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Figure 1. Graph of oil production for the last 10 yr for individual oils. Asterisk denotes projection.

Figure 2. Oilseed solvent extraction flow sheet.

Figure 2. Oilseed solvent extraction flow sheet.

Origin and Cultivation. Archaeological evidence of earliest corn places its age at greater than 7,000 yr. The evidence further shows that this corn was domesticated, ie, natural seed dissemination was impossible. Corn probably originated in Mexico and spread north and south. Early

European explorers brought it to Europe, from where it spread to Africa and Asia (18). Every continent except Antarctica produces corn.

Today, the U.S. Corn Belt is the largest area of corn cultivation in the world. Through years of managed hybridization, Corn Belt corn is also the world's most productive variety. In fact, depending on climatic conditions, the per acre yield of corn is greater than any other crop. Over the last 60 yr, U.S. corn-growing area has decreased by half while production has doubled because of increased yields (18). Corn grows in the middle latitudes of both hemispheres. The growing season lasts through the freeze-free period. Corn grows from seed to a mature plant, 2-4 m tall, in about four months. Weather changes cause corn yield to vary across the Corn Belt by as much as 20% in a given year.

Composition and Uses. Grain makes up more than 40% of the dry matter of the corn plant. Stover, the nongrain parts of the plant, make up the rest of the dry matter. Because of its low oil content, corn is not generally considered an oilseed. More than 60% of the kernel is starch; oil comprises less than 4% (Table 1). In the United States, corn is primarily an animal feed crop, with less than 15% used for human consumption or various industrial purposes. For nonfeed purposes, corn is processed in one of two ways. Dry milling involves separating the germ from the whole kernel with an abrading action. The germ is then pressed or solvent extracted to remove the oil, which is used primarily as a salad and cooking oil. The rest of the kernel is then milled to produce grits, cornmeal, and flour. These products are used in a variety of applications, including snack products, breakfast cereals, brewing, pharmaceuticals, and building products. In wet milling, the corn is first softened by soaking it in a steeping liquor. The softened corn is then drained, coarsely ground, and combined with water to make a slurry. The slurry is then separated, in either hydroclones or floatation tanks, into an oil-bearing germ overflow and a starch underflow. The germ is further processed to extract oil. Most of the starch is processed into sweeteners and ethyl alcohol.

Cottonseed

Description. Four species of cotton are cultivated: Gos-sypiurn arboreum, L. G. herbaceum L., G. hirsutum L., and G. barbadense L. These are divided into two groups: the Old World (or Asiatic) and the New World. The Asiatic group, consisting of G. arboreum L. and G. herbaceum L., has short, harsh fibers that limit their use in fabrics. Their yield is comparatively low. The New World group consists of G. hirsutum L. and G. barbadense L. Their fibers are long, from 2 to 4.5 cm, and fine, making them well suited for a variety of uses. The seeds of the former are egg shaped and about 0.8—1.2 cm in length. They are densely covered with short cotton fibers, called linters, which remain after the fiber has been removed by ginning. The seed coat, or hull, is quite strong. The seeds of G. barbadense are similar in shape and size but have no adhering linters after ginning.

Origin and Cultivation. Archaeological evidence suggests that cotton was used for string and fabric in India around 3000 b.c. Although there have been claims that cotton fabric was used earlier than this in Egypt and Peru, the most reliable information suggests that this earlier material was actually linen (flax). The earliest reference to cotton in recorded literature appears in a Hindu hymn around 800 b.c. Evidence exists that the oil from cottonseed was also used by early Hindus and Chinese (19,20). However, throughout much of history, cultivation of the cotton plant was for fiber; the seeds were generally left to decay and yield fertilizer. In modern history, one of the earliest uses of cottonseed as a by-product of the cotton plant was in 1665, when inhabitants of the British West Indies made oil from the cotton flower to use for medicinal purposes. In 1769, a group ofPennsylvanians exhibited oil expressed from cottonseed and presented a sample of it to the American Philosophical Society to promote its use (21). The value of the residue of the seed after removal of the, oil, ie, cottonseed cake, soon began to generate interest. The Royal Society of Arts of London discussed the value of cottonseed cake as cattle feed and the potential of using sugar mill equipment for expression of the oil. In 1783, to spur the development of this technology, the Society offered a gold medal to any planter in the British West Indies who could produce 11 of oil and 500 lb of cake within one year. Although this offer was renewed annually for six years no one ever succeeded; the large quantity required was, apparently, too great an obstacle. The difficulty of manually separating seed and fiber caused cotton, and consequently cottonseed, production to be relatively small. However, with the invention of the cotton gin in 1793, this manual operation became mechanized and production of cotton rapidly increased. The problem of disposing the large amount of seed being produced soon became apparent. Although methods did exist for crushing seeds to extract oil, cottonseed presented a particular problem. The kernel, which contains most of the oil, is surrounded by a tough hull making, it difficult to grind. Furthermore, this hull is covered with short fibers that absorb the oil being expressed, thus reducing yields. This changed in 1829 when the first cottonseed hulling machine was patented. That same year, the first cottonseed oil mill was put into production in Petersburg, Va. Because these early hullers applied a grinding action to the seed, screening did not completely separate the hulls, fibers, and meats. In 1857 an improved huller was patented that cut the seed open so that the kernels could fall cleanly out of the hulls. This huller, which uses the same principles as modern hullers, was instrumental in the rapid expansion of the cottonseed crushing industry following the Civil War.

