Combine tangerine juice, 1/4 cup of the lemon juice, lime juice, chicken broth, garlic, honey and sugar in a heavy saucepan over high heat.

Boil until slightly syrupy and reduced to 1 cup, about 15 minutes.

Set tangerine sauce aside. (Can be made up to 1 day in advance. Cover and refrigerate, then rewarm before using.)

Whisk together egg whites, arrowroot, remaining 2 tablespoons lemon juice, salt and cayenne pepper in a large bowl until blended.

Add scallops and toss to coat.

Place sesame seeds in a wide, shallow dish.

One by one, dip the scallops in the sesame seeds, coating all sides.

Transfer scallops to a nonstick baking sheet as done and set aside.

Heat oil in a large nonstick skillet over medium high heat until very hot.

Carefully add half of the scallops to the hot skillet, partially covering the skillet with a lid to lessen the splattering.

Sear scallops until golden, about 2 minutes.

Turn scallops over and continue to sear the other side for 2 minutes more, or until golden on the outside and just opaque on the inside.

Transfer to a plate. Repeat with remaining scallops and reserve skillet.

Put 1/3 cup water and 1/4 cup of the reserved tangerine sauce into skillet and bring to a boil.

Add bok choy and cover.

Reduce heat to low and steam for 2 to 4 minutes, or until the bok choy is just tender and bright green.

Remove from the heat and toss bok choy in skillet to coat in sauce.

Transfer bok choy to individual plates, then arrange scallops on top.

Drizzle with remaining tangerine sauce and serve.