Micro-foaming of plant protein based meat analogues for tailored textural properties

Meat analogues: The relationship between mechanical anisotropy, macrostructure, and microstructure

Texture of meat analogues is crucial for consumer acceptance, yet it remains poorly defined, but it known that it is influenced by mechanical properties and structure at different length scales. This study describes the relationships between macrostructure, microstructure, and mechanical anisotropy in meat analogues. Two distinct meat analogue product sets are produced with shear cell technology varying in formulations and processing conditions to obtain a wide range of product structures: one based on mung bean protein-rich fractions and the other based on combinations of soy protein isolate and pectin. Mechanical properties are assessed using tensile testing, microstructure is studied using X-ray tomography and confocal laser scanning microscopy, and macrostructure is quantified using a computer vision algorithm based on segmentation and shape features. Both correlation analyses on the response parameters and parameter variance are studied to distinguish the product sets. Strong correlations are found between anisotropy-related parameters, such as fibre score in macrostructure, air anisotropy in microstructure, and the toughness anisotropy index from mechanical properties. Some correlations are found to be product-set independent, such as air bubble anisotropy and fibre score, indicating universal relationships within this study, while other correlations are product-set dependent, such as between fibre score and the anisotropy index of the Young's Modulus in the mung bean fine fraction product set. The relationship between microstructural air bubbles and macrostructure and mechanical properties is apparent in all correlation analyses. Last, univariate feature selection provided insight into which parameters are most important for selected target features.

Tenderness in meat and meat alternatives: Structural and processing fundamentals

The demand for meat alternatives based on ingredients sourced from nonanimal materials with equivalent quality of muscle tissue is increasing. As more consumers switch to meat alternatives, a growing body of research has investigated the tenderness and related texture attributes in plant-based meats to increase consumer acceptance. A deeper understanding of tenderness including the differences and similarities between meat and meat alternatives is crucial to developing products that meet consumer expectations, as it directly influences consumer acceptance. Meat tenderness is commonly quantified using sensory evaluation and instrumental tests and is influenced by various factors such as the intrinsic features of the animal before the slaughter, naturally occurring proteolysis during the post-slaughter process, and several tenderization techniques. In contrast, meat alternative tenderness can be actively tailored through the selection of ingredients and the operating conditions of the structuring process. Especially, extrusion parameters such as moisture content and barrel temperature can greatly modulate tenderness-related attributes. Postprocessing methods that have traditionally been utilized for tenderizing have also been applied to meat alternatives, but more studies are needed to fully reveal the underlying mechanisms. This review offers an overview and critical discussion on tenderness, covering the structural origins, influencing factors, analytical methods, oral processing, and tenderization processes for both meat and meat alternatives. The discussion is based on the existing knowledge of muscle tissue, which evolves to critically reviewing how this understanding can be applied to the textural attributes of meat alternatives and what kind of novel tenderization techniques can be developed for these new sustainable food products.

Perforated imprinting on high moisture meat analogue confers long range mechanical anisotropy resembling meat cuts

Meat cuts, when cooked and masticated, separate into fibrous structures because of the long-range mechanical anisotropy (LMA) exhibited by muscle fascicles, which is not fully recapitulated in alternative proteins produced using molecular alignment technology like high moisture extrusion. We have developed a scalable perforated micro-imprinting technology to greatly enhance LMA in high moisture meat analogue (HMMA). By imprinting 1 mm thick HMMA sheets with perforated patterns (optimized by AI), we observed up to 5 × more anisotropic separation of fibrous structures in a one-dimensional pulling LMA analysis, to match the fibrousness of the cooked chicken breast, duck breast, pork loin and beef loin. We stacked and bound imprinted sheets with transglutaminase (TG) to produce imprinted whole-cuts. Controlling fiber separation in the imprinted cuts achieved hardness ranging from 6578 g to 18467 g (2 cm × 2 cm × 1 cm, 50% strain), which matched meats from different species. Imprinted cuts improved meat-like fiber separation over HMMA when masticated, measured by Euclidean distances (0.057 and 0.106 respectively) to animal meat cuts on image features. In sensory evaluation, imprinted cuts improved consumer acceptance by 33.3% and meat-like fibrousness by 20%, by significantly enhancing the HMMA appearance, texture, and mouthfeel.

