Search

With growing consumer demand for plant‐based products that mimic the eating experience of animal‐based products, there is a need for improvement in instrumental measurements of sensory texture. This study aimed to characterize textural differences between dairy and non‐dairy cheeses, and to investigate whether Large Amplitude Oscillatory Shear (LAOS) rheometry could discriminate sensory texture better than Texture profile analysis. Commercial dairy and non‐dairy cheddar, mozzarella, and cream cheese were selected to provide a wide range of textures. Sensory evaluation used the check‐all‐that‐apply methodology with 73 consumers. Texture profile analysis force‐distance data were analyzed empirically, and also converted to stress and strain (see https://shiny.csiro.au/texture%5fdash). The major textural differences between dairy and non‐dairy cheddar were related to structural cohesion, according to both instrumental measures (dairy cheddar had 1.5‐fold higher failure stress and 2.2‐fold higher failure strain) and sensory measurements (dairy cheddar was more chewy and less crumbly). In contrast, cream cheeses showed similar textural properties using sensory testing but significant instrumental differences (non‐dairy cream cheese had 5.7‐fold higher modulus of deformability, 4.7‐fold higher failure stress). For mozzarella, there were large differences in both sensory attributes (chewy, crumbly, jelly‐like, stretchy) and instrumental parameters (13.6‐fold difference in modulus, 2.7‐fold difference in failure stress). LAOS rheometry gave insights into the mechanisms by which samples absorbed or dissipated mechanical energy at nonlinear strains. The LAOS parameter G3′/G1′$$ {G}_3^{\prime }/{G}_1^{\prime } $$ correlated well with sensory attributes creamy, fatty/oily, and moist, indicating the potential of this technique to measure structural phenomena linked to sensory attributes that resonate with consumers. [ABSTRACT FROM AUTHOR]

This study examined the effects of spread formulation and the structural/lubricant properties of six different commercial hazelnut and cocoa spreads on sensory perception. Rheology, tribology, and quantitative descriptive analysis (QDA) was assessed by also evaluating the correlation coefficients between the quality descriptor and the rheological and textural parameters. The viscosity was evaluated at different temperatures to better simulate conditions before and after ingestion. Tribological analysis was executed at 37°C to mimic the human oral cavity. The effect of saliva presence and the number of runs on tribological behaviors was investigated. Moreover, textural, calorimetric, and particle size distribution measurements were performed to reinforce the correlation between structural/thermal parameters (e.g., firmness, stickiness, sugar melting point) and sensory aspects. "Visual viscosity," defined as a sensory attribute evaluated prior to consumption, negatively correlated with apparent viscosity measured at 20°C and 10 s−1, whereas "body," defined during oral processing and related to creaminess, positively correlated with apparent viscosity measured at 37°C and 50 s−1. These attributes were mainly influenced by particulate microstructure and solid volume fraction within the formulation. Textural stickiness positively correlated with sensory "adhesiveness" and was related to fat composition and milk powder addition, while "sweetness" was related to sucrose content and sugar melting enthalpy. Tribological data provided meaningful information related to particle‐derived attributes, as well as after‐coating perception (fattiness/oiliness), thus better predicting food evolution during oral consumption. [ABSTRACT FROM AUTHOR]

Abstract In recent years, the extraction, processing, and application of edible gums, in the food and healthcare sector has skyrocketed and extensively explored. Edible gums are derived from multiple sources such as plants/trees, animals, microorganisms, and seaweed. Edible gums are typically employed to perform certain functions including modification of rheology, gel formation, stability, encapsulation, and fat replacement. The unique interaction of edible gums with food molecules enables the achievement of desired characteristics of specific food products belonging to various sectors. This review delivers a comprehensive understanding of the classification and characterization of edible gums and their applications in the food industry. Despite several advantages offered by edible gums, there exist certain challenges that are encountered during commercialization by manufacturers and proposed strategies to overcome the hurdles, regulatory aspects, and safety of edible gums upon consumption have been highlighted in this review.

In recent years, the extraction, processing, and application of edible gums, in the food and healthcare sector has skyrocketed and extensively explored. Edible gums are derived from multiple sources such as plants/trees, animals, microorganisms, and seaweed. Edible gums are typically employed to perform certain functions including modification of rheology, gel formation, stability, encapsulation, and fat replacement. The unique interaction of edible gums with food molecules enables the achievement of desired characteristics of specific food products belonging to various sectors. This review delivers a comprehensive understanding of the classification and characterization of edible gums and their applications in the food industry. Despite several advantages offered by edible gums, there exist certain challenges that are encountered during commercialization by manufacturers and proposed strategies to overcome the hurdles, regulatory aspects, and safety of edible gums upon consumption have been highlighted in this review. [ABSTRACT FROM AUTHOR]

