History of Tempeh - Page 1
by William Shurtleff and Akiko Aoyagi
A Chapter from the Unpublished Manuscript, History of Soybeans and
Soyfoods, 1100 B.C. to the 1980s
©Copyright 2004 Soyfoods Center, Lafayette, California
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Tempeh (pronounced TEM-pay) is an Indonesian word referring collectively to a variety of fermented foods (typically tender-cooked legumes) bound together by a dense mycelium of fragrant white Rhizopus mold into compact cakes (Ko and Hesseltine 1979). The most popular of these is soy tempeh, and hereafter we will use the term "tempeh" to refer to soy tempeh, unless otherwise noted. In the West tempeh is usually sold in cakes 6 by 8 by 3/4 inch thick (15 x 20 x 2 cm). These are sliced then served fried, baked, or steamed. When fried, tempeh's flavor and texture are meaty, resembling those of southern fried chicken or fish sticks. Before cooking, soy tempeh contains 19.5% protein, compared with 17.9% for hamburger and 21% for chicken, on average.
To make tempeh, cooked and dehulled soybean cotyledons (which may be lightly acidified with a traditional lactic acid prefermentation or, nowadays, with lactic acid or vinegar) are well drained then inoculated with spores of Rhizopus oligosporus mold, packed into perforated containers (polyethylene bags or banana leaves, holding about 8 ounces) and incubated at 30-31*C (86-88*F) for about 24 hours, until the beans are bound together tightly by the mycelium. The tempeh is then ready to sell or to cook.
Tempeh is unique among major traditional soyfoods in that it is the only one that did not originate in China or Japan. It originated in today's Indonesia, almost certainly in Central or East Java, almost certainly prior to 1800, and perhaps as long ago as a thousand years or more. Tempeh is also distinctive in that less is known about its origins and early history than about those of any other soyfood.
Etymology . In Indonesia, traditionally and in dictionaries since at least 1875, the name for this food was written témpé , with various accents being used, especially to indicate the ay pronunciation of the final letter "e." Soy tempeh was called témpé kedelé . In August 1972, when Indonesia modernized its language as part of an Indonesian-Malaysian effort to make the two similar languages even more similar, the accents were dropped and the word came to be spelled tempe (still pronounced TEM-pay).
In English and other European languages, the word has come to be spelled "tempeh," the final "h" being added to prevent the word from being pronounced "temp." Most Westerners feel that the correct pronunciation is more important than the correct spelling. The first Westerner to use the spelling tempeh was the Dutchman H.C Prinsen Geerligs in an 1896 German article about soyfoods. But other early Western authors (especially the Dutch) wrote the word as témpé (Gericke and Roorda 1875; Heyne 1913), tempé (Boorsma 1900; Stahel 1946), or tèmpé (Vorderman 1902). The earliest English language references to this food, both translations of Dutch publications (Ochse 1931, Burkill 1935), referred to it as témpé . Van Veen and Schaefer (1950) were the first to spell it tempeh in an English language article. The new spelling quickly caught on. Steinkraus et al. (1960) were the first in the US to spell it tempeh . Since the early 1960s, the word has consistently been spelled this way in European languages, except in a few Dutch and English language articles written by Indonesians.
In Japanese, Nakazawa (1928) first wrote the word in Roman letters as tempeh. Nakano (1959) wrote temupe , in katakana. Ohta et al. in 1964 started writing it as tenpe , which thereafter became the standard katakana form, although a few reports have written it as tenpei .
