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Binding agents have emerged as an important and required class of ingredients to manufacture a wide range of new food products, especially semi-solid or solid vegan meat and dairy analogues. In this review, we give a definition for this class of ingredients, look at what constitutes required functionalities for binders, and highlight what molecular mechanisms are involved to give rise to these functionalities. Furthermore, an overview on food binders, such as animal-derived/plant-based proteins (myofibrillar proteins, egg white protein, gluten etc.) and carbohydrate-based (methylcellulose, carrageenans etc.) is given and their functions are explained. Three functions have been identified as critically important: stickiness, hardening and water binding. Analytical methods to determine these characteristics are presented and it is recommended to study those simultaneously in model systems, where methylcellulose or gluten might serve as benchmark. [Display omitted] • Characteristics of binders in complex meat and dairy analogues have been defined. • Mechanisms of binder functionalities are explained. • Analytical methods to determine binder characteristics are outlined. [ABSTRACT FROM AUTHOR]

Abstract Whey proteins (WP) were replaced with rapeseed proteins (RP) at various protein mixing ratios at neutral pH and ionic strength of 150 mM. Protein gels were formed at 95 °C and another temperature of 80 °C, below the denaturation temperature of RP, to understand the importance of whether RP gelled or not for changes in rheological properties in mixed gels. Gels were analyzed for their microstructure, rheological responses (e.g. G') and water holding (maximum amount of exuded water (A max) and ease with which water can be exuded (k)). The rheological responses obtained for mixed gels was compared to the ones of the single systems at the corresponding concentrations to understand the importance of the rheological moduli of the single systems to the modulus of the mixed gel and to enable the quantification of synergistic stiffening (S = G΄ mixture /(G΄ WP + G΄ RP)). For gels formed at 95 °C a broader window for synergistic stiffening was formed compared to gels formed at 80 °C. Synergistic stiffening occurred when gel coarseness decreased and/or when the differences between the moduli of the individual protein gels were minimized. Water holding properties of mixed gels were tailored due to changes in the gel microstructure or due to synergistic stiffening. The behavior of k as a function of protein mixing ratio in mixed gels was similar to the behavior of gel stiffness. The decrease of k correlated well with an increase in gel stiffness. Gel coarseness and gel stiffness were inextricably linked in regards to their importance for changes in A max. Graphical abstract Image Highlights • Mixing selectively WP with RP results to tailored textural properties. • When gel coarseness decreases, synergistic stiffening is pronounced. • Synergy occurs when the rheological moduli of the individual gels are minimized. • Synergistic stiffening modifies water holding properties of mixed gels. [ABSTRACT FROM AUTHOR]

The effects of using different breadcrumbs (3 wheat, 2 gluten-free: pea and rice) to improve yield and modify the texture of a lean poultry product were evaluated. All breadcrumbs significantly reduced cooking loss (P < 0.05), with one of the wheat crumbs showing the best results (35% reduction). Light microscopy revealed that breadcrumbs were well connected to the cooked meat matrix, and fully hydrated, that is, forming well-structured composite gels. The presence of breadcrumbs resulted in lower hardness, chewiness, and gumminess values of 3 of the treatments (compared to the control with no breadcrumbs), while the other 2 did not affect those parameters. Overall, selected breadcrumbs that are commonly used in ground beef products can be employed to improve yield/modify texture in poultry products but have to be selected to address certain needs. [ABSTRACT FROM AUTHOR]

To design food products based on mixtures of proteins from animal and plant sources, understanding of how the structural and mechanical properties of mixed protein systems can benefit from selectively mixing is essential. Heat-induced gels were prepared from mixtures of whey proteins (WP) and soy proteins (SP) at different ratios and constant total protein concentration (10 w/w %). The effect of mixing on the aggregation phenomena (light scattering), mechanical response, and microstructure (CLSM, SEM) was investigated at ionic strengths of 0.1 and 0.3 M. Having similar gelation mechanisms, whey and soy proteins formed one network with both proteins contributing to the gel properties. With an increasing fraction of SP in the mixed protein gel, gel strength and stiffness decreased and water holding increased. In addition, a decrease in gel coarseness was observed, which was most significant for 0–3 w/w % SP fraction. A similar transition was also observed in the aggregation kinetics and aggregate size in dilute solutions. [ABSTRACT FROM AUTHOR]

