FOCUS
Issue Number 54
March 1995
Corning Hazleton
Flavoring healthful diets--
Spices continue to show steady gain in popularity
By John Wolf
The current stress on a healthful diet--with reduced sodium, fat, and sugar--has helped generate an escalating interest in spices as a source of novel flavors. In the United States, demand for spices, particularly the "hot" kinds, has risen sharply since the early 1980s. Since 1990, Americans have consumed over 800 million pounds of spices annually; the hot varieties--including black pepper, red pepper, mustard, and ginger--now account for over 40% of spices used in the U.S.
A number of herbs, especially those used in pizza and spaghetti sauce, have also experienced rapidly increasing popularity. Annual imports of basil doubled from 2.6 million pounds in 1983 to 5.4 million pounds in 1993. In the same period, oregano went from 8 million pounds to 15.1 million pounds. Less dramatic was the rise in sage imports, which climbed from 3.4 million pounds to 4.1 million pounds during that time.
Table 1 shows that most spices add an insignificant amount of sodium--as little as 0.3 mg per serving--to the diet and so can be used safely in place of salt to flavor foods. The sodium content of table salt is 38,758 mg/100g.
Table 1
Sodium content of some
popular spices
(mg/100 g)
Anise seed 16
Basil 34
Bay leaf 23
Capsicum 30
Celery seed 160
Chervil 83
Chili powder 1010
Cumin 168
Dillseed 20
Dillweed 208
Fennel seed 88
Garlic powder 26
Marjoram 77
Mustard seed 5
Onion powder 54
Oregano 15
Paprika 34
Pepper, black 44
Pepper, white 5
Poppy seed 21
Rosemary 50
Sage 11
Savory 24
Sesame seed 40
Tarragon 62
Thyme 55
Source: Farrell 1990
What are spices?
Spices and herbs, fresh or dried, are used to add flavor and color to food. Spices are the seeds, fruits, bark, or roots of plants, while herbs are the leafy parts. Despite this botanical distinction, spices and herbs are grouped and classified as spices by the U.S. Food and Drug Administration (FDA) and by the spice industry.
The chief sources of flavor in many spices are oils that volatilize at low temperatures. Most spices contain between 0.5% and 3.0% volatile oils. Grinding disrupts the cell structure of spices and causes a rapid loss of volatile oils. Spices also lose volatile oils as they age and when they are heated.
The two peppers and where they grow
The term pepper comprises two unrelated groups of plants, although
both groups yield hot spices. Black, white, and green peppers are the
berries of an evergreen vine, Piper nigrum, native to the southwestern
coast of India. The pungency of these "black" peppers is due to an
alkaloid, piperine. Black pepper is the dried berry (peppercorn) that
was picked just after turning red; white pepper is the ripe peppercorn
with the dark hull removed; green pepper is the immature berry. Black
peppers are grown in India, other countries in the East Indian region,
and Brazil.
Capsicum peppers, Capsicum frutescens, are natives of South and
Central America and the West Indies. They include red (or cayenne)
pepper, chili pepper, and sweet bell peppers. Red pepper is the ground
product of the smallest capsicum pods; the hottest red peppers now
come from Africa and China. Larger, milder peppers, primarily from
California, New Mexico, and Mexico, are ground to produce chili pepper.
Capsicums can be rated on pungency by Scoville heat units. Sweet bell
peppers have 0 heat units, jalepeños range from 2,500 to 10,000, and
habeneros exceed 200,000. The heat is a function of the "red" peppers'
capsaicin content, which originally was rated by trained testers but
which now can be measured directly by high-performance liquid
chromatography.
The black pepper and red pepper groups are both highly popular in the
U.S. Consumption of black pepper jumped nearly 60% from the
mid-1970s (58.2 million pounds per year) to the early 1990s (92.8 million
pounds per year). The increase for red pepper was even more
spectacular, going up almost 170% in the same period (32.5 million
pounds per year in the mid-1970s to 87.4 million pounds per year in
the early 1990s).
The source of spices
Although many spices are imported, the U.S. now produces nearly 40% of the volume of spices used each year in this country. The major U.S. spice products include dehydrated onion and garlic, paprika, chili peppers, and mustard seed. Canada ranks second among the suppliers of spices to the U.S.; the major product is mustard seed, but Canada is also a source of coriander seed and caraway seed. Rounding out the top five spice suppliers to the U.S. in 1993 were India, Indonesia, and Mexico. Other source countries are listed in Table 2.
