[h=2]INTRODUCTION[/h]Essential oil plants and culinary herbs include a broad range of plant species that are used for their aromatic value as flavorings in foods and beverages and as fragrances in pharmaceutical and industrial products. Essential oil plants derive from aromatic plants of many genera distributed worldwide. In the United States, the most economically important sources of domestically produced essential oils are industrial by-products from citrus, balsam fir, pine, and cedarwood (Table 1, 2) while the most important crops grown in the U.S. for essential oils are peppermint and spearmint (Table 3). Most other essential oils used in the U.S. are imported (Table 4) at an annual cost in 1988 of $150 million (USDA 1989b). A significant quantity of the essential oil imported into the U.S. is further processed for export along with domestically produced oil (Table 5).
Culinary herbs are herbaceous aromatic plants grown and marketed fresh or dried and include many of the same aromatic plants which are grown for their extractable essential oils. Significant quantities of dried culinary herbs are imported annually into the U.S. (Table 6). Recent estimates by the USDA Foreign Agricultural Service reported that more than $349 million of dried condiments, seasonings, and flavorings (Table 4) and $20 million of spice oleoresins were imported into the U.S. in 1988 (USDA 1989a). A significant amount of selected herbs are domestically produced for the dried spice or condiment market Domestic production of these and other herbs and spices now imported is increasing for both processing and fresh market.
The objectives of this paper are to provide an overview to the plants which are processed in the U.S. for essential oils and to identify fresh culinary herbs that are or can be grown in the continental U.S. The potential opportunities and constraints for production of these new crops in American agriculture will be highlighted. [h=2]ESSENTIAL OILS[/h][h=3]Chemistry and Extraction of Essential Oils[/h]Essential oils are natural plant products which accumulate in specialized structures such as oil cells, glandular trichomes, and oil or resin ducts. The formation and accumulation of essential oils in plants have been reviewed by Croteau (1986), Guenther (1972) and Runeckles and Mabry (1973). Chemically, the essential oils are primarily composed of mono- and sesquiterpenes and aromatic polypropanoids synthesized via the mevalonic acid pathway for terpenes and the shikimic acid pathway for aromatic polypropanoids. The essential oils from aromatic plants are for the most part volatile and thus, lend themselves to several methods of extraction such as hydrodistillation, water and steam distillation, direct steam distillation, and solvent extraction (ASTA 1968, Guenther 1972, Heath 1981, Sievers 1928). The specific extraction method employed is dependent upon the plant material to be distilled and the desired end-product. The essential oils which impart the distinctive aromas are complex mixtures of organic constituents, some of which being less stable, may undergo chemical alterations when subjected to high temperatures. In this case, organic solvent extraction is required to ensure no decomposition or changes have occurred which would alter the aroma and fragrance of the end-product. Newer methods of essential oil extraction such as using supercritical CO[SUB]
2[/SUB] which yield very high quality oils are commercially used, but are less common and beyond the financial means of most processors.
The recovery of nonvolatile essential oils are also obtained by solvent extraction although the process is more difficult and complex than the recovery of the volatiles. This process yields an aromatic resinous product known as an oleoresin, which is more concentrated than an essential oil and which has wide application in the food industry (Heath 1981). [h=3]Essential Oils as Industrial By-products[/h]Although a primary focus of this review is to highlight aromatic plants and culinary herbs produced in the U.S., it is important to recognize that the largest quantities of essential oils produced in the U.S. are actually byproducts from industrial processes yielding higher value primary products. Citrus essential oils are recovered from the peel which contain the oil sacs or glands located irregularly in the outer mesocarp of the fruit (Matthews and Braddock 1987). These glands are embedded at different depths in the flavedo, the colored, outer portion of the fruit and must be removed by first rupturing the glands by pressure or mechanical rasping (Matthews and Braddock 1987).
The recovery of citrus oils by mechanical expression is generally obtained by two types of commercial extractors, the FMC Citrus juice Extractor (FMC Corp.) and the Brown Extractor (Automatic Machinery Corp.) (Kealey and Kinsella 1979, Kesterson et al. 1971). Citrus oils are recovered as cold-pressed oils or as a specific constituent such a d-limonene as by-products of the juice and beverage industry and yield important aromatic and flavoring compounds used in a wide array of food, cosmetic and industrial products.
The other large quantity of essential oils produced as industrial by-products in this country comes from the wood and pulp manufacturing industries. More than 1650 tonnes of such oils, predominantly from cedarwood, are produced annually (Lawrence 1979). [h=3]Essential Oil Plants[/h]In the United States, only a relatively few plant species are now cultivated and produced for essential oils. The most important species includes the mints. The value, production, and areas of mint production in the United States for 1988 is shown in Table 3. The production and processing of mint in the United States has a rich history (Landing 1969, Rabak 1916) and is the most mechanized system of essential oil production in the world (Ellis 1937, Ellis et al. 1941; Green 1975, 1963, Lacy 1981, Smith and Robertson 1941). Mint oils are obtained by steam distillation.
The only other essential oil crop in the United States of significant volume is dill where the oils are used in the manufacture of pickles. Although dill oil can be obtained from the steam distillation of either seeds or foliage, it is often obtained by harvesting dill as a green herb after the seeds have formed but have not yet ripened. Dill seed oil is from the seeds and dill weed oil is from the green herb prior to flowering (Heath 1981).
While many other herbs have been produced for essential oil in limited quantities (Table 7), a complete list of crop species and production area is difficult to obtain and confirm. Most all the essential oils derived from temperate zone aromatic plants currently imported could be produced for essential oil domestically. However, opportunities for domestic production are limited because most essential oils from traditional herbs have limited markets making penetration into established markets very difficult. Many buyers and users have little interest in changing their suppliers unless supplies from abroad become limited due to political instability, contamination (such as the Chernobyl release of radioactive materials), or crop failure which permits new suppliers into the marketplace. An additional difficulty in establishing new sources of traditional essential oils is in demonstrating the ability to produce the quantity and quality demanded by the industry at a competitive price.
