Aggregation behavior of solubilized meat - Potato protein mixtures

The interplay of muscle and pea proteins in low-salt gels: An insight into in situ structure formation in hybrid meat alternatives

The present study investigated thermal gelation of mixed sarcoplasmic (Sarc), myofibrillar (Myof), and pea proteins corresponding to partial meat replacements (0, 25, and 50%) by pea protein isolate (PPI) at reducing salt levels (0.6 → 0.1 M NaCl) to understand in situ (simulated) structure-forming properties of hybrid meat analogues. The amount of soluble proteins in hybrids generally increased with salt concentrations and PPI substitution. While muscle proteins (mixed Sarc and Myof) had the strongest gelling capacity, hybrid proteins also exhibited moderate aggregation and gelling activity based on the sol→gel rheological transition and gel hardness testing. Sarc and pea 7S/11S globulins collectively compensated for the attenuated gelling capacity of mixed proteins due to diminishing Myof in the hybrids. Immobilized water within hybrid protein gels was tightly bonded (T2 from nuclear magnetic resonance), consistent with the dense and uniform microstructure observed. These findings offer a new knowledge base for developing reduced-salt hybrid meat analogues.

Effect of insoluble dietary fiber on printing properties and molecular interactions of 3D-printed soy protein isolate-wheat gluten plant-based meats

Insoluble dietary fiber (IDF) has been characterized to prevent chronic diseases and improve gastrointestinal health, and it has been added to 3D printing plant-based meats (PM) to enhance texture and increase nutritional properties. Therefore, the aim of this study was to investigate the effects of IDF on 3D printing properties and molecular interactions of soy protein isolate (SPI) - wheat gluten (WG) PM. Without the participation of IDF, PM appeared to collapse. When the IDF concentration increased from 0 to 10 %, PM displayed good printing properties, water holding capacity, tensile strength, and elongation at break were increased. Tensile strength and elongation at break reached a maximum at 10 % IDF, and clearly similar results were found for texture attribute indices such as hardness, gumminess, chewiness, and cohesiveness after cooking. All printing inks exhibited shear-thinning behavior and solid-like viscoelasticity, but the structural recovery properties of 3D-printed PM deteriorated when the IDF content was over 10 %. Intermolecular forces indicated that the addition of IDF enhanced the disulfide bonds so that 10 % IDF presented better printing properties. These results indicated the potential for developing PM with dietary fiber functionality through 3D printing technology.

Meat color and iridescence: Origin, analysis, and approaches to modulation

Meat color is an important aspect for the meat industry since it strongly determines the consumers' perception of product quality and thereby significantly influences the purchase decision. Emergence of new vegan meat analogs has renewed interest in the fundamental aspects of meat color in order to replicate it. The appearance of meat is based on a complex interplay between the pigment-based meat color from myoglobin and its chemical forms and light scattering from the muscle's microstructure. While myoglobin biochemistry and pigment-based meat color have been extensively studied, research on the physicochemical contribution of light scattering to meat color and the special case of structural colors causing meat iridescence has received only little attention. Former review articles focused mostly on the biochemical or physical mechanisms rather than the interplay between them, in particular the role that structural colors play. While from an economic point of view, meat iridescence might be considered negligible, an enhanced understanding of the underlying mechanisms and the interactions of light with meat microstructures can improve our overall understanding of meat color. Therefore, this review discusses both biochemical and physicochemical aspects of meat color including the origin of structural colors, highlights new color measurement methodologies suitable to investigate color phenomena such as meat iridescence, and finally presents approaches to modulate meat color in terms of base composition, additives, and processing.

Effect of high intensity ultrasonic treatment on structural, rheological, and gelling properties of potato protein isolate and its co-gelation properties with egg white protein

The study aimed to investigate the effect of high intensity ultrasonic (HIU) treatment at different times (0, 10, 20, and 30 min) on the structure and gel properties of water-soluble potato protein isolate (WPPI) and to further investigate the improvement of gel properties of ultrasonicated WPPI (UWPPI) by the addition of egg white protein (EWP). HIU reduced the particle size of WPPI, whose structure became loose and disordered, which improved gelling properties of UWPPI. Fourier transform infrared results indicated that α-helix content decreased, whereas the proportion of irregular curl increased with the increase in ultrasonication time (0-20 min), indicating that the initially ordered structure of UWPPI became disordered. After HIU treatment, the free sulfhydryl groups of UWPPI and surface hydrophobicity decreased and fluorescence intensity increased. These results demonstrated that the HIU loosened the structure of UWPPI, exposing more chromogenic groups while embedding more hydrophilic groups. After thermal induction, UWPPI gel hardness increased and exhibited excellent water holding capacity. After the addition of EWP, rheological properties stabilized, and the hardness of UWPPI-EWP gels increased significantly, forming internally structured protein gels with a tightly ordered structure and increased brightness. Thus, HIU changed the structure and gelling properties of WPPI, and the addition of EWP further enhanced the performance of hybrid protein gels. PRACTICAL APPLICATION: High intensity ultrasonic changed the structure of water-soluble potato protein isolate (WPPI) and improved the properties of WPPI gels. The addition of egg white protein significantly improved the quality of mixed protein gels which showed great potential industrial value.

