H Micheal Tarver & Austin W Allan. Cambridge World History of Food. Editor: Kenneth F Kiple & Kriemhild Conee Ornelas. Volume 1. Cambridge, UK: Cambridge University Press, 2000.
Sago is an edible starch derived from the pith of a variety of sago palms, but mostly from two species of the genus Metroxylon—M. sagu and M. rumphii. The sago palms flower only once (hapaxantic) and are found in tropical lowland swamps. Other genera of palms that yield sago starch include Arecastrum, Arenga, Caryota, Corypha, Eugeissona, Mauritia, and Roystonea. In all, there are about 15 species of sago palms distributed in both the Old World and the New, with the most significant of these, M. sagu, located mainly on the islands of the Malay Archipelago and New Guinea. As a staple foodstuff, only the Metroxylon genus appears to be in regular use, generally among populations located in coastal, lacustrine, or riverine areas. Worldwide, sago provides only about 1.5 percent of the total production of starch and, consequently, is fairly insignificant as a global food source (Flach 1983). It is processed into flour, meal, and pearl sago, and is often used for thickening soups, puddings, and other desserts.
Sago starch is extracted in a variety of ways, although the general process is similar from area to area. The trunk of a felled palm is chopped into sections and then split vertically to allow the pith to be removed. The extracted pith is ground and then repeatedly washed and strained. The strained material is allowed to dry, and the result is pellets of sago starch. When processed in this manner, the average yield of one palm (of 27 to 50 feet meters in height) generally ranges between 130 and 185 kilograms (kg) of sago, which can feed a family of between two and four persons for up to three months.
The early history of sago palm use as a food is still unclear. Ethnologists and anthropologists have generally relied on native myths and legends to judge when it was introduced into the diets of many groups worldwide. Some, such as E. Schlesier and F. Speiser, have tended to believe that the sago palm has been utilized as a food source in the Pacific islands since prehorticultural days. J. B.Avé (1977), for example, has stated that Neolithic and Mesolithic artifacts found in insular Southeast Asia included tools used in sago preparation. Although this suggests that sago has been cultivated since ancient times, paleohistorians are not so sure. E. Haberland and others, for example, have contended that sago consumption was a postagricultural development (Ruddle et al. 1978).
By most accounts, the sago palm was essential to the early inhabitants of Southeast Asia, and was probably one of the first plants they exploited as part of their subsistence strategy (Avé 1977; Rhoads 1982; Flach 1983). Geographer Carl O. Sauer believed that the plant’s domestication took place there, where people in freshwater areas were able to employ native palms in a variety of ways, including the production of starch, drugs, and fish poisons, as well as fishing nets and lines (Isaac 1970). According to the folk history of the Melanau of Sarawak, the tribe has “always eaten sago,” even though they claim that rice, not sago, is their staple food (Morris 1974).
Sago, however, has also been an important food source for peoples in other parts of the world. Evidence, although limited, indicates that during the Chinese Tang Dynasty (618 to 907),sago starch from palms grown in southeast China came to rival milled grain for use in making cakes. Additionally, the nutritive value of Metroxylon sago was discussed in the Pen Ts’ao Kang mu (The Great Herbal), and Caryota palms are mentioned in Ki Han’s Nan Fang Ts’ao Mu Chuang(“Account of the Flora of the Southern Regions”) (Ruddle et al. 1978). For the peoples of the Southwest Pacific, sago palms have been important from ancient times to the present; stands of M. sagu and M. rumphii have provided staple foods over the centuries for many millions of people (McCurrach 1960).
In the Western Hemisphere, the use of sago starch has been less common, although Arecastrum romanzoffianum, Mauritia flexuosa, and Roystonea oleracea are all varieties that have provided nutritional relief during times of food scarcity. For example, many Paraguayan peasants are said to have survived on sago in the 1870s, following the devastation wrought by the war of the Triple Alliance. And some peoples, such as the Warao Indians of Venezuela, continue to utilize M. flexuosa as a dietary staple (Ruddle et al. 1978).
