[CH] OTOT (Off Topic; On Tofu)
George Nelson (70431.3065@compuserve.com)
Wed, 20 Nov 2002 08:26:02 -0500
Discussion about tofu and jerky got me thinking about the differences
between tofu and TVP. Their behavior has a lot to do with how they are
made. Tofu is coagulated from soy milk by the addition of a calcium or
magnesium salt solution. The change of ionic strength re-orients the
protein so it becomes insoluble and begins to aggregate in flakes and
globes. These simply stack together pushing the water out. The tofu maker
collects them in a cheesecloth and presses more of the water out to make
bricks. Choice of the coagulating salt composition, pressure applied and
drying time dictates whether the tofu is firm or soft.
TVP is made somewhat the same way except it is pressed through spinnerets
to make fibers into a curing solution that hardens their exterior somewhat
by promoting more chemical linking at the surface. This gives it more
structure, making it more fit for veggie burgers, chili and jerky, but it
also significantly reduces its ability to absorb water (and flavors from
the surroundings).
Tofu, with its looser packing of essentially spherical particles that can
pick up and release water easily, has no structure to it, but it can pick
up flavors into the mass either by absorption on the surface or by
infiltration into the particles themselves. This makes it fail in jerky
since there is no fibrous structure; it simply falls apart when rehydrated.
This property does make it excellent in soups, though. Rael's use of it as
a substitute for fat in desserts is innovative, but we expect that from a
redneck (once-upon-a-time) cook in Idaho. I may try adding some in my next
Chile Verde to see if it adds some wholesome "stick-to-your-ribs" fullness.
George Nelson