The sensory perception of foods is directly related to gel morphology. The aim of this research was to investigate the relationship between gel water holding and stiffness for gels with a different morphology. Whey protein gels were prepared by varying ionic strength to create fine and coarse-stranded gels. These gels were characterized for their coarseness, stiffness and their water holding capacity. Fine gels were referred to typical coarseness length scale smaller than 0.1 μm and coarse gels were referred to coarseness length scale larger than 0.1 μm. Water holding was measured both as a function of time and of applied pressure. Increased gel coarseness length scale in both fine and coarse gels resulted in a larger extent of network deformation at a certain applied force. For fine gels, the coarseness length scale of the gel was shown to determine water removal. In the case of coarse gels, coarseness length scale and stiffness had a counteracting effect, but coarseness length scale was still dominant. These results show that the tuning of coarseness length scale of protein networks independent of stiffness or, the other way round, provides a tool to set the water holding capacity in food gels. [ABSTRACT FROM AUTHOR]

To understand the origin of water holding of mixed protein gels, a study was performed on water exudation from mixed whey protein (WP)-gelatin gels upon applied pressure. Mixed gels were prepared with varying WP and gelatin concentration and gelatin type to obtain gels with a wide range of gel properties. Gels were characterized for their water holding (maximum of exuded water, A max , and ease with which water can be exuded, k ), gel coarseness (from CLSM image analysis) and gel stiffness (Young's modulus) at 20 and 40 °C, below and above the melting temperature of gelatin. Gelatin caused an increase in gel coarseness of the WP network, as induced by phase separation between WP and gelatin. The effect of gel coarseness and gel stiffness on A max was found to be intertwined but above all, dictated by the gelatin concentration and gelatin network. At 20 °C, a transition point in gelatin concentration was observed above which stiffness surpassed coarseness in importance for A max . Above this concentration, gelatin dominates the mechanical response of the mixed system. At 40 °C, when gelatin is melted, coarser and less stiff networks, as set by the WP network, lead to higher A max . Tailoring of the coarseness and stiffness and therefore A max and k , can be achieved by selective mixing in terms of protein concentrations, and type of gelatin. By varying gelatin type from A to B, altered phase behavior leads to gels with higher coarseness and lower stiffness but similar A max . [ABSTRACT FROM AUTHOR]

To increase understanding of water holding in heat-set ovalbumin gels, the relation between aggregate structure (both in solution and in gels) and gel coarseness or gel stiffness is studied. The aggregate morphology obtained by preparation of ovalbumin gels between pH 5.8 and 6.8 differs, as shown by a combination of light scattering, confocal microscopy, electron microscopy and neutron scattering techniques. It is shown that with decreasing pH larger aggregates are formed that are more compact, indicated by the fractal dimension that increased from 1.9 to 2.6. Furthermore, larger, more compact aggregates at pH 5.8 as compared to pH 6.8 resulted in more coarse gels with a less merged microstructures. In addition, a lower gel stiffness is observed at lower pH. The combination of a higher coarseness and lower gel stiffness explains both the lower total water holding and the easier exudation of water from the gel upon applied forces. [ABSTRACT FROM AUTHOR]