Food texture is a collective term for all texture‐related features of a food product. A comprehensive description of food texture is therefore practically challenging due to too many parameters that are associated simultaneously with the food. Using every day, non‐technical (layman's) language, we attempt in this work to rationalize the different dimensions that contribute to the texture of foods, and we explain the rheological reasons behind the concept. For solid foods, three dimensions are identified being the "hard–soft," "strong–weak," and "brittle–plastic." For liquid foods, three further dimensions are suggested, being "elastic–viscous," "thick–thin," and "shear thinning–shear thickening." As these dimensions are bipolar, for foods where any of the dimensions are not relevant, we conceive that dimension takes on a zero value, aligning at the center of the scale. [ABSTRACT FROM AUTHOR]

Food processes have been requiring increasingly more accurately designed operations. Successful design results in products with high quality, in addition to offering energy and cost savings. To these ends, fundamental knowledge regarding the physical properties and thermodynamic mechanisms of the material is essential. The aim of this review was to highlight important concepts and applications of some thermophysical properties (density, specific heat, thermal conductivity and thermal diffusivity), as well as recent methods for their determination. The rheology of fluids and solids is widely discussed according to the concepts, classification, modeling and applications involved in food and equipment design. Herein, we report destructive and non-destructive assays for the evaluation of food properties. Due to the complexity of food systems, the effects of modifications of the structure and physicochemical reactions on the quality of the resulting food are addressed based on thermodynamic aspects. This analytical perspective was adopted in food systems rich in fats, proteins, polysaccharides and simple sugars. Using the information reported in this study, formulations and unit operations can be better designed. In addition, process failures become more predictable when fundamental knowledge is available. Therefore, food losses can be avoided, quality can be maintained and operations can be effectively resumed when deviations from ideal conditions are evidenced. [ABSTRACT FROM AUTHOR]

Molecular interactions determine the microstructure of food, as well as its response to deformation and flow. In order to design efficient processing equipment, to produce high-quality, stable end products, to predict textural and sensory properties, and to ensure consumer acceptance, the characterization of food rheology is essential. Deformations are rapid and large during the processing of foods and during consumption. In food studies, large amplitude oscillatory shear (LAOS) has become increasingly popular due to its ability to mimic real-life processes. When food is subjected to dynamic oscillatory shear tests, a sinusoidal deformation is applied, the mechanical stress (or strain) is probed, and the response is recorded. This chapter summarize main methods to extract meaningful rheological parameters from complex LAOS response of selected food materials. A time-resolved nonlinear rheology method, sequence of physical processes (SPP), gave detailed interpretations of transient microstructures, whereas the Fourier Transform coupled with Chebyshev decomposition (FTC) method provide static measurements at specific strains. LAOS behavior and its relationship to food microstructures and texture still needed to be studied in depth. By constructing more accurate mechanical models of complex food systems, the fundamental knowledge can be applied to evaluate the nonlinear rheology of food for consumer acceptance and efficient processing.

Classical flow and small amplitude oscillation shear (SAOS) often do not meet the emerging needs of food research in practical scenarios to provide food texture information for processing in similar mechanical deformation range. Large amplitude oscillation shear (LAOS) has been developing rapidly in the last decade, but is yet to be widely used in food rheology due to the uncertainty of which LAOS analytical tools are most suitable for particular types of foods. This review aims to provide a significant update on the recent application of LAOS for different types of foods. While a brief summary of common analytical tools used in food LAOS rheology is given, the focus of this paper is on the use of LAOS for different food macro components (proteins, polysaccharides, fats), food formats (emulsion, foam), and categories (dough, cheese, confectionery). The applicable LAOS analytical tools and typical results in each category are presented. The common tools in food LAOS rheology include strain curve shape analysis (strain/amplitude sweep), Lissajous curve analysis (raw/elastic/viscous/3D Lissajous curves and Pipkin diagram), and nonlinear viscoelastic parameters (higher harmonic intensities, strain-stiffening/thickening ratios, large/minimum strain modulus/viscosities, etc.). Different tools were found to suit the analysis of different food components or categories. LAOS rheological analysis of foods can provide a richer dimension than the traditional SAOS analysis, particularly in understanding the phase change processes of food ingredients and the effects of food processing on food structure. • LAOS is a promising method for food processing and formulation. • LAOS data are summarised based on food ingredients and categories. • Strain/Lissajous curves are predominant analytical tools to visualise LAOS behaviour. • Higher harmonics and nonlinear viscoelasticity can quantify food mechanical response. [ABSTRACT FROM AUTHOR]

Abstract The use of flours or phenolic extracts obtained from non-traditional sources or agri-food industry by-products has been a strategy used to formulate new bakery products with characteristics of a functional food. However, phenolic compounds present great structural diversity, as well as the ability to interact in a complex way with the macromolecules that constitute the bread matrix. Therefore, the addition of these flours, extracts or pure compounds produces various effects on the microstructure of bread, and several of its sensory properties. This is mainly due to interactions between phenolic compounds and gluten proteins. The objective of this review is to analyze some of the most recent published works on the addition of phenolic compounds in wheat bread to identify the type of positive and negative effects that have been observed and how they can be related to the physicochemical interactions between phenolic compounds and the macromolecules that constitute the food matrix, mainly gluten. The effect of monomeric and polymeric phenolic compounds on the strength of these interactions and on the properties of dough and bread are discussed. Graphical Abstract