World Overview . Tempeh probably originated several centuries ago on the island of Java, in today's Indonesia. The earliest know reference there was in 1875. Much early research and publication was done by Dutch scientists, in Dutch. Tempeh was first produced commercially in Europe sometime between 1946 and 1959 and by 1984 there were 18 tempeh companies in Europe. The earliest known reference to tempeh in the United States was by Stahel in 1946. Extensive research work on tempeh began in the early 1960s at Cornell University (under Dr. Steinkraus) and at the USDA Northern Regional Research Center (under Dr. C.W. Hesseltine and Dr. H.L. Wang). America's first commercial tempeh was produced in 1961 by Indonesian immigrants, and the first commercial production by a Caucasian started in 1975. The number of tempeh companies in America increased from 13 in 1979 to 53 in 1984. The earliest known reference to tempeh in Japan was by Nakazawa in 1928. Starting in 1983, with the soymilk boom in full swing, Japanese food companies started to make tempeh in large quantities. By early 1984 the world's largest tempeh companies were:
HISTORY OF TEMPEH IN INDONESIA
Early History (pre 1875) . Tempeh probably originated on the island of Java at least several centuries ago. At that time the people of Java, without formal training in microbiology or chemistry, developed a remarkable family of fermented foods called tempeh. Today we might call these products meat analogs, since they have much the same texture, flavor, and high protein content as various flesh foods. The people also learned to make tempeh from oilseed presscakes (the protein-rich cakes left after pressing the oil from oilseeds such as peanuts or coconuts), okara (the soy pulp remaining after making soymilk or tofu), and other agricultural wastes, whose high fiber content and relative indigestibility make them otherwise suited only for livestock feeds (Steinkraus 1983).
Since ancient times the Malay language has been the lingua franca of the archipelago that includes today's Malaysia and Indonesia. The people of Java have had a written language since antiquity, with existing stone inscriptions dating from the seventh century A.D. This early literature concerned primarily religion, philosophy, and culture, with very little information about food.
The world's earliest known reference to tempeh appeared in the Serat Centini , which was probably written around A.D. 1815 on the orders of Sunan Sugih, then Crown Prince and later Pakubuwana V of Surakarta, in today's eastern Central Java. The main author was probably Rangga Sutrasna. This classic work of Modern Javanese literature contains a line mentioning "onions and uncooked témpé ."
Although the Serat Centini was written in about 1815, it is quite possibly based on much older sources; the story is set in the reign of Sultan Agung (1613-45), and the descriptions purport to be of that time. Thus tempeh may well have existed in the early 1600s. However the actual document in which this reference appears (Codex Orientalis 1814 of the Leiden University Library) bears the date 1846, making it conceivable (but highly unlikely) that reference to tempeh was added just prior to publication.
The Serat Centini , written in verse, tells of the adventures of "students" wandering in the Javanese countryside in search of truth. In the course of the story, detailed information is given on many subjects including Javanese culture and life. The passage mentioning tempeh occurs in a description of Wanamarta, a prosperous place, in the context of a reception given to Jayengwesti, and involving all sorts of foods. These, including "onions and uncooked témpé ," are simply listed without further information.
Conservative estimates that tempeh originated at least several centuries ago are also supported by evidence based on the food's present widespread geographical distribution, popularity, and large number of varieties. Tempeh is known in even the most remote rural areas throughout most of Java, is an integral part of the cuisine served in a wide variety of popular dishes (90 named Indonesian recipes are given in our Book of Tempeh ), and by the mid-1970s it was being made from at least 17 indigenous seeds and presscakes by more than 41,000 shops, using simple, traditional methods.
But where did tempeh come from? The earliest known written record of soybeans in Indonesia was by the Dutch botanist Rumphius (1747), who reported that they were being used in Java for food and as green manure. Yet soybeans may well have been introduced to Indonesia at the time that regular trade started with south China in about 1000 A.D. One Sundanese (West Javan) name for soybeans is kachang jepun (Japanese bean), which may be historically significant. At least one East Asian scholar (Anderson 1983, personal communication) believes that tempeh developed from an application to soybeans of an earlier fermentation used on coconuts, perhaps the now famous coconut presscake tempeh ( tempeh bongkrek ). The well-traveled Indonesian Dr. Sastroamijoyo (1971) feels that tempeh may have originated over 2,000 years ago. He has pointed out that even before that time the Chinese were making a similar product, the soybean koji for their soy sauce, produced by inoculating cooked dehulled soybeans with wild molds such as Aspergillus oryzae . This method could have been brought to Java from China by early traders and modified to suit Javanese tastes; the use of Rhizopus may have been due to its better adaptation to the Indonesian climate. The rise of tempeh's popularity in West Java (where the culture is Sundanese), and its spread to other Indonesian islands and other countries of the world, probably began in the 20th century. We hope that Indonesian scholars will soon begin a serious search of their literature to help us construct a more reliable picture of tempeh's early history.