Sago palms generally reach maturity at about 15 years of age, at which time the tree develops its enormous mass of pith. The pith makes up approximately 68 to 74 percent of the total weight of the tree, whereas the starch content of the pith constitutes about 25 to 30 percent of the pith weight. Raw sago from Metroxylon spp. will yield a range of approximately 285 to 355 calories per 100 grams. Nutritionally, about 70 to 90 percent of raw sago is carbohydrate, 0.3 percent is fiber, and 0.2 percent is protein. Although it has a negligible fat content, sago does contain various minerals, including calcium (10 to 30 milligrams [mg]), phosphorus (approximately 12 mg), and iron (0.7 to 1.5 mg) (Peters 1957; Barrau 1960; Platt 1977; Ruddle et al. 1978).
Sago supplies energy needs, but because it is deficient in most other nutrients, its consumption must be complemented with other foods that yield good-quality proteins as well as a range of vitamins. Climate and other environmental factors generally dictate the supplements. In some areas of New Guinea, for example, the inhabitants use leaves and other greens (sometimes grown on platforms raised above water or in limited garden space) along with the products of fishing and hunting. Another source of animal protein is the sago grub, especially for those groups located inland from the wetlands and rivers. Still others have supplemented their diet with coconuts, tubers, roots, and pulses, in addition to greens (Barrau 1960).
The first Western description of sago consumption appears to be that penned by Marco Polo during his travels to Indonesia in the thirteenth century. Polo wrote “Of the Sixth Kingdom, named Fanfur, where Meal is procured from a certain Tree,” with the “meal” in question clearly sago starch. A few centuries later, S. Purchas, during his travels in Sumatra, also mentioned sago as a food source (along with rice and millet) (Ruddle et al. 1978). In 1687, W. Dampier noted that sago was one of the more common foods at Mindanao (Tan 1980).
Toward the end of the nineteenth century, sago palms were observed in a number of regions of the world, and Ceram, Borneo, and Sarawak were mentioned as areas of starch production. Today, a survey of sago use would encompass a vast area, ranging over Malaysia and the Pacific Islands (Boulger 1889; Flach 1983).
Sago is fairly common in the western Pacific, where cultivated stands of the palm cover an estimated 10,000 hectares (Firth 1950). It is also present throughout much of the southwestern Pacific area. In Papua New Guinea, for example, there are approximately 1,000,000 hectares of wild sago stands and 20,000 hectares of cultivated stands. Similarly, in Indonesia there are 1 million hectares of wild stands and 128,000 hectares that are cultivated. Rounding out the major areas of sago palm stands are Malaysia with 33,000 hectares of cultivated stands and Thailand and the Philippines with 5,000 hectares each (Flach 1983).
Unlike most plants, the sago palm has not been geographically dispersed, and in experimenting with ways to introduce this crop to new areas, M. Flach (1983) discovered a number of possible reasons for the failure of previous attempts. His own efforts failed in Surinam, probably the result of inadequate care of the plants. An attempt in the south Sudan also failed, most likely because of that region’s low humidity. Flach did have success in Vietnam, where a sago palm stand succeeded at Can Tho. But, as he discovered, there are two additional factors that make it difficult to disperse sago palms. One is the problem of obtaining generative material, and the other is the cumbersome size of the vegetative material (Flach 1983).
Moreover, depending on location, the peoples of the different sago palm regions of the world call the palms by a great variety of names.The Papuans, for example, have 23 names for Metroxylon and sago. In pidgin English, it is saksak. In other areas of New Guinea, the sago palm is known as abia, aisai, akiri, ambe, api, baiao, balega, barian, da, dou, fi, ipako, na, nafa, ndana, no, poi, pu, and wariani. In the New Hebrides, it is known as natangora. In the Fiji Islands, sago is referred to as ota or oat and as soqo or soqa, and in the Moluccas it is lapia. In Indonesia, sago is known asrambia, rembia, rembi, and rumbia, along with other similar cognates (Barrau 1960).
