Edamame

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Project experiments for 1998 / 1999

Edamame Links

• Purdue University, Indiana
• GPPIS (FAO)
• Thailand
• International Legume Database and Information Service

Species: Glycine max

Family: Leguminosae

Crop status: New

Varieties

Germplasm has been imported to Australia, cleaned of viral infections and multiplied by DPI. The preferred variety was Kaoshiung No. 1 from AVRDC.

CSIRO Tropical Agriculture is breeding new soybean varieties for better agronomic traits, with emphases on broader adaptation to sowing date, for northern NSW to northern Qld and improved disease resistance and yield. They are using some edamame types as parents, though they are not breeding for edamame. Research is funded by the CSIRO Tropical Agri-Exports Initiative.

Washington State has been screening varieties for short growing season, and developing their own varieties. Conditions are possibly similar to Tasmania.

Agronomic trials

NSW Agriculture had trials of edamame from 1990 to promote into domestic and Japanese markets. They have already done research on varieties, growing, processing, marketing and production for seed. Twenty two breeding lines that were imported from Japan in 1989/90 were screened in 1991/92 and 1992/93. Two lines, GSB-1 and GSB-4, were successfully selected as the most promising varieties for NSW. Fresh edamame has been supplied to Sydney markets since 1994 for promotion, at the rate of a few hundred kg/year (Vong Nguyen 1998, pers. comm.). 500 kg of frozen edamame was commercially produced in March 1996 for sending to Japan as samples (Nguyen 1996).

Varieties GSB-1 and GSB-4 were trialled in Devonport, Tasmania, but growth was poor in the short summer season, indicating that different varieties would be needed (Vong Nguyen 1998, pers. comm.). The first two years were suitable and the third year was not. Yields were sound as was quality. When producing for seed, pods tended to split at dry maturity and throw seed onto the ground just prior to threshing. Threshing was not perfected and many beans at dry harvest had their seed coats damaged making them unsuitable for marketing. Green pod yield was good with many having three beans per pod and totally suitable for export. Lack of industry support stopped further work (Peter Simmul 1998, pers. comm.).

Edamame was also trialled in Queensland by Ron McMahon in conjunction with Edgells. Some problems at Bowen were attributable to photoperiod and vernalisation issues, since Bowen is at a much lower latitude than AVRDC in Taiwan. The Bowen season is also aligned with Japan, reducing the chances for export (Ross Wright 1998, pers. comm.).

Production

Production is identical to ordinary soybean (Nguyen 1998a). Seed production is better at higher latitudes, such as Victoria (Nguyen 1993).

Season: Edamame is a summer crop, and should be sown in November (Vic and Tas), and December to early January (NSW) (Nguyen 1993) for highest yields. A January to March harvest also coincides with high prices in the Japanese market. Later sowing increases the risk of cool weather, which results in unfilled pods (Nguyen 1998a). Early harvests are achieved in Japan by use of CO2 enriched, heated greenhouses (Lumpkin et al. 1993).

Soil type: Edamame grows on a wide range of well drained soils (Nguyen 1998a).

Bed preparation: Use of plastic covered beds reduces growing time of the crop and may increase yield (Andrews 1993).

Germination: Requires soil temperature above 18ºC (Peter Simmul 1998, pers. comm.), and preferably 20-25ºC (Nguyen 1998a).

Inoculation: Use Bradyrhizobium japonicum strain CB1809 (Nguyen 1998a).

Plant density: 15-20 cm x 90 cm (55 000 to 74 000 plants/ha). Higher densities will result in fewer pods/plant, which is less desirable for selling as attached type even if yields are similar (Nguyen 1993), and smaller pod size (Konovsky et al. 1994). Seed production is enhanced with densities up to 130 000 plants/ha (Nguyen 1998a).

Weed control: It is very important to keep weeds under control as they affect both yield and quality of product. A possible pre-emergent is Dacthal® at 6 kg/ha (Nguyen 1998a).

Nutrition: An NPK basal dressing and a side dressing of potassium nitrate during flowering is recommended. Lack of nutrition at reproductive stage could lead to an increase in the number of unfilled or poorly filled pods (Nguyen 1998a). Phosphorous applied after anthesis may darken pods slightly (Konovsky et al. 1994).

