Improving rheology and 3D printability of pea, fava and mung bean proteins with raw and fermented millet flour

Abstract

This study aims to enhance the rheological, 3D printing, textural, and nutritional properties of meat analogs by adding the raw and fermented finger millet (RFM and FFM) flour in pea, fava, and mung bean protein isolates (PPI, FPI, and MPI). The gel strength of all samples increased significantly by increasing the protein concentration. The tanδ values for all samples were below 1 (0.16–0.26) indicating elastic and solid-like behavior (G’ > G″). Frequency index increased for FPI (0.09–0.12), PPI (0.10–0.12), and MPI (from 0.10 to 0.13 for) based samples containing both RFM and FFM. The yield stress increased for FPR (111.34–128.47 Pa), FPF (122.73–132.1 Pa), PPR (93.37–166.39 Pa), PPF (126.31–180.4 Pa), MPR (46.17–162.93 Pa), MPF (86.12–189.28 Pa). The optimal formulation in terms of printing, smoothness, texture, and post-processing design retention for all protein-based inks was at finger millet flour to protein ratio of 1:4. However, the MPI-based samples exhibited superior characteristics of elasticity, shear thinning behavior, printing performance, frying stability, and texture. The structural analysis confirmed the higher interactions between FFM flour and proteins, enhancing rheological and textural properties. The protein digestibility values of the analogs ranged from 81.8 % to 91.2 %, with MPI samples exhibiting the highest protein digestibility. This research highlights the potential of utilizing lesser-known cereals to create edible and nutritious analogs through 3D printing.