  In this manuscript we propose, analyse, and discuss a possible new principle
behind traditional cuisine: the Food-bridging hypothesis and its comparison
with the food-pairing hypothesis using the same dataset and graphical models
employed in the food-pairing study by Ahn et al. [Scientific Reports, 1:196
(2011)].
  The Food-bridging hypothesis assumes that if two ingredients do not share a
strong molecular or empirical affinity, they may become affine through a chain
of pairwise affinities. That is, in a graphical model as employed by Ahn et
al., a chain represents a path that joints the two ingredients, the shortest
path represents the strongest pairwise chain of affinities between the two
ingredients.
  Food-pairing and Food-bridging are different hypotheses that may describe
possible mechanisms behind the recipes of traditional cuisines. Food-pairing
intensifies flavour by mixing ingredients in a recipe with similar chemical
compounds, and food-bridging smoothes contrast between ingredients. Both
food-pairing and food-bridging are observed in traditional cuisines, as shown
in this work.
  We observed four classes of cuisines according to food-pairing and
food-bridging: (1) East Asian cuisines, at one extreme, tend to avoid
food-pairing as well as food-bridging; and (4) Latin American cuisines, at the
other extreme, follow both principles. For the two middle classes: (2)
Southeastern Asian cuisines, avoid food-pairing and follow food-bridging; and
(3) Western cuisines, follow food-pairing and avoid food-bridging.
