Table 2.

Main hypotheses concerning meat analog structuring in extruders.

1	Structure formation occurs at three length scales:
	a)protein aggregate alignment at the nanoscale,
	b)second biopolymer phase elongation at the microscale, and
	c)phase separation of water via syneresis at mm scale.
2	For structuring a second biopolymer phase is not per se required, as a single protein phase already exhibits syneresis. But, the additional second biopolymer phase will improve texture via enhancing fracturing during eating.
3	Size of protein aggregate/fibrils at the nanoscale is controlled by balance between mechanical (shear) energy and thermal energy.
4	Elongation of the dispersed phase is governed by shear and elongational flow, following common rules for emulsions and biopolymer blends.
	This mainly happens in the transition zone between the screw section and the cooling die.
5	In the cooling die syneresis is induced by an increase in elasticity, due to a lowering of temperature, leading to a decrease in water holding capacity and subsequent expulsion of water.
6	Thermomechanical treatment above 120oC induces significant weakening of SS-bridges, and other non-covalent bonds between protein molecules, required for the alignment of aggregates into fibers.