Formation and characterization of plant-based emulsified and crosslinked fat crystal networks to mimic animal fat tissue

Abstract

Animal fat tissue (that is, pork or beef fat) is composed of liquid and solid fat incorporated in a network of connective tissue. Hence, their rheological and thermal properties may differ significantly from plant-derived fats. Specifically, animal fats have elastic and melting properties that give rise to not only a certain comminution behavior during processing, but also provide meat products such as sausages with certain organoleptic properties. To mimic key properties of animal fat tissue with plant-derived materials, a new structuring approach was used. Canola oil was mixed with <30% (w/w) of fully hydrogenated canola oil at 65 °C, hot-emulsified with a soy protein suspension (8%, w/w) at a lipid content of 70% (w/w) using a high-shear disperser, and cooled to 37 °C. The concentrated, emulsified fat crystal networks were then incubated with transglutaminase for 1 hr to induce protein crosslinking. Microscopy images showed that samples were composed of tightly packed lipid particles with regions of coalesced or unemulsified lipids appearing at higher solid fat concentrations. Texture analysis and rheological measurements showed that crosslinked samples possessed elasticities that decreased with increasing solid fat concentration. Above 30% solid fat, matrices reverted back to exhibiting a mainly plastic behavior. Results were attributed to the formation of either a droplet-filled protein network, a particulate fat crystal network, or a mixture thereof. Taken together, results show that plant-based crosslinked emulsified fat crystal networks are able to mimic mechanical properties of animal fat provided that not too much solid fat (<30% in this study) is used. This makes them useful for the manufacture of meat products or analogues. PRACTICAL APPLICATION: This study introduced a new structuring approach to mimic properties of animal fat tissue with only plant-derived materials. The structured lipids can, for example, be used for the manufacture of processed meat analogues.

Keywords: animal fat replacement; crosslinking; emulsion; fat crystal network; protein network.