After 5 minutes of steaming, the tenderloin, portobello, and zucchini required 186, 199, and 239 grams of force, respectively, to be compressed (or “bite”) 3 millimeters into the food. Tasters noted that all of these samples were tender.
This picture changed rapidly after 5 more minutes of steaming. At the 10-minute mark, the tenderloin, portobello, and zucchini samples required 524, 195, and 109 grams of force, respectively. Tasters found the tenderloin tough and leathery and the zucchini overly soft. The portobello, on the other hand, remained largely unchanged.
Over the course of the next 30 minutes, the tenderloin continued to toughen, eventually turning a whopping 293 percent tougher, while the zucchini decreased in firmness 83 percent and turned mushy and structureless. The portobello, meanwhile, increased in firmness just 57 percent over the same period of time; after a full 40 minutes of cooking, tasters found the mushroom to still be properly tender.