Extrusion of food proteins

Abstract

Protein extrusion has frustrated earlier predictions regarding its impact in the development of food products. The main reason for this disappointing performance has been its failure to yield fabricated food products with textural quality close enough to that of natural products at competitive prices. Texturized soya protein by extrusion is presently the only commercial success in this area, being incorporated into several convenience products, increasing their protein content and quality and conferring them some desirable sensory properties. Technological and scientific gaps in the extrusion texturization are still to be bridged if this technique is to be applied for upgrading unconventional protein. The precise mechanisms responsible for protein texturization through extrusion are still unclear. Proteins show a very wide range of extrusion behavior that is probably related to large differences in their association properties. New peptide bonds, formed by free amino and carboxylic groups of the protein, were postulated as being responsible for the cross-linking that takes place in protein extrusion. However, disulfide bonds and electrostatic and hydrophobic interactions are regarded presently as the texturization mechanism in this process. The recently suggested suspension (or filled "melt") model for biopolymer extrusion offered a new framework for testing extrusion of novel proteins. According to this view, the large differences between the association properties of proteins produce different types of aggregates. Some of them can be insoluble under extrusion conditions and act as a dispersed phase within the melt phase. The extrusion performance of a protein will thus depend on the amount of insoluble aggregate produced inside the extruder and on protein-protein interactions that occur after the superheated molten mass leaves it.

New natural injection-moldable composite material from sunflower oil cake

“…Besides, further to the denaturation, the temperature can promote a set of association reactions involving the other protein fractions, the phenolic compounds, possibly the ligneous by-products released by the defibration of the husk fragments and sugars (Maillard reactions) (Arêas, 1992).…”

“…The use of a die was more restricting than effective and was thus not retained. Because of an important number of different interactions, proteins do not undergo a "melted" state (Arêas, 1992). The optimized screw profile for the SFOC treatment is described in Figure 1.…”

Twin screw extrusion of kodo millet-chickpea blend: process parameter optimization, physico-chemical and functional properties

“…Increase in ER leads to lower BD and hardness, thus expansion ratio, bulk density and hardness are inter-related. ER depends on starch content of the feed material, protein addition affects the ER inversely and increases hardness (Areas 1992), which shows that addition of protein to starch-rich flours results in the usual 'protein type' extrudates that are harder and expands less. Crispiness is inversely proportional to bulk density and hardness; expansion ratio does not seem to depict the crispiness.…”

Volatile compounds in the thermoplastic extrusion of bovine rumen

“…The process of extrusion employs high temperature and shear rate for a short time, and yields textured and expanded products such as breakfast cereals, snacks, textured vegetable proteins, pet foods, pasta, and confectionery: toffee, chewing gum, wine gums and jellies, taffy, hard candy and caramels, licorice and chocolate. [7][8][9][10] Rumen protein after extrusion can be used as a food ingredient, adding value to a series of comminuted products, especially meat products. Acceptability of this potential ingredient is dependant on several factors like texture, color and aroma.…”