Enzymatic degradation of pea fibers changes pea protein concentrate functionality

Pea proteins are gaining increased interest from both the food industry as well as from consumers. Pea protein isolates (PPI) excel at forming meat-like textures upon heating while pea protein concentrates (PPC) are more challenging to transform into highly sought-after foods. PPCs are richer in dietary fibers (DF) and are more sustainable to produce than PPI. In this work, degradative enzymes were used to modify the functionality of PPC-water blends with a focus on texturization upon heating. Three enzyme solutions containing β-glucanases, hemicellulases, pectinases, xylanase, and cellulases were added to 65 wt% PPC blends. The effect of these enzymatic pretreatments was measured by monitoring the torque in a mixing reactor during blending, differential scanning calorimetry (DSC), high-pressure shear rheology (HPSR), and DF content and size analysis. Four endothermic peaks were detected in the DSC thermograms of PPC, namely at 63 °C, 77 °C, 105 °C and 123 °C. The first three peaks were attributed to phase transition and gelation temperatures of the starches and proteins constituting PPC. No endothermic peaks were measured for PPI blends. Enzyme solutions containing β-glucanases, hemicellulases, pectinases, and xylanases increased the endothermic energy of all peaks, hinting at an effect on the gelation properties of PPC. The same enzymes decreased the resistance to flow of PPC blends and induced a shift of the weight average molecular weight (Mw) distribution of soluble dietary fibers (SDF) towards smaller values while increasing the fraction of SDF by decreasing the insoluble dietary fiber (IDF) content. The solution containing cellulases did not change the DSC results or the viscosity of the PPC mixture, nor did it affect the IDF and SDF contents. On the other hand HPSR measurements of heated PPC samples up to 125 °C showed that all tested enzyme solutions decreased the complex viscosity of PPC-water blends to values similar to PPI-water blends. We demonstrated that degradative enzymes can enhance the functionality of less refined protein-rich ingredients based on pea and other vegetal sources. Using optimized enzyme blends for targeted applications can prove to be a key changer in the development and improvement of sustainable protein-rich foods.

Structural and mechanical anisotropy in plant-based meat analogues

The rising demand for plant-based meat analogues as alternatives to animal products has sparked interest in understanding the complex interplay between their structural and mechanical properties. The ability to manipulate the processing parameters and protein blend composition offers fundamental insights into the texturization process and holds economic and sustainable implications for the food industry. Consequently, the correlation between mechanical and structural properties in meat analogues is crucial for achieving consumer satisfaction and successful market penetration, providing comprehensive insights into the textural properties of meat analogues and their potential to mimic traditional animal produce. Our study delves into the relationship between structural and mechanical anisotropy in meat analogues produced using high moisture extrusion cooking, which involves blending protein, water, and other ingredients, followed by a controlled heating and cooling process to achieve a fibrous texture akin to traditional meat. By employing techniques such as scanning small-angle X-ray scattering, scanning electron microscopy, and mechanical testing we investigate the fibrous structure and its impact on the final texture of meat analogues. We show that textural and structural anisotropy is reflected on the mechanical properties measured using tensile and dynamic mechanical techniques. It is demonstrated that the calculated anisotropy indexes, a measure for the degree of textural and structural anisotropy, increase with increasing protein content. Our findings have significant implications for the understanding and development of plant-based meat analogues with structures that can be tuned to closely resemble the animal meat textures of choice, thereby enabling consumers to transition to more sustainable dietary choices while preserving familiar eating habits.