Many countries have government funded programs to establish new industries for export and which absorb much of the developmental costs associated with the evaluation and introduction of new crops. When these programs are coupled with crop champions and a strong relationship with the processing industry, the success of new crop development significantly increases. Such a program encouraged extensive work with several herbs for potential production in the prairies of western Canada (Embong et al. 1977a-e). Such programs have allowed Israel to go from an importer to a significant exporter of essential oils (128 tonnes of essential oils annually) in a relatively short time period (Putievsky 1989). International development programs have also contributed to the creation of essential oil industries. Technical assistance and funding from the Marshall Plan, enabled the large scale cultivation of herbs, spices and medicinal plants in Hungary (Mathe 1989). Prior to WWII, most Hungarian herbs were collected from the wild, but in part as a result of such an economic development program, Hungary has emerged as a significant exporter of cultivated essential oils (65,808 tonnes produced in 1982).
One of the challenges in developing new essential oil crops or in establishing a new geographical area for the production of an essential oil already on the market is procuring or developing generic lines with the suitable agronomic characteristics and desirable chemical constituents. The evaluation of a large and diverse germplasm collection thus becomes the first step in new crop development. This stage alone could take many years unless a processor supplies the particular chemotype that meets their processing needs. Unlike peppermint which must be vegetatively propagated, most essential oil crops are open pollinated and available seed have not been selected for homogeneity in growth or for flavor and aroma. Two examples will suffice to illustrate both the chemical diversity of herb cultivars and germplasm and approaches to crop improvement.
Parsley oil. Little information was available on the compounds responsible for the flavor of parsley and the genetic variability of the essential oil constituents of this important culinary herb. A recent study showed that essential oil content of a large germplasm collection ranged from 0.00 to 0.16% (v/fresh weight) and that the oil constituents varied significantly although the major constituent was 1,3,8-p-menthatriene, followed by ß-phellandrene, myristicin, and myrcene (Simon and Quinn 1988). In parallel study evaluating the essential oils of commercially available parsley curly-leaf types had as high essential oil content as the flat-leaf types, commonly believed to be more flavorful (Simon et al. 1989).
Basil oil. Sweet basil (
Ocimum basilicum L.) is a popular culinary herb and a source of essential oils (ITC 1986) extracted by steam distillation from the leaves and flowering tops and used to flavor foods, in dental and oral products, and in fragrances. There are several types of basil oil on the world market European, French, or sweet basil; Egyptian; Reunion or Comoro; Bulgarian; and Java (Heath 1981). The European basil oils, considered to be the highest quality, contain methyl chavicol d-linalool and to a lesser extent 1,8-cineole, plus many other compounds (Guenther 1985, Simon et al. 1984). Egyptian basil oil is similar to the European, except that the concentration of d-linalool is lower and methyl chavicol is higher. Reunion or Comoro contains little d-linalool, but has a very high concentration of methyl chavicol (Lawrence et al. 1972, Simon et al. 1984). Bulgarian basil oil is rich in methyl-cinnamate and Java basil oil is rich in eugenol (Heath 1981). From an evaluation of the entire USDA collection plus other commercial and wild sources, we observed a wide range of chemical variation within
O. basilicum and other species (
O. canum, O. sanctum, O. gratissimum, and
O. kilimandscharicum). We have identified chemotypes that represent each of the commercial types of basil oil. Promising lines are being screened for chemical stability, vigor, and uniformity. The characteristics of the population has continued to improve under mass selection. Isolation blocks serve as seed sources. We are currently developing a new line rich in methyl cinnamate (Simon et al. 1990). [h=3]Prospects[/h]Market surveys have reviewed world production of essential oils and identified areas of future growth (Greenhalgh 1979, Lawrence 1985, ITC 1986). For essential oil crops to be successfully developed in the United States, a long term coordinated strategy is required with either strong support from industry and grower groups or significant support by state and/or federal programs in concert with growers and the users of essential oils. Regions where the industrial infrastructure already exists (e.g. extraction equipment growers familiar with essential oil production, with brokers, buyers and processors in the proximity) will have the greatest opportunities and chance of success in developing new essential oil crops into American agriculture. New essential oil crops must be compatible with existing crops in a farm operation and offer economic returns at levels higher than those presently received.
Successful introduction of new plant sources of raw aroma chemicals for the fragrance industry could allow the rapid development of a new industry. An example is the development through selection of
Monarda spp. rich in geraniol in Morden, Manitoba (Rafe Guadiel, personal communication) or
Ocimum spp. rich in methyl cinnamate or methyl chavicol (Simon et al. 1990). The creation of new markets for specialized oils can take many years and would be most successful when working in collaboration with an end-user whose needs can be met by the new product.
The incorporation of new aromas into perfumes and fragrances and the development of new products is critical to the success of the perfumer and flavor chemist. The difficulty for the agricultural researcher is to learn the types of aromas and chemical constituents desired by the perfumer and flavorist. The identification of new species rich in desirable essential oils may be a promising route to pursue. [h=2]CULINARY HERBS[/h][h=3]Consumption Pattern[/h]Americans are consuming ever increasing amounts of fresh, frozen, processed and dried culinary herbs and spices, and this trend appears to be here to stay. The same trend is true for specially fruits and vegetables (Fielding 1988). Factors accounting for increased consumption include interest in new foods and tastes, availability of more fresh herbs, advertising and promotion to food services and institutional food chains, and expanding ethnic populations demanding foods and flavorings of their homeland. Who will be supplying these herbs and are there opportunities for commercial growers in the production of dried and fresh herbs? Much of the dried herbs produced domestically are produced in California by well-established food companies that own and operate drying and processing facilities and already package, transport and market these products. Growth in this area will continue as long as increased demand and consumption of these herbs continue. Additional growth is likely to occur in the contract growing of herbs by private growers to supply raw product to drying and processing companies. Some companies both grow and process their own product, but most contract practically all of their raw material needs to growers. Processing companies that are now procuring most of their dried herbs abroad may be more willing to obtain some of the same materials domestically Growth in the dried herbal market will also probably occur with an increasing number of spice companies and natural food wholesalers and retailers catering to specialized markets (e.g. organic or pesticide free-herbs and spices, specially restaurants) and which unlike many of the larger food and flavor houses produce specialized herb and other food products.