In this paper we relate rheological properties of whole caseinate and various caseinate fractions to the improved water holding capacity of caseinate gels on which we reported previously. In that separate paper it was found that α s -casein (ASCN) enriched sodium caseinate (NaCN) fractions gave a substantially better water holding capacity. We hypothesized that this was due to the ‘telechelic’ character of ASCN. Here we systematically investigated the low shear rheology and viscoelastic properties as a function of concentration, salt content, pH and temperature. It was found that the ASCN enriched fraction had a considerably lower overlap concentration. The overlap concentration depends on the ‘bulkiness’ of a polymer but also on the interaction. By considering ASCN as a telechelic (two hydrophobic parts connected by a middle hydrophilic part) poly-electrolyte molecule it is understandable that ASCN has a considerably lower overlap concentration (0.058 w/w) than NaCN or β-casein, which both have an overlap concentration greater than 0.1 w/w. We tested the telechelic vis a vis the overlap concentration hypothesis by mildly cross linking NaCN and ASCN depleted NaCN using transglutaminase. Viscosity was increased by a factor 1.5 to 2 and found a lower overlap concentration by almost a factor of two. In a separate paper we also found that the water holding capacity of a caseinate gel depends directly on the cross linking of the gel, which may be physical e.g. by a telechelic ASCN, or chemical, though enzymatic cross linking. [ABSTRACT FROM AUTHOR]

To better understand sensory perception of foods, water exudation studies on protein-based gels are of a high importance. It was aimed to study the interplay of gel coarseness and gel stiffness on water holding (WH) and water flow kinetics from the gel once force is applied onto the material. Ovalbumin heat-set gels were used as a model system, where protein volume fraction was kept constant and ionic strength was varied to obtain a range of different gel morphologies and stiffness. WH of gels was measured both as a function of time and force applied. From experimental data (i) an effective gel permeability coefficient and (ii) an effective water flux coefficient were obtained and related to gel coarseness and stiffness. Gel coarseness determined maximum amount of water removed from the gel at defined conditions, where lower (≤0.1 μm) and upper (≥0.4 μm) limiting scales for water removal were identified. Gel stiffness is the major determinant for water removal kinetics from the gel. The combination of gel coarseness and gel stiffness showed a cooperative effect on gel WH. The insights can be exploited in product development to predict and tune oral perception properties of (new) products. [ABSTRACT FROM AUTHOR]

The water holding capacity of casein gels was investigated by measuring the swelling and de-swelling under a variety of conditions of temperature and salt concentration. Transglutaminase cross-linked sodium caseinate (15% w/w) gels will swell in good solvents or shrink in poor solvents until an equilibrium casein volume fraction is reached, and this is determined by the cross-link density. The results are interpreted using extended Flory–Rehner theory for weak polyelectrolytes. NaCl and CaCl 2 solutions tend to shrink the gels through the decreased Donnan pressure. In contrast, high volume fraction renneted casein (48% w/w) gels tend to swell in NaCl and CaCl 2 . These results are consistent with theory since the equilibrium volume fractions appear to be at an intermediate value (estimated about 20%). Experiments on casein micelles, which can be considered nano-gels, show the same behavior and trends. Physically cross-linked gels such as a highly concentrated renneted casein gel and casein micelles show the same (de-)swelling behavior. Cross-linked caseinate gels (15% w/w) have a lesser tendency to swell due to the lower casein volume fraction. Physically cross-linked gels will eventually completely dissolve in a good solvent. The results presented give a clear picture of the parameters that determine the equilibrium water content of a food polymer gel. [ABSTRACT FROM AUTHOR]

Abstract: The combined effect of blade tenderization (TD,NTD), pre-massaging (0 and 30min), moisture enhancement and post-injection tumbling (2h) on the chemical, binding and textural characteristics of pre-cooked roasts made from beef top round was investigated. Properties of the beef roasts were determined by measuring processing (i.e., cooking yield, expressible moisture (EM)) and textural characteristics (Warner–Bratzler shear, Kramer shear (KS), texture profile analysis). Brine injection helped to improve the cook yield and had the largest effect on tenderness of semimembranosus muscles. Post-injection tumbling did not significantly improve yield and textural properties of roasts; however, combined with the tenderization, it had beneficial effects on water holding and moisture retention. Pre-tumbling and blade tenderization treatments prior to injection generally were found to be beneficial for textural characteristics; pre-tumbling also tended to improve cook yield, but did not influence EM. However, no synergistic effect between these two variables was observed. An interaction between injection/tumbling and pre-tumbling was observed for KS. There was a significant improvement of KS values of roasts due to pre-tumbling observed for either non-injected roasts or those injected but without tumbling. However, no additional reduction in shear force was observed with pre-tumbling when roasts were tumbled after injection. This suggests that pre-tumbling may not be necessary to ensure more tender roasts when post-injection tumbling is applied, but would be beneficial for non-injected roasts or when tumbling is not applied after injection. [Copyright &y& Elsevier]

