Working with trained judges in a sensory panel, Meullenet
et al. (1994) reported that an increase in collagen fibers increases
toughness and decreases juiciness of chicken frankfurters, and they
also found good fits (no significant lack of fit) with amounts of water and collagen added to frankfurter batters for sensory hardness
(R2=0.82), even though the addition of pork collagen was manifested
in the quadratic term.