Use of pennywort pomace and tyrosinase in making of fibre-rich pasta: effects on proximate composition, textural profile, cooking quality and overall acceptability of the product

Pennywort pomace, a by-product of pennywort juice production, was used as a partial substitution for durum semolina in the making of fibre-rich pasta. The effects of ratio of pennywort pomace powder (PPP) and tyrosinase (TYR) treatment of pasta dough on the product quality were investigated. The increase in PPP level from 0 to 20% of the flour blend resulted in higher dietary fibre and phenolic contents as well as higher antioxidant activities of the product. However, such a use of PPP in pasta recipe reduced its cooking performance, textural properties and overall acceptability. For the pasta dough supplemented with 10% PPP, the increase in TYR dosage from 0 to 75 U g(-1) of the flour blend significantly enhanced the tensile strength and elongation rate while reduced the cooking loss of treated pasta; further increase in TYR concentration from 75 to 100 U g(-1) of the flour blend did not change the cooking and textural properties. In addition, when the TYR treatment time lasted for 20 min, the tensile strength and elongation rate of high-fibre pasta were improved; increase in treatment time from 20 to 40 min did not cause any significant effect on its cooking quality and textural profile. At the TYR dosage of 75 U g(-1) of the flour blend and incubation time of 20 min, the overall acceptability of pasta fortified with 10% of PPP was statistically similar to that of the control. TYR treatment can be considered as a novel approach to improve the quality of high-fibre pasta.