Imported spices typically enter the U.S. through ports in New York City, Los Angeles, and San Francisco, where they are checked for wholesomeness and cleanliness by FDA inspectors. The spices are sold to various spice companies throughout the country for further processing, including cleaning, grinding, blending, and packaging.
Table 2
Top 12 spices consumed in the U.S. in 1993
Spice Total Major source countires
consumption
(x 1,000 lb)
Dehydrated
onion & garlic 213,242 U.S., China, Mexico
Mustard seed 140,283 Canada, Japan, Hungary
Red pepper 92,746 U.S., Mexico, India, China
Sesame seed 81,380 Guatemala, Mexico, El Salvador, Nicaragua
Black pepper 80,733 India, Indonesia, Brazil
Paprika 59,089 U.S., Spain, Morocco
Cinnamon 31,788 Indonesia, China, Sri Lanka, India
Oregano 15,124 Turkey, Mexico, Greece
White pepper 12,080 Indonesia, Singapore, Brazil
Cumin seed 11,529 Turkey, Pakistan, Syria
Poppy seed 11,377 Australia, Netherlands
Ginger 9,645 Brazil, India, China
TOTAL 759,016*
*This amount represents about 95% of U.S. spice consumption in 1993.
Source: ASTA 1993
Foreign matter and microbes
Flavor is the critical factor for spices, but cleanliness and freedom from microbial contamination are also crucial elements of spice quality. Many spices contain extraneous matter such as insect parts and stones, or support colonies of bacteria or fungi, when they arrive from suppliers. Processors must treat these problems of contamination before spices are put on the market.
Dealing with defects
The FDA and the American Spice Trade Association (ASTA) each have developed specifications for foreign material ("defects") in imported spices. Both sets of guidelines recognize that spices need additional cleaning by processors after they arrive from suppliers. One method of testing for foreign matter involves placing a spice sample in a dense organic solvent such as carbon tetrachloride; the heavy extraneous matter sinks while the spices float. Foreign matter in a spice can also be determined by burning a sample of the spice and then analyzing the components of the ash before and after it has been treated with acid. Processors use air separators, gravity separators, and centrifugal separators to rid spices of foreign matter.
Managing microbes
Microorganisms in spices can lead to spoilage or disease if infected spices are incorporated into food products. Although microbial contamination is often attributed to the lack of good sanitary conditions in some countries where spices are produced, even onion powder grown and processed in the U.S. may have total plate counts of 1 million/g. Other spices likely to be heavily contaminated by microbes include allspice, black pepper, caraway, celery seed, chili peppers, cumin, paprika, thyme, and turmeric.
Cloves, fennel, garlic powder, and mint, which originate from plants that produce natural antimicrobial substances, generally contain smaller bacterial populations. Cinnamon, mustard, and nutmeg are other spices with low levels of bacteria.
Among bacteria of concern in spices are Clostridium perfringens, Bacillus cereus, and Salmonella. Various fungi in spices can also pose a potential health threat.
Treating spices with ethylene oxide can reduce microbial counts by 90%. This gas has been classified as a carcinogen, and it can react with chlorides in foods to produce toxic and persistent chlorhydrins. Since traces of ethylene oxide remain on spices after treatment, use of the gas for ridding spices of microbes is being phased out worldwide. Propylene oxide is an alternative to ethylene oxide, but it is less effective at reducing microbes and also generates chlorhydrins.
Sterilization by heat seriously degrades the flavor of spices. Microwave treatment of spices has been attempted but does not effectively reduce microbe levels. Ultraviolet radiation does not have enough penetrating power to decontaminate spices.
Probably the most effective way to reduce or eliminate bacterial and fungal populations on spices--and the least likely to cause flavor changes--is to subject them to ionizing radiation. In fact, the FDA permits low levels of radiation for treating spices (see Table 3), although such products must be labeled as "treated with radiation." The spice industry is still leery of the public's reaction to irradiated food. As a result, no spices sold in retail stores in the U.S. are known to be treated with radiation, and less than 1% of spices used in processed foods in this country have been irradiated. Foods that contain irradiated ingredients do not have to carry the irradiation label.
