Effects of different mechanical processing methods on physicochemical properties of potato starch-plant protein-carrageenan composite gels
Evgenia N. Nikolaou, Evangelia Karvela, Eftychios Apostolidis, Vaios Τ. Karathanos
Abstract
Abstract Mechanical processes impact (conventional mixing, high-speed shear mixing, and ultrasonication) on the physicochemical, mechanical, and thermal properties of starch gels combined with plant protein concentrates (pea, fava-bean, pumpkin, rice) and κ-carrageenan were evaluated. Conventional and high-speed shear mixing reduced values of strain (γl), yield stress (τf) storage modulus (G’), complex viscosity (η*), and increased tanδ magnitudes, being more prominent in fava-bean (G’ PSF C = 11416 ± 48, G’ PSF HS = 5421 ± 37), pea (G’ PSP C = 6188 ± 39 G’ PSF HS = 2984 ± 30), and pumpkin protein-starch gels (G’ PSPU C = 14840 ± 107, G’ PSF HS = 7066 ± 42), ( p < 0.05).While no significant rheological alterations were observed for rice-protein gels (G’ PSR C = 10802 ± 98, G’ PSR HS = 10044 ± 76). Ultrasonication process had a smaller effect on viscoelastic properties compared to other shear methods (e.g. G’ PSP C = 6188 ± 39, G’ PSP US = 5775 ± 72). Firmness increased with high shear processing, ∼ 3 times for fava bean and ∼ 2 times for pea and pumpkin protein-starch gels. In contrast, shearing of rice protein-starch complex resulted in softer gels, particularly with ultrasound treatment. The thermomechanical properties displayed shear-induced changes in onset, peak, and conclusion temperatures of gelatinization, and decreased enthalpy values, with varying sensitivity to each protein concentrate. Research findings have important implications for optimizing food product development by customizing processing techniques and hydrocolloids interactions to achieve desired texture and functionality in various food applications such as extrusion-based three-dimensional food-printing.