During the crushing industry's early years, oil was not much in demand. It was not well suited for illumination, lubrication, or drying purposes and was not particularly desired as an edible oil in the United States. However, a market for edible cottonseed oil did develop in Europe that led to a significant export trade with the United States. In the early 1870s, 9 million gal were being produced in the United States, mostly for export. Later, the discovery that an acceptable substitute for lard could be made by mixing cottonseed oil with certain animal fats greatly increased the domestic market for the oil. By 1883 yearly production of cottonseed oil had reached 15 million gal, most of which was consumed domestically. By the turn of the century, annual production was 115 million gal.

The Asiatic group is grown mainly in China, India, and Pakistan, although cultivars from the New World group are replacing them. G. hirsutum, commonly referred to as American Upland Cotton, probably originated in southern Mexico and Guatemala and eventually spread to the southeastern United States. American Upland accounts for most of the U.S. production and 75% of the cotton produced worldwide. Sea Island cotton, the common name for G. barbadense, originated in Peru and spread to the Caribbean Islands. It adapted to islands off the coast of Georgia and the Carolinas and to nearby coastal areas of the mainland. Because of its limited growing regions and eventual devastation from the boll weevil, its production in the United States has been abandoned. A variety of G. barbadense, called Pima or Egyptian, is still produced in the United States although it accounts for only a small percentage of the U.S. production, its demand has increased in recent years due to its long, silky fibers. This variety, probably developed by crossing G. barbadense with G. hirsutum, was transferred from the Americas to Egypt and is the only variety of cotton grown in that country. The Egyptian government is very protective of the seed's germplasm, prohibiting export of the seed or import of other varieties.

Composition and Use. The cottonseed kernel makes up about 55% of the seed's weight. The surrounding hull and linters comprise about 32% and 13%, respectively. After processing, the seed yields about 16% crude oil, 45% meal, 9% linters, and 26% hull by weight (22). Most of the oil is in the kernel, which contains 35% oil and 39% protein. The hull contains less than 1% oil and 4% protein. Figure 3 shows a cross section of seeds from two varieties of G. hirsutum. The dark specks distributed over the glanded cross section (Fig. 3a) are pigment glands, which contain various material that impart the characteristic yellow-red color to the oil and extracted meal. The major constituent of these glands is gossypol, a yellow polyphenolic pigment found in all parts of the cotton plant, although it is concentrated mostly in the seed. Gossypol is insoluble in water but is soluble in oil, which accounts for the dark color of extracted crude oil. The amount of gossypol in a moisture-free kernel varies for different varieties and growing conditions, generally ranging between 0.39 and 1.7% (23). The presence of gossypol is a major problem in the use of cottonseed as an animal feed. Although cattle, sheep, and other ruminating animals can consume large quantities of raw cottonseed with no ill effects, rabbits and swine are very sensitive and can die from the gossypol's interference with the oxygen-carrying capacity of the blood. Chickens are moderately sensitive; green egg yolks result when chickens are fed too much cottonseed.

The gossypol in ginned seed before any processing treatment is said to be free. Once moist heat is applied to the seed, as is done in expeller processing or in the cooking step before solvent extraction, the gossypol reacts with the protein and is largely inactivated. This form of gossypol is said to be bound. Once bound, the gossypol's toxicity to

Figure 3. Photograph of a cross section of (a) glanded and (b) glandless cottonseed.

nonruminating animals and its ability to discolor hen eggs is, for the most part, negated. However, because gossypol binds to the lysine, the quality of the protein is reduced.

