I would not call a 90x110cm Elinchrom softbox “portable”, however I set for myself the limit of one light source or when I want to shoot food outside of my studio, and albeit I tried and get the results that I wanted with a beauty-dish reflector (smaller and sturdier), I decided I would not settle for less than my biggie.
However, since I still need something to fill up the shadows a bit, I prepared some foam board.
Inside the softbox I used the golden reflector for warm light. In order to achieve some colour contrast and fill the shadows with cooler light, I prepared my foam core boards with some blue paper stuck on it. I also added some aluminium for extra reflection.