Lumpkin, T.A., J.C. Konovsky, K.J. Larson, and D.C. McClary. 1993. Potential
new specialty crops from Asia: Azuki bean, edamame soybean, and astragalus.
p. 45-51. In: J. Janick and J.E. Simon (eds.), New crops. Wiley, New York.
Potential New Specialty Crops from Asia: Azuki Bean, Edamame Soybean,
and Astragalus
 T.A. Lumpkin, J.C. Konovsky, K.J. Larson, and D.C. McClary
Agricultural
exports help to maximize the utilization of United States agricultural
potential, strengthen the overall economy, and improve the balance of
trade. For example, Japan imports about $23 billion worth of agricultural
commodities each year, about $8 billion from the United States. Major
agricultural exports like wheat and soybeans, which are in surplus on
the world market, comprise only a small portion of the value of Japan's
agricultural imports. About 60% of Japan's $23 billion in food imports
are niche market commodities, many having potential for development
as new crops and value-added exports from the United States. Niche markets
for agricultural commodities common in Pacific Rim countries (e.g. Japan,
Korea, Taiwan), but not important on a worldwide basis, have received
relatively little attention from United States researchers or food corporations.
This paper presents information on two of the numerous East Asian crops
that have niche market export potential. In addition, many East Asian
crops have potential for use as forage, fodder, and soil reclamation
within the United States. The East Asian Crop Development Program of
the IMPACT Center at Washington State University studies some of these
East Asian crops, including azuki bean, edamame vegetable soybean, and
Astragalus adsurgens Pall.
AZUKI BEAN
Botany
Azuki seeds are subcylindric
with subtruncated ends with a length of 5.0 to 9.1 mm, width of 4.0 to 6.3
mm, thickness of 4.1 to 6.0 mm, and weight of 50 to 250 mg/seed (McClary
1990). Much of the size variability among cultivars can be attributed to
the development of two distinct market classes in Japan, regular-sized (>4.2
mm length) and a larger dainagon type (>4.8 mm length) (Hoshikawa 1985).
The seed has a smooth seed coat, a strongly defined cotyledonary ridge,
and an elevated micropyle. The white azuki hilum is 2.4 to 3.3 mm long and
0.6 to 0.8 mm wide. Seed colors range from a common solid maroon to solid
black, blue-black, grey, brown, straw, white, and various mottled combinations
of these.
Seedlings emergence
is hypogeal; seed leaves are cordate, long-petioled, and simple. The plant
is a bushy, usually erect and slightly pubescent annual that grows from
27 to 90 cm high. Some azuki cultivars exhibit viney growth and can climb
from 1 to 3 m. Stem color is normally green but some cultivars are purplish.
Branching occurs between the 4th to 9th main stem nodes (Hoshikawa 1985)
and secondary branching does not occur under normal planting densities.
Stipules are small,
entire or faintly 3-lobed, peltate, lanceolate, acuminate, and have basal
appendages. The leaf is pinnately trifoliate with the middle leaflet being
broadly ovate and attached to the petiole by a long petiolule; leaflets
are 5 to 8 cm wide and 5 to 10 cm long. Some cultivars produce lanceolate-shaped
leaflets (Hoshikawa 1985).
Azuki has a taproot
type of root system that can extend in a sphere 40 to 50 cm from the point
of seed germination; secondary branch development occurs later in the
season and can reach 40 cm. Root nodules resulting from cowpea group rhizobium
infections are spherical, 4 to 10 mm in diameter, and begin developing
when primary leaves start to unfold (Hoshikawa 1985).
Azuki flowers are
bright yellow, have hairy styles, flattened stigmas, and an asymmetrical
keel that curves to the left and has a hornlike appendage on one side.
Inflorescence and flower primordium start developing 23 and 21 days before
anthesis, respectively; anthesis normally starts in the morning and can
continue for up to 40 days (Hoshikawa 1985). Racemes are axillary, borne
on long pedicels on higher parts of the plant and short-subsessile pedicels
on the lower parts, and consist of from 6 to 20 flowers. Floral development
progresses upward with anthesis beginning on lower main stem nodes and
branches first.