Another possible lead may lie in China. In 1931, in Beijing (Peking), William Morse observed a fermented soyfood closely resembling tempeh and called tou chiah ping ("soybean fried cake"; Morse 1928-31). Details on this product are given later at China. No other reference to such a product has been found in European-language soyfoods literature. If this is a type of tempeh, it is probable that it was taken to China from Indonesia (the East Indies) by Chinese traders and that it became established on a local scale in China. There is the possibility, however, that the product originated in China and migrated to Indonesia, where it was developed, perhaps because of a similar existing product made from coconut (tempeh bongkrek). It would be very interesting to know more about tou chiah ping : Is it fermented with Rhizopus ? What is known of its history? There are no known references to it after 1931.
There is a great need for more research on the origins and early history of tempeh. Promising areas for additional searching include early Malay-Dutch dictionaries, the classical Malay literature of the 18th and 19th centuries, the writings of foreign travelers to Java (especially European missionaries, botanists and naturalists, or Dutch or Japanese traders or explorers), and perhaps even Chinese historical records. Professors of Malaysian literature have told us that they think they have seen reference to tempeh in the classical Indonesian literature of the 18th and 19th centuries, but we have been unable to find a specific reference. In 1928 the Malay language was declared the official language of the future Indonesia. Despite the long history of written documents in Indonesia, no known records of tempeh's origin or early history have yet been found in the native language. In fact, the earliest records in Indonesian seem to date from the 1950s!
Early European References (1895-1939) . Since Indonesia (formerly the Dutch or Netherlands East Indies) had been a Dutch colony since the late 1600s, it was only natural that the first Westerners to study tempeh came from Holland. The earliest known reference to tempeh (actually témpé) in Indonesia by a European appeared in 1875 in a Javanese-Dutch dictionary, the Javaansch-Nederduitsch Handwoordenboek by J.F.C. Gericke and T. Roorda. The term was defined as "Fermented soybeans or presscake ( bunkil ) baked or fried in flat pressed cakes. It is well-liked as a side dish with rice." The term does not appear in Marsden's dictionary of 1812, but then he was in Sumatra and tempeh was most widely found in Java. In 1895 the Dutch microbiologist and chemist H.C Prinsen Geerligs made the first attempt to identify the tempeh mold in his classic article titled "Eenige Chineesche voedingsmiddelen uit Sojaboonen bereid" (Some Chinese Foods Made with Soybeans). After describing Indonesian soy sauce, and miso ( taucho ), he noted: "In a similar way, in Java, other molds are used to make leguminous seeds into more digestible foods. Thus the presscake, which remains after making peanut oil and would be indigestible without further preparation, is subjected to the action of molds. In central and eastern Java Chlamydomucor Oryzae [now known as Amylomyces rouxii ] is used, whereas in western Java an orange mold of the family Oospore (Neurospora) is used. In the former case, the food is called `bongkrek,' and in the latter `ontjom.' If soybeans are molded with Chlamydomucor the spice is called `tempets.' In the preparation the seeds are boiled, spread, mixed with a little molded cake from a former batch, and left alone for a while, until the mass is bound into a solid cake." A year later, when this article was published in German, he corrected two mistakes he had made in the 1895 Dutch version. He changed the name of the mold from Chlamydomucor Oryzae to Rhizopus Oryzae and he changed the name of the product from "tempets" to "tempeh." He added in conclusion that "it was finally sliced and enjoyed, mold and all." But he continued, apparently mistakenly, to refer to tempeh as a Chinese soyfood. Prinsen Geerligs' two articles ushered in the era of scientific research on tempeh by European microbiologists and food scientists.
Prinsen Geerligs and his Dutch colleague F.A. Went were particularly interested in the utilization of by-products from Java's expanding new sugar industry (Went and Prinsen Geerligs 1895, 1896). They wrote many articles about sugar, but also studied tapeh, arak, and other Indonesian fermented foods. In 1901 Went, then at Utrecht, the Netherlands, described onchom (formerly spelled "ontjom," a close relative of tempeh) and studied the mold involved, which he called Monilia sitophila ; it is now called Neurospora . In 1900 and 1901 the German Wehmer studied Javanese ragi (starter culture cakes, also called "Chinese yeast") occasionally used for making tempeh. In 1917 Prinsen Geerligs discussed tempeh as a food made using natural enzymes in East Asian home industries.