Five commercial hazelnut/cocoa spreads with different compositions were tested by rheology/tribology. The impact of each formulation on the structural/lubricant performances was investigated. Rotational/oscillatory rheology was chosen to assess material behavior during flow. Viscosity variation as a function of temperature and chamber geometry was evaluated. Oscillatory mode tests were carried out to obtain information on product viscoelasticity. Tribological analysis was performed at different temperatures aiming at simulating the chewing/swallowing process. All samples were categorized as pseudo‐plastic and viscoelastic materials, with the elastic component prevailing over the viscous one. Major differences were detected in terms of consistency index, depending on the total lipid content. Temperature increase enhanced spread fluidity with a decreasing viscosity according to the Arrhenius model (R2 > 0.942) and greater values of activation energy reflecting higher sensitivity to microstructural changes. An inverse relationship between Casson viscosity ηc and sugar/fat ratio highlighted additional correlations between structural parameters and spread formulation. Tribological measurements at 25°C highlighted that, at the initial eating stage, the friction factor (0.112–0.262 at sliding velocity of 8 × 10−6 m/s) was strongly affected by either the amounts of solid fat or hazelnut percentage. Tribological data corroborated the theory for which tribology and rheology cover different domains. [ABSTRACT FROM AUTHOR]

Abstract Legumes have gained increased dietary importance in recent years due to their recognized health benefits. Recent plant protein revolution has elevated legumes to the forefront from consumers' and food industry's perspective. Unlike cereal proteins and starches, there is a scarcity of information on the structural properties of legume starches. Consumption of legume‐derived dietary fibers have a positive impact on the human health, in particular, gut health, which is a current research focus for nutrition and health professionals. Knowledge of legume ingredients properties (e.g., protein denaturation, starch gelatinization, pasting, and thermal properties) could aid in understanding functionality and potential uses of these materials. The physicochemical, thermal, and the functional properties of legume proteins, starches, and dietary fibers are elucidated. Both the food ingredient manufacturers and research and development professionals in the food industry can benefit from the information provided in this review article.

In this work, extra-virgin olive oil (EVO)- and sunflower oil (SFO)-based oleogels were structured using rice bran wax (RBW) at 10% by weight (w/w). Bamboo fiber milled with 40 (BF40), 90 (BF90) and 150 (BF150) µm of average size was added as a structuring agent. The effect of fiber addition and cooling temperature (0, 4, and 25 °C) on thermal and structural parameters of achieved gels was assessed by rheological (both in rotational and oscillatory mode), texture, and differential scanning calorimetry tests. Oleogelation modified the rheological behavior of EVO and SFO, thus shifting from a Newtonian trend typical of oils to a pseudoplastic non-Newtonian behavior in gels. Moreover, oleogels behaved as solid-like systems with G′ > G″, regardless of the applied condition. All samples exhibit a thermal-reversible behavior, even though the presence of hysteresis suggests a partial reduction in structural properties under stress. Decreasing in cooling temperature negatively contributed to network formation, despite being partially recovered by low-granulometry fiber addition. The latter dramatically improved either textural, rheological, or stability parameters of gels, as compared with only edible oil-based systems. Finally, wax/gel compatibility affected the crystallization enthalpy and final product stability (gel strength) due to different gelator–gelator and gelator–solvent interactions. [ABSTRACT FROM AUTHOR]

Various rheological techniques were applied to study pizza cheese, as a model anisotropic material. Small Amplitude Oscillatory Shear (SAOS) was combined with Large Amplitude Oscillatory Shear (LAOS) rheology, and the data compared to large deformation tests and confocal microscopy. Pizza cheese was analyzed at various stages of processing: before/during mixing, freshly stretched and after 1 and 2 weeks of storage. Directional sampling and testing were of critical importance for data interpretation. LAOS data were evaluated using a recently developed software that, with visual interactive analysis, including layover plots and similarity maps, allowed to provide a rheological fingerprint of the cheese's process and storage-induced structural changes. This work demonstrated that by using complementary rheological and microstructural techniques it is possible to improve our understanding of the anisotropy at different length scales, and to distinguish the differences in the networks among samples after various processing stages. [Display omitted] • LAOS provides advanced rheological information for food structures. • Improved visualization with VAOS eases data analysis. • Structural differences detected in pizza cheese during processing and storage. • Complementary techniques enhance understanding across length scales. • Directional sampling crucial for testing anisotropic structures. [ABSTRACT FROM AUTHOR]