Azuki pods are smooth,
cylindrical, thin-walled, and green turning white to grey as they mature.
Pods hang down and are restricted between seeds when mature. They are
6 to 13 cm long, 0.5 cm in diameter, with 2 to 14 seeds/pod, 2 to 6 pods/pedicel,
and 5 to 40 pods/plant. Maturation is indeterminate but, 85% of all pods
mature at about the same time. Pod shatter during seed ripening and harvesting
is a problem under certain conditions. Components of yield were reported
by Nakaseko (1983) to range from 53.4 to 81.2 pods/plant, 1.0 to 1.67
pods/node, 5.1 to 7.5 seeds/pod, and 31.8 to 74.4 g dry seed yield/plant
for six cultivars.
Production
Azuki is or could be
grown in ecosystems with between 530 to 1730 mm of annual precipitation,
a 7.8° to 27.8°C range in mean annual air temperature, a soil
pH between 5.0 to 7.5 and up to 48deg.N latitude (Duke 1981). However, current
sites of major azuki production are between 40 to 45°N.
Almost all production
of azuki occurs in four countries: Japan, China, Taiwan, and South Korea.
Other past or present azuki producing countries include Australia, the
Philippines, Japan, the Republic of Congo, Thailand, India, Italy, New
Zealand, USSR, China, Belgium, United States, Brazil, Argentina, Malaysia,
Kenya, Zaire, and Angola.
Japan produces about
90,000 t of azuki each year on about 64,000 ha, of which 60% is on the
island prefecture of Hokkaido. Yields average about 1,500 kg/ha in Japan
but can vary widely, especially on Hokkaido, depending mostly upon the
length of the growing season, accumulated degree days and weather conditions.
The main site of
Chinese production occurs in Wuging county, Hebei province, with 4,000
to 5,000 ha annually. Other azuki producing areas are western Jilin province,
Tai Lai county of Heilongjiang province, north of the Huaihe River and
near Qinling. In Taiwan, azuki is an important winter crop grown in rice
paddies, especially in Pingtung and Kaohsiung provinces which account
for 98% of all Taiwanese production. Azuki is one of the four most important
grain legumes produced in South Korea in terms of planted area and production.
Production is scattered throughout the country, usually on hill-side land
in rotation with wheat and barley or some in converted paddy fields.
Azuki is believed
to have been introduced into the United States by the Perry expedition
in 1854. Piper and Morse (1914) provided a list of early introductions
of azuki into the United States. The United States has never been a major
world producer of azuki although the crop has been grown experimentally
and/or on a limited production scale in several states over the past 130
years. Early adaptation experiments were conducted in Kansas, Virginia,
and North Carolina, and it was used as a green fodder crop in some southern
sections of the country (Hoshikawa 1985; Sacks 1977).
Uses
Azuki has been consumed
in East Asia for over 2,000 years in a myriad of ways that take advantage
of the seed's maroon color and delicate flavor; it is traditionally served
on festive days such as weddings, birthdays, or New Year parties (McClary
et al. 1989). Azuki is made into a sweet confectionery paste (an),
candied whole beans (amanatto), a component of sweet soups (zenzai
and sarashi ame), a mixture with rice (azuki-mochi and sekihan),
sprouts (moyashi), or flour.
The most common
use of azuki is the sweetened paste form called an. Azuki an,
either in a smooth or chunky form, is used in numerous East Asian foods
and desserts such as cakes, manju (steamed an-filled buns),
yokan (cold gelatinized an slices), taiyaki (an-filled
waffle), ice cream, snow cone toppings, and as a base for a beverage served
hot from vending machines (Shiruko). About 30% of all an
is used by the Japanese and Korea ice cream industries. An can
also be flavored with soy sauce or with sweet syrups. A white seeded azuki
is also used to make high quality white an for specialty Japanese
bakery products (Narikawa 1972).