Water: Liberal watering is required, with less water reducing flower numbers and early abscission of pods (Nguyen 1998a). Water level also affects pod colour (Konovsky et al. 1994).

Harvest (green pods): Harvest when 90% of pods are filled and are fresh green, approximately 10-14 weeks from planting. Yields decline rapidly just a few days before or after optimum harvest time, at up to 0.5 t/ha/day (Nguyen 1998a). Flavour quality (sugar and amino acids) peaks before visual quality (pod colour and seed size) by a few days. Edamame harvested around sunset of a sunny day will have a higher amino acid content (Konovsky et al. 1994). The crop is mostly harvested by hand (Lumpkin et al. 1993) though harvesting machinery is available commercially in Japan (Pan 1995). A fresh bean harvester causes approximately 24% loss and 5% bruising (Nguyen 1998a).

Harvest (seeds): Problems of uneven maturity and splitting of seed pods before maturity occur in Hokkaido, Japan as well as Australia. It may be necessary to routinely dessicate seeds after an early harvest, to avoid postharvest losses (Andrews 1993).

Yield: Japanese yields have fallen from 9 t/ha in 1975 to 6.08 t/ha in 1995 (Figure 1). These yields have been equalled in NSW. An average of 40-50 pods per plant is good. Pod shattering during ripening is a major problem for production in hotter, less humid climates (Nguyen 1998a). Yield for dry seed is also comparable to Japan, averaging 1.8 t/ha (Nguyen 1993). Optimisation of quality is generally more important than optimising yield, due to the high value of quality product (Konovsky et al. 1994).

Postharvest

Handling: Green pods should be blanched and frozen within 8 hours of harvesting to avoid decreases in sensory quality (Masuda et al. 1988). Whole plants can be sealed in low density polyethylene bags for storage up to a week (Konovsky et al. 1994).

Blanching: Blanching at 95ºC for two minutes may cause pods to pop (Nguyen 1998a).

Temperature: Freeze using IQF (either carbon dioxide or nitrogen). Cool immediately after blanching to avoid darkened and bruised pods (Nguyen 1998a).

Humidity: 90-95 %. Can wrap in wet newspaper (Nguyen 1993).

Processing: Most important in maintaining quality of frozen edamame is the time from harvest to processing, requiring processing to be located near farms (JETRO 1994). Japanese processing and packing machinery has thus been developed for low volumes, suitable for one or two farms but still labour intensive. A competitive Australian industry may need larger, high volume processing equipment (Andrews 1993). Trial shipments of frozen edamame to Japan were prepared by Parle Foods (Nguyen 1995).

Quality assessment

Green pods: Taiwanese are extremely good at preventing substandard product from being sold (JETRO 1994). Usual standards are (Vinning 1995):

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• Two or more seeds per pod. Pan (1995) also states no more than three seeds.
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• Pods > 4.5 cm long
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• Pods > 1.3 cm wide
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• Fewer than 350 pods/kg
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• Fresh green colour, white pubescence and a colourless hilum (Nguyen 1998a).
   

A more detailed description of quality aspects is given in Konovsky et al. (1994).

Seed: Seeds must be of uniform size, weight and roundness, free from contamination such as soil, weed seeds, disease and trash. Germination must be a minimum of 90%. These requirements, along with the low seed yield, may make this crop unprofitable (Andrews 1993).

Pests and diseases

Disease is favoured by warm and moist conditions. Most common problems were Sclerotium crown rot (Sclerotium rolfsii), caterpillars of budworms (Helicoverpa armigera) and cutworms (Agrotis spp.) (Nguyen 1998a).

Infestation with noctuid moths, Pyralid moths, thrips, oriental tobacco budworm (Helicoverpa assulta), armored scales, and so on, have been observed on Japanese imports. Anthracnose (Colletotrichum) and other diseases have also been found. With diseases and pests being detected so frequently, it is recommended that holes be made in plastic packaging in advance of shipment (JETRO 1995).

Potential viruses are listed at Plant viruses online (Brunt et al. 1996).

Domestic market

Edamame is currently imported into Australia (Andrews 1993). The fresh market is very small at about 150 kg/week, with the attached type being preferred as the detached type is similar to frozen imports. Domestic prices would be approximately $6.00/kg (Nguyen 1995).

