Quality of mashed potatoes: effect of adding blends of kappa-carrageenan and xanthan gum

The texture of potato mashes is impacted by blanching induced changes in their extracellular starch fractions

The texture of potato mash significantly influences consumer satisfaction. We here investigated the impact of blanching and different methods thereof on the texture and extractable extracellular fractions (EEFs) of potato mash when extracted with water or with dimethyl sulfoxide (DMSO) to seek determining factors of potato mash texture. Mashes prepared from potatoes blanched in 2.04 mM CaCl2 (CaB-M) exhibited hardness (24.9 N) and stickiness (1.0 N·s) readings intermediate to those from potatoes that were not blanched (NB-M, 19.2 N and 1.2 N·s), or blanched in deionized water (WaB-M, 30.5 N and 0.6 N·s), which aligned with their levels of intact cells. Starch was the main constituent (57.2 % - 64.4 %, w/w) in all EEFs and more starch was present in (1) NB-M and (2) the DMSO extracts. The chain length distributions of DMSO-extracted extracellular starch (DEES) revealed that the amylopectin content increased in the order WaB-M (46.3 %), CaB-M (55.1 %), and NB-M (76.6 %), which was attributed to more intracellular amylopectin being released to the extracellular phase of mashes. The relative contents of shorter chain amylose (degree of polymerization 110-1000) and the DEES yield were significantly correlated to the hardness while the yield of DEEFs was positively correlated with the stickiness.

Essential Guide to Hydrogel Rheology in Extrusion 3D Printing: How to Measure It and Why It Matters?

Rheology plays a crucial role in the field of extrusion-based three-dimensional (3D) printing, particularly in the context of hydrogels. Hydrogels have gained popularity in 3D printing due to their potential applications in tissue engineering, regenerative medicine, and drug delivery. The rheological properties of the printing material have a significant impact on its behaviour throughout the 3D printing process, including its extrudability, shape retention, and response to stress and strain. Thus, understanding the rheological characteristics of hydrogels, such as shear thinning behaviour, thixotropy, viscoelasticity, and gelling mechanisms, is essential for optimising the printing process and achieving desired product quality and accuracy. This review discusses the theoretical foundations of rheology, explores different types of fluid and their properties, and discusses the essential rheological tests necessary for characterising hydrogels. The paper emphasises the importance of terminology, concepts, and the correct interpretation of results in evaluating hydrogel formulations. By presenting a detailed understanding of rheology in the context of 3D printing, this review paper aims to assist researchers, engineers, and practitioners in the field of hydrogel-based 3D printing in optimizing their printing processes and achieving desired product outcomes.

Viscosity decay of hydrocolloids under oral conditions

The aim of this study was to understand the contribution of hydrocolloids to oral structure breakdown of starch-based systems in relation to mouthfeel sensations. For this, carrot purees were prepared using corn starch and a different second thickener (λ-carrageenan, carboxymethylcellulose (CMC), xanthan gum, or an extra amount of starch). The viscosity decay of purees under in vitro oral conditions was measured (starch pasting cell adapted to a rheometer) when shearing at a constant shear rate in the presence of artificial saliva. Sensory properties of purees were described using the Flash Profile technique by a group of 13 panellists. Oral viscosity decay of systems was modelled using a second order structural kinetic equation that included three parameters: initial viscosity, rate of breakdown, and viscosity at equilibrium. Although they had the same initial viscosity, the structural breakdown of the purees in oral conditions varied, depending on the second thickener used. The structure of purees containing xanthan and λ-carrageenan were more resistant under oral conditions exhibiting a slow and smaller breakdown. In contrast, purees containing only starch showed a rapid and large decay because of the complete structure breakdown by amylase. For puree containing CMC, there was also a rapid decrease, but smaller than starch, indicating that part of the structure remained after digestion. Texture sensations freely described by assessors varied according to two main sensory dimensions, that were clearly related to the structural breakdown parameters. As expected, the dimension of thickness (from watery and liquid to thick and viscous) separated base purees from thickened purees and was related to the initial viscosity. The smoothness dimension (from rough and lumpy to the smooth and creamy) was related to the viscosity at equilibrium indicating that after the oral digestion, the characteristics of the remaining structure can explain differences in complex attributes of semisolid systems such as smoothness and creaminess.