In 1953 a variety of G. hirsutum was discovered being grown by the Hopi Indians in Arizona that was free of gossypol glands on the leaves and bolls. The seeds, however, were still glanded. When these Hopi strains were crossed with cultivated Upland cotton, selections with glandless seed were found. After several generations of selecting for a reduced number of glands a true breeding glandless type was produced (24,25) (Fig. 3b). The glandless variety has a number of advantages. The crude oil is much lighter in color and consequently easier and less costly to refine. The meal is completely edible to both ruminants and monogas-tric animals. A variety of human food products, such as breads and snack items, can be produced from glandless cottonseed flour (26). However, despite the advantages, glandless varieties have not been a commercial success because the glandless varieties increase the potential value of only the seed, not the fiber. Because cottonseed represents less than 10% of the value of the cotton crop, farmers see no reason to shift to new cultivars (with all of the attendant uncertainties) for only a small potential increase in profits.

Of all the oilseeds, cottonseed probably has the most uses. The three major constituents of the seed, ie, kernel, hulls, and linters, all have economic value (27). The crude oil extracted from the kernel is refined and used in an assortment of food products. Snack and fast-food frying oil, salad and cooking oil, salad dressing, shortening, and margarine are major uses. One nonfood use for the refined oil has been as a carrier for agricultural sprays. By-products from the refining process are used in soap manufacture and as a source of fatty acids, which in turn have innumerable industrial uses. The meal is used as feed for beef and dairy cattle, swine, poultry, and fish and as fertilizer. The hulls are used in animal feed, as poultry litter, and as a mulch for soil conditioning. The linters are used in the preparation of high-quality bond paper and as felts for pads, cushions, comforters, and mattresses. They can be made into yarns or used as absorbent cotton for medical purposes. They can be processed so that the cellulose can be used in such diverse products as plastics, food casings, x-ray film, and many other industrial uses.

In recent years, the feeding of whole cottonseed to dairy cows has become increasing popular among dairy farmers (28). In 1981, 72% of the cottonseed production was crushed and 22% was fed as whole seed. In 1988, 64% was crushed and 35% was fed as whole seed (29). The whole seed is high in fat that, after digestion, increases the fat content, and hence the value, of the cow's milk.

Although gossypol has not yet been used commercially, much work has been done to find economically viable uses for it (30). Its antioxidant properties are well known. It also has significant antimicrobial properties. Possibly the area receiving the most attention is gossypol's potential use as a male contraceptive. In 1957 a Chinese researcher reported that a particular village had not had a single childbirth for a 10-year period between 1930s and 1940s. Before and after this time there did not seem to be a birthing problem. The researcher found that because of poor economic times, the villagers had switched to crude cottonseed oil for cooking. He postulated that its use might have caused female infertility. In the early 1970s researchers found it is the male who is actually affected. The gossypol initially reduces sperm motility and subsequently blocks sperm production (31). Much current research is being conducted on gossypol's potential contraceptive uses.

Olive

Description. The olive tree, Olea europaea L., is the only member of the Oleaceae family (which contains trees such as ash and shrubs such as lilacs) that is an important food source. The tree is a perennial evergreen, pyramidal in shape, that can grow to 20 m, but under cultivation is pruned to under 5 m. The fruit is fleshy, oblong or crescent in shape, and has a center stone. Olives change in color from green to red to black as they ripen.

Origin and Cultivation. The age of the olive tree is uncertain, but olives have been crushed for their oil for more than 6,000 years. The tree probably originated in Lebanon and Syria. It is believed to have been brought to Italy, through Greece, by Phoenician traders before the end of the fifth century b.c. (4). Olive trees grow in subtropical areas having dry summers and mild winters. For centu ries, olives and olive oil have been among the most important agricultural products of Italy, Spain, Greece, and northern Africa.

Composition and Uses. The components of the olive are the edible pulp, which makes up 65-85% of the ripe fruit; the pit which consists of 13-23%; and the seed inside the pit, which is about 2-3% of the fruit. Olives have a high oil content but little protein. Green table olives are unripe and must be soaked in lye to remove oleuropein, a bitter principle, before pickling in brine. Ripe black olives do not need caustic treatment.

