Herbs and spices are both used in cooking to modify the taste and smell of food. A clear distinction between herbs and spices is difficult to draw, but there are some broad differences that are useful to know. Plants referred to as herbs, such as basil (Ocimum basilicum) or rosemary (Rosmarinus officinalis), typically have been used in temperate regions throughout much of recorded history. Herbs can be distinguished from spices in that herbs are the leaves of nonwoody plants, used for their flavor or therapeutic properties. Spices, in contrast, are derived from other parts of plants, such as buds, stems, or bark, and are more strongly flavored, often because of the essential oils produced in these plant parts. More often than not, the leaf is the important plant part used for seasoning. The word “spice” also evokes a more exotic connotation, referring to plants obtained from distant places such as India or Ceylon. Spices are typically native to tropical areas.
History of Herbs
Herbs and spices have been used for thousands of years to add zest to meals, to help preserve food, and even to cover up the taste and smell of spoiled food. The Sumerians were known to have used laurel (Laurus nobilis), caraway (Carum carvi), and thyme (Thymus vulgaris) more than five thousand years ago. Other early records suggest that onion (Allium cepa) and garlic (Allium sativum) were also used. At least as early as 1000 b.c.e., the Egyptians used garlic and mint (Mentha) along with many other plants, for medicine, in religious ceremonies, or in embalming. The Greeks and Romans greatly expanded the uses of herbs to include their use as symbols, magical Most of the historical information on herbs deals more directly with the medicinal properties of the plants. The first book available to the Europeans was De material medical written by Pedanius Discords, a Greek physician, in 100 c.e. This work on herbal medicine was so important that it was one of the first books printed after the printing press was developed. De material medical continued to be the authoritative reference on the use of herbs in medicine for sixteen centuries. Another early work on medicinal herbs is Pen-ts’ao (The Great Herbal), a sixteenth century Chinese pharmacopoeia, attributed to Li Shih-chen, which lists more than eighteen hundred plants and medical preparations. The use of herbs as medicines began to decline in the seventeenth century as new ways of treating illnesses developed, but herbal remedies continue even today in natural and homeopathic medicines.
Among the herbs most commonly used in cooking are members of the Lamiaceae, or mint, family. Mint, rosemary, basil, oregano (Origanum vulgare), sage (Salvia officinalis), thyme (Thymus vulgaris), and marjoram (Origanum majorana) are the most frequently used members of this family. These herbs are important staples in most cuisines of the Mediterranean region. The key features that most mint family members share are square stems and simple leaves (having undivided blades) attached in groups of two leaves in an opposite position on the stem. The flowers are also distinct in that the tips of the petals are grouped into two clusters that bear a resemblance to lips.
The most commonly used herb in the United States today is parsley Petroselinum crispum, a member of the Apiaceae, or carrot, family. Other important members of this family include dill (Anethum graveolens), cilantro (Coriandrum sativum, also known as coriander), fennel (Foeniculum vulgare), cumin (Cuminum cyminum), anise (Pimpinella anisum), celery (Apium sativum), and caraway. Members of this family are easy to recognize, particularly when in flower. The leaves are compound (having blades subdivided into leaflets), and the petiole (base of the leaf) is expanded such that the base wraps around the stem. The flowers are small and occur in clusters known as umbels. Umbels are clusters of flowers in which the flowers have stems of varying lengths so that all are located in one plane, forming a broad, flat inflorescence. Depending on the plant, the leaves or “seeds” or both might be used to impart characteristic musky flavors to a dish. Botanically, these are not simply seeds but seeds plus dried portions of the fruit. The fruit splits apart during maturation, forming two structures that appear to be “seeds.” This type of fruit is called a schizocarp (schizo meaning “split,” carp meaning “body”) and is characteristic of members of the carrot family.
Chemistry of Herbs
Plants used as herbs contain compounds called aromatic oils, or essential oils. These are relatively small compounds of low molecular weight that are easily separated from the plant. The essential oil of a particular plant is usually mixture of compounds, rather than one single ingredient. Essential oils impart the characteristic taste and odor of the herbs. In nature, oils often serve as attractants to animals pollinating flowers or dispersing fruits. Many of the compounds may also act in defense against the invasion of fungi, bacteria, or predation by herbivores.
A discussion of herbs would not be complete without mentioning some of the uses of these plants not related to food or medicine. Crushing the plant releases the aromatic volatiles, making them useful as perfumes to cover up odors on bodies or in spaces. Undoubtedly this practice began by simply crushing the plant to release the odor into the air or rubbing the crushed plant onto an object. Burning the plant is another way to release its odors. The Egyptians were quite skilled at the art of perfumery and passed these skills on to the Greeks and Romans. Additionally, herbs were commonly used in the nineteenth century as components of floral bouquets designed to deliver messages to recipients. The flowers had particular meanings; for example, roses meant love. The herbs were added for greenery to deliver additional messages. Rose mary was used to denote friendship, and basil meant hatred.