There has been tremendous growth in the fresh herb market as evidenced by the increased variety of herbs available both in the larger supermarkets, the smaller grocery outlets, farmers markets, and roadside farm markets (Simon 1986, Simon et al. 1989, Simon and Clavio 1989, Simon and Grant 1987a, b). Herbs that were only available dried, or fresh during a few months of the year, are now being marketed fresh cut and more recently, as live potted herbs in the produce sections of supermarkets all year long. Recognizing this growth, the USDA (1989c) now lists weekly prices for herbs sold in nineteen major wholesale markets plus the type of container, package, and weight count, and quality of each unit in the National Market News Report. The herbs now covered include anise, arrugala, basil, borage, chervil, chives, cilantro, dill ginger root horseradish, parsley lemongrass, marjoram, mint, oregano, rosemary savory, sage, sorrel tarragon, thyme, and watercress.
The successful introduction of new culinary herbs into commercial production requires a purposeful strategy and a solid information base. Unfortunately culinary herbs and essential oil crops have been studied little compared to all other food and fiber crops (Craker et al. 1986). While several extension guides have been published on herbs, few guides based on research are available in this country In a bibliographic review of the scientific literature from 1971-1980 (Simon et al. 1984), over 10,000 authors are listed with published research articles on the major economical herbs of the temperate zone involving horticultural research (38%), botany (17%), chemistry (14%), pharmacology (11%), ecology and germplasm (8%). With the exception of peppermint and spearmint most all crop research on herbs was conducted outside of the United States. Although the United States is the principal world producer of mint oils, only 10% of all published mint research from 1971-1980 originated in the U.S. (Craker et al. 1986). [h=3]Promising Herbs[/h]There is a wide range of culinary herbs that can be grown in the continental United States and which may offer potential for production. Many herbs are already being commercially produced, albeit in small quantities, often in relatively small farms. Those herbs which show promise for the fresh market are listed in Table 8. Three examples of culinary herbs with great promise are discussed below.
Coriander (
Coriandrum sativum L). This annual herb native to the eastern Mediterranean and southern European region has long been prized for its spicy aromatic seeds which are used either whole or in ground form as a main ingredient in curry and other food and flavor products. Coriander can be grown as a seed crop in the U.S. using existing mechanization and production technology but seeds ripen unevenly and the mature seeds shatter from the plant. Present demand for coriander seed is met by existing foreign suppliers and although the yield of coriander seed is moderately high (1,100-1,700 kg/ha) and the cost of production relatively low, there is still a question whether domestic commercial opportunities exist for coriander seed production as a spice. The profit margin of coriander would at best match the more traditional cash crops (maize, soybeans). Postharvest costs of cleaning the seed, handling and shipping can be major factors determining the profitability of this seed spice crop. Coriander seed is also processed via steam distillation for the extractable essential oil of which d-linalool is the major constituent. The oil is then used in the food and perfume industries.
Recently, American consumers have witnessed the introduction of coriander leaves into the marketplace. This fresh product, known as cilantro, is marketed in bunches as a leafy green spice. While new to American cuisine, cilantro has long been a popular herb in Oriental, Middle Eastern and Latin American cooking.
Coriander, a cool season crop, is easy to grow as a culinary herb and is most suited to fertile loam soils. The plant is direct seeded with a seed drill at rates of 13-18 kg/ha in very early spring. In Florida and New Jersey, coriander is often planted weekly At harvest, the whole plant is manually cut and bunched in the field.
One of the major problems in producing cilantro is premature flowering. Bolting becomes acute as the days get hotter and longer. A number of seed companies now offer slow-to-bolt (long-standing) cultivars. There are significant differences among coriander cultivars regarding the response to premature flowering, and while some are less susceptible, none are totally unresponsive to high temperatures and long days (Simon et al. 1989). Thus, cilantro is planted as a spring, early summer, or fall crop.
The aroma of cilantro is also due to an extractable essential oil, although its composition is distinctly different from the seed oil. Quality of fresh cilantro is based upon strong green color, strong aroma, and visual appearance (i.e. freedom from insects, discolorations). To the grower, yield and the cultivars' resistance to bolt are additional factors to be considered. Cilantro has a relatively short shelf life and requires refrigeration. Cilantro can be kept for 3 to 4 weeks at 0°C, but only 2 to 3 weeks when stored at 5°C (Cantwell 1989). Cilantro is routinely iced after harvest. Cilantro is expected to become increasingly important in the U.S. due in part to the expanding Hispanic and Arabic populations, its unique flavor, and increasing familiarity in the marketplace.
Sweet Fennel (
Foeniculum vulgare Mill.). Sweet fennel has highly aromatic leaves and attractive green fern-like foliage but is best known for its seeds which are sold commercially as a spice. Limited domestic production for seed has occurred periodically, but demand is relatively small and adequate supplies can be obtained abroad. Successful domestic production of fennel for the seed as a spice will probably not occur unless the yields can be significantly improved, supplies from abroad become limited, or a government program makes the production of new crops more beneficial.
Fennel is a perennial but grown as an annual. It is most suited to well drained light loam soil. The plant is easy to grow and is typically direct seeded (3.5-5 kg/ha seed/acre) into the ground in beds with a specialized planter adapted to small-seeded crops. Plant spacing varies significantly with rows in the beds 60-1 00 cm apart and with final plant stands of 10-30 cm apart in the row. Fennel is a cool-season crop, seeds are sown in early spring and germinate at temperatures >7°C (optimum soil temp. approx. 16-18°C). Yields of up to 2,240 kg/ha have been achieved, although earlier USDA estimates were only in the range of 650-900 kg/ha (Sievers 1948). The plant requires 100-115 days to mature before harvest.