In 1900 the Dutchman Dr. P.A. Boorsma, who lived in Java and did original laboratory tests, published an excellent 13-page article on soybeans. In a detailed 4-page description of the traditional process for making Tempe kedeleh , Boorsma reported that the soybeans were parboiled, soaked in water for 2-3 days, drained, steamed in a steamer, spread in a layer several centimeters thick on woven bamboo trays in shelves, and covered completely with banana leaves. They were then inoculated by mixing in "mold-containing residues of a previous preparation" and covered lightly with banana leaves. "In the evening the mass is remolded a little and after two 24-hour periods one will obtain a coherent cake, which is cut into pieces and taken as is to the market." Boorsma then described the rise in temperature to 10-12*C above ambient temperature during the tempeh fermentation, the formation of ammonia in tempeh after 3 days of fermentation, and the likelihood that stories about nonsoy tempehs causing food poisoning were true. After microscopic examination, he concluded that Prinsen Geerligs and others were mistaken in stating that (1) the mold hyphae penetrate and dissolve the hard soybean cell walls and (2) cellulose is decreased during tempeh fermentation. He studied the chemical and compositional changes at four different stages during a 3-day tempeh fermentation, observing that fats and soluble carbohydrates decreased substantially, while nitrogen decreased only slightly. He also discussed the hydrolysis of soybean lipids and why tempeh is easier to digest than whole soybeans.
In 1893 the Dutch microbiologist Vorderman had described ragi, a traditional tempeh inoculum (though he did not mention tempeh), then in 1902 he discussed in detail two processes he observed for wrapping and fermenting soy tempeh. In the first and best-known way the soybeans were incubated between banana leaves; in the second the soybeans were wrapped in banana leaves to form a packet 20 cm long and 7 cm wide, then wrapped in a jati leaf. The packets were stacked in a bamboo basket for 24 hours covered with bags, then removed to prevent overheating and spread on the floor for 24 hours more. He noted (as Prinsen Geerligs had in 1896) that tempeh was fermented with Rhizopus oryzae . Vorderman (1902) was the first to describe other varieties of Indonesian tempeh and their close relatives. Ontjom beureum was made in West Java from peanut presscake fermented with the orange mold Monilia sitophila . Tempe bongkrek katjang and ontjom bodas , made in Banyumas in central Java, were each like peanut presscake tempeh but fermented with Rhizopus molds. Tempe bongkrek kelapa , from south Banyumas, was made from pressed coconut, inoculated with and in leaves already used for making soy tempeh. Low in price, it was eaten mostly by poor people. Tempe morrie , from Banyumas, was made from a mixture of soybeans and coconut milk residue, which had been washed and steamed. After inoculation with ground bibit leaves, on which were Rhizopus oryzae spores, the mixture was packed in the sheaf of the banana tree stem to form small long packages, then incubated. Tempe enthoe and tempe tjenggereng were made with steamed coconut oil presscake and coconut milk residue. The latter contained steamed corn bran and both were fermented packed in the sheaf of the banana tree stem for 48 hours. He concluded noting that tempe tjenggereng , like tempe bongkrek kelapa , had led to several cases of fatal food poisoning.
In 1913, K. Heyne published a lengthy review of earlier literature on tempeh. In 1923 the Dutchman Jansen wrote "The Need of the Animal Organism for the Anti-beriberi Vitamin and the Amount of this Vitamin in Various Foodstuffs." He showed that in tempeh the content of anti-beriberi vitamin (first isolated by Jansen and Donath in 1926, and later named vitamin B-1 or thiamine) was reduced during fermentation. Jansen and Donath (1924), in "Metabolic Experiments on Rats and Digestibility of the Proteins of Some Foodstuffs" showed that tempeh protein is of good quality and makes a good supplement to the protein in rice. The vitamin A content was about the same as that of raw soybeans. The content of vitamins B-1 and B-2 in tempeh was further investigated by A.G. van Veen (1932, 1935); he found it to be a good source of both.
