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Physics Nobel laureate Giorgio Parisi recently proposed a novel approach to cooking pasta that is more energy-efficient: Bring the water to a boil, add the pasta, cover the pot with a lid, and turn off the heat source. This heat-off-lid-on (hofflon) method saves energy. Other suggestions recommend soaking dried pasta in cold water to shorten the cooking process. However, there is a paucity of research examining the impact of different cooking methods on pasta texture and quality. In order to gain a deeper understanding of the effects of different cooking methods on the texture and strength of the pasta, a series of experiments were conducted. The experiments demonstrated significant variations in mechanical properties, adhesiveness, and cohesion. The hofflon method requires a longer cooking time due to the gradual decline in temperature. The process of soaking increases the water content of the pasta prior to cooking, which subsequently affects the behavior of proteins and starch when heated. These effects influence the manner in which proteins undergo alteration, the formation of cross-links, and the gelatinization of starch. Pasta prepared using the hofflon method exhibits reduced cohesion and softness, resulting in a texture that is softer and more mushy than that of al dente pasta. Presoaked samples display increased stickiness and a mushy texture when compared to pasta prepared using the classic method and hofflon pasta. The results of this study indicate the promise of developing straightforward models to illuminate the unique roles of proteins and starch during the structural transformation. [ABSTRACT FROM AUTHOR]

Introduction: Elephant foot yam starch is highly susceptible to enzymatic digestion. To address this, heat-moisture treatment (HMT) has been used to modify its digestive properties and functionalities. However, when using modified starch in various food compositions, it is ultimately necessary to cook it in waterrich environments. The present work thus offers a systematic understanding of the heating and cooking procedures for modified starch, with a view to maintaining its structural and digestive properties. Methods: Experimental investigations employing X-ray diffraction, scanning electron microscopy, and enzymatic digestion have been utilized to gain insights into the characteristics of cooked starches. The interactions between amylose and amylopectin in native starch are more susceptible to disruption during cooking, which results in changes in texture and a reduction in resistant starch (RS) retention. Additionally, these preparations have been investigated by tribology to test structure and and friction. Results and discussion: The application of HMT has been observed to induce changes that stabilize the interactions between amylose and amylopectin, thereby ensuring better maintenance of granular integrity and higher RS retention under specific cooking conditions. The findings indicate that following a 2-min cooking period at 100°C, the modified elephant foot yam starch (EFYS) demonstrated enhanced granular stability, which was subsequently compromised after 10 min of cooking. Additionally, when modified elephant foot yam starch (EFYS) was heated at a temperature of 86°C for 2 and 6 min, it demonstrated superior preservation of resistant starch (RS) in comparison to a cooking time of 10 min. Moreover, the HMT starch exhibited the highest RS retention when cooked at 100°C for 2 and 6 min at approximately 39.12% and 20.23%, respectively. However, this retention decreased significantly to 1.08% after 10 min of cooking. Furthermore, the insights from tribology, when combined with the proposed naive models, enhance the understanding of how preparation conditions affect the functionalities of starches, which is crucial for designing food products with desired textural and nutritional qualities, especially in water-rich environments, where maintaining structural integrity and RS content is important. [ABSTRACT FROM AUTHOR]

Oleosomes have emerged in the last decade as a multipurpose oil-in-water emulsion suitable for engineering new lipids materials. The need to increase alternative and sustainable methods to modulate the rheological properties of emulsions has been the leading research interest in the oleogelation field. Soybean oleosomes are evaluated as building blocks for creating oleogels in combination with sodium alginate or ι-carrageenan as the structuring elements. Polymer bridging provides a route to produce compact soft, malleable gels by exploiting attractive electrostatic interactions between negatively charged polysaccharides and oleosome surfaces. We investigated the viscoelastic properties of concentrated polymer bridged gels by oscillatory rheological measurements. The rheological characteristics are governed predominantly by the type of polysaccharide and by the ratio between polysaccharide and oleosome content. One yielding step at low strains indicates the breaking of polysaccharide bridging bonds and was visible in all samples. A two-step yielding process, where the second step corresponds to the cage-breaking process, was present at polysaccharide/oleosome ratios where optimum bridging occurs for alginate and carrageenan, 0.005 g/g, 0.01 g/g, respectively. Nonetheless, the bumps corresponding to the second yielding point were more prominent in alginate gels than in carrageenan gels due to the greater bridging ability of alginate. Identifying these rheological hallmarks could provide new ideas towards the improved design of plant-based fatty food products, e.g., cream cheeses and vegan sausages surrogates.

