Seeds provide balanced nutrient packages comparable to those of nuts, and the oil-rich seeds can substitute for nuts in many of the recipes that require nuts as an ingredient. Seeds can be used in a variety of ways to add versatility to the diet, and their health-providing properties will certainly benefit the consumer. The oil in oilseeds consists largely of polyunsaturated fats, mono-unsaturated fats and small quantities of saturated fats which come prepacked in the whole seeds with the necessary antioxidants to prevent autoxidation. The problems associated with extracted oils, as discussed in the chapter on oils and fats, do not apply to whole seeds and processed whole seeds, and whole seeds can thus be used to supply the essential fatty acids which our bodies require, and in addition they will also supply a balanced variety of vitamins, minerals and proteins of exceptional quality.
Pumpkin seeds
Pumpkin seeds are one of the best sources of primary proteins and they are packed with vitamins and minerals. The protein content of pumpkin seeds is high, and in some varieties can reach up to 31%. Moreover, it is a complete protein with all the essential amino acids being
well supplied. A handful of pumpkin seeds will supply approximately half the daily protein needs of the average person, and a comparison with steak will show that the relative quantities of the essential amino acids in pumpkin seeds exceed those of steak. Pumpkin seeds are a good source of vitamins and minerals, particularly zinc and iron, the latter occurring in more than three times the concentration found in steak.
Pumpkin seeds are relatively inexpensive, and they can be incorporated into many dishes to improve the protein quality and to enhance the flavour. To prepare one’s own pumpkin seeds, simply remove the seeds from the pumpkin, and spread them out to dry. The seeds can also be dried in the oven, and a light roasting will make them extremely palatable. Hulled seeds are easier to buy than to prepare oneself, but the unhulled seeds can be eaten as a snack, or they can be ground fine in a coffee grinder to be used in bread or protein dishes. Used in this way they add spice to the food which compares favourably to commercial stocks and food flavourants, and they improve the nutritional value of the meal.
Sesame seeds (Sesanum indicum)
Sesame seeds are a superb food originating from the Middle East, where this versatile seed has found a variety of uses. Many traditional dishes, cookies and cakes, sweets and spreads include sesame seeds as one of the prime ingredients. The most common form in which sesame seeds are available is in the hulled form, which is the form of choice for spreads and sweets, as the unhulled form is slightly bitter. Sesame seeds should be crushed or ground into a paste before consumption, as the small seeds will pass through the intestine without being digested. If sesame seeds are ground until the oil is released, a paste is formed that is called Tahini. Tahini originated in Turkey and is a nutrient-rich spread that can substitute for butter. Other Middle Eastern delicacies include Halva, a sweet that is sesame-based. Moreover, sesame seeds can be used to make a wholesome milk which can be used as a substitute for cow’s milk, and can also be used in cooking or for making home-made ice-cream.
Sesame seeds contain almost 30% complete protein of good quality, with all the essential amino acids, particularly methionine, being present in substantial amounts. The oil in sesame seeds is a mixture of the glycerol esters of oleic and linoleic acids, and it also has some unique features. It contains the compound sesamin, a lignin from sesame oil, which lowers cholesterol levels by decreasing the rate of absorption from the intestine, increasing the rate of faecal excretion and inhibiting its formation in the liver.74 Moreover, sesame seeds contain antioxidant substances73 which act as preservatives and give the ground seeds and sesame oil a long shelf life. Sesame seeds are a good source of the minerals magnesium, zinc, calcium and iron, and the calcium levels are in fact, more than twenty times higher than in steak, and the iron concentration is more than three times as high as in steak. Of course, people would consume more steak than sesame seeds and, therefore, obtain more iron from this source than from the seeds, but if sesame seeds were regularly incorporated into foods such as bread or spreads, they could make a significant contribution to dietary mineral requirements.
Sunflower seeds (Helianthus annuus)
Sunflower seeds are native to America, and contain almost 23% primary protein, and all the essential amino acids are well supplied. The 50% fat content of sunflower seeds consists mainly of polyunsaturated fats of which the essential fatty acid, linoleic acid, comprises some 30% of the total fat content, and the mono-unsaturated fatty acid, oleic acid, accounts for some 10% of the total fat content. The vitamin E content of sunflower seeds is very high, and this is
vital in view of the high levels of polyunsaturated fats. The relationship between the polyunsaturated fats and vitamin E prevents autoxidation of the fatty acids and production of free radicals. For this reason it is safe to use whole and freshly ground or liquidised sunflower seeds on a regular basis in contrast to the consumption of large amounts of extracted oils, such as sunflower-seed oil, which have been associated with an increased incidence of cancer (see chapter on fats).
Sunflower seeds are a good source of the minerals calcium, phosphorus, magnesium and iron and are one of the prime suppliers of B-group vitamins. This together with their high vitamin E and balanced primary nutrient content, makes them an energy food that we would do well to exploit. Use sunflower seeds in baking and incorporate them into breakfast foods such as muesli and granola. Furthermore, they can be used to prepare nutritious sauces and mock cheeses, or they can be added to nut or other milks to improve their nutritional value.