Microbial polysaccharides have interesting and attractive characteristics for the food industry, especially when produced by food grade bacteria. Polysaccharides produced by lactic acid bacteria (LAB) during fermentation are extracellular macromolecules of either homo or hetero polysaccharidic nature, and can be classified according to their chemical composition and structure. The most prominent exopolysaccharide (EPS) producing lactic acid bacteria are Lactobacillus, Leuconostoc, Weissella, Lactococcus, Streptococcus, Pediococcus and Bifidobacterium sp. The EPS biosynthesis and regulation pathways are under the dependence of numerous factors as producing-species or strain, nutrient availability, and environmental conditions, resulting in varied carbohydrate compositions and beneficial properties. The interest is growing for fruits and vegetables fermented products, as new functional foods, and the present review is focused on exploring the EPS that could derive from lactic fermented fruit and vegetables. The chemical composition, biosynthetic pathways of EPS and their regulation mode is reported. The consequences of EPS on food quality, especially texture, are explored in relation to producing species. Attention is given to the scientific investigations on health benefits attributed to EPS such as prebiotic, antioxidant, anti-inflammatory and cholesterol lowering activities. [ABSTRACT FROM AUTHOR]

ABSTRACT: Green or “detox” juice is a mixture of fruit juice with vegetables, which has been used intensively by consumers seeking for healthy food. Physicochemical properties of Green juice were accessed in the present research, which brings new insights for the use of this beverage in human diet. A total phenolic content of 2833.60 mg GAE (Gallic acid equivalent)/ g of juice and a Total Antioxidant Capacity by FRAP of 323.62 µM Fe2SO4 / g of juice and by ABTS•+ of 333.11 µM Trolox/ g of juice, indicated good antioxidant properties. Low energy and reducing sugar content indicate its use for low calorie diet, but low carbohydrate and protein content prove that Green juice cannot be used as meal replacement. The addition of a microbial biosurfactant (YlBio) and chia gel as bioemulsifiers was tested in the Green juice formulation to reduce solid decantation and increase consistency. YlBio and chia gel were able to change the Newtonian behavior of the Green juice to a Pseudoplastic behavior due to stabilization properties and also increase consistency, without the need to add synthetic stabilizers.

For the successful implementation of emerging electrical technologies in the oil pressing process, optimization of process parameters in combination with parameters from electrical process are crucial. The rheological property could be a simple and reliable efficiency indicatort of oil pressing. Knowledge of rheological properties is necessary for the design and development of appropriate equipment and process calculations. The objective of this work was to evaluate the effect of the following pre-treatments: pulsed electrical discharge (PED), temperature (28, 38 and 45 °C), overpressure (980, 1805 and 2800 Pa) and effect of initial oil content (40, 48.5 and 56%) on rheological properties of sunflower seed cake. The rheological behavior of sunflower seed cake was determined by using a rotational viscometer with a hydraulic system and thermostatic bath attached to the equipment. Using the mathematical apparatus and experimental data it was observed that the plastic viscosity of sunflower seed cake corresponds to the viscosity of the vegetable oil, which confirmed Bingham rheology assumption put forward in this work. Samples treated by PED had a modified material structure with an oil droplets and oil film on the surface. Single PED pre-treatment decreased initial shear stress from 24.36 to 22.89 Pa in samples where number of PED was 1800 per 60 s. Decrease in initial shear stress from 30.3 to 25.1 Pa was also observed when combination of temperature, pressure and PED was applied on seed cake. Reduction of the shear stress value, due to PED pre-treatment, enables to spend less energy during the oil pressing process. A positive linear relationship for overpressure and negative linear relationship for oil content and number of discharges on shear stress were obtained. The effect of temperature characterized by a decreasing of the plastic viscosity of the test material from 0.0985 to 0.0917 Pa s. The obtained parameters of the engineering rheological model allow prediction of rheological behavior of sunflower seed cake viscoplasticity flow over a wide range of shear rates in the pressing channel of the oil press.

In this work, extra-virgin olive oil (EVO)- and sunflower oil (SFO)-based oleogels were structured using rice bran wax (RBW) at 10% by weight (w/w). Bamboo fiber milled with 40 (BF40), 90 (BF90) and 150 (BF150) µm of average size was added as a structuring agent. The effect of fiber addition and cooling temperature (0, 4, and 25 °C) on thermal and structural parameters of achieved gels was assessed by rheological (both in rotational and oscillatory mode), texture, and differential scanning calorimetry tests. Oleogelation modified the rheological behavior of EVO and SFO, thus shifting from a Newtonian trend typical of oils to a pseudoplastic non-Newtonian behavior in gels. Moreover, oleogels behaved as solid-like systems with G′ > G″, regardless of the applied condition. All samples exhibit a thermal-reversible behavior, even though the presence of hysteresis suggests a partial reduction in structural properties under stress. Decreasing in cooling temperature negatively contributed to network formation, despite being partially recovered by low-granulometry fiber addition. The latter dramatically improved either textural, rheological, or stability parameters of gels, as compared with only edible oil-based systems. Finally, wax/gel compatibility affected the crystallization enthalpy and final product stability (gel strength) due to different gelator–gelator and gelator–solvent interactions.