Azuki an
is produced from seed by the following generalized steps: soaking, boiling,
rinsing with water to remove antidigestive compounds, crushing, removal
of seed coats, drying, and then combined with sugar and various stabilizing
ingredients such as agar agar (Duke 1981). Traditional an is composed
of equal parts azuki paste and sugar. Rice beans and various common beans
are occasionally substituted for azuki in Japanese an production,
but azuki is the preferred seed for high quality an (McClary et
al. 1989). An can substitute for other traditional Western-style
fillings and flavorings in sweet rolls, donuts, and ice cream. Japanese
azuki consumption is currently broken down into the following categories:
an paste (68.9%), candied seeds (12.8%), boiled seeds (2.4%) and
other (15.9%) (Japan Bean Fund Assoc. 1987). In the mid 1970s, 85% of
Japanese domestic production and imports of azuki were being used in the
production of an.
EDAMAME SOYBEAN
Botany
Edamame is a specialty
soybean [Glycine max (L.) Merrill] harvested as a vegetable when
the seeds are at the immature R6 stage and have expanded to fill 80 to 90%
of the pod width. The botany of edamame is similar to the field soybean
except for minor morphological and physiological differences (Konovsky et
al. 1992).
Production
Immature soybean seeds
are consumed as vegetables in almost every country that produces soybeans.
In Japan, China, Korea, and Taiwan special cultivars of soybeans were selected
for the eating quality of their immature seeds. These edamame cultivars
of soybean can be transplanted or direct seeded. In Japan, transplants are
used in forced and early production systems (Kono 1986). Forced production
occurs in CO2 enriched, heated greenhouses. Planting starts in
November and production ends with the last harvest in July. Early spring
field production starts in February with the planting of seedling nurseries.
Seedlings are transplanted in to small plastic tunnels 25 to 30 days later
and harvested by the end of July. Regular field production begins in March
and ends by October. Early summer demand pressures farmers to harvest as
early as possible to obtain higher prices, therefore the onset of harvest
is being continually advanced through improved crop management and cultivar
development.
Most edamame is
harvested by hand. When edamame is sold on the stem, plants are hand cut
or pulled out with roots intact, unacceptable pods and lower leaves are
culled, and branches are tied together in small, aesthetically pleasing
bundles. For sale of harvested pods, plants are cut and pods stripped
off, sorted, and packaged. In Japan, electrical powered, stationary pod
strippers are available and in Taiwan, an Italian single row bean picker
is being tested (Konovsky et al. 1992). Initial studies on mechanical
harvesting have been conducted in Tennessee (Collins and McCarty 1969)
and at INTSOY (1987). For frozen product, standard methods for processing
have been described (Liu and Shanmugasundaram 1982).
Japan is the largest
commercial producer, nearly 105,000 t in 1988 (MAFF 1990), and the largest
importer, over 33,000 t in 1989 (JTA 1989). Taiwan supplies over 99% of
those imports as frozen edamame. Almost all Japanese production is consumed
as fresh product during the summer months (Kono 1986). Other countries
which have produced commercial quantities of edamame include Argentina,
Australia, Israel, Mongolia, New Zealand, Taiwan, and Thailand. Home gardeners
are known to produce it in Bhutan, Brazil, Britain, Chile, France, Germany,
Indonesia, Malaysia, Nepal, Philippines, Singapore, and Sri Lanka (after
Wang et al. 1979).
Uses
In most of East Asia,
vegetable soybeans are harvested and sold as pods-on-stems, loose pods,
or shelled beans (mao dou in China, edamame in Japan, and
poot kong in Korea). The pods-on-stems form is no longer commonly
consumed in China or Korea, but is still a popular form in Japan, partially
because appearance and flavor factors decline more slowly after harvest
while pods remain attached to the stem. In China, vegetable soybeans are
usually cooked as shelled immature seeds, but sold in the pod or shelled;
they are used primarily as an ingredient in stir fry dishes. In Korea,
the beans are added to rice and cooked together (pub mi kong).
In Japan, vegetable soybeans are usually sold as loose pods, occasionally
on the stem, and rarely shelled, although shelled forms have been used
to make a sweetened paste (zunda) and edamame tofu.