The production of fennel as a culinary herb, cultivated both for its aromatic leaves and enlarged leaf stalk is on the rise. This type, called Florence fennel or finocchio fennel, is a different subspecies than regular fennel produced as a seed spice. Very popular in Europe as a specially vegetable in many culinary dishes, it is commonly consumed raw in Italy and cooked in France. Finocchio is becoming commonplace in U.S. supermarkets and consumer interest and familiarity is increasing. One of the limiting factors to increased consumption is the public's unfamiliarity with it's preparation, use and taste. Unfortunately finocchio fennel is often marketed under the misnomer of anise, another culinary herb (
Pimpinella anisum L.), which has led to market and consumer confusion. Both plants contain high amounts of anethole in the essential oil, imparting the licorice-like aroma and taste.
The time to harvest fennel bulbs is difficult to assess because the thickened leaf stalk continues to grow and develop until flowering takes place. Care in harvesting, grading and packing fennel must be taken to ensure a high quality fresh pack. Harvesting, cleaning, trimming and packing is done by hand. The foliage must be dark green and fresh in appearance and the stalk and bulb (enlarged base of leaf stalk) a lighter greenish-white color. The bulb must be firm and the product free from insects and discolorations. Once harvested, fennel should be kept at 0 to 2°C (Seelig 1974). The plants are retailed individually, either wrapped in plastic or simply displayed like celery.
Great variability (in growth and aroma) in commercially available cultivars of fennel and finocchio fennel exist (Simon et al. 1989) making the proper selection of cultivars for spring and fall production important. Finocchio fennel shows excellent potential for future growth in the U.S.
Oregano (
Origanum spp.). Their has been a significant increase in the consumption of oregano for both the fresh and processed market (Tucker 1987). Oregano, the common name for a wide number of plant species with a characteristic aroma and flavor, is a perennial aromatic plant native to the dry calcareous soils of southern Europe, southwest Asia, and the eastern Mediterranean (Simon et al. 1984). A major problem which has limited domestic production was in the difficulty in distinguishing the many plant species and types of oregano imported and marketed as oregano. Imported oregano was found to be derived from 16 plant genera and more than 40 plant species (Calpouzos 1954), resulting in oregano being described as a flavor and aroma rather than an individual plant. Taxonomic work by Tucker (1986, 1989) has identified the major types of commercial cultivars and cultivated taxa in this country and the major types of imported oregano. Yet much of the imported oregano arrives as a blend of plants. Selection of an individual line for domestic production, particularly for the dried leaf or as an essential oil, remains difficult.
The European type of oregano comes mainly from subspecies of
O. vulgare L. including ssp.
hirtum (Link) Ietswaart, ssp.
virens (Hoffmanns. & Link) Ietswaart and ssp.
viride (Boiss.) Hayek (Tucker 1989). In contrast Mexican oregano, also called Mexican sage, is principally gathered from the small Mexican shrub,
Lippia graveolens H.B.K. (Simon et al. 1984), although leaves from other species are collected.
The essential oil of European oregano is composed mainly of carvacrol and thymol. The range of each can be very wide and many chemotypes are available. The herb or the extracted oil is used in a variety of meat and sausage products, salads, stews, sauces and soups. European oregano and to a larger extent Mexican oregano, are used in flavoring Mexican foods, pizza, and barbecue sauces.
Oregano is generally transplanted to the field and grown on light, dry well-drained soils for periods of 3 to 6 years. Domestic horticultural studies on this species are limited. Although yields of more than 14 tonnes fresh herb/ha or almost 4 tonnes dried herb/ha were obtained from one commercial line by a single annual harvest (Simon et al. 1989), typically yields are much lower (1.5-3 tonnes dried herb/ha). Plants can be harvested multiple times each year (from 2 to 6) depending upon the location and end-use. Opportunities exist for dried product as well as for the fresh market. Once harvested for the fresh market oregano should be kept at 0deg.C to maximize shelf-life (Cantwell 1989). [h=3]Prospects[/h]Production of culinary herbs for the fresh, frozen processed and dried market will likely increase. The large growth in the production of fresh culinary herbs provides opportunities to growers that either develop a market niche or cooperate closely with a broker or specialist in marketing. It is likely that the large volume herbs will continue to come from areas of intensive vegetable production such as Florida, New Jersey and California. Herbs can be expected to become fully integrated with fresh market vegetables in packaging, cooling, transport, and marketing operations. Unless governmental regulations change, there will be strong competition from Mexico, the Caribbean, and other areas to supply fresh herbs to the American public. Overproduction of specific herbs within a limited marketplace can result in significant decreases in the wholesale market prices. Greater opportunities for small producers maybe in the development of specialized markets, rather than for the wholesale trade.
[h=2]REFERENCES[/h]
- Ames, G.R. and W.S.A. Matthews. 1969. The distillation of essential oils. Perf & Essential oil Rec., January:9-18.
- ASTA. 1968. Official analytical methods of the American Spice Trade Association ASTA, Inc., Englewood Cliffs, NJ.
- Calpouzos, L. 1954. Botanical aspects of oregano. Econ. Bot. 8:222-223
- Cantwell, M. 1989. Conserving fresh herb quality. Herbs'89. Proc. Fourth Nat. Herb Growing and Market. Conf. July 22-25, 1989, San Jose, CA. Intern. Herb Growers and Market. Assoc. Silver Springs, PA. p. 105-106.
- Croteau, R. 1986. Biochemistry of monoterpenes and sesquiterpenes of the essential oils. Herbs, spices and medicinal plants: Recent advances in botany, horticulture, and pharmacology. Vol. 1:81-135. Oryx Press, Phoenix, AZ.
- Craker, L.E., A.F. Chadwick, and J.E. Simon. 1986. An introduction to the scientific literature on herbs, spices, and medicinal plants. Herbs, spices and medicinal plants: Recent advances in botany horticulture and pharmacology. Vol. 1:1-10. Oryx Press, Phoenix, AZ.
- Ellis, N.K. 1937. Mint culture in northern Indiana. Purdue Univ. Agric. Exp. Sta. Circ. 227.
- Ellis, N.K., K.I. Fawcett, F.C. Gaylord and L.H. Baldinger. 1941. A study of some factors affecting the yield and market value of peppermint oil. Purdue Univ. Agric. Exp. Sta. Bull. 461.
- Embong, M.B., D. Hadziyev and S. Molnar. 1977a. Essential oils from spices grown in Alberta. Anise oil (Pimpinella anisum). Canad. J. Plant Sci. 57:681-688.