Introduction: Fluid gels exhibit a unique flow behaviour. Their pronounced viscoelastic behaviour arises from irregular microgel particles, leading to plasticity and yielding, as well as a characteristic transition from a solid to a fluid-like state. This is defined by both the core and the surface structures of the particles. Adding co-solutes such as sucrose alters the network properties at the molecular scale, affecting texture and lubrication. This study investigates how the microscopic changes due to sucrose addition correlate with macroscopic changes. Material and methods: Agarose fluid gels with varying sucrose concentrations were prepared and studied using the rheometer. Temperature dependent viscosity behaviour during gelation under shear was investigated in situ. Light microscopy and particle size measurements were examined, and complemented by amplitude, frequency and flow sweeps as well as tribological studies. These tests allow us to understand the influence of sucrose on the particle network formation. Results and discussion: Sucrose concentration influenced the sizes, shapes, and interconnected network structure of the microgel particles. These microstructural changes are closely related to the dynamic competition between gelation and disruption of the agarose chains during shear, which directly influences the rheological and tribological properties of the resulting fluid gels. Additionally, the association of the agarose chains and their gelation process is also influenced depending on whether the sucrose or agarose was first dissolved in water. The experimental observations suggest specific molecular mechanisms, explaining the role of sucrose in structure formation of agarose-based fluid gels. These results have the potential to expand the applications of fluid gels, which play a crucial role in modifying the texture and flow behaviour of foods and beverages, particularly in addressing challenges such as dysphagia. [ABSTRACT FROM AUTHOR]

Crystallization from highly supersaturated, agitated (sheared and stirred) solution is a highly non-equilibrium process. Despite being an often observed and intended process, basic scientific research on the rheology of such systems is lacking. This paper presents findings on changes in flow properties and particle formation during crystallization out of highly supersaturated sucrose solution under shear. For this, sucrose solution is subjected to steady shear in a plate-plate rheometer until a high crystal fraction is reached. Rheo-microscopy is performed in order to allow in situ visual observation of the crystal formation. These experiments show the complex interactions of crystal growth and rheological properties. While a high amount of hard particles is formed, the system changes from a homogeneous solution to a highly concentrated hard-particle suspension. At the same time, overall viscosity and loss modulus drop significantly, while the storage modulus rises during crystallization. In addition, image analysis is performed on microscopy images taken at different stages of the process. It confirms that significant decrease in viscosity coincides with major crystal growth, which is explained by the decrease in solute concentration in the continuous phase. [ABSTRACT FROM AUTHOR]

Supersaturated sucrose solutions that have been sufficiently cooled without nucleation represent a metastable system in which agitation promotes fast crystallization. Applications of this physically interesting process can be found, for example, in the production of fondants in confectionery. This work considers supersaturated sucrose–water solutions under agitation, different temperatures, and concentrations as simplified fondant model systems. Although simple in composition, such solutions undergo complex kinetic and thermodynamic processes during crystallization under agitation. Main attention is paid to the torque during constant kneading of the samples at controlled temperature, accompanied by light microscopic examination of a characteristic sample. All torque curves show a characteristic minimum followed by a sharp peak during crystallization, which are attributed to an interplay of changes in concentration of the continuous liquid phase, formation of big conglomerates, and breaking of largest particles during continued growth. When comparing the crystallization times with classical nucleation theory, it is found that the variations are related to temperature and supersaturation in the same way as given by induction time models of thermodynamics and statistical physics. [ABSTRACT FROM AUTHOR]

A simple method for structuring natural oleosome emulsions by polymer-bridging mechanism is proposed. Polymer bridging of oleosome droplets was induced by the addition of two different adsorbing polymers. Over a range of polymer/oleosome ratios, the mixture results in the formation of a particle gel network of aggregated oleosome droplets. It is found that polymer bridging ability is heavily influenced by the strength of binding between polymer and oleosome surface where sodium alginate interacted stronger to oleosome surface than ι-carrageenan. These effects are associated with the different molecular architecture and physical differences between the two hydrocolloids. Alginate has a co-block arrangement of charged and uncharged units. The polymer promotes stronger adsorption to the oleosome surface, in contrast to ι-carrageenan, where the negative charges are distributed uniformly along its chain. The polymer bridging ability will influence the resulting microstructure and therefore rheological properties. Confocal scanning laser microscopy showed that the difference in microstructure is mainly in the extent of heterogeneity over different length scales where sodium alginate produced the most heterogeneous microstructures. Bridging-flocculated emulsions showed power-law scaling behavior of the storage modulus with the oleosome concentration, which was explained using percolation theory. [ABSTRACT FROM AUTHOR]

Plant based meat surrogates attract increasing interest. Modern methods of biotechnology, food chemistry/technology, and process engineering allow for surrogates with high optical similarity. Nowadays, targeted molecular-sensory methods taste and smell to be largely approximated to the original products. Nevertheless, the products appear completely different on a molecular scale, which is clearly noticeable in texture, oral processing, friction, and bolus formation. A consequent physical consideration of the function and effects of the proteins of different origin reveals the strengths of the respective products and offers suggestions how sensory weak points can be understood better and avoided. This is illustrated here by means of exemplary examples and experiments joined with underpinned by molecular models. Meat sausages, vegetarian, and vegan surrogates are microscopically investigated by rheology, tribology, and tensile experiments. The interpretation of the results is illustrated and supported by simple models. [ABSTRACT FROM AUTHOR]

