The primary ingredients in Japanese sauce are vegetables and fruits, to which vinegar and many spices are blended. This had the effect of deepening the richness and increasing the appetite. Japanese tonkatsu sauce uses a lot of vegetables and fruits like tomatoes and apples, which make it a highly viscous sauce well suited for deep-fried foods, without getting them greasy or soggy.
This breaded meat dish and sauce made from vegetables, fruit, vinegar, and spices pair well with the delicate Japanese staple food white rice. Likewise, the sourness of the sauce gives heavy fried foods a taste that is refreshing and easy to eat.