The most important palm trees in sago production are from the genus Metroxylon, a term that comes from the Greek words metra, meaning “heart of a tree,” and xylon, meaning “wood” (Whitmore 1973). Metroxylon sagu and Metroxylon rumphii are economically the most important species in the genus (Flach 1983) and appear to be closely related, as they are found in wild stands mixed together with what appear to be intermediates (Flach 1983).
M. sagu and M. rumphii share a great number of characteristics, as well as the common name “sago palm.” It is thought that M. rumphii originated in Malaysia, New Guinea, and Fiji, whereas M. sagu originated in western New Guinea and the Moluccas. The trunks of the two species reach a height of approximately 10 to 15 meters and are generally about 45 centimeters (cm) in diameter (McCurrach 1960; Whit-more 1973). Their leaves grow to 600 or more centimeters in length, and the leaflets are about 60 to 120 cm long and 2.5 to 7.6 cm broad. The flower stalk, which appears above the leaves, is 4 to 5 meters in length. The flower stalk of M. rumphii is black and covered with spines, whereas that of M. sagu lacks spines. The fruit produced is spherical, dull yellow, and about 5 cm in diameter. The growth cycle of the sago palm ranges from 8 to 17 years (McCurrach 1960; Flach 1983). Although their ideal temperature range has not yet been determined, it is known that sago palms thrive in areas where the temperature only occasionally drops below 15° C.
What is known about the natural habitat of the sago palms has been gleaned largely from observations in environments where they now grow. Indeed, with so little information available, scientists have been forced to study conditions in the natural habitat as well as the centers of cultivation to glean what they can (Flach 1983). Typical of natural habitats are the swamp forests of sago palms in New Guinea, where fresh water is abundant (Barrau 1960).
Outside of swamps, if a climate is too wet, grasses tend to take over and limit propagation. If, on the other hand, the climate is too dry, taller trees will win in competition with the sago palm. It has been suggested that sago palms might survive under drier conditions if well tended. Although sago palms are relatively tolerant of salinity, if the water becomes too brackish, other trees in the vicinity, such as the nipa palm (Nipa fruiescens), tend to take over the swamp (Ruddle et al. 1978).
To the conditions of the sago palm’s natural habitat, Rhoads (1982) has added the proviso that they are generally “alluvial freshwater swamps” that are frequently located inland from the mouths of large rivers. He has also noted that the mineral soils in which sago palms grow best, especially those high in organic content, need regular flooding for the consistent replacement of nutrients and to discourage the growth of taller trees that keep out sunlight (Rhoads 1982).
Numerous other palms can be sources of sago starch, but they are not so fruitful as M. sagu and M. rumphii. G. S. Boulger (1889) noted that “inferior” sago could generally be obtained from the Gomuti palm (Arenga saccharifera), the Kittool palm (Caryota urens), and the Cabbage palm (Corypha umbraculifera). In the East Indies, sago could be gotten from Raphia flabelliformis, Phoenix farinifera, and M. filare, and in South America from Mauritia flexuosa andGuilielma speciosa (Boulger 1889). There are also a number of Metroxylon species in Oceania, including amicarum, bougainvillense, warburgii, vitiense, upolense, salmonense, and, presumably, oxybracteatum (Ohtsuka 1983).
In South America, additional sago-producing palms have been identified among four different genera: Syagrus, Copernicia, Mauritia, and Manicaria; moreover, many South American tribes have extracted sago from Syagrus romanzoffianum and Copernicia cerifera (Wilbert 1976).
Sago Palm Grove Management
Rhoads (1982) determined three general methods of sago palm grove management. The first is simply the process of harvesting sago trees for starch, which (even if only an unintended result) does increase the vitality of the grove: The cutting of palm trunks allows more sunlight to reach nearby shoots, a process that enhances growth and helps to ensure the maturation of at least one sucker, and the damage caused during harvesting by fallen palms and by the construction of work sites in the grove tends to give young sago palm shoots advantages over competitors. Such “unintended management” can be very important to the maintenance and promotion of a sago palm grove (Rhoads 1982).