- Embong, M.B., D. Hadziyev and S. Molnar. 1977b. Essential oils from spices grown in Alberta. Caraway oil (Carum carvi). Canad. J. Plant Sci. 57:543-549.
- Embong, M.B., D. Hadziyev and S. Molnar. 1977c. Essential oils from spices grown in Alberta. Dill seed oil, Anethum graveolens L. (Umbelliferae). Canad Inst. Food Sci. Technol. J. 10:208-214.
- Embong, M.B., D. Hadziyev and S. Molnar. 1977d. Essential oils from herbs and spices grown in Alberta. Sage Oil, Salvia officinalis L. (Labiatae). Canad. Inst. Food Sci. Technol. J. 10:201-207.
- Embong, M.B., L. Steele, D. Hadziyev and S. Molnar. 1977e. Essential oils from herbs and spices grown in Alberta. Peppermint oil, Mentha piperita var. Mitcham L. Canad. Inst. Food Sci. Technol. J. 10:247-256.
- Fielding. T. 1988. Specially trend shows no sign of let-up. Fresh Produce Council Dig. Sept:8, 9.
- Green, R. Jr. 1975. Peppermint and spearmint production in the United States-Progress and problems. Int. Flav. & Food Addit. 6:246-247.
- Green, R. Jr. 1963. Mint farming. USDA, Wash., DC. Agric. Info. Bul. 212.
- Greenhalgh, P. 1979. The markets for mint oils and menthol. Rpt. Trop. Prod. Inst. London G126.
- Guenther, E. 1985. The essential oils. Vol. 3:400-433. Krieger Publ. Co., Malabar, FL
- Guenther, E. 1972. The production of essential oils: methods of distillation, enfleurage, maceration, and extraction with volatile solvents. In: Guenther, E. (ed.). The essential oils. History-origin in plants. production analysis. Vol. 1:85-188. Krieger Publ. Co., Malabar, FL.
- Heath, H.B. 1981. Source book of flavors. AVI, Westport, CT.
- International Trade Center. 1986. Essential oils and oleoresins: a study of selected producers and major markets. ITC UNCTAD/GATT, Geneva.
- International Trade Center. 1982. Markets for selected medicinal plants and their derivatives. ITC UNCTAD/GATT, Geneva.
- Kealey, K.S. and J.E. Kinsella. 1979. Orange juice quality with an emphasis on flavor components. CRC Crit. Rev. Food Sci. & Nutrit. 11(1):1-40.
- Kesterson, J.W., R. Hendrickson, and R.J. Braddock. 1971. Florida citrus oils. Florida Agric. Exp. Sta. Tech. Bul. 749.
- Landing. J.E. 1969. American essence: A history of the peppermint and spearmint industry in the United States. A.M. Todd Foundation, Kalamazoo, MI.
- Lacy, M.L., C.T. Stephens, R.J. Green, and A.C. York. 1981. Mint production in the midwestern United States. North Central Reg. Ext. Pub. 155.
- Lawrence, B.M. 1985. A review of the world production of essential oils (1984). Perf. & Flav. 10:1-16.
- Lawrence, B.M. 1979. Commercial production of non-citrus essential oils in North America. Perf. & Flav. 3:21-33.
- Lawrence, B.M., J.W.Hogg, S.J. Terhune and N. Pichitakul. 1972. Essential oils and their constituents. IX. The oils of Ocimum sanctum and Ocimum basilicum from Thailand. Flavor Ind. Jan. 47-49.
- Mathe, A. 1989. Spice and medicinal plant production and processing in Hungary and the neighboring countries. Herbs '89. Proc. Fourth Nat. Herb Growing and Marketing Conf. July 22-25, 1989, San Jose, CA. International Herb Growers and Marketers Assoc., Silver Springs, PA. pp. 74-79.
- Matthews, R.F. and R.J. Braddock. 1987. Recovery and applications of essential oils from oranges. Food Tech. 41
l):57-61.
- Putievsky, E. 1989. Production of aromatic plants in Israel. Proc. Third Nat. Herb Growing and Market Conf. July 24-27, 1988, Louisville, KY. Purdue Univ. Agric. Exp. Sta. Bull. 552:130-133.
- Rabak, F. 1916. The effect of cultural and climatic conditions on the yield and quality of peppermint Oil. USDA Wash., DC. USDA Bul. 454.
- Runeckles, V.C. and T.J. Mabry (eds.). 1973. Terpenoids: structure, biogenesis, and distribution Academic Press, New York.
- Seelig, R.A. 1974. Anise. United Fresh Fruit & Vegetable Association, Fruit & Vegetable Facts & Pointers, Alexandria, VA.
- Sievers, A.F. 1948. Production of drug and condiment plants. Farmers' Bul. 1999. USDA., Wash., DC.
- Sievers, A.F. 1947. The production of minor essential oils in the United States. Econ. Bot 1:148-160.
- Sievers, A.F. 1928. Methods of extracting volatile oils from plant material and the production of such oils in the United States. USDA Tech. Bull. 16. USDA., Wash., DC.
- Simon, J.E. 1987. Developing herbs as cash crops in the United States. Proc. First Nat Herb Growing and Market. Conf. July 19-22, 1986, West Lafayette, IN. Purdue Univ. Agric. Exp. Sta. Bul. 518:13-32.
- Simon, J.E., E. Cebert, and D. Reiss-Bubenheim. 1989. Cultivar evaluation of culinary herbs. Herbs '89. Proc. Fourth Nat. Herb Growing and Market. Conf. July 22-25,1989, San Jose, CA. International Herb Growers and Marketers Assoc., Silver Springs, PA. p. 12-21.
- Simon, J.E., A.F. Chadwick, and L.E. Craker. 1984. Herbs: An indexed bibliography 1971-1980; the scientific literature on selected herbs, and aromatic and medicinal plants of the temperate zone. Archon Books, Hamden, CT.
- Simon, J.E. and L.Z. Clavio (eds.). 1989. Proc. Third Nat. Herb Growing and Market. Conf July 24-27, 1988, Louisville, KY. Purdue Univ. Agric. Exp. Sta. Bul. 552.