Export markets

(click here for exchange rates).

Edamame was rated a priority Asian vegetable for developing a frozen export market by workshop members reported in Lee (1996). It was also considered as a dry seed crop for sale to the Northern hemisphere, at perhaps $2 000 to $3 000/ton (Nguyen 1993).

Annual Taiwanese consumption is 40 000 t (Barton 1997). Taiwan used to supply almost all of Japanese imports as frozen edamame (Lumpkin et al. 1993), but much production of frozen edamame has been moved to the South China coast, such as Fujian province (JETRO 1994). Previously, Chinese edamame has been lower quality and thus received a lower price, but prices have risen with Taiwanese investment (Nguyen 1998a). Taiwanese packers have accumulated a great deal of expertise in producing and processing edamame, and have developed varieties with high blight and pest resistance and very high quality (JETRO 1994). Taiwan has also imported small volumes (1-2 t/year) of fresh edamame and larger volumes (50-350 t/year) of frozen edamame from such sources as Thailand, Vietnam, USA and Indonesia (MarketAg website 1999). Taiwan has an import tariff of 40% (Vinning 1995), and requires a guarantee that it is free from Mediterranean fruit fly. There appears to be no opportunity for Australian export (Pan 1995).

Figure 1: Japanese production of edamame (MAFF 1999).

Annual Japanese consumption is 160 000 t (Nguyen 1998a), of which 50 000 t is imported. Japanese demand appears to be greater than Taiwanese production and there is a widening supply gap of 10 000 t/year. Freshness is a major issue, even with frozen produce, therefore Australia can aim to fill the January to March gap when prices are high (Vinning 1995). Imports from Taiwan and China occur mainly from April to May (Pan 1995). The Japanese government has recently dropped import restrictions from mainland Australia, previously in place to guard against fruit fly. Australia will have a good market if we can produce at a lower cost (Vong Nguyen 1998, pers. comm.). A tariff of 10% is applied (Vinning 1995).

Most of the fresh edamame has been supplied domestically (JETRO 1994), but domestic production is falling (Figure 1). Fresh edamame is marketed in three forms:

Whole plant. A higher price is obtained when the whole plant is shipped because freshness can be judged by the attached vegetable matter, but shipping costs are increased (Vinning 1995). This form is uncommon in China and Korea but still popular in Japan (Lumpkin et al. 1993).
Pods. Better pods are marketed in plastic net bags (Nguyen 1998a).
Shelled beans. This is more popular in ethnic Chinese markets, such as Taiwan, Hong Kong and Singapore but is unusual in Japan (Nguyen 1998a).

Figure 2: Prices (¥/kg, red), and throughput (t/month, blue) of fresh edamame at Tokyo Wholesale market (adapted from Nguyen 1998a).

Figure 3: Japanese imports of fresh edamame (Compiled data from the Japanese Ministry of Finance, via JETRO 1995 and Nguyen 1998a).

Figure 4: Origins of Japanese imports of frozen edamame during 1995 (adapted from Nguyen 1998a).

Figure 5: Japanese imports of frozen edamame (Compiled data from Nguyen 1998a and the Japanese Ministry of Finance, via JETRO 1996b).

Almost all frozen edamame is consumed as a snack with beer (Barton 1997) in 'izakaya' drinking establishments (JETRO 1992). However it is also sold at supermarkets for home use, and this use is increasing. Imports from China have been increasing rapidly since the late 1980s because of technical assistance and crop introduction from Taiwan (JETRO 1996b), and because Japanese domestic production has waned with higher labour costs. Imports from Thailand also rose sharply in 1996, as a large Japanese trading firm established a large frozen edamame plant in Chiang Mai. The factory's capacity is currently being expanded, so a further increase in imports from Thailand can be expected. The quality of imported frozen edamame has improved dramatically, and the degree of processing is also increasing. For example, some products now come pre-salted. Recent advances in processing also enables frozen edamame to be eaten immediately after defrosting, whereas they used to require boiling for 4-5 minutes (JETRO 1996a). These advances have led to increasingly better taste of frozen edamame, such that some Japanese restaurateurs actually prefer frozen over fresh (JETRO 1994).