A second process of sago palm management, termed “horticulture” by Rhoads (1982), involves the planting of suckers or the nurturing and replanting of seedlings. This method, however, is either rare or poorly documented.
A third method of “palm cultivation” involves both the planting of suckers and conscious efforts to change the environment in ways that will promote sago palm growth. One process in which the environment is changed is the creation of artificial swamps by damming streams to flood the groves. Another, observed by Rhoads, is the clearing of the canopy of higher trees to promote sago palm growth. Groves are also sometimes laid out higher up on the slopes of mountains to provide more sunlight for the palms (Rhoads 1982).
Generic Sago Extraction Process
Although sago extraction methods differ somewhat throughout cultures and regions, there are procedures common to all. At the “domestic level,” the entire process of sago extraction takes place in the grove itself, thus eliminating the need to transport heavy palm trunks (Flach 1983). Felling the tree occurs when the flowering of the palm indicates that the starch content is at a maximum (Flach 1983). It is also possible to estimate the starch content by taking a small slice from the palm trunk and sampling the starch, either by chewing the pith or by allowing the starch to dry on the axe. If the starch content is too low to merit harvesting the palm, the sample hole is patched with mud (Flach 1983).
If the palm is ready for harvesting, it is felled with an axe, after which the trunk is split lengthwise. (In an alternative method, only the bark is split—and removed.) The pith, when exposed, is “rasped” with a chopper or small hoe (Flach 1983). In the past, choppers were often constructed out of bamboo, but modern choppers are more generally made of metal. The pith is rasped at a straight angle to the fiber while the worker sits on the trunk. The resulting mixture of fiber and rasped pith is next placed on a kind of trough made from palm leaves that has a sieve attached to the lowest end (Flach 1983).
At this point, water is added and kneaded into the mixture to start it flowing, whereupon fibers are caught by the sieve while the starch, suspended in water, flows through the sieve and is collected in a tank, perhaps an old canoe. The starch eventually settles to the bottom, whereas the extra water flows over the side of the tank. The fibrous materials are given to pigs, ducks, and chickens to consume. With this process, it is possible to produce approximately 1 kg of dry starch per hour (Flach 1983).
Larger, although still “small-scale,” extraction operations require waterways to transport the sago palm trunks to a processing plant. There they are cut into sections of about 1 to 1.2 meters in length that are easier to work with than entire trunks (Flach 1983). Extraction methods employed at such facilities follow the general model already outlined, although at times different instruments and processes are employed (Flach 1983).
Rasping, for example, is done with a variety of instruments. A board with nails driven through it is sometimes used, but there are also numerous types of engine-powered raspers. At times, a “broad side rasper,” which runs parallel to the bark, is employed (Flach 1983).
The kneading and sieving process also varies at the extraction plants. At some, the mixture is trampled, whereas at others a slowly revolving mesh washer constructed of wood or metal is used. Still other plants employ horizontal screen washers or spiral screw washers. It is also possible to combine mechanical stirring with a mesh washer to process the overflow (Flach 1983).
Small ponds are often utilized for the settling process, although another method involves “settling tables.” This has the advantage of settling the largest and “cleanest” starch granules—those that bring the highest price on the market—first. The smaller granules, which may contain clay, settle later and yield a grayish, low-quality flour (Flach 1983). Sunlight is often the sole drying agent for the processed starch.
Water quality is a key factor in the entire procedure: Poor water tends to yield sago starch of lesser quality. The refuse created in the production of sago is only of value if domestic animals are nearby. When this is not the case, the refuse is often simply discarded behind plant buildings, creating a stench that is noticeable at quite some distance (Flach 1983).
Extraction Methods in Different Areas
In New Guinea, good use is made of natural stands of sago palms, as well as planted seedlings and suckers. In the swampy lowlands, the semiwild stands require only a minimum of pruning. Those who plant and harvest sago palms throughout the year make periodic visits to the various groves to determine the proper time for harvest (Barrau 1960; Ooman 1971; Ohtsuka 1983).
