Soya, tofu, beans, pulses, nuts and seeds as a food commodity group: their nutritional value as plant protein foods, protein complementation, their value in vegetarian and vegan diets, and their use and storage.

What this dot point is asking

You need to know what soya, tofu, beans, pulses, nuts and seeds provide in the diet, why their protein is mostly low biological value, how protein complementation works, and why this group is so important in vegetarian and vegan diets.

What this group gives us in the diet

These foods are valued as plant sources of protein and as meat alternatives. They provide:

• protein for growth and repair (mostly low biological value, except soya),
• dietary fibre (NSP), which helps digestion and helps you feel full,
• iron and B vitamins,
• unsaturated fats in nuts and seeds (a healthier type of fat),
• slow-release energy, while being low in saturated fat.

Many also count towards five-a-day (beans and pulses count once a day) and are cheap and sustainable compared with meat.

Biological value and protein complementation

Most plant proteins are LBV, each missing different essential amino acids. By combining plant proteins so that the amino acids missing from one are provided by another, the diet still supplies them all. This is protein complementation, for example:

• beans on wholemeal toast,
• hummus (chickpeas) with pitta,
• rice and peas, or lentil dhal with rice.

Soya is the important exception: soya beans and tofu provide HBV protein on their own, which is why soya products are so useful in vegan diets.

The main types

• Soya and tofu: soya beans, tofu (set soya protein), soya milk and textured soya protein.
• Beans and pulses: kidney beans, chickpeas, lentils, peas and baked beans.
• Nuts: almonds, walnuts, peanuts (note: a common, serious allergen).
• Seeds: sunflower, pumpkin, sesame and chia seeds.

Why this group matters for vegetarians and vegans

Vegetarian and vegan diets leave out meat and fish (and, for vegans, all animal foods), so this group replaces the protein, iron and B vitamins those foods would have provided. Using soya and complementing plant proteins ensures all essential amino acids are supplied. Vegans also need to plan for vitamin B12 (found mainly in animal foods, so fortified foods or supplements are used), iron (eaten with vitamin C to aid absorption), and calcium (from fortified plant milks).

Using and storing these foods

• Dried pulses are soaked and boiled before use; some (such as red kidney beans) must be boiled hard for 10 minutes to destroy a natural toxin. Canned pulses are ready to use.
• Tofu takes on the flavour of marinades and is fried, baked or added to stir-fries.
• Storage: keep dried pulses, nuts and seeds cool, dry and sealed; nuts and seeds can go rancid, so use within the date. Keep fresh tofu and opened plant milks refrigerated.