- Simon, J.E. and L. Grant (eds.). 1987. Proc. Second Nat. Herb Growing and Marketing Conf. July 19-22, 1987, Indianapolis, IN. Purdue Univ. Agric. Exp. Sta. Bul. 530.
- Simon, J.E. and L. Grant (eds.). 1987. Proc. of the First Nat. Herb Growing and marketing Conf. July 19-22,1986, West Lafayette, IN. Purdue Univ. Agric. Exp. Sta. Bul. 518.
- Simon, J.E., A. Kestner and M. Buehrle (eds.). 1989. Herbs '89. Proc. of the Fourth National Herb Growing and Marketing Conf. July 22-25, 1989, San Jose, CA. International Herb Growers and Marketers Assoc., Silver Springs, PA.
- Simon, J.E. and J. Quinn. 1988. Characterization of essential oil of parsley. J. Agric. Food Chem. 36:467-472.
- Simon, J.E., J. Quinn, and R.G. Murray 1990. Basil: A source of essential oils. p. 484-489. In: Janick, J. and J.E. Simon (eds.). Advances in new crops. Timber Press, Portland, OR.
- Simon, J. E. and D. Reiss-Bubenheim. 1988. Field performance of American basil varieties. Herb, Spice and Medicinal Plant Digest. Mass. Coop. Ext. Serv. Amherst, MA. Vol. 6:1-4.
- Smith, M.G. and L. Robertson. 1941. An economic analysis of the production of peppermint and spearmint oils in Indiana. Purdue Univ. Agric. Exp. Sta. Bul. 459.
- Staff of Liberty Hyde Bailey Hortorium. 1976. Hortus third. MacMillan, New York.
- Tucker. A.O. 1986. Botanical nomenclature of culinary herbs and potherbs. Herbs, spices, and medicinal plants: Recent advances in botany, horticulture, and pharmacology. Vol. 1:33-80. Oryx Press, Phoenix, AZ.
- Tucker, A.O. and M.J. Maciarello. 1987. Plant identification. Proc. First Nat Herb Growing and Market. Conf. July 19-22, 1986, West Lafayette, IN, Purdue Univ. Agric. Exp. Sta. Bull. 518:126-172.
- Tucker, A.O. and E.D. Rollins. 1989. The species, hybrids, and cultivars of Origanum (Lamiaceae) cultivated in the United States. Baileys 23:14-27.
- USDA 1989a. U.S. essential oil trade. USDA Foreign Agr. Serv. FTEA 2-89.
- USDA 1989b. U.S. spice trade. USDA Foreign Agr. Serv. FTEA 1-89.
- USDA 1989c. National wholesale herb market news report. USDA Agr. Marketing Service. Fruit and Vegetable Market News. Chicago, IL. (issued weekly).
- Williams, L.O. 1960. Drug and condiment plants. USDA Agr. Res. Serv. Agr. Handbk 172.
*Acknowledgements: I thank Jules Janick, John Pasquale, Tom Burns, Bob Braddock, Art Tucker, Dee Phillips, Rex Dull, Bob Griffin and Denys Charles for their comments and assistance in the preparation of this manuscript J. Paper No. 12, 114, Purdue Univ. Agric. Expt. Sta., West Lafayette, IN. 47907.
Table 1. Essential oils obtained from wild plants and trees as industrial by-products.[SUP]
z[/SUP]
| Essential oils | Species |
| Cedar leaf oil | Thuja occidentalis L. (American or eastern white cedar |
| Balsam fir oil | Abies balsamea (L.) Mill. (Balsam fir) |
| Hemlock oil | Tsuga canadensis (L.) Carr. (Canadian or eastern hemlock) |
| T. caroliniana Engelm. (Carolina hemlock) |
| T. heterophylla (Raf) Sarg. (Western hemlock) |
| T. mertensiana (Bong.) Carr. (Mountain hemlock) |
| Spruce oil | Picea glauca (Moench) Voss (White spruce) |
| P. mariana (Mill.) BSP. (Black spruce) |
| Tsuga canadensis (L.) Carr. (Canadian or eastern hemlock) |
| Cedarwood oil | Juniperus mexicana Scheide (Texas cedarwood) |
| J. virginiana L. (Virginia cedarwood or red cedar) |
| Sweetbirch oil | Betula lenta L. (Cherry birch, sweet birch) |
| Wintergreen oil | Gaultheria procumbens L. (Wintergreen) |
[SUP]
z[/SUP]Modified from Lawrence (1979).
Table 2. Major essential oil crops produced in the United States.[SUP]
z[/SUP]
| Citrus | |
| Grapefruit | Citrus x paradisi Macfady |
| Lemon | Citrus limon (L.) Burm. f. |
| Lime | Citrus aurantifolia (Christm.) Swingle. |
| Orange, Sweet | Citrus sinensis (L.) Osbeck |
| Tangerine and Mandarin | Citrus reticulata Blanco |
| Mint | |
| Peppermint | Mentha x piperita L. |
| Spearmint (native) | M. spicata L. |
| (Scotch) | M. x gracilis Sole |
| Other spice oils | |
| Nutmeg | Myristica fragrans Houtt[SUP]y[/SUP] |
| Pepper | Piper nigrum L.[SUP]y[/SUP] |
| Pimento (Allspice) | Pimenta dioica (L.) Merrill[SUP]y[/SUP] |
[SUP]
z[/SUP]Modified from International Trade Center (1986) and Lawrence (1979).
[SUP]
y[/SUP]Processed in the USA only.
Table 3. United States production, yield and value of peppermint and spearmint essential oils, 1988.
| Peppermint | Spearmint | | | | |
| State | Area harvested (1,000 ha) | Avg. yield (kg/ha) | Value ($1,000,000) | Area harvested (1,000 ha) | Avg. yield (kg/ha) | Value ($1,000,000) |
| Idaho | 4.8 | 76 | 10.1 | 0.8 | 97 | 2.3 |
| Indiana | 2.9 | 30 | 5.3 | 1.6 | 22 | 1.4 |
| Michigan | — | — | — | 0.6 | 26 | 0.6 |
| Oregon | 16.2 | 80 | 47.7 | 0.6 | 82 | 1.6 |
| Washington | 6.7 | 96 | 20.0 | 3.9 | 146 | 14.6 |
| Wisconsin | 2.0 | 22 | 2.2 | 1.6 | 26 | 1.7 |
| Total | 32.6 | 61 | 85.3 | 9.1 | 6b | 22.2 |
Modified from: USDA (1989a).