One of Indonesia's most famous (or infamous) types of tempeh is tempeh bongkrek, which is made from coconut presscake or the residue from homemade coconut milk, rather than from the usual soybeans. When contaminated it becomes toxic, and for as long as the local people can remember, it has periodically caused food poisoning and death in Central Java, mainly in the province of Banyumas and surrounding areas. The first outbreak of bongkrek poisoning was recorded by Dutch authorities 1895. Vorderman described several types of tempeh bongkrek in 1902 and noted that they caused fatal food poisoning. During Indonesia's economic depression between 1931 and 1937, when villagers tried to make bongkrek themselves rather than buying it from experienced producers, the poisonings became very numerous, up to 10 or 12 a year. There were few survivors. The local villagers believed that the poisonings were due to evil spirits or to the Goddess of the Indian Ocean in an angry mood! Starting in the early 1930s a group of Dutch scientists, starting with W.K. Mertens and A.G. van Veen from the Eijkman Institute in Jakarta, began to investigate the causes of bongkrek poisoning (van Veen 1967). Between 1933 and 1938 Mertens and van Veen published nine studies in Dutch and German on the bongkrek poisonings in Banyumas and the toxicology of bongkrek . In about 1933 they found the cause of the poisonings and discovered that the bacterium Pseudomonas cocovenenans was producing the toxins. Soon thereafter they isolated and named the two poisonous substances (toxoflavin and bongkrek acid). Amar?? and Grevenstuk (1935) and Baars and van Veen (1937) also published on bongkrek poisoning. In 1950 van Veen showed that at least one of the poisons is also a strong antibiotic for tempeh's Rhizopus mold. After 1950 many more investigations were conducted on tempeh bongkrek.
The first English-language information about tempeh appeared in 1931 in J.J. Ochse's Vegetables of the Dutch East Indies , an excellent 1005-page tome published in Buitenzorg (today's Bogor), Java. Ochse, a Dutchman, described the tempeh-making process in detail, saying that the mold used was Rhizopus oryzae , and that it was obtained from a former batch of tempeh. The next English-language reference appeared in 1935 in I.H. Burkill's A Dictionary of the Economic Products of the Malay Peninsula , a two-volume, 2,400-page work published in England. It contained six pages of information about tempeh and other soyfoods, including a description of the tempeh-making process. Burkill was a British authority on the flora of southern and southeastern Asia.
Tempeh During World War II and the Postwar Era (1940-1959) . During World War II almost the entire Malay archipelago was brought under Japanese control. Tempeh served as an important food in Indonesia and surrounding countries during the war, both for the native population and for foreigners in Japanese prisoner of war (POW) camps there.
The first English-language article specifically about tempeh was written in 1946 by Gerold Stahel, director of the Agricultural Experiment Station in Paramaribo, Surinam (a Dutch colony). Stahel described how, during World War II, the United States shipped soybeans to New Guinea in order to feed the Europeans and Indonesians living there. The shippers did not realize that residents of Indonesia, accustomed to eating fermented soyfoods, considered plain boiled soybeans to be unpalatable. Moreover, during the Japanese occupation of New Guinea, tempeh production had stopped and the local New Guinea starter cultures had, therefore, all been lost. Stahel, asked to furnish new cultures from Surinam, sent both fresh tempeh cakes and pure-culture starters to the Netherlands Indies Civil Administration (NICA) in New Guinea. Soon NICA kitchens all over the territory started using the US soybeans to make tempeh for the people.
