To bake tenderloin:
sprinkle with salt and pepper
wrap in aluminum foil
For a small (1 1/2 in. diameter) tenderloin bake 1 1/2 to 2 hours at 350 degrees. Cool and slice.
For Sauce heat in a sauce pan:
1 cup pineapple juice
3/4 cup water
1/4 cup vinegar
1 Tbsp. soy sauce
1/4 cup brown sugar
1/2 tsp. salt
Bring to a boil. In a small cup mix 2 Tbsp. cornstarch and 2 Tbsp. cold water. Stir into the hot sauce mixture to thicken.
Add sliced port to sauce and serve over hot cooked rice.