Sago extraction is usually done by extended family groups in New Guinea. The men fell the palm, making the cut approximately 40 to 70 centimeters above the ground. Next, using axes, they remove half of the surface wood (2 to 4 cm thick) in order to expose the pith. While this is going on, the women construct troughs in which the sago starch will be washed out. Once the men have exposed the pith, the women scrape it out of the trunk and pound it into a mass (Barrau 1960; Ohtsuka 1983).
For starch extraction, the Papuans employ an abol, a tool made from two hard sticks and a toughened string of cane that is used much like an adze. (In fact, adze-like tools are common throughout New Guinea.) The actual cutting implement is most often made of stone, wood, or sharpened bamboo, although in areas that have contact with Europe, metal piping is frequently employed (Barrau 1960; Ohtsuka 1983).
In New Guinea, as is typical elsewhere, leaves, a trough, and a sieve are used in the kneading and straining process. The starch-bearing liquid is collected in pans made from leaves or leafstalks, then partly dried and wrapped with palm leaves, usually in the shape of a cylinder or a cone. In one study, it was observed that five women, in about 8.5 hours of extracting, sieving, and drying, were able to produce 54.7 kg of sago (Barrau 1960; Ohtsuka 1983).
In Malaysia, the average yield per sago palm has been estimated at between 113 and 295 kg. The fallen palm tree is cut into logs of 120 to 183 cm in length for rasping. The tools used in rasping have evolved from the palu, a sharpened bamboo cylinder with a long wooden handle (which caused many leg injuries), to the garut, a wooden board with nails, to mechanized scraping machines, introduced in 1931. One such device consists of a spinning metal disc with serrated edges. Kneading is usually done by trampling, and drying takes place in the sun (Knight 1969; Whitmore 1973).
The extraction process that takes place in a factory is quite similar to the more primitive methods already described. In Singapore, for example, an axe is used to remove the bark, and a two-man nail board is employed in the rasping process. Care is taken to process sago trees in the order in which they arrive at the factory, so as to prevent spoilage. The extracted sago is made into blocks, mixed with water, and then blocked again. They dry in the sun, with occasional turning.
Tikopia provides an example of sago extraction in the western Pacific, where the task proceeds during the rainy season because excess water is readily available. Hoops of iron are used to scrape the trunk after the bark is removed; before iron was introduced, sharp coconut shells were employed. If the work is to be performed in the village instead of in the field, the trunk is cut into sections. Kneading is done in coconut-leaf mesh baskets and the material is then sieved. A trough is filled with the water-and-starch solution and covered with coconut and sago fronds. After the starch has settled, the water is poured off, and the sago is dried and made into flour (Firth 1950).
In South America, where the Warao Indians extract sago from Manicaria saccifera, the methods, again, vary only a little from those employed elsewhere. After the tree is felled, the bark is removed, and an adze or hoe (nahuru) is utilized to rasp the pith. This hoe typically consists of a blade made of Mauritia bark, with a handle constructed of rounded wood and a binding consisting of a two-ply cord made from Mauritia bast. The trough employed in the process is made from the trunk of the temiche palm. After water has been added to the pith and the mixture kneaded through a strainer, a ball of light brown sago is made.
In South America, sago extraction practices may be part of a disappearing tradition, as the starch is slowly giving way to other agricultural staples, even among the tribes who have used it since prehistoric times (Wilbert 1976).
Sago As Food
It is mainly in New Guinea and neighboring islands that Metroxylon has been exploited as a food. A typical swamp grove will have approximately 25 palms per acre per year ready for felling. These will yield a total of about 2,837 to 3,972 kg of crude starch, which will provide from 7 to 10 million calories to its consumers. Sago can be used like any other starch, and peoples familiar with it have developed numerous ways of preserving and consuming it (Boulger 1889; Barrau 1960; Flach 1983).
In the swamp areas of New Guinea, where sago is a staple, the average daily ration per person is a little less than a kilogram, with individual consumption ranging from a bit over 0.5 kg to about 1.5 kg per day. Such quantities of sago deliver from 1,700 to about 4,000 daily calories, which the average family in New Guinea devotes 10 days of each month to acquiring (Ooman 1971).