Edamame is consumed
mainly as a snack, but is also used as a vegetable, an addition to soups,
or processed into sweets. As a snack, the pods are lightly cooked in salted,
boiling water and then consumed by pushing the seeds directly from the
pods into the mouth with the fingers. As a vegetable, the beans are mixed
into salads, stir fried, or combined with mixed vegetables. In soup (gojiru
in Japanese), the beans are ground into a paste with miso and is used
to form a thick broth. Confectionery products such as sticky rice topped
with sweetened edamame paste are occasionally prepared (zunda mochi
in Japanese). For marketing, edamame pods are sold fresh on the stem with
leaves and roots, or stripped from the stem and packaged fresh or frozen
as either pods or beans.
In North America,
edamame is usually called vegetable soybean, but also beer bean, edible
soybean, fresh green soybean, garden soybean, green soybean, green vegetable
soybean, immature soybean, large-seeded soybean, vegetable-type soybean,
and the Japanese name, edamame (Shurtleff pers. commun.). The use of the
word green is confusing because mature soybean seeds with a green seed
coat or cotyledons are also called green soybeans.
Edamame research
as been conducted in the United States for over 50 years. Dorsett and
Morse collected extensive germplasm from 1929 to 1931, and Morse used
it to develop 49 cultivars of edamame (Hymowitz 1984). Research flourished
during the 1930s and 1940s because of a protein shortage (Smith and Van
Duyne 1951). A second surge of research began with the interest in organic
farming in the 1970s. The Rodale Research Center focused edamame research
on adaptability and quality (Hass et al. 1982). Basic agronomic research
was begun at Cornell (Kline 1980) and seed companies developed new cultivars,
e.g. `Butterbeans'. Today, some home gardeners grow edamame, but there
is little commercial production. Asian-Americans seeking edamame are usually
limited to frozen imports in specialty supermarkets.
ASTRAGALUS
Botany
Astragalus adsurgens
Pall, Fabaceae (upstanding milkvetch, green great wall astragalus, or sha
da wang which means flourishes in sand storms, in Chinese) is a perennial
plant distributed throughout northern and southwestern China and northern
North America. It is very cold tolerant and well suited for high temperature,
arid to semi-arid regions with poor or saline soils, previously considered
wastelands. Its deep tap root system can access water from deep within the
soil profile. In sandy, arid areas of China, it is cultivated for fodder,
green manure and is used for soil conservation.
Plants have several
stems which grow to a height of 1.5 to 2.0 m, and are covered with compound
pinnate leaves having T-shaped soft hairs. The primary root is thick and
long with many lateral roots. The secondary root system begins 20 to 30
cm below the soil surface and can attain 150 cm in width. Rhizobium nodules
develop on the upper portions of the roots near the soil surface.
Seedlings grow slowly,
averaging 0.5 cm daily, the first year. Once established, its growth exceeds
that of competing weeds. Rapid growth continues from the second to fourth
year, primarily in May and June (1 cm daily). Plants will reach a height
of 70+ cm and tiller during July and August, reaching a final height of
105 to 110 cm with 20 to 25 tillers.
Flowers bloom throughout
August. Some racemes are apical, but most are axillary. Inflorescences
are indeterminate and have 17 to 79 small blue, purple or blue-purple
papilionaceous flowers. Pod development is evident 2 or 3 days following
bloom and pods are square in cross-section, consisting of two chambers
with 10 dark brown seeds per chamber and are 6 to 13 mm long with a bent
beak-shaped top. Seed development begins 7 days post-anthesis (Barneby
1964).
Production
An estimated 670,000
ha of potential grasslands were aerially sown between 1979 and 1986 with
A. adsurgens seed in China (Ning et al. 1984b). The seed is pelletized
along with Rhizobium in a peat medium. The pelleted seed is then aerial
sown in sandy, semi-arid regions to promote vegetative growth. These pastures
of mixed forbes traditionally feed camels, sheep, and goats.
Studies on forage
yield and quality, along with seed production have shown that A. adsurgens
is capable of producing 75 t/ha of coarse, fresh fodder. The crop can
be harvested 2 or 3 times yearly beginning the second year. Crude protein
values range from 12 to 14% and crude fiber range from 27 to 30%. Profuse
seed production continued even under semi-arid growing conditions. The
A. adsurgens planted at Pullman, Washington has been growing successfully
for five years under 500 mm mean annual rainfall.
A superior Rhizobium
strain, CA 8116, was identified for A. adsurgens (Ning et al. 1984a,b).