Table 4. United States imports of specified oils, 1988.
| Selected essential oils | Quantity
(MT) | Value of
production
($1,000,000) | Major source |
| Anise oil | 49 | 0.6 | China, Spain, France |
| Bergamot oil | 53 | 2.2 | Italy, France, FRG |
| Camphor oil | 33 | 0.2 | Taiwan, China, France |
| Caraway oil | 8 | 0.2 | Netherlands, France, Poland |
| Cedar leaf oil | 32 | 1.5 | Canada |
| Cedarwood oil | 720 | 2.2 | China, Hong Kong |
| Citronella oil | 517 | 4.9 | China, Taiwan, Argentina |
| Citrus oils, other | 53 | 0.6 | Mexico, Brazil |
| Comment oil (Mentha arvensis) | 273 | 2.5 | China, Brazil, England |
| Eucalyptus oil | 312 | 1.9 | China, Australia, Brazil |
| Geranium oil | 83 | 3.5 | France, China, Egypt |
| Grapefruit oil | 85 | 1.2 | Brazil, Israel, Belize |
| Lavender oil (inc. spike) | 75 | 1.3 | France, Spain, Bulgaria |
| Lemon oil | 744 | 10.2 | Argentina, Spain, Italy |
| Lemongrass oil | 74 | 0.9 | Guatemala, India |
| Lignaloe (Bois de rose oil) | 53 | 1.3 | Brazil, France |
| Lime oil | 870 | 13.0 | Mexico, Peru, Brazil |
| Neroli (orange flower oil) | 1 | 0.5 | France, FRG |
| Onion and Garlic oil | 13 | 1.3 | Mexico, Egypt Netherlands |
| Orange oil | 5,684 | 8.8 | Brazil, Mexico, Israel |
| Origanum oil | 7 | 0.3 | Spain, France |
| Orris oil | 2 | 1.1 | FRG, France |
| Palmarosa oil | 15 | 0.4 | India, Guatemala, Brazil |
| Peppermint oil (mentha x piperita) | 13 | 0.4 | Hong Kong, France |
| Petitgrain oil | 119 | 2.3 | Paraguay, Brazil |
| Pine oil | 618 | 0.6 | Mexico |
| Pineneedle oil | 257 | 1.0 | Mexico, Canada |
| Rose oil (Attar of roses) | 2 | 8.7 | France, Turkey, Brazil |
| Rosemary oil | 48 | 0.5 | Spain France, Tunisia |
| Sassafras oil | 344 | 1.6 | Brazil, China |
| Spearmint oil | 69 | 0.8 | China, Hong Kong |
| Thyme oil | 14 | 0.5 | Spain, France |
| Vetiver oil | 96 | 6.0 | Haiti, Indonesia, France |
| Ylang ylang (Cananga oil) | 41 | 2.7 | France, Comoros, Indonesia |
| Other essential oils | 1,545 | 40.0 | France, China, Brazil |
| Total | 12,921 | 125.5 | |
Note: All values refer to f.o.b. country of origin.
Modified from: USDA (1989a).
Table 5. United States exports of selected essential oils, 1988.
| Essential oils | Quantity
(MT) | Value
($1,000,000) |
| Cedarwood, clove & nutmeg oils | 660 | 4.5 |
| Lemon oil | 317 | 4.8 |
| Orange oil | 1,701 | 5.3 |
| Peppermint oil | 1,236 | 41.4 |
| Spearmint oil | 461 | 14.2 |
| Other oils | 4,062 | 52.6 |
Modified from: USDA (1989a).
Table 6. United States imports of selected dried culinary herbs and spices, 1988.
| Item | Quantity (MT) | Value
($1,000,000) | Major source |
| Anise | 767 | 1.4 | Spain, Turkey, Egypt |
| Basil[SUP]z[/SUP] | 1,806 | 2.5 | Egypt, France |
| Capers | 1,124 | 6.5 | Spain, Morocco |
| Capsicum/Red peppers[SUP]z[/SUP] | 10,169 | 14.0 | Pakistan, China, Mexico, India |
| Caraway | 2,838 | 2.4 | Netherlands, Egypt Poland |
| Celery seed | 2,253 | 1.8 | India |
| Coriander[SUP]y[/SUP] | 5,938 | 3.3 | Mexico, Morocco, Romania |
| Cumin | 3,700 | 4.5 | Turkey, China |
| Dill | 364 | 0.6 | India, Egypt |
| Fennel | 1,754 | 1.8 | Egypt, India, China |
| Garlic | 3,714 | 1.4 | China |
| Ginger[SUP]x[/SUP] | 5,054 | 4.6 | Fiji, Brazil, China |
| Laurel[SUP]z[/SUP] | 616 | 0.9 | Turkey |
| Marjoram[SUP]z[/SUP] | 382 | 0.5 | Egypt |
| Mint leaves[SUP]z[/SUP] | 172 | 0.6 | FRG, Egypt |
| Mustard[SUP]z[/SUP] | 47,416 | 18.2 | Canada, France |
| Onions (dried, dehydrated) | 107 | <0.1 | Canada |
| Origanum | 3,837 | 7.2 | Mexico, Turkey Greece |
| Paprika | 4,917 | 8.5 | Spain, Hungary |
| Parsley | 964 | 1.1 | Mexico, Israel |
| Poppyseed | 3,693 | 4.0 | Australia, Netherlands |
| Rosemary | 810 | 0.7 | Spain, France, Yugoslavia |
| Sage | 1,666 | 5.6 | Yugoslavia, Albania |
| Savory | 194 | 0.1 | Yugoslavia, France |
| Sesame seed | 33,146 | 25.7 | Mexico, Guatemala, El Salvador |
| Tarragon | 62 | 0.6 | France, New Zealand |
| Thyme | 956 | 2.1 | Spain, Jamaica, Morocco |
| Turmeric | 1,639 | 2.0 | India |
| Mixed spices, others | 2,473 | 6.7 | India, Morocco, Thailand |
[SUP]
z[/SUP]Crude & all other forms.
