Tofu is a food widely used in Asian, vegetarian, and vegan cuisines. Available in several varieties, tofu is an excellent substitute for meat consumption, a healthy, economical and ecological choice, but it is still necessary to know how to choose, use, and preserve it.
To obtain tofu, soybeans must first be soaked, grinded, and filtered to produce soy milk. This milk is then heated and curdled with a coagulating agent such as salt (magnesium chloride or calcium) or gypsum (calcium sulfate) or an acidic agent (glucono delta-lactone or lemon juice). This causes soy milk to clot and lumps to form, which are then filtered and pressed into tofu blocks.
Depending on the processing and agents used, varieties of tofu are obtained that have different tastes, textures, and uses. But the main difference is the amount of water extracted from tofu when pressed into blocks. The more water is extracted, the firmer it becomes, with a higher protein and fat content.
Depending on whether it contains more or less moisture, it can be extra-firm, firm, semi-firm, or soft. Depending on the texture, it can be sliced, cubed, crumbled, grated, or used as a puree. The extra-firm type retains its shape better, but absorbs marinades more slowly. It is ideal for stir-fries and to be used on the grill. Soft tofu is easily crushed with a fork and is best suited for smoothies, dips, and spreads.
This type of tofu has a consistency similar to gelatin.
It is made in a similar process to regular tofu, except that soy milk is coagulated without curdling the milk. It is also left unpressed, so that it retains all its moisture during cooling. Because a curd does not form, this type of tofu has a smooth, “silky” appearance. Much more delicate than regular tofu, silky tofu also requires a delicate manipulation, as it breaks apart very easily.
It is usually pureed to make smoothies, dips, and spreads (less thick than with soft tofu) and is often used for desserts. When flavored, it is eaten with a spoon, as a dessert.
Tofu is a good source of complete protein, but the protein content depends on the type. Firm tofu provides 15 to 17 g per 100 g serving (about as much as 60 g of cooked chicken or 70 g of cheddar cheese). Silken tofu contains much less protein, just 5 to 6 g per 100 g serving.
Regarding the presence of FODMAPs, according to the Monash app the green portion of drained firm tofu is 170 g, while the green portion of drained silken tofu is only 39 g. If you follow a low-FODMAP diet you can therefore consume regular tofu, but avoid the silken type. Why the difference? This is due to differences in the processing methods. FODMAPs, especially fructans and GOS, are water soluble, so firm, drained tofu (with a low water content) contains less FODMAPs than silky tofu which has a higher water content.
*FODMAPs are fermentable carbohydrates that are partly responsible for causing symptoms in people with irritable bowel syndrome (IBS). For more info, read this article.