Comparison of 3D printed and molded carrots produced with gelatin, guar gum and xanthan gum

This study examined the effects of different hydrocolloids (guar gum, xanthan gum and gelatin) on the sensory and textural properties of pureed carrots. There were eight products involved in the study; 3D printed carrots and molded carrots without the addition of gums and with guar gum, xanthan gum and gelatin. All products were evaluated using trained panelists (n = 12) and underwent a texture profile analysis. No significant differences were found between the molded and 3D printed pureed carrots; instead, the samples were grouped based on the gum used in their production. The samples made with gelatin and xanthan gum were the hardest (texture profile analysis) and the densest samples when evaluated by the trained panelists. The 3D printing did not affect the taste properties of the pureed carrots, as they were evaluated to be similar to that of the molded carrots (p > .05). This study demonstrated that 3D printing did not affect the textural and sensory properties of pureed carrots when compared to molded carrots. However, changes in the printing parameters (infill percentage, nozzle diameter, flow rate, nozzle height) need to be evaluated to determine their effect on the sensory properties of 3D printed pureed carrots.

Characterizing the Dynamic Textural Properties of Hydrocolloids in Pureed Foods-A Comparison Between TDS and TCATA

Pureed foods, a compensatory diet for dysphagia, require the incorporation of hydrocolloids in order to be swallowed safely. The effect of hydrocolloid addition on textural dynamics of pureed foods has not yet been investigated. Starch and xanthan were added to levels that allowed products to meet the criteria of the International Dysphagia Diet Standardization Initiative. Nine pureed carrot matrices made with two concentrations of starch, xanthan, and their blends were characterized for textural evolution using two dynamic sensory techniques: Temporal Dominance of Sensations (TDS) and Temporal Check-All-That-Apply (TCATA). Each test, with four replications, was conducted with 16 panelists. Results indicate that purees were divided into two groups based on sensory responses--grainy and smooth were the primary differentiating attributes for these two groups. Grainy was associated with starch-added samples, while samples with xanthan (alone and in blends) were smooth and slippery. For both groups, thickness was perceived during the first half of processing, adhesiveness in the second half of oral processing, and mouthcoating was perceived toward the end of processing. A comparison of results from these tests showed that both TDS and TCATA gave similar information about texture dynamics and product differentiation of pureed foods.

Influence of Biopolymer Carrageenan and Glycerine on the Properties of Extrusion Printed Inks of Carbon Nanotubes

This article focuses on the preparation of extrusion printing composite inks of multiwall carbon nanotube (MWNT) dispersed separately in iota-carrageenan (IC) and glycerine (G) solution. Both composites (IC-MWNT and G-MWNT) showed shear-thinning behavior when their flow characteristics were tested. Conductive solid tracks/patterns of both printed composite inks were deposited on glass slide, PET (polyethylene terephthalate) sheet, and IC gel films substrates. The conductive patterns were characterized with microscopy, scanning electron microscopy (SEM), and profilometer. Moreover, their contact angle and electrical conductivity were measured. Profilometry showed that increased number of extruded layers gave increased cross-sectional area. SEM study showed that printing ink is embedded into the surface of IC film, discontinuous on glass slide and smoother on PET sheet. Conductivity of IC-MWNT track was 9 ± 1 S/m and that of G-MWNT was 2942 ± 84 S/m on glass substrate of one layer thick. This is because fewer carbon nanotubes (CNT) are present in G-MWNT track as confirmed by SEM study. The nature of substrate also affects the conductivity of printed patterns. The impressive result of conductivity of printed patterns of composite inks can make them useful for bioelectronic application.