Table 3
Radiation needed to yield
safe microbe levels in spices
Spice Dose (kGy)
Anise 5
Basil 4-10
Capsicum 5-8
Caraway 7
Cardamom 5-8
Cinnamon 5-10
Coriander 5
Cumin 5-6
Fennel 8
Fenugreek 5-10
Garlic powder 5-7
Ginger 5-10
Mace 5
Marjoram 5-10
Mustard seed 4-10
Nutmeg 5
Onion powder 5-10
Oregano 4-10
Paprika 4-8
Pepper, black 4-6
Pepper, white 5-10
Sage 4
Savory 5
Thyme 5-7
Turmeric 5-7
Adapted from: Kiss & Farkas 1988 and Sjöberg et al. 1991
Spice extractives
Another method for overcoming microbial contamination is to use the essential oils and oleoresins extracted from spices. Spice extractives are virtually free of microorganisms. Frequently, however, the flavor and blending qualities of an extractive do not match those of its whole or ground counterpart.
Essential oils are the volatile fractions of spices and are typically extracted by steam distillation. Mint oils used in confectionery products are an example of essential oils. Often it is one of the minor components of a complex essential oil that produces the characteristic aroma and flavor.
Oleoresins, which are extracted with solvents (see Table 4), are the essential oils plus the nonvolatile components of spices. They produce a closer approximation of the natural spice flavor than essential oils do. Rosemary, black pepper, capsicum, celery, ginger, nutmeg, paprika, and turmeric oleoresins are widely employed in food production. Oleoresins have a flavor strength that ranges from six times greater than unprocessed celery to more than 40 times greater than natural nutmeg.
Each manufacturer standardizes its essential oils and oleoresins so that these spice extractives produce the same flavor from batch to batch and from year to year. This process of standardization reduces the differences caused by the varying quality and sources of spice crops.
Table 4
Common solvents for extracting oleoresins
from spices and their maximum allowable residues
Solvent Residue levels (ppm)
Acetone 30
Ethylene dichloride 30
Isopropyl alcohol 50
Methyl alcohol 50
Methylene chloride 30
Hexane 25
Trichloroethylene 30
Note: A number of countries do not permit chlorinated solvents for extracting oleoresins.
Source: Guzinski & Lupina 1992
Labeling, safety, and storage
FDA rules specify that spices must be the actual products described by their common name on the package label and that no volatile oils or other source of flavor can be removed. The identity of spices is established by their botanical name; thus anise is defined as the dried fruit of Pimpinella anisum L.
When spices are incorporated into a food product, they may be declared on the ingredient listing without naming the specific spices. Only if a representation is made concerning a specific flavor of the food product does the spice or other flavoring ingredient need to be named.
An expert panel sponsored by the Flavor and Extract Manufacturers Association (FEMA) evaluates flavoring ingredients, and FEMA publishes lists of flavorings that are generally recognized as safe (GRAS) when used in various categories of food at or below the levels specified by the panel. The FDA recognizes the FEMA lists of GRAS flavoring substances.
Most spices are dried and ground before being sold. These processing techniques affect the flavor qualities and the storage life of spices. Processed spices are ideally kept in dark-glass jars, although typically they are sold in clear-glass, metal, or cardboard containers. ASTA recommends pull dates ranging from 2 to 4 years for processed spices sold in retail stores.
Fresh spices
The consumption figures cited at the beginning of this article represent estimates for dried spices only. Although no comparable figures are available for fresh spices and herbs, these products have enjoyed a rising popularity in recent years. The increasing value of fresh spices and herbs has led to greater attention to the factors affecting their perishability. More research is needed, however, before standards can be set for such qualities as the aroma and flavor of fresh herbs. Postharvest conditions that are suitable for one fresh herb may not be appropriate for another.
Some critical factors in determining the shelf life of fresh herbs and spices include:
Temperature. In experimental situations, most herbs retain good visual quality after being held up to 4 weeks at 0°C. Fresh thyme, oregano, rosemary, mints, sage, parsley, cilantro, savory, marjoram, dill, tarragon, and watercress last longest when kept at 0°C. Basil suffers chilling injury, including loss of flavor, after 5 to 7 days at 7.5°C and after only 2 days at 2°C. The sensitivity of basil to injury at these temperatures poses practical problems because basil is often shipped with other herbs. Maintaining the shipping temperature at 5°C leads to some chilling damage to the basil and accelerates damage to the other herbs.