For playing a role of filling a hole in the applicable range of standard rheometer, ultrasonic spinning rheometry (USR) is presented; it is based on equation of motion to explain the fluid rheology and to quantify the rheological properties satisfying the considered equation of motion for complex fluids. Some examples of rheological evaluation for multi-phase fluids using USR were presented; clay dispersion with thixotropy, polymer solution with large-spherical particles, dessert paste with pectin gel including fruit pulps. The efficacy of USR was discussed through those practical tests for complex fluid. [ABSTRACT FROM AUTHOR]

Green or "detox" juice is a mixture of fruit juice with vegetables, which has been used intensively by consumers seeking for healthy food. Physicochemical properties of Green juice were accessed in the present research, which brings new insights for the use of this beverage in human diet. A total phenolic content of 2833.60 mg GAE (Gallic acid equivalent)/ g of juice and a Total Antioxidant Capacity by FRAP of 323.62 µM Fe2SO4 / g of juice and by ABTS•+ of 333.11 µM Trolox/ g of juice, indicated good antioxidant properties. Low energy and reducing sugar content indicate its use for low calorie diet, but low carbohydrate and protein content prove that Green juice cannot be used as meal replacement. The addition of a microbial biosurfactant (YlBio) and chia gel as bioemulsifiers was tested in the Green juice formulation to reduce solid decantation and increase consistency. YlBio and chia gel were able to change the Newtonian behavior of the Green juice to a Pseudoplastic behavior due to stabilization properties and also increase consistency, without the need to add synthetic stabilizers. [ABSTRACT FROM AUTHOR]

In the present study, rheological properties of twelve different licorice root extracts were evaluated using a rotational viscometer as a function of soluble solids content (15–45 °Bx) and temperature (30–70 °C). Response Surface Methodology was used to understand the relationships between the parameters. The experimental data were then fit into mathematical models. The results, for the first time, revealed that the licorice solutions had non-Newtonian shear-thinning behaviors with flow behavior indexes of 0.24 to 0.91, depending on the licorice extract samples, temperature, and °Bx. These observations were different from those reported in the literature and the present study elaborated on reasons for such observations. Further, the shear-thinning behavior generally increased by increasing the °Bx and decreasing the temperature. In addition, the power-law model was found to be suitable for predicting the experimental data. The newly revealed information can be particularly important in designing the unit operations for licorice extract processing.

Microbial polysaccharides have interesting and attractive characteristics for the food industry, especially when produced by food grade bacteria. Polysaccharides produced by lactic acid bacteria (LAB) during fermentation are extracellular macromolecules of either homo or hetero polysaccharidic nature, and can be classified according to their chemical composition and structure. The most prominent exopolysaccharide (EPS) producing lactic acid bacteria are Lactobacillus, Leuconostoc, Weissella, Lactococcus, Streptococcus, Pediococcus and Bifidobacterium sp. The EPS biosynthesis and regulation pathways are under the dependence of numerous factors as producing-species or strain, nutrient availability, and environmental conditions, resulting in varied carbohydrate compositions and beneficial properties. The interest is growing for fruits and vegetables fermented products, as new functional foods, and the present review is focused on exploring the EPS that could derive from lactic fermented fruit and vegetables. The chemical composition, biosynthetic pathways of EPS and their regulation mode is reported. The consequences of EPS on food quality, especially texture, are explored in relation to producing species. Attention is given to the scientific investigations on health benefits attributed to EPS such as prebiotic, antioxidant, anti-inflammatory and cholesterol lowering activities.

The aim of this paper was to study, step by step, the effect of ingredients and storage conditions on several properties of both the maize-based dough and the final product, during the new polenta-based snack food developing. Two different maize flours were characterized through water activity determination, particle size analysis, scanning electronic microscopy; then, dough made with different ratio of these were evaluated for mechanical properties and microstructure. According to the preliminary physicochemical characterization of both flour and dough, the final formulation was chosen for the polenta-based snacks. Thus, mechanical and sensory analyses, as well as microstructure determination, were performed on the final product. Results showed that the two maize flours presented different particle size distribution and gelatinization enthalpy, and affected the mechanical properties of intermediate products. The storage conditions dramatically affected the characteristics of the final products. Sensory results demonstrated that breading improves the crispness of external part but keeping creamy the product inside. The chosen approach was useful for understanding that flour particle size and storage are the critical factors that should be considered for this type of snack. The best formulation was made by mixing coarse and fine maize flours and by adding a batter. [ABSTRACT FROM AUTHOR]

Non-extrusion texturization technology is essential to broaden the application of alternative proteins to advance sustainability and address the challenges of climate change. We propose a gelation technique to texturize non/low-gelling plant protein using curdlan gum, and to manipulate the gel texture by controlling thermal history. Pea protein and curdlan gum can form soft gel at 55–60 °C, but will form rigid gel at 80 °C. Isothermal incubation for up to 1 h could further develop the gel network with significantly higher storage modulus (e.g. 1.3 kPa without incubation, 288 kPa with 1-h incubation at 80 °C). Although curdlan-pea protein gels formed at 55–60 and 80 °C showed similar modulus ranges after 1-h incubation, the microstructure is noticeably different under microscopes (optical, CLSM, SEM). At 60 °C, large pea protein particles are still visible and only partially embedded into the curdlan network; at 80 °C, smaller protein particles are fully embedded into the gel network. When protein concentration increased from 4% to 8% w/w, the gel network became less organised as more space was occupied by protein particles. We demonstrated that heterogenous structures could be achieved by controlling the thermal history of curdlan-pea protein gels to mimic animal tissue with different stiffness (modulus) between the layers. This gelation technique can potentially be applied to other plant-sourced or alternative proteins without the need of an extruder. [Display omitted] • Curdlan gum forms composite gel with pea protein. • Pea protein particles fully merge into the gel network at 80 °C. • Gel strength modulated by thermal history to produce heterogenous texture. [ABSTRACT FROM AUTHOR]