Oil is removed from olives by pressing. The oil obtained from the first pressing is called virgin. Virgin olive oil, which is used with no refining, is considered to be the highest quality salad and cooling oil. A second pressing of the olive yields an oil of lesser quality that must be refined, bleached, and deodorized. The residue from pressing can be solvent extracted to remove the remaining oil. The remaining olive cake has no feed use, because of its low protein content, and consequently is used as a soil conditioner.

Palm and Palm Kernel

Description. The oil palm, Elaeis guineensis Jacq., has a single stem that grows to 35 m in height and is topped by leaves typically 7 m in length. About six months after pollination, the fruit matures. It consists of a reddish orange oily pulp surrounding a kernel. The fruit, which is oval or pear shaped, about 3x5 cm, and weighs up to 30 g, grows in bunches in the axil of the leaves. These bunches can contain 1,500 fruits and weigh 20 kg. An adult palm tree is capable of producing 12 bunches per year. The trees are commercially useful for about 30 years.

Origin and Cultivation. E. guineensis Jacq. originated in west Africa along the Guinea coast. It was spread to other tropical regions by 15th-century Portuguese explorers. Palm oil, however, did not enter world trade until the end of the 18th century, making it one of the youngest of the major vegetable oils. Malaysia and Indonesia are the major producers of palm oil.

Composition and Uses. Both the pulp and kernel yield oil; each has a different fatty acid composition (Table 2). The pulp makes up 60-90% of the fruit's weight. On a dry weight basis, more than 70% of the pulp and 40% of the kernel consists of oil. A fruit bunch will yield about 20% palm oil and 2% palm kernel oil. Because palm oil is a relatively saturated oil, its food uses are mostly as shortening and frying oil. It is also used in the manufacture of soaps and fatty acids. Palm kernel oil is similar in composition and use to coconut oil.

Peanut

Description. Arachis hypogaea L., called peanut or groundnut, is a member of the family Leguminosae. Many varieties exist, but two general types are grown commercially. One is an upright plant with a single central stem reaching 30 cm in height and numerous upright branches. The second is a recombinant type, reaching 20 cm in height, with numerous creeping branches. The upright plant is better suited to mechanical harvesting. In all varieties of the peanut plant, small flowers form at the end of auxiliary branches called pegs. A few days after fertilization, the pegs push the flowers into the ground, where the peanut pod develops. At maturity, the pod contains one to three nuts or kernels.

Origin and Cultivation. The peanut originated in eastern South America. Evidence exists of its cultivation in Peru around 2000-3000 b.c.; it probably has a much longer history of domestication (9). By the time of the Columbus expedition in 1492 the peanut plant had spread to Central America and the Caribbean. Early European explorers probably brought the plant from Brazil to West Africa, from where it spread to India. Many varieties of peanuts now grown in the United States come from stocks developed in Africa. The plant requires sunshine and high temperatures. It can grow as far north as Canada and as far south as southern Argentina.

Composition and Uses. Most of the world production of peanuts is processed for recovery of the oil for edible use. Peanut oil, typically produced by solvent extraction, has a high smoke point, about 227°C, making it a good frying oil. However, peanuts are one of the few oil crops that can be used directly as food. They are among the highest protein content oilseeds (Table 1) and thus are nutritionally desirable. Eaten whole after shelling and oil- or dry-roasting (the terms used for deep-fat frying or hot-air cooking, respectively), they are one of the most popular snack foods in the United States. Peanuts are also used in a variety of confections, candy bars, and baked goods. About 25% of the U.S. supply of peanuts is processed into peanut butter, which is recognized as a nutritious, satisfying, and stable food and snack item for people in all age groups.

Rapeseed-Canola

Description. Rape refers to the oilseed forms of Brasica napus L. and Brassica campestris (32), which are in the same family as mustard seeds and are closely related to cabbage, cauliflower, broccoli, and other cole vegetables. The round seeds, about 0.1 cm in diameter, contain approximately 40% oil and yield a meal with more than 40% protein. The meal is used primarily as a feed supplement for livestock and poultry.

Origin and Cultivation. This family of oilseeds appears to have evolved separately in the Himalayan region of Asia and in the Mediterranean area of Europe. Sanskrit writings of2000-1500 b.c. specifically mention the use of rape-seed oil for cooking and illumination; Greek, Roman, and Chinese writings between 500 and 200 b.c. ascribe medicinal value to them. It has been cultivated in Europe since about a.d. 1200. The Canadian rapeseed industry, the world's largest, started after World War II. By 1955 rape-seed oil was being used in Canada by major processors for salad oils (33).