Edgells was interested in exporting frozen detached edamame to Japan and conducted development work with DPIQ. Fresh edamame was not considered because of the cost of disinfecting against Meditteranean fruit fly. Although satisfied with the product, the idea was dropped after Edgells was taken over by Simplot in the early 1990's (Ross Wright 1998, pers. comm.).

No market appears to exist in Hong Kong or Singapore (Pan 1995).

Production in USA is minimal despite considerable research throughout this century on the crop. Therefore most edamame consumed is imported (Lumpkin et al. 1993).

References

Andrews, J. (1993). Study tour of vegetable soybeans to Japan, July 1993. Horticultural Research and Development Corporation final report; project VG320.

Barton, N. J. (1997). Edamame (vegetable soybean): the potential for a new Victorian industry. Melbourne, Agriculture Victoria 45 pp.

Brunt, A.A., Crabtree, K., Dallwitz, M.J., Gibbs, A.J., Watson, L. and Zurcher, E.J. (eds.) (1996 onwards). `Plant Viruses Online: Descriptions and Lists from the VIDE Database. Version: 16th January 1997.'

JETRO (1992). Frozen Vegetable. Japan External Trade Organisation, Market Report.

JETRO (1994). Frozen Vegetable. Japan External Trade Organisation, Market Report.

JETRO (1995) Fresh Vegetables: Access to Japan's Import Market - Mini Report 1995 August. Japan External Trade Organisation, Market Report.

JETRO (1996a) Frozen Vegetables: Access to Japan's Import Market-1996. Japan External Trade Organisation, Market Report.

JETRO (1996b) Process Vegetables: Your Market in Japan-1996. Japan External Trade Organisation, Market Report.

Konovsky, J., Lumpkin, T. A. and McClary, D. (1994). Edamame: the vegetable soybean. Understanding the Japanese food and agrimarket: a multifaceted opportunity. Food Products Press,Binghamton, New York, USA. Ed.: : 173-181.

Lee , B. (1996). Assessment of economic benefits for Asian vegetables. RIRDC project CON-4A review meeting 14 November 1996.

Lumpkin, T. A., Konovsky J. C., Larson K. J. and McClary D. C. (1993). Potential new specialty crops from Asia: azuki bean, edamame soybean, and astragalus. New crops. John Wiley and Sons, Inc,New York, USA : 45-51.

MAFF (1999). Abstract of statistics on agriculture, forestry and fisheries. Statistics and Information Department, The Ministry of Agriculture, Forestry and Fisheries of Japan.

Masuda, R., Hashizume, K. and Kaneko, K. (1988). Effect of holding time before freezing on constituents and flavour of frozen green soyabeans (edamame). [Japanese]. Nippon Shokuhin Kogyo Gakkaishi = Journal of the Japanese Society of Food Science and Technology 35(11): 763-770.

Nguyen, V. Q. (1993). Development of green soybean vegetable for domestic and Japanese markets. Horticultural Research and Development Corporation final report; project VG130.

Nguyen, V. Q. (1995). Production of vegetable green soybean for domestic market and trial shipments to Japan. Horticultural Research and Development Corporation final report; project VG433.

Nguyen, V. Q. (1996). Research and development of Asian vegetables for Asian markets, particularly Japan. First Australian New Crops Conference, The University of Queensland Gatton College, Rural Industries Research and Development Corporation.

Nguyen, V. Q. (1998a). Edamame (vegetable green soybean). The New Rural Industries. Ed.: K. W. Hyde. Canberra, Rural Industries Research and Development Corporation: 196-203.

Nguyen, V. Q. (1998b). Report on the study tour to Japan on pickling of Asian vegetables and attendance at an international symposium on vegetable quality in Seoul, Korea 1997. Gosford, Horticultural Research and Advisory Station. 96 pp.

Pan, C. (1995). Market opportunities for fresh and processed Asian vegetables. RIRDC Research Paper No. 95/14. Canberra, Rural Industries Research and Development Corporation 117 pp.

Vinning, G. (1995). Market Compendium of Asian Vegetables. RIRDC Research Paper No. 95/12. Canberra, Rural Industries Research and Development Corporation 386 pp.