Plants inoculated with CA 8116 increased nodulation from 27 to 47% at
the first leaf stage, while, total biomass increased by 81%.
Uses
Chinese research focuses on soil conservation and livestock feeding trials.
Feeding trials have included but are not limited to pigs (Chen et al. 1987)
and broiler chickens (Lei et al. 1987). Studies have shown comparable growth
on pigs and chickens when fed limited quantities (4% for broilers and 20%
for pigs) of A. adsurgens meal incorporated in daily diet rations
as compared to alfalfa meal. No signs of toxicity were noted in the liver
and kidney or blood glucose levels. These studies are significant, as both
species are non-ruminant animals and require greater care in daily diets
as compared to sheep and cattle, both ruminants.
CONCLUSIONS
Both edamame and azuki
share a common challenge to their development as viable new crops: the lack
of adequate information about the cultivation and processing required to
produce products that satisfy the quality conscious Japanese market. Edamame
production is similar to soybean production, but there are unique cultivars
and management practices used in Japan that enhance its quality. The management
practices are not well documented in English-language journals. A small
literature review on azuki was prepared by Sacks (1977), but left many questions
concerning cultivation and processing unanswered. There is an extensive
body of literature in Japanese about azuki that has been reviewed in a book
(Lumpkin and McClary 1992). By drawing on Japanese research, the development
of these two Japanese crops as new crops in the United States can be hastened.
Edamame and azuki
each face other issues related to quality. Japanese consumers show a strong
preference for the taste and other qualities of Japanese cultivars of
edamame over those from Taiwan or the United States. The edamame germplasm
collection of 600 accessions at Washington State University (WSU) will
be used to develop cultivars well suited to the Pacific Northwest climate
with the qualities the Japanese desire.
For azuki, there
are no industry standards for the quality of an paste in the United
States and a very poor understanding of Japanese quality standards. While
a rudimentary understanding of the general process and technology required
for paste production was obtained on a tour of azuki facilities, quality
issues are being studied at WSU to find quantifiable characters. Future
United States an paste production will depend upon our understanding
and meeting Japanese quality standards.
The introduction
of two new crops to the Pacific Northwest will further diversify United
States agricultural exports away from surplus commodities. With proper
research, the potential exists for United States producers to capture
a large share of the Japanese and Korean market for imported azuki and
edamame. Market analyses for both commodities indicate a consistent opportunity
for export of high quality raw and processed products to Japan (Cook 1988).
A market study by our research group on azuki has just been completed
and is available from the IMPACT Center at Washington State University
(McClary et al. 1989). Several East Asian countries cannot meet their
own needs for many niche crops and the long-term demand in the marketplace
is stable, thus the United States has the opportunity to export products
needed in foreign markets if they are of higher quality and more competitively
priced than current imported.
New East Asian crops
should also be considered for solving environmental problems within the
United States Chinese selections of A. adsurgens were recently
introduced into the United States. Although limited research has been
conducted within the United States thus far, the plant holds great potential
for restoration and conservation in cold arid regions where soil erosion
is a problem.
REFERENCES
- Barneby,
R. 1964. Atlas of North American astragalus part II. Mem. New York Bot.
Gard. Vol. 13.
- Chen,
W.Z., M. Ni, F. Li, and H. Liu. 1987. Feeding effects of various ratio
of ground fodder from alfalfa, Astragalus adsurgens Pall, and
Sesbania cannabina in pig's daily rations. China Grassland 4(4):12-16.
- Collins,
J.L. and I.E. McCarty. 1969. Handling of vegetable soybeans mechanically.
Soybean Dig. 12:20-21.
- Cook,
A.K. 1988. The evolution of Japanese food spending patterns: 1963-1984.
Washington State University, IMPACT Center Rpt 26. Pullman.
- Duke,
J.A. 1981. Vigna angularis (Willd.) Ohwi & Ohashi, p. 288-293.
In: Handbook of legumes of world economic importance. Plenum Press,
New York.
- Haas,
P.W., L.C. Gilbert, and A.D. Edwards. 1982. Fresh green soybeans: analysis
of field performance and sensory qualities. Rodale, Emmaus.