Humidity. Most herbs retain their freshness and quality best at relative humidities between 90% and 98%. Fungal growth is likely to occur if the relative humidity rises above 98%, as is likely to happen when herbs are packed in plastic film and exposed to light or fluctuating temperatures. On the other hand, polyethylene-lined cartons reduce water loss, and thus help maintain quality, in salad herbs including watercress, dill, chives, chervil, and coriander. Most fresh herbs become unsalable once they have lost between 5% and 40% of their water content.
Atmosphere. Oxygen levels below the normal 21% and carbon dioxide levels above the normal 0.035% reduce the degradation of many fresh herbs by lowering concentrations of ethylene in storage areas. Ethylene is produced in small amounts by plant tissue but is also likely to be present in the storage environment from exhaust of gasoline engines and other sources. Leaves react to ethylene by yellowing, falling off the main plant, or wilting. Responses to ethylene occur at concentrations ranging from 0.1 to 10 µL/L. Fresh herbs that are sensitive to ethylene include basil, marjoram, mint, oregano, parsley, and savory.
Light. The interaction of light, ethylene, and carbon dioxide on fresh herbs is complex. Light can lead to reduced levels of carbon dioxide in the storage atmospheres of fresh tarragon, oregano, and dill, thereby increasing the levels of ethylene. On the other hand, light can stimulate the production of ethylene at high levels of carbon dioxide.
Handling. Herbs such as mint, basil, and cilantro are especially susceptible to physical injury, which leads to tissue deterioration and greater likelihood of microbial damage.
Contamination from packaging materials is possible if the oils in spices interact with inks, adhesives, and colorants. Migration from packaging materials, particularly polyethylene, may also cause contamination of fresh herbs and spices, but research is lacking on this topic.
The future of spices
ASTA predicts continued growth in spice consumption as people seek ever more exotic elements in their diets. Research will continue on the possible role of spices in nutrition and medicine, including such factors as the antioxidant and antimicrobial properties of some spices. Growing, harvesting, shipping, processing, and packaging techniques will also be improved as demand for spices rises. Artificial flavors are certain to be developed that will be valuable in some food-processing applications, but the plants that yield natural spices are unlikely to be relegated to the endangered species list.
References
American Spice Trade Association (ASTA). Spice consumption report '93, ASTA, Englewood Cliffs, NJ, 1993.
Anon. Setting the record straight on irradiation. Food Processing Newsletter 14(13):3, March 30, 1992.
Cantwell, M.I., and M.S. Reid. Postharvest physiology and handling of fresh culinary herbs. Journal of Herbs, Spices & Medicinal Plants 1(3):93-127, 1993.
Charalambous, G. (ed). Spices, Herbs and Edible Fungi. Elsevier, New York, 1994.
Farrell, K.T. Spices, Condiments, and Seasonings, second edition. Van Nostrand Reinhold, New York, 1990.
Giese, J. Modern alchemy: Use of flavors in food. Food Technology, February 1994, pp. 106-108, 110, 112-116.
Guzinski, J.A., and T.M. Lupina. Spices and herbs: Natural extractives. In: Y.H. Hui (ed.), Encyclopedia of Food Science and Technology, John Wiley & Sons, New York, pp. 2406-2410, 1992.
Kiss, I., and J. Farkas. Irradiation as a method for decontamination of spices. Food Reviews International 4:77-92,1988.
Kneifel, W., and E. Berger. Microbiological criteria of random samples of spices and herbs retailed on the Austrian market. Journal of Food Protection 37:893-901, 1994.
Sjöberg, A.-M., et al. Irradiation of spices and its detection. Food Reviews International 7:233-253, 1991.
Tainter, D.R. Spices and seasonings. In: Y.H. Hui (ed.), Encyclopedia of Food Science and Technology, John Wiley & Sons, New York, pp. 2410-2418, 1992.
Tucker, A.O., and M.J. Maciarello. Shelf life of culinary herbs and spices. In: G. Charalambous (ed.), Shelf Life Studies of Food and Beverages, Elsevier, New York, pp. 469-485, 1993.
FOCUS is published as a source of information for the food science industry.
John Wolf, editor
©Corning Hazleton Inc. 1995