[SUP]
y[/SUP]For seed and dried leaf (cilantro).
[SUP]
x[/SUP]Includes only ground and unground ginger root and sweet ginger.
Modified from: USDA (1989b).
Table 7. Estimated annual production of essential oils from aromatic plants grown in the United States.[SUP]
z[/SUP]
| Herbs | Species | Quantity
of oil
(MT) |
| Dill weed | Anethum graveolens L. | 70 |
| Clary sage | Salvia sclarea L. | 5 |
| Perennial wormwood | Artemisia absinthium L. | 3 |
| Basil | Ocimum basilicum L. | 1 |
| Wormseed | Chenopodium ambrosioides L. | 1 |
| Tansy | Tanacetum vulgare L. | 0.5 |
| Snakeroot (Canadian) | Asarum canadense L.[SUP]y[/SUP] | 0.1 |
| Celery herb | Apium graveolens L. | na[SUP]x[/SUP] |
| Celery seed | Apium graveolens L. | na |
| Marigold | Tagetes minuta L. | na |
| Parsley herb | Petroselinum crispum (Mill.) Nym ex A. W. Hill | na |
[SUP]
z[/SUP]Modified from Lawrence (1985), based on 1984 production.
[SUP]
y[/SUP]Roots of 'snakeroot' are also collected from Virginia snakeroot (
Aristolochia serpentaria L.)
[SUP]
x[/SUP]Data not available.
Table 8. Selected culinary herbs which can be grown in the continental United States.[SUP]
z[/SUP]
| Herb | Species[SUP]y[/SUP] |
| Apiaceae (Umbelliferae) | |
| Angelica | Angelica archangelica L. |
| Anise | Pimpinella anisum L. |
| Caraway | Carum carvi L. |
| Chervil | Anthriscus cerefolium (L.) Hoffm. |
| Cilantro | Coriandrum sativum L. (see coriander) |
| Coriander | Coriandrum sativum L. |
| Cumin | Cuminum cyminum L. |
| Dill | Anethum graveolens L. |
| Fennel | Foeniculum vulgare Mill. |
| Lovage | Levisticum officinale Koch |
| Mitsuba | Cryptotaenia japonica Hassk. |
| Parsley | Petroselinum crispum (Mill.) Nym. ex A. W. Hill |
| Asteraceae (Compositae) | |
| Chamomile | Chamaemelum nobile (L.) All (Roman) |
| Chamomilla recutita (L.) Rauschert (German) |
| Chicory | Cichorium intybus L. |
| Chrysanthemum (edible) or Chopsuey greens | Chrysanthemum coronarium L. |
| Costmary | Balsamita major Desf. |
| Curry Plant | Helichrysum angustifolium (Lam.) DC |
| Dandelion | Taraxacum officinale G. H. Weber |
| French Tarragon | Artemisia dracunculus L. |
| Boraginaceae | |
| Borage | Borago officinalis L. |
| Brassicaceae (Cruciferae) | |
| Arrugula or rocket salad | Eruca vesicaria (L.) Cav. ssp. saliva (Mill.) Thell |
| Horseradish | |
| American | Armoracia rusticana P. Gaertn. |
| Japanese | Wasabia japonica (Miq.) Matsumura |
| Mustard | Brassica spp. |
| Black | Brassica juncea (L.) Czern. |
| Brown | Brassica nigra (L.) W. Koch |
| White | Sinapsis alba L. |
| Pepper grass or garden cress | Lepidium sativum L. |
| Watercress | Nasturtium officinale R. Br. |
| Capparaceae | |
| Capers | Capparis spinosa L. |
| Iridaceae | |
| Saffron | Crocus sativus L. |
| Lamiaceae (Labiatae) | |
| Anise-hyssop | Agastache foeniculum (Pursh) Kuntze |
| Basil | Ocimum spp. |
| Beebalm | Monarda spp. |
| Hyssop | Hyssopus officinalis L. |
| Korean mint | Agastache rugosa (Fisch. & C. A. Mey) Kuntze |
| Lavender | Lavendula spp. |
| Lemon balm | Melissa officinalis L. |
| Mint | Mentha spp. |
| Peppermint | Mentha x piperita |
| Native spearmint | Mentha spicata L. |
| Scotch spearmint | Mentha x gracilis Sole |
| Marjoram | Origanum marjorana L. |
| Oregano | Origanum vulgare L. |
| Perilla | Perilla frutescens |
| Rosemary | Rosmarinus officinalis L. |
| Sage | Salvia officinalis L. |
| Savory | Satureja hortensis L. (summer savory) |
| Satureja montana L. (winter savory) |
| Thyme | Thymus spp. |
| Lauraceae | |
| Bay Laurel | Laurus nobilis L. |
| Liliaceae | |
| Chives | Allium schoenoprasum L. |
| Chinese chives | Allium tuberosum Rattler ex Spreng. |
| Garlic | Allium sativum L. |
| Kurrat | Allium kurrat Schweinf. ex K Krause |
| Leeks | Allium ampeloprasum, Porrum group |
| Shallots | Allium cepa, Aggregatum group |
| Polygonaceae | |
| Sorrel | Rumex acetosa L. |
| Ranunculaceae | |
| Black cumin | Nigella sativa L. |
| Rosaceae | |
| Burnet | Sanguisorba minor Scop. |
| Rutaceae | |
| Rue | Ruta graveolens L. |
| Verbenaceae | |
| Lemon verbena | Aloysia triphylla (L'her.) Britton |
| Mexican oregano | Lippia spp. |
[SUP]
z[/SUP]This list includes those already commercially produced and those with potential for commercial production.
[SUP]
y[/SUP]As taxonomically cited by Tucker (1986) and Staff of Liberty Hyde Bailey Hortorium (1976).
Last update March 21, 1997 by aw
