Original photo from: Sugarcharms
What are those green plastic cut-outs in bento boxes for?
This is one question that I never got to ask when I was in Japan, thinking that the answer was fairly obvious – as food decoration. But one American visitor to Japan did, and apparently there’s more to this “bento grass” (haran or baran) than meets the eye:
They are indeed intended to add color, an essential part of food presentation in Japan, but as you guessed, there’s more to it than that.
I took your question to Ayao Okumura, a chef, food consultant and cookbook author with a keen interest in the history of cooking. He explained that a variety of dividers, including plastic grass, are used when making bento to prevent assertive flavors from seeping from one tidbit into another. Separating foods also slows bacterial growth, thus extending the shelf-life of these highly perishable prepared meals.