Fu
Fu is wheat gluten, a Japanese ingredient that’s been eaten for centuries. Historically, it was used as a protein source for vegetarians, especially under the Buddhist shojin ryori diet, and for kaiseki tea ceremony foods.
Today, there are two main types of fu: nama-fu, and yaki-fu. Nama-fu is raw while yaki-fu is leavened and dry-baked. Yaki-fu is more widely available, especially in the US, given its longer shelf-life and ease of distribution. Between these two types of fu, there are subtypes often differentiated by shape or other ingredients.
Fu has a very neutral flavor and readily absorbs the flavors of other ingredients, marinades, and broths that it’s cooked with. Texturally, with it being primarily gluten — i.e. wheat protein — it has a similarly meaty bite and mouthfeel. Together, that makes fu popular in soups and hot pots, especially dashi-based ones that are savory but rather delicate, where it adds texture and soaks up the flavor of the stock without contributing intense flavors that could overwhelm the rest of the ingredients.
As it’s essentially just wheat protein with few other additives — sometimes mochiko rice flour, for example — fu is, naturally, extremely high in protein.
You can find fu at Uwajimaya stores in our Grocery department.