Fun Weekend Project: Cranberry Swirl Loaf phase II

Thank you for tuning in =)

This morning, I began my experiment of making a cranberry loaf from 500 Best Muffin Recipes (author: Esther Brody). I know, the recipe was supposed to be for muffins, however there was one recipe that inspired me to turn it into a loaf. So here I am. Unfortunately, it didn't turn out quite as marvelous as I had expected! It almost didn't rise and I think I used too much cranberry sauce. I was expecting nice swirls as the loaf is being sliced What I found were splotches of wet cranberry sauce.. Boo.. I think I have to say that I failed this project. The end result was still edible though.

One thing I really need right now is an advice on how to make my loaf better next time. FYI, I substituted shortening with vegetable oil, the egg white was cold from the fridge, the lemon juice was additional (not from the original recipe) and perhaps I did overmix. You can analyse further by seeing the recipe below:

Cranberry Swirl Muffin (Loaf)
1/4 cup shortening
1/2 cup sugar
2 egg whites
1 1/2 cup all purpose flour
1 tsp baking powder
1/2 tsp salt
3/4 cup milk
1/2 lemon, squeezed
1/2 cup cranberry sauce

Direction:
Preheat oven to 400 degrees F (350 degrees for loaf)
1) In a bowl, cream together shortening and sugar. Add egg whites, beat until fairly smooth.
Add flour, baking powder, salt, lemon juice and milk; stir just until blended.
Add cranberry sauce, swirl with your spatula.
2) Spoon the batter into prepared muffin tin (or pour into a loaf pan).
Bake for 20 minutes until golden brown (1 hour for loaf)

There you are!
Where did I go wrong?
Does the egg white have to be at room temperature? Why is that?
It won't be enough if I don't show you the pictures of my loaf. Although I think I failed this, they still look yummy and edible =P

~ Before Baking ~

~ After Baking ~

Notice that the end result is very dense with small air holes. Not soft and spongey as I expected =(
Help. Anyone?