As a result of his involvement in this project, Stahel's interest in tempeh grew, and in 1946 he wrote a detailed description of the way Javanese women in Surinam made and sold tempeh. He was the first to report on the bacterial acid fermentation of the soybeans during soaking that preceded the basic mold fermentation. Roelofsen, a Dutchman, was a prisoner of war (POW) in Japanese camps in Indonesia, where many Europeans were starving. Their basic foods were corn, sweet potatoes, chilies, and soybeans. Roelofsen made the soybeans into tempeh there and in 1946 reported the great shortage of protein in the camps and the important role played by tempeh in reducing deaths. He was the first to describe the use of pulverized dried tempeh as an inoculum. Roelofsen (1964) also did important nutritional studies of the food after his release. By a strange twist of fate, van Veen was made a POW during World War II and held in Indonesian camps where tempeh was widely served. In 1946 he reported that even POWs suffering from dysentery and oedema, who could not digest cooked whole soybeans, were able to assimilate tempeh. Fuel was sometimes so short in the camps that the soybeans, served as whole beans or for tempeh, were not adequately cooked. Yet the tempeh process helped to make these undercooked soybeans much more digestible. Van Veen concluded that many POWs owed their very survival to tempeh. De Bruyn, van Dulst, and van Veen (1947) came to the same conclusion. In 1951 Smith and Woodruff and in 1952 Grant wrote articles on "Deficiency Diseases in Japanese Prison Camps." They reported that the POWs, apparently in Hong Kong and Singapore, had made soybeans (often inadequately cooked) into tempeh to make them more palatable and digestible.
The first study in English on the chemical and microbiological changes occurring during tempeh fermentation, was published in 1950 by the Dutch microbiologists van Veen and Schaefer. This classic paper, based partly on van Veen's experiences in a POW camp, was more extensive than that published by Boorsma in Dutch in 1900. It described the tempeh-making process then attempted to show why tempeh was so much more digestible than soybeans. Also in 1950 Tammes published a detailed description of how tempeh was made in Java, including a description of how tempeh starter (ragi) was made.
Other than the Serat Centini (1815, 1846), the earliest known reference to tempeh in Indonesian or by an Indonesian appeared in 1956 (any earlier??) when Soetan mentioned it briefly in a booklet entitled Kedelai (Soybeans).
It is curious to note that, despite the fact that tempeh has long been a very important and widely used Indonesian food, all of the scientific studies on tempeh from 1895 to 1960 (and virtually all of the references to it in any language) were done by Europeans living in Indonesia. There are several reasons for this: First, while Indonesia was a Dutch colony, very few Indonesians were able to attend a university or to do scientific research of any type. There were very few Indonesian food scientists or microbiologists, and these were not encouraged to study indigenous foods. Second, during Dutch colonial rule, public opinion was strongly influenced by the Dutch emphasis on Western values and lifestyles, and the devaluation of indigenous values and lifestyles. Consequently a food such as tempeh, which was unknown in the West, and which was a low-priced food of the common people, acquired the image of an inferior, lower-class, or even poor-people's food, even though it was consumed by people of all classes. No Indonesian scientists felt it was worthy of their attention or research. Unfortunately, this attitude persisted even after independence. Sukarno, President of the Indonesian Republic from 1945-1967, admonished his fellow citizens on numerous occasions, saying "Don't be a tempeh nation," or "Don't be a tempeh scientist," implying that tempeh was somehow second class or inferior. Only by the mid-1960s did that image begin to change. And third, there was little interest in tempeh outside of Indonesia to stimulate interest inside.
New Interest in Tempeh (1960-82) . A new wave of worldwide interest in tempeh began in the early 1960s, sparked largely by the initiation of tempeh research on the part of two groups of American microbiologists and food scientists: one at Cornell University's New York State Agricultural Experiment Station in Geneva, New York, and the other at the USDA Northern Regional Research Center at Peoria, Illinois. Each group had an Indonesian as a catalyst and co-worker for its tempeh research. The Cornell group, under the leadership of Dr. Keith H. Steinkraus, worked with Ms. YAP Bwee Hwa, starting in 1958. This group did extensive, original research on tempeh and from 1960 published a series of pioneering scientific papers on all aspects of the new-found fermented soyfood. The USDA group, under the leadership of Dr. Clifford W. Hesseltine, got interested in tempeh as soon as the Indonesian microbiologist KO Swan Djien arrived in Peoria in 1960 to study industrial fermentations. There Hesseltine encouraged him to start by studying the tempeh fermentation.