- Hoshikawa,
K. 1985. Azuki beans (in Japanese), p. 460-471. In: Edible crops. Yokendo
Publisher, Tokyo.
- Hymowitz,
T. 1984. Dorsett-Morse soybean collection trip to East Asia: A 50 year
perspective. Econ. Bot. 38:378-88.
- INTSOY.
1987. INTSOY research focuses on green soybeans as commercial frozen
vegetable. INTSOY Newsletter 37:1-2.
- Japan
Bean Fund Association. 1987. Information on miscellaneous beans (in
Japanese). (July) Tokyo.
- Japan
Tariff Association (JTA). 1989. Japan exports and imports. Tokyo.
- Kline,
W.L. 1980. The effect of intra and interrow spacing on yield components
of vegetable soybeans. MS Thesis, Cornell Univ., Ithaca, NY.
- Kono,
S. 1986. Edamame, p. 195-243. In: K. Tanaka, E. Ishida, S. Kono, and
M. Kohata (eds.). Methods of bean production (Sakukei o Ikasu Mamerui
no Tsukurikata). Nosangyoson Bunka Kyokai, Tokyo.
- Konovsky,
J., T.A. Lumpkin, S. Shanmugasundaram, and T.S.C. Tsou. 1992. Edamame:
the vegetable soybean. Asian Vegetable Research and Development Center,
Tainan, Taiwan.
- Lei, Z.Y.,
Z. Zhang, X. Feng, and J. Wang. 1987. The effects of feeding diets containing
Astragalus adsurgens Pall. and Coronilla varia L. on broiler
chickens. Acta Veterinaria Zootechnica Sinica. 18(3):157-162
- Liu, C.
and S. Shanmugasundaram. 1982. Frozen vegetable soybean industry in
Taiwan, p. 199-212. In: M.C. Ali and L.E. Siong (eds.). Vegetables and
ornamentals in the tropics. Univ. Pertanian Malaysia, Serdang.
- Lumpkin,
T.A. and D.C. McClary. 1992. Azuki bean: botany, production and uses.
Commonwealth Agr. Bureau Int., Oxon, UK.
- McClary,
D.C. 1990. Azuki, Vigna angularis (Willd.) Ohwi & Ohashi:
A literature review and agronomic evaluations for production in the
Columbia Basin. MS Thesis, Washington State Univ., Pullman.
- McClary,
D.C., T.L. Raney, and T.A. Lumpkin. 1989. Japanese food marketing channels:
a case study of azuki beans and azuki products. Washington State Univ.,
IMPACT Center Rpt. 29. Pullman.
- Ministry
of Agriculture, Forestry, and Fisheries (MAFF). 1990. Statistical handbook.
Norinsuisansho, Tokyo.
- Nakaseko,
K. 1983. Studies on dry matter production, plant type, and productivity
in grain legumes (in Japanese, English summary). Ann. Hokkaido Univ.
Agr. Dept. 14(2):103-158.
- Narikawa,
T. 1972. Kidney bean and azuki bean in Japan with reference to breeding
in Hokkaido, p. 179-188. In: Symposium on food legumes: Proc. Symposium
on Tropical Agriculture Researches, 12-14 September 1972. Trop.Agr.
Res. Ser. 6.
- Ning,
G.Z., Y. Li, Y. Wu, Y. Huang, and D. Yu. 1984a. Selection and application
of rhizobium astragalus. J. Soil Fert. 6:35-36. Inst. Soil Fert., Chinese
Acad. Agr. Sci., Beijing.
- Ning,
G.Z., Y. Li, Y. Wu, Y. Huang, and D. Yu. 1984b. Study on the characterization
and application of rhizobium strain CA 8116 (Astragalus adsurgens
Pall). J. Soil Fert. 6:37-38. Inst. Soil Fert., Chinese Acad. Agr. Sci.,
Beijing.
- Piper,
C.V. and W.J. Morse. 1914. Five oriental species of beans. U.S. Dept.
Agr. Bul. 119:1-32.
- Sacks,
F.M. 1977. A literature review of Phaseolus angularis--the adzuki
bean. Econ. Bot. 31:9-15.
|