This work presents a novel way of utilizing the design freedoms available in 3D printing (3DP) to produce ready-to-eat sweetmeats with varied textures using finite element analysis (FEA) simulation and the rheological characterization of the 3DP material to get better predictability of the complicated 3DP process. Modeling the influence of crucial printing variables: polyol concentration, nozzle diameter, infill, and layer pattern demonstrated that these significantly impact the texture attributes of 3D printed constructs. The quality attributes were evaluated using weight, void fraction, and geometric precision. While textural attributes were evaluated as hardness, gumminess, and cohesiveness using a Box-Behnken design for four variables at three levels. Results indicated that nozzle diameter and infill density both have a significant (p < 0.05) effect on the weight and void fraction of the printed construct. At the same time, layer pattern does not affect these. The hole volume, hardness, and gumminess varied significantly (p < 0.05) in the printed construct with changing layer orientation pattern. Also, the increased polyol concentration significantly influenced the rheological properties of the formulation, length, cohesiveness, and void fraction of the printed constructs. Modeling and simulating deformation and residual stress in 3D printed geometries has enormous promise for facilitating the widespread use of this technology in food manufacturing. The work is an innovative approach to addressing sensory/satiety perception issues and meeting the demands of those with special dietary requirements. • 3D printing (3DP) sophisticated food patterns to generate customized sweetmeats. • Novel use of Finite element analysis and rheology to increase 3D process predictability. • Reliable simulation method to quantify stress and deformation in 3D-printed foods. [ABSTRACT FROM AUTHOR]

This review summarised the compositional, thermal, and rheological properties and food applications of chestnut ( Castanea spp.) flour systems. The compositional, structural, and physicochemical properties of chestnut starch, which is a major determinant for product quality, were also reviewed. Future research directions on how to better utilise chestnut flour and starch for food product developments were suggested. Chestnuts are important food items for many people around the world. The world production of chestnuts has kept increasing during the last decade. There has been growing interest to utilise chestnut flour for various food applications (e.g. gluten-free food products). The major component of chestnut is starch which amounts to over 50% of the dry weight of the fruit. Chestnut starch may as well have potential for food and non-food applications. Overall, this review provides a scientific basis to develop chestnuts as sustainable and cash crops. [ABSTRACT FROM AUTHOR]

The knowledge of fluid food rheological properties plays an important role in process engineering. Unfortunately, characterization of non-Newtonian fluids requires a notable effort in terms of time and resources. As a consequence, the aim of this research was to set up an method, based on the combination of the inversion of a simple finite element model and a laboratory measurement, carried on with a simplified tool. Although the method has a more general applicability, for illustrative purpose, it is here mainly shown with reference to power-law rheological model and two different materials (tara gum mixture and dough of water and flour). To measure the rheological parameters, the square of distance between simulated and experimental data was considered as an objective function, and some well-known optimization algorithms were tested. In order to verify the feasibility of the method, the experimental rheological characterization of the considered materials were carried out using a rotational rheometer. The calculated rheological parameter values were comparable with those obtained by traditional procedure (mean percentage error 6.47 ± 5.57). The most efficient optimization algorithm, in terms of iterations number, computational speed and minimum of the objective function, was the Levenberg–Marquardt one, but even other tested algorithms drove to similar final results (maximum difference of 18% between the optimized k and n values). The results demonstrated also that the precision of the calculated rheological parameters does not depend on the initial parameter values. In the light of the obtained results, the method could represent a feasible technique and well suited for various rheological models and viscosity range of food materials. Moreover, the method could be susceptible to some development by an industrial point of view being possible to hypothesize the development of an integrated automatic instrument, equipped with finite element software, useful both for laboratory and industrial purposes. [ABSTRACT FROM AUTHOR]

Conventional methods often impose difficulties when measuring the viscosity of fluids containing particles or fibres, e.g. tomato paste or fruit preparations, mainly due to the narrow gaps of the viscometer. In order to solve these problems different geometries have been developed, e.g. different mixer systems and wide gap double concentric cylinders. However, these can not be evaluated assuming a constant shear rate throughout the fluid. In this study, three different kinds of mixer systems have been studied; a small and a large paddle and a helix. For the mixer systems an average shear rate must be determined and a quotient between torque and shear stress must be found. In addition, a wide gap double concentric cylinder (DCC) was examined and evaluated using two different methods. When evaluating the mixer systems a method based on the Couette analogy has been used successfully for a number of complex fluids, including prepared sauces and fruit samples containing particles of different size. The DCC has been evaluated using a numerical as well as an approximate method, both giving results of good accuracy. All systems had the limitation that no consistent results were obtained for tomato paste. However, when starch was added to the diluted tomato paste dispersion, satisfying results were once again obtained.