Left dry, sago becomes moldy and spoils. But the starch can be stored by simply placing it in a basket, covering it with leaves, and sprinkling water on it from time to time. With moisture, sago ferments and forms lactic acid, which prevents spoiling. If pottery is available, fresh sago is placed in a jar and covered with water (Barrau 1960; Ooman 1971; Flach 1983).
There are, however, methods of storing sago in a dry state. One is to make sago paste into briquettes by dehydrating it rapidly on a surface above a fire. This method permits the sago to be kept for about one month. Sago can also be dried in the sun, although it is said that this makes it taste “flat” (Barrau 1960; Flach 1983). In general, Papuans tend to think that dried sago loses its flavor.
As has been mentioned, nutritional supplements are vital to a diet centering on sago. It must be eaten with some fish or meat (or other whole protein) and with vegetables to provide consumers with a satisfactory intake of the chief nutrients. Thus, in New Guinea, the peoples reliant upon sago, who supplement their diet with fish, hunted game, sago grubs, sago palm heart, leaves, and nuts, probably enjoy a relatively well-balanced diet (Ooman 1971; Dwyer 1985).
After harvesting, it is common for some of the just-produced sago to be eaten immediately. The women usually prepare it by wrapping a portion in palm leaves or packing it into a section of cane (actually rattan, Calamus spp.) and baking it (Ohtsuka 1983). Sometimes, before the sago is baked in a fire, it is mixed with grated coconut or with bean flour (Flach 1983).The remainder of the freshly harvested sago is then wrapped in dry palm fronds to be carried back to the village (Ohtsuka 1983).
The starch is prepared in a number of ways. In areas with pottery, a sago porridge is often served along with condiments, grains, fish, and meat. A biscuit of sago is also made by those who have pottery. In what was Netherlands New Guinea, for example, a sago biscuit was baked in an earthenware mold, which served as the oven.
Areas without pottery will often bake sago paste, rolled in green leaves, in a hot stone oven. This produces a flat cake that often has grated coconut, meat, fish, or greens mixed into it. A cake with grated coconut is called sago senole. Sago briquettes, wrapped in sago leaves, are referred to as sago ega. Sago bulu comes from the cooking of sago paste in green bamboo. A roasted stick of sago paste is called sago boengkoes.
In Borneo, sago pellets are used occasionally as a substitute for rice (Barrau 1960). A sago ash may also be produced by burning the wide part of the sago leaf midrib. This can be an important nutritional supplement providing sodium, potassium, calcium, and magnesium.
Pearl sago—another common product from sago starch—is made by pressing wet sago flour through a sieve and then drying it in a pan while stirring continuously. The “pearls” formed are round, and the outer part of the sago pearl gelatinizes to hold them together. Pearl sago is an important ingredient in soups and puddings (Flach 1983). In Sarawak, wet sago flour is mixed with rice polishings and cooked into pearl form, creating an “artificial rice,” certainly a more nutritious food than polished rice. Flach believes that this product has potential as a substitute for rice in Southeast Asia (Flach 1983).
In Tikopia, sago is often made into a flour that is considered a delicacy by those who produce it. On occasion, sago is mixed with other foods to add body, flavor, and softness. Big slabs of sago are also baked for many days in large ovens, and then put aside for times of famine. However, this sago product is considered virtually “unpalatable” by its makers (Firth 1950).
Sago is also employed in foods that are more common in other parts of the world. For example, sago starch can be used in high-fructose syrup as a partial replacement for sucrose (Flach 1983). Sago has also been experimentally added to bread flour. It has been found that adding 10 percent sago to the recipe can improve the quality of the bread produced, although adding more will lower it (Flach 1983).
In addition to the consumption of the palm pith, other parts used as food include the inner shoot of the crown (as fruit or snack), sap from the male inflorescence (boiled into palm sugar, fermented as vinegar or distilled spirit), and the inner kernel (cooked in syrup as a dessert) (Lie 1980). Overall, the uses of sago are as varied as those of other starches.