Influence of wet extrudates from pumpkin seed proteins on drying, texture, and appearance of dry-cured hybrid sausages

Hybrid meat products represent a promising, more sustainable alternative to all-meat formulations. However, differences among plant- and animal-based proteins may alter traditional handling and final product properties. In this study, pork meat was partially replaced with texturized pumpkin seed proteins at 12.5, 25, 37.5, and 50% to obtain dry-cured hybrid meat sausages and their ripening (acidification, drying) during 21 days and final product properties (texture, sensory) were characterized and compared to a control (all-meat formulation). The drying behavior and distribution of moisture and free water of hybrids with extrudate contents of 12.5 and 25% were comparable to the sample made with meat and no significant (p > 0.05) differences in proximate composition were found. In contrast, higher meat replacement levels resulted in distinct changes of compositional and textural attributes i.e. chewiness was decreasing by up to 70%. Results suggested 25% of extrudates as an important threshold in manufacture of hybrid dry-cured sausages due to alterations in their ability to bind or release water. Results may be used to understand the influence of alternative texturized proteins in hybrid formulations and help product developers to understand related process and product relevant changes.

Effect of varying pH on solution interactions of soluble meat proteins with different plant proteins

The exchange of animal-based for plant-based proteins is becoming more and more popular due to an increasing demand for alternative and more sustainable protein sources. In this study, solubilized water- (ws) or salt-and-water (sws) meat proteins were evaluated in their pH-dependent interactions with soluble protein fractions from wheat, pumpkin, sunflower, rapeseed, or potato proteins. For this purpose, 1 : 1 (v/v) mixtures of 1.0 wt% meat (ws or sws) and plant proteins were prepared at a sodium chloride concentration of 1.8 wt% (ionic strength: 0.31 mol L^-1) and adjusted to different pH-values in between 4.5-7.0. While only slight differences were found upon comparison of interactions of ws and sws batches (p > 0.05), interactions among these animal-based and soluble plant proteins took place. First, optical observations, light microscopy, and SDS-PAGE revealed increasing protein solubility with increasing pH. Second, particle size distributions (PSDs) revealed a shift towards slightly larger particle sizes e.g. at pH 5.3 and 7.0 with d_4,3 of 43.2 and 21.3 μm (sws) to 45.4 and 23.9 μm (sws + potato), respectively. Furthermore, heat-induced gel formation was improved at pH > 6.0, in particular in mixtures of meat and wheat or rapeseed proteins that formed a homogenous gel structure. Based on the obtained results, protein-protein complexations mainly by electrostatic forces are suggested which occur due to various pI of meat and plant proteins e.g. pH 7.5 (wheat), 7.2 (potato), and 6.6 (rapeseed) in comparison to 5.1 (ws) and 5.6 (sws). The filamentous microstructure of some gels (soluble fraction of rapeseed, potato and wheat proteins) led to the assumption that meat proteins, mainly at pH values greater than 5.8 (optimally ≥6.5), had a structuring effect on plant proteins.

Impact of replacing pork backfat with rapeseed oleosomes - Natural pre-emulsified oil - On technological properties of meat model systems

The application of natural oil droplets called oleosomes (OSs) as a potential fat replacer in comminuted meat products was investigated by evaluating the influence of rapeseed OS incorporation at 0, 25, 50, 75 and 100% pork fat substitution levels on the technological properties of meat model systems. The moisture content, pH, L* and b* of meat model systems increased while the fat content and a* decreased with the increasing levels of fat replacement. Treatments prepared with OSs showed improvements in emulsion and oxidative stability of meat batters. Texture profile analysis revealed the production of softer, less gummy and less chewy meat systems, whereas micrographs showed smaller-sized fat globules within compact protein matrices as OS levels were increased. Sensory evaluation results exhibited that treatments with partial replacement (≤ 50%) of pork fat by OSs were generally acceptable. The results demonstrate the possibility of maintaining or improving certain technological properties of meat systems with the use of OSs as fat replacer.