The first Indonesian to do scientific research on tempeh, and to write a post-graduate thesis on the subject was Ms. Yap Bwee Hwa - a Chinese Indonesian whose name comes from the Hokkian dialect of Fujian (Fukien) province. After graduating from the Fakultet Ilmu Pasti dan Alam (Faculty of Natural Sciences and Mathematics) in Bandung with a major in biochemistry (degree equivalent of MSc), she went to work in Jakarta at the Nutrition Institute under Dr. Poorwo Sudarmo, a progressive physician interested in nutritious, low-cost foods for infants. She then won a Fulbright scholarship to the United States and Sudarmo encouraged her to study tempeh. After reading an article by van Veen on the value of tempeh in prisoner of war camps, she made up her mind. The Fulbright committee suggested that she study at Cornell University, so she wrote Dr. Hand, head of the Department of Food Science and Technology at Cornell's New York State Agricultural Experiment Station. She visited plants tempeh plants in Indonesia to study the process, collected tempeh from the Jakarta market, then dried it and put it in a little brown bottle for later use as tempeh starter. She left Indonesia for the USA in August 1957. In the summer of 1958 she started to work in Dr. Steinkraus' laboratory at Geneva, New York, where, for the first time, she prepared tempeh. This was probably the first tempeh ever made in America. A graduate student in nutrition and food science, Ms. Yap pursued her interest in tempeh as a nutritious food for infants and children, in part because of the high rate of infant mortality in Indonesia caused by undernutrition (Yap 1984, personal communication). In 1960 she wrote her MS thesis titled Nutritional and Chemical Studies on Tempeh, an Indonesian Soybean Product . That same year she co-authored the Cornell group's first tempeh publication "Studies on Tempeh--An Indonesian Fermented Food" (Steinkraus et al. 1960). It is also interesting to note that it was from the pulverized sample of tempeh that Yap brought with her from Indonesia that the group isolated the culture of Rhizopus oligosporus , which Dr. Hesseltine later identified and gave the number NRRL 2710. This is still the most widely used tempeh culture strain in the USA.
Other early but brief descriptions of the tempeh process were given by Prawiranegara (1960) and Hardjo (1964, in Indonesian).
In 1961 Ko Swan Djien became the second Indonesian to publish scientific research on tempeh. Like Yap Bwee Hwa, he was a Chinese Indonesian whose name comes from the Hokkian dialect of Fujian (Fukien) province. By authoring or co-authoring at least six important articles about tempeh, Ko played a key role in introducing this food to the West, and in giving it a better image in Indonesia. Ko studied at the University of Wisconsin at Madison from August 1959, then did research at the NRRC from February to August 1960. Thereafter, he returned to the Bandung Institute of Technology, where his Laboratory for Microbiology began doing cooperative research on tempeh with the Cornell and USDA groups. Ko's first article, co-authored with Hesseltine in 1961, was about "Indonesian Fermented Foods;" it contained detailed information about tempeh making and recipes in Indonesia. Ko noted that there were thousands of tempeh shops in Indonesia and estimated that half or more of the country's 1959 soybean production of 17 million bushels (463,000 metric tons) was used to make tempeh.
Ko's most important and original article, presented in May 1964 at the International Symposium on Oilseed Proteins in Tokyo (and unfortunately never published) was "Tempe, A Fermented Food Made from Soybeans." The best report to date on tempeh in Indonesia, it discussed tempeh's history, traditional production methods, inoculum, packaging, chemistry and microbiology, contamination, shelf life, recipes, and price, plus a review of other research (including the best English-language bibliography of Dutch research to date) and a description of a tempeh pilot plant being developed in Bandung (complete with a mechanical roller-mill dehuller, water flotation hull removal, heated incubator and trays, and improved inocula). It was the first English-language publication to refer to the use of okara (soy pulp) in tempeh. In this article Ko signaled what he hoped would be the beginning of a new image for tempeh in Indonesia: "But there is no doubt that the time will come when Indonesians will be proud of their tempe, in the same way as the Japanese are proud of their sake, the French people of their wine, Italians of their macaroni, Indians of their curry, Russians of their caviar, the Dutch of their cheese, etc."
