Rheology and tribology of starch + κ‐carrageenan mixtures

Abstract

In this study, we investigated the rheological and tribological properties of biopolymer mixtures of gelatinized corn starches (0.5 – 10.0 wt%) and κ‐carrageenan (κC) (0.05 – 1.0 wt%). Two different starch samples were used. The first starch (CS1), despite extensive heating and shearing contained “ghost” granules, while the second starch (CS2) had no visible ghost granules after the same gelatinization process as CS1. Apparent viscosity measurements demonstrated that κC + CS1 mixtures were shear thinning liquids, with viscosity values being lower than the corresponding weight average of the values of the individual equilibrium phases at shear rates < 50 s−1. Tribological results revealed that κC ≥ 0.5 wt% was required to observe any decrease in friction coefficients in the mixed lubrication regime. Starch (CS1) showed an unusual behavior at ≥ 5 wt%, where the friction coefficient decreased not only in the mixed regime but also in the boundary regime, probably due to the presence of the “ghost” granules, as the latter became entrained in the contact region. The CS1 + κC mixtures showed significantly lower friction coefficients than that of pure CS1 and κC in the mixed regime. However, the CS2 + κC mixture (i.e., containing no ghost granules) showed similar behavior to pure κC in the mixed regime, while lower friction coefficients than that of the pure CS2 and κC in the boundary regime. These findings illustrate new opportunities for designing biopolymer mixtures with tunable lubrication performance, via optimizing the concentrations of the individual biopolymers and the gelatinization state of the starch.

Rheological and tribological nature of flaxseed gum influenced by concentration and temperature and its application as a coating agent for potato chips

“…According to Nejatian et al (2020), variation in rheological behavior may be associated with the modification in the interchain interactions and the molecular deformation and orientation that are somehow linked with particle size. The viscosity (which has a direct relationship with particle size) of the dispersions is one of the factors affecting film thickness and, in turn, friction coefficients of the polysaccharide gum dispersion influenced the mixed and hydrodynamic regimes (Pradal & Stokes, 2016;You et al, 2021).…”

“…Rheological characteristics of polysaccharide gums play a substantial role in their application in food systems (Zaim et al., 2020). The capability of gums to improve the texture of food (liquid or semisolid) is linked with its lubrication properties (You et al., 2021). Accordingly, tribology has been used to describe the relationship between the structure and texture of foodstuff (Huang et al., 2020).…”

In vitro oral simulation based on soft contact: The importance of viscoelastic response of the upper jaw substitutes

“…As a method of studying lubrication behavior, the Stribeck curve has been widely used in food oral tribology (de Vicente, Stokes, & Spikes, 2006; You, Murray, & Sarkar, 2021). The curve takes the friction coefficient as the function of experimental speeds or the combined function of speed, viscosity, and load.…”

“…The application of biological mucosal tissues (porcine mucosa and porcine esophagus) in friction experiments seems to be more appropriate, but the repeatability of friction data remains a challenge (de Hoog et al, 2006). Rubber is considered to be an ideal substitute material because of its easy availability and better stability (Nguyen et al, 2016; You et al, 2021). The viscoelastic response of this material in frictional motion can approximately reflect the shear behavior of tongue and the upper jaw (Sarkar et al, 2019; Sarkar & Krop, 2019).…”

Lubrication study of representative fluid foods between mimicked oral surfaces

“…In recent years, tribology has been widely used in the sensory evaluation of various food systems (Brossard, Cai, Osorio, Bordeu, & Chen, 2016; Campbell, Foegeding, & van de Velde, 2017; Kokini, Kadane, & Cussler, 1977; Meyer, Vermulst, Tromp, & de Hoog, 2011; Ng, Nguyen, Bhandari, & Prakash, 2018; Rovers, Sala, Van der Linden, & Meinders, 2016; Shewan, Pradal, & Stokes, 2019; You, Murray, & Sarkar, 2021). People's perception of food is mainly through visual, auditory, and tactile sense.…”