Because rapeseed can survive at relatively low temperatures, they are one of the few vegetable oil sources that can be successfully cultivated in the colder temperate regions. For this reason they have become a major crop in Canada and throughout Europe. This characteristic also makes it possible for them to be cultivated as a winter crop in the subtropics. The winter form of rapeseed, typically found in Europe and Asia, is normally sown in August to September and is harvested in July. The summer form, found in Canada and Europe, is sown in April to May and harvested in September.

Composition and Use. Rapeseed oil differs from other vegetable oils because it contains significant quantities of eicosenoic and erucic fatty acids (Table 2). Studies since 1949 showed that erucic acid was poorly metabolized by rats and caused much physiological damage. In July 1956 the Canadian Department of National Health and Welfare ruled that rapeseed oil was not approved for edible purposes in Canada and all sales of oil for edible purposes were to cease immediately. In October of that same year the ban was rescinded, pending a thorough review, because of lack of evidence of harm to humans. Even though the ban was never implemented, the perception remained that health problems could arise from rapeseed oil consumption. Because of this, breeders began work to produce new varieties with reduced erucic acid content. In 1968 Oro, a variety of B. napus, was the first of several low-erucic-acid rapeseeds to be released. Industry began changing to these new rape-seed cultivars in the early 1970s. To differentiate the new oil composition, the terms low-erucic acid rapeseed (LEAR) and Canbra have been used. Sinola is the term used in the FGR for rapeseed containing less than 2% erucic acid. Most countries currently use the name canola for low-erucic acid rapeseed (Table 2).

Because rapeseed oil is increasing in importance for both edible and industrial uses in the United States, the U.S. Department of Agriculture is currently formulating standards for rapeseed. The proposed standards require that rapeseed oil with an erucic acid content of greater than 40% be used for industrial purposes only. Rapeseed oil with no greater than 2% erucic acid is edible and is called canola oil. Rapeseed oil containing between 2 and 40% erucic acid has little known commercial value. Although canola is used exclusively as an edible oil, rapeseed oil's high viscosity has traditionally made it a favorable lubricant for metal surfaces (34). However, where it was once used extensively for lubrication of steam locomotives and marine engines, synthetic derivatives are now used. Long-chain fatty amides of erucic acid are good plasticizers for vinyl chloride resins.

Soybean

Description. The cultivated soybean, Glycine max (L.) Merr., is an annual legume. It is usually erect, about 75 cm in height, and produces pods throughout its many branches. These pods, typically 2-10 cm in length, contain three yellow round seeds each about 0.5-1 cm in diameter.

Origin and Cultivation. G. max probably evolved from the wild species Glycine soja Sieb. and Zucc. Soy is sometimes referred to as one of the oldest cultivated crops. How ever, the earliest written record of it was 11th century b.c., long after the domestication of sesame in the Middle East. Although soybeans were first domesticated in northeastern China, the most recent evidence suggests that the plant originated in Australia (9). Seeds obtained from China were planted in Europe in the 1700s. In the early 1800s soybeans were introduced to the United States and later that century to Brazil. Not until the early 20th century was oil expressed from domestic soybeans in the United States, now the world's largest producer. Soybeans have only recently become important in Brazil; that country, the United States, and China are the world's major producers. Although soybean is a warm-temperature plant, it adapts well to temperate climates. Canada, the former USSR, South Africa, and Australia are some of the 35 countries that commercially produce soybeans.

Composition and Uses. Soybeans have the highest protein content of all the oilseeds. Processing the whole bean for food use is particularly popular in Asia. Soymilk, made by grinding beans that have been soaked in water, is consumed directly or used as a base for making tofu. Soy sauce is prepared by fermenting soybeans. The oil, obtained by solvent extraction, has many uses. Most of the production is consumed as salad oil, cooking oil, and margarine. It is also used in a variety of prepared foods such as frozen desserts, confections, and coffee whiteners (creamers). Because of its high linolenic acid content, soybean oil is considered a semidrying oil and has a variety of industrial uses. The major nonfood markets for the oil are in paints, resins, and plastics. Even though soybean oil is the dominant vegetable oil worldwide, the major economic value of soybean is in the protein. Defatted soybean meal is used mostly as animal feed; some, however, is also processed into flour, protein concentrate, and protein isolate, used in the manufacture of prepared foods.

Sunflower

Description. Helianthus annuus L. is the most common of