During the 1960s at the microbiology laboratory in Bandung, Ko worked to stimulate new research on and interest in tempeh. When Indonesian newspaper reporters finally discovered that he had studied tempeh at a University and in the United States, they were simply astonished. Articles with bold headlines such as "Tempeh Steps to a Higher Throne" appeared in several widely read Indonesian newspapers in September 1965. This marked the beginning of a change in attitude toward tempeh in Indonesia. In 1965 a summary of Ko's work on tempeh was published in Indonesian; it included details of an extensive survey proving that Rhizopus oligosporus was the main tempeh microorganism. In 1968 Ko joined the Department of Food Science at the Agricultural University, Wageningen, in the Netherlands. There he began to stimulate new interest in tempeh in Europe. In 1974 Rusmin and Ko wrote an article on rice-grown tempeh inoculum and Ko (1974) showed that the tempeh mold prevented aflatoxin production by Aspergillus flavus . In 1979 Ko and Hesseltine wrote "Tempeh and Related Foods," an excellent expanded and updated version of Ko's unpublished 1964 paper, with more details on previous Dutch tempeh research. There Ko reported that, following the change in attitude towards tempeh in Indonesia from the mid-1960s, studies by universities and by government agencies during the 1970s had paid more attention to tempeh. Ko insisted on using the Indonesian spelling for tempeh, even in English-language articles.
Yap and Ko had pioneered the way for Indonesians to do research on tempeh in the United States. Many others followed in their footsteps. The next Indonesian to study tempeh was Nasruddin Iljas, who wrote his MS and PhD theses on tempeh at Ohio State University in 1969 and 1972. His was the first PhD dissertation ever to be written on tempeh. In 1970 and 1973 he published two studies with Peng and Gould at Ohio State; the first was a short article on ways of preserving tempeh and the second, "Tempeh: An Indonesian Fermented Soybean Food," was one of the best and most extensive works to date, containing a lengthy review of the literature. In 1970 Dwidjoseputra wrote her PhD thesis on the microbiology of ragi (starter) at Vanderbilt University in Tennessee. In 1975 Sudarmadji wrote his PhD thesis on tempeh at Michigan State University, and by 1978 had authored or co-authored five publications on the subject. He found that the phytic acid in soybeans (which can bind dietary minerals) was significantly reduced during the tempeh fermentation. In 1980 Rivai wrote his MS thesis on tempeh at the University of Minnesota.
Interest in and publications about tempeh in Indonesia increased rapidly after the late 1960s. In 1967 the Indonesian Department of Agriculture published Mustika Rasa ("Gems of Taste"), a huge (1,123-page) cookbook of the best recipes from throughout the Indonesian archipelago. Referred to as the "Bible" of local cooks, it contained 35 Indonesian tempeh recipes and seven onchom recipes. Also in 1967 several types of tempeh were included in the official Indonesian Food Composition Tables (Direktorat GIZI 1967). Dwidjoseputra and Wolf (1970) studied the microorganisms in tempeh inocula. Sastroamijoyo (1971) was the first Indonesian to suggest that tempeh offered an answer to the world food crisis. Hermana was senior author of six important articles between 1970 and 1974, and Indrawati Gandjar wrote the first two of her many publications on tempeh in 1972. In 1972 and 1975 Thio published on tempeh. Winarno was the senior author of three publications written between 1973 and 1976. The most important of these was The Present Status of Soybean in Indonesia (1976), compiled as part of the ASEAN Project on Soybeans and Protein-Rich Foods by an interdisciplinary team of Indonesia's top authorities on soybeans. It contained the first detailed analysis of the tempeh industry in Indonesia. This ASEAN Protein Project served as a major stimulus for additional research on tempeh by Indonesians, and numerous papers were published in its periodical progress reports (Saono et al. 1974, 1976, 1977; Suhadi 1979; Jutono 1979; Hartadi 1980). Tempeh was discussed extensively at workshops on Solid Substrate Fermentation sponsored by the ASEAN Sub-Committee on Protein, held in Bandung, Indonesia, in 1978, and Kuala Lumpur, Malaysia, in 1980. Other studies on soy tempeh were published by Noor (1975), Khumaidi (1976), Loegito (1977), and others.