An analysis of food materials often involves characterization of the molecular composition of the food matrix and measuring its mechanical properties. However, there is a gap in understanding how food materials organize at the microscopic level. This article shows the application of minimally invasive coherent anti-Stokes Raman scattering (CARS) microscopy to visualize the fat distribution in duck liver-based products. Further, in combination with quantitative image analysis, CARS provides a viable route for understanding how food texture is related to food microstructure. Strong correlations were found between microscopic structural descriptors of the fat particle (abundance, shape, and size) and rheological and textural parameters (hardness, storage modulus). Foie gras was found to have an irregular shaped fat network connected via relatively weak links that yield under stress correlating with foie gras being harder, more elastic, and more brittle in comparison with a homemade duck liver pâté. In turn, the higher total number of fat particles, more round and smooth in shape, found in the pâté was responsible for it being softer and less prone to fracture. Understanding the relation between molecular composition, microscopic structure, and macroscopic texture provides opportunities for future modification of pâté formulation and/or a new preparation technique using microstructure as a texture indicator. [ABSTRACT FROM AUTHOR]

Using large scale molecular dynamics simulations we investigate the static and dynamic properties of a linear polymer melt confined between two solid surfaces. One of the walls is repulsive and the other is attractive wall. The bottom attractive wall is characterized by different degrees of roughness which is tuned by an array of short perpendicular rigid pillars with variable grafting density. We demonstrate that the conformations of polymers at the interfaces do not depend on substrate-polymer interactions, rather they show similar conformations of a single end-grafted chain under critical adsorption condition, consistent with the Silberberg's hypothesis. This observation is found to be in a good agreement with the analysis of the size distributions of trains, loops, and tails of melt chains at the walls known from the theoretical prediction of the end-grafted single chains at critical adsorption. Furthermore, we find that the pressure of the melt PN decreases as PN - P∞ ∝ N-1 with growing length of the chains N (where P∞ is the extrapolated pressure for N∝∞). Moreover, the surface tension γ near both walls is found to follow γ N ∝N-2/3. Eventually, the lateral dynamics near rough surface drops suddenly when the separation between the neighboring pillars becomes smaller than 2Rg, where Rg is the bulk radius of gyration. [ABSTRACT FROM AUTHOR]

Using a molecular dynamics simulation, we study the thermo-mechanical behavior of a model hydrogel subject to deformation and change in temperature. The model is found to describe qualitatively poly-lactide-glycolide hydrogels in which acrylic acid (AA)-groups are believed to play the role of quasi-mobile nodes in the formation of a network. From our extensive analysis of the structure, formation, and disintegration of the AA-groups, we are able to elucidate the relationship between structure and viscous-elastic behavior of the model hydrogel. Thus, in qualitative agreement with observations, we find a softening of the mechanical response at large deformations, which is enhanced by growing temperature. Several observables as the non-affinity parameter A and the network rearrangement parameter V indicate the existence of a (temperature-dependent) threshold degree of deformation beyond which the quasi-elastic response of the model system turns over into plastic (ductile) one. The critical stretching when the affinity of the deformation is lost can be clearly located in terms of A and V as well as by analysis of the energy density of the system. The observed stress-strain relationship matches that of known experimental systems. [ABSTRACT FROM AUTHOR]

We investigate the localization of a hydrophobic-polar regular copolymer at a selective solvent–solvent interface with emphasis on the impact of block length M on the copolymer behavior. The considerations are based on simple scaling arguments and use the mapping of the problem onto a homopolymer adsorption problem. The resulting scaling relations treat the gyration radius of the copolymer chain perpendicular and parallel to the interface in terms of chain length N and block size M, as well as the selectivity parameter χ. The scaling relations differ for the case of weak and strong localization. In the strong localization limit a scaling relation for the lateral diffusion coefficient D∥ is also derived. We implement a dynamic off-lattice Monte Carlo model to verify these scaling predictions. For chain lengths in a wide range (32≤N≤512) we find good agreement with the scaling predictions. [ABSTRACT FROM AUTHOR]

We present using simple scaling arguments and one step replica symmetry breaking a theory for the localization of semiflexible polymers in a quenched random environment. In contrast to completely flexible polymers, localization of semiflexible polymers depends not only on the details of the disorder but also on the ease with which polymers can bend. The interplay of these two effects can lead to the delocalization of a localized polymer with an increase in either the disorder density or the stiffness. Our theory provides a general criterion for the delocalization of polymers with varying degrees of flexibility and allows us to propose a phase diagram for the highly folded (localized) states of semiflexible polymers as a function of the disorder strength and chain rigidity. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]