The correlation between the Bostwick degree and the static rheological properties of yield stress food fuids is first revisited and then reformulated in this work. The role of the yield stress in the free surface flow of the Bost-wick test is studied using dimensional analysis. Results from experiments on 48 different samples of yield stress fluids are considered and included to check the adequacy of the proposed correlation. Asymptotic dynamic behaviour is also presented and discussed as a mechanism of complete self similarity with respect of the dimensionless time. This approach would seem to support the opinions in favor of the yield stress as a key parameter, and thus offers an interesting new viewpoint useful to both future experiments on the Bostwick test and studies of 'dam-break' like dynamics.

The traditional methods of measuring viscosity with rotational viscometers, i.e. cone-plate and concentric cylinder systems, are often not suitable for suspensions. To be able to measure viscosity on suspensions mixer viscometers have been developed. In this study a new design of a helical ribbon impeller has been evaluated and the Metzner-Otto approach has been used to calibrate the impeller. Different kinds of food products were studied. The Metzner-Otto parameter obtained from tomato products was lower than those obtained from starch products. The study showed that the Metzner-Otto parameter varied but seemed rather to be dependent on the composition of the food material than on the flow behaviour index. The impeller could handle high concentration of quite large particles. This type of helical ribbon impeller viscometer is thus recommended for rheological studies of suspensions with high concentration of particles.

Dielectrostriction is a rheodielectric phenomenon that describes the variation of dielectric properties of a material with deformation and is a fundamental property of any dielectric material. During the study of the dielectrostriction phenomenon in polymers, it was found that under small deformations a linear relationship exists between the change in dielectric constant and the stress. Like polymers, most foods are dielectric materials; hence, a change in their dielectric properties with deformation can be expected as well. In this study, the dielectrostriction effect was investigated in food for the first time. Nutella was chosen for this study. It has been found that a linear stress–dielectric relationship exists in Nutella during shear flow. The potential applications of the stress–dielectric relationship in food rheology and processing control are discussed. [ABSTRACT FROM AUTHOR]

This paper discusses the influence of fat type in the structure of ice cream, during its production by means of rheo-optical analysis. Fat plays an important part in the ice cream structure formation. It's responsible for the air stabilization, flavor release, texture and melting properties. The objective of this study was to use a rheological method to predict the fat network formation in ice cream with three types of fats (hydrogenated, low trans and palm fat). The three formulations were produced using the same methodology and ratio of ingredients. Rheo-optical measurements were taken before and after the ageing process, and the maximum compression force, overrun and melting profile were calculated in the finished product. The rheological analysis showed a better response from the ageing process from the hydrogenated fat, followed by the low trans fat. The formulation with palm fat showed greater differences between the three, where through the rheological tests a weaker destabilization of the fat globule membrane by the emulsifier was suggested. The overrun, texture measurements and meltdown profile has shown the distinction on the structure formation by the hydrogenated fat from the other fats.

Highlights: [•] The heterogeneity of fundamental material parameters of Gouda cheese is examined. [•] Young’s moduli and residual Prony coefficients are higher near the crust. [•] Fracture stresses and strains are inversely proportional to the moduli. [•] The variability of the parameters is mainly caused by the dry matter variability. [Copyright &y& Elsevier]

Two types of starch gels made with various starch/water concentrations were studied in terms of their mechanical behaviour. Indentation tests were performed which revealed a rate independent load-deflection response. An inverse analysis based on the Marquardt-Levenberg optimisation algorithm and Finite Element Analysis was used to derive the stress-strain behaviour from the indentation data. The inverse predictions for the stress-strain curves are in good agreement with the direct measurements from uniaxial compression and shear tests up to high values of strain. The validity of the method was proven for both self-supporting and non self-supporting gels, with initial moduli ranging from a very small 60 Pa to 55 kPa. Thus the indentation characterisation method is proven as a powerful, fast and efficient way of evaluating and/or monitoring the behaviour of gels.

