1 1/2 pounds pork tenderloin
1/4 cup orange juice, fresh
1/4 cup grapefruit juice, fresh
2 tablespoons cilantro, chopped
1 teaspoon cumin
1 teaspoon dried oregano
2 cloves garlic, finely chopped
1/2 teaspoon kosher salt
1/2 teaspoon red pepper flakes
Using thin knife, trim silver skin from tenderloin. Mix orange juice, grapefruit juice, cilantro, cumin, oregano, garlic, salt, and hot pepper in gallon-sized zip-top plastic bag. Add pork, close, and refrigerate for at least 30 minutes and up to 4 hours.
Prepare outdoor grill for direct medium-hot grilling. For a gas grill, preheat grill on high. Adjust temperature to 400 degrees F. For a charcoal grill, build fire and let burn until coals are covered with white ash. Spread coals and let burn for 15-20 minutes.
Lightly oil cooking grate. Remove pork from marinade, drain briefly, but do not scrape off solids. Place on grill, cover grill. Cook, turning occasionally, until browned and instant-read thermometer inserted in center of pork reads 145 degrees F, about 20-27 minutes. Transfer to carving board and let stand 3-5 minutes. Cut on slight diagonal and serve.
Per Serving: cal. (kcal) 140, Fat, total (g) 3, chol. (mg) 75, sat. fat (g) 1, carb. (g) 3, fiber (g) 0, pro. (g) 24, sodium (mg) 220, Percent Daily Values are based on a 2,000 calorie diet