Tuning texture and serum release in meat analogues

Plant-based meat analogues play a vital role in the transition toward more sustainable protein sources. Yet, their sensory qualities, particularly texture and juiciness, often fall short compared to conventional meat. These attributes depend on the mechanical behaviour of the product and the release of serum (water and oil) during consumption. Developing a better mechanistic understanding of these functional properties and how they can be modulated is crucial for improving the quality of meat analogues. Therefore, this PhD thesis investigated how the three primary bulk ingredients—textured vegetable protein (TVP), oil, and binding agents—affect the mechanical, lubrication, and serum release properties of meat analogues.

In Chapter 2, structural characteristics of TVP such as porosity, pore size and wall thickness were quantified using X-ray microtomography. TVPs with thinner walls and higher porosity absorbed and retained more water, while those with thicker walls absorbed water faster, but in smaller quantities. When incorporated into meat analogues, TVPs with lower water-holding capacity caused greater serum release under compression, and TVPs with smaller pores produced stiffer products. These findings showed that the structural characteristics of TVPs influenced their rehydration behaviour and specific functional properties of patties made with them.

Chapter 3 investigated how oil release could be controlled through emulsion design. The role of oil droplet size and surface properties was studied using emulsions stabilised with different emulsifiers. Whey protein isolate and sodium dodecyl sulphate produced tightly integrated, active filler droplets that released only under mechanical stress. In contrast, lecithin-stabilised oil droplets acted as inactive fillers, and were partly released already during heating and more extensively under mechanical stress. This greater oil release for inactive filler droplets, particularly evident at small oil droplet sizes, underscores the importance of oil droplet mobility in oil release from the meat analogue matrix.

Chapter 4 investigated the gelation behaviour of mixtures of methylcellulose and plant proteins. Pea protein isolate (PPI) formed microphase-separated inclusions within methylcellulose gels, increasing syneresis without affecting gel strength. Potato protein isolate (PoPI) acted as a dispersed phase at low concentrations and formed a bicontinuous network with methylcellulose at higher concentrations, strengthening the gel and preventing syneresis through improved water retention. Overall, these findings highlighted that protein characteristics had a broad impact on gel structure, mechanical strength and syneresis behaviour, whereas the molecular weight of methylcellulose primarily affected syneresis.

Chapter 5 assessed the lubrication behaviour of meat analogues and the role of serum release in lubrication. Model systems showed that methylcellulose and oil droplets effectively lubricated oral surfaces, while proteins had negligible impact. In actual meat analogue boli, higher moisture, softer, and more adhesive textures led to higher friction coefficients. The results indicated that bolus texture, rather than serum release properties, dominated frictional behaviour during mastication.

Overall, this thesis demonstrated that serum release, mechanical and lubrication properties in meat analogues can be systematically tuned through targeted structural design, e.g., by controlling TVP microstructure, emulsion characteristics, and gelation behaviour of binding agents. These insights provide clear routes to developing plant-based meat products with improved sensory quality.