Abstract: The consumption of liquid and solid foods is primal to the maintenance of adequate hydration and nutrition in man. Ingestion is a complex process where palatable material is broken down and discretized into boluses after which they are conveyed to the stomach for digestion. There exists difficulty in monitoring the efficacy of bolus transport through the deglutitive apparatus in vivo, especially in patients which exhibit pathological difficulties. To understand the effects of bolus rheology on the deglutition process we propose to develop a bio-mimetic mechatronic swallowing device. This will facilitate investigation of the rheological properties as the bolus is in transit to determine how they interact with the swallowing process. These properties are of interest to food technologists who aim to develop foods for meeting consumer acceptance of various requirements, such as for dysphagic populations to facilitate safe swallowing. The purpose of this review is to develop an awareness of the physiological system and the transferability of the geometrical, actuation, and control concepts into the engineering domain, for the purpose of building a swallowing robot. It presents a body of knowledge, beginning with the behavior and measurement of the deglutitive apparatus, followed by an investigation of deglutitive adaptation in response to rheological stimuli. The neural control strategies are then discussed before concluding with the state of, and demand for, research in the medical, food textural, and swallowing robotic fields. [Copyright &y& Elsevier]

To assess the effect of food form (FF) on postprandial (PP) plasma amino acid (AA) concentrations, ten older adults (five men and five women, age 72 (sem 2) years, BMI 26·0 (sem 0·9) kg/m2) consumed, on separate days, energy and macronutrient-matched test meal replacement products (MRP) (approximately 25 % of the subject's daily energy need; approximately 54 % carbohydrate, 21 % protein, 25 % fat) in beverage and solid form. Blood samples were taken during fasting and throughout the 4 h PP period; plasma AA concentrations were assessed using HPLC. Consumption of each MRP led to an increase in total AA, branched-chain AA (BCAA), essential AA (EAA), non-essential AA (NEAA) and leucine concentrations (4 h area under the curve, AUC) (time effect; P < 0·05). The beverage MRP resulted in a greater initial (i.e. 30 min) and sustained (4 h AUC) increase in total AA, BCAA, EAA, NEAA and leucine concentrations compared with the solid MRP (each effect of FF; P < 0·05). Although there was no effect of FF on PP insulin response, glucose concentration was greater 1 and 2 h after the solid MRP was consumed (FF × time interaction; P < 0·05). For all PP time points combined, total AA concentration was positively associated with plasma insulin (r 0·25) and glucose (r 0·24) concentrations for the solid MRP but not for the beverage MRP. In conclusion, older adults can achieve higher plasma AA concentrations when a protein-containing MRP is ingested in beverage form. The implications of the higher AA availability on anabolic processes warrant investigation. [ABSTRACT FROM PUBLISHER]

Abstract: Proteins and surfactants behave very differently under shear and dilatational deformation. In this work, we compare specifically their surface properties by evaluating their rheological response. Oil-soluble surfactant, sorbitan tristearate (Span 65), and globular protein, β-lactoglobulin, were spread and adsorbed onto the surface, respectively. A 2D searle-type measuring geometry with a biconical bob was used for measuring the surface shear rheology, and a pendant drop film balance was used for measuring the dilatational rheology. Both equipments provided the viscoelastic properties (surface shear and dilatational complex moduli) of interfacial layers. Also, the linear and non-linear rheology of these systems was studied by increasing the amplitude of the oscillation. Linear rheology showed that dilatational deformation is mostly affected by the nature of the molecular structure at the interface, whereas shear deformation is affected by the strength of the surface film due to the intermolecular interactions. Furthermore, large-amplitude oscillatory shear rheology indicated that the non-linearity increases with the surface concentration, and is higher for insoluble Span 65 spread films than for soluble protein adsorbed layers. Dilatational and shear deformation provide complementary information about interfacial layers that can be optimized so as to fully characterize the surface depending of the type of film (spread or adsorbed) and the technique used (shear or dilatational rheology under linear or non-linear regimes). This information is useful to correlate the structure and the mechanical properties of interfacial systems. [Copyright &y& Elsevier]

The purpose of the present study was to determine whether a protein-rich beverage leads to a differential response in appetite, satiety and subsequent energy intake compared with an energy- and macronutrient-matched solid version in young people. A total of fifteen adolescents (eight girls and seven boys; age 14 (sem 1) years, BMI percentile 79 (sem 4) %) randomly completed two testing days that included protein-rich (PR) breakfast meals (38 % of energy as protein, 48 (sem 2) g/meal) provided as a solid (S) or beverage (B). Breakfast was 24 % of estimated daily energy needs (2146 (sem 96) kJ/meal). Perceived appetite and satiety responses were collected over 5 h followed by an ad libitum lunch buffet. The PR-S meal led to greater reductions in 4 h postprandial appetite ( − 6221 (sem 1171) mm × 240 min) v. the PR-B meal ( − 3570 (sem 957) mm × 240 min; P < 0·05). When examining the data according to hourly responses, the PR-S meal led to greater reductions in appetite during postprandial hours 2, 3 and 4 v. the PR-B meal (all comparisons, P < 0·05). No differences in postprandial hourly or total (4 h) fullness were observed following the PR-S v. PR-B meals. The PR-S meal led to approximately 480 kJ less energy consumed at the ad libitum lunch buffet (1418 (sem 222) kJ) v. the PR-B meal (1900 (sem 326) kJ; P < 0·05). These data indicate that, although the food form of the PR breakfast meals had little, if any, effect on satiety, the appetitive responses were diminished and the subsequent food intake was greater when protein was consumed as a beverage v. a solid meal. [ABSTRACT FROM PUBLISHER]