The combined effect of blade tenderization (T, NT) and tumbling time (0, 2, 16 h) on quality characteristics of cooked beef roasts processed with 20 or 40% injection level was investigated. Properties of the beef roasts were determined by measuring processing and textural characteristics (shear force, texture profile analysis). Extended tumbling (to 16 h) favorably affected hydration properties and thermal stability, yielding lower cooking loss and purge and higher WHC for beef roasts. It also decreased shear force and hardness of beef samples by 50–60%, but was unable to increase cohesiveness. Blade tenderization prior to injection generally was found to be beneficial for textural characteristics, tended to improve cook yield, but did not influence other hydration properties. An interaction between tenderization and tumbling was observed for shear force. Blade tenderization decreased shear values by 15–20% for roasts tumbled for 0 or 2 h, but did not improve tenderness with extended tumbling. [Copyright &y& Elsevier]

The aim of this study was to determine the influence of cutting methods on the fiber structure and quality attributes of the cooked pork loin muscle. The culinary portions were cut perpendicularly (D, diagonal) or along the muscle fibers (P, parallel). The samples were heated to 72 °C in water bath (85 °C or 95 °C), steam (100 °C), or oven (125 °C or 150 °C). The P samples had a significantly smaller cooking loss (2–4.5%), greater water-holding capacity (3–5%), and lower shear force (0.35–2.2 N) than D samples except for the 100P, whose cooking loss was higher (by 1.9%) than the 100D. Heat-induced structural changes in the muscle, sarcomere shortening, and destruction of the perimysium and endomysium were affected by the cutting methods and cooking conditions. The findings justify the advisability of cutting individual culinary portions from pork loin muscle in parallel to the muscle fibers in order to increase raw meat efficiency. [ABSTRACT FROM AUTHOR]

Hybrid model systems, containing pork shoulder meat and Zophobas morio larvae in different insect:meat ratios, were subjected to isothermal heating at 70 or 80 °C to investigate how this would affect the rheological behavior, water holding properties and textural properties of these model systems. Meat and insect model systems were also studied for comparison. Rheological and textural characteristics were significantly higher in meat model systems compared to insect and hybrid model systems. Furthermore, insect:meat ratio had little to no effect on the studied attributes of the hybrid model systems. It was also demonstrated that heating the hybrid model systems at 80 °C resulted in similar viscoelastic and water holding properties compared to meat model systems heated at 70 °C. However, even when heated at this higher temperature, the maximum force measured during penetration of the hybrid model systems was still approximately 3 times lower compared to meat model systems. This study investigated the effect of insect:meat ratio and heating temperature on structure formation and water holding in hybrid model systems. The results offer important insights with regard to the composition and processing of hybrid meat products. They indicate that similar viscoelastic and water holding properties compared to meat products may be obtained by applying higher heating temperatures. However, results showed that obtaining the desired texture may pose an important challenge when developing hybrid meat products. • Structure formation and water holding in hybrid model systems was studied. • Overall, meat model systems showed better properties than hybrid model systems. • Insect:meat ratio had little to no effect on the properties of hybrid model systems. • Hybrid model systems had good viscoelastic and water holding properties at 80 °C. • Hybrid and insect model systems had poor textural properties at 70 and 80 °C. [ABSTRACT FROM AUTHOR]