transglutaminase treatment on cooking quality, textural properties, and overall acceptability of high fibre pasta incorporated with pennywort residue

Pennywort juice is a herbal drink extracted from pennywort leaves and stems. Pennywort residue is a by-product of pennywort juice production. In the present work, this by-product was proved to be a good dietary fibre ingredient in the making of high fibre pasta. Nevertheless, the addition of 10% pennywort residue reduced cooking properties, textural profiles, and overall acceptability of the pasta samples. The effects of transglutaminase treatment of pasta dough on the product quality were then investigated. Increase in transglutaminase dosage from 0.00 to 0.75 U/g protein of the flour blend decreased the cooking loss of pasta by 19% while improving its tensile strength and elongation rate by 15 and 49%, respectively. Further increase in enzyme dosage from 0.75 to 1.00 U/g protein, on the other hand, decreased the tensile strength and elongation rate. When the enzyme treatment lasted for 30 min, the cooking loss was reduced by 10%, while the tensile strength and elongation rate of high fibre pasta were both enhanced by 10%. However, increase in treatment time from 30 to 40 min did not cause any significant differences in textural and cooking properties of the fibre-rich pasta. The appropriate transglutaminase dosage and biocatalytic time were 0.75 U/g protein and 30 min, respectively, under which the overall acceptability of the sample incorporated with 10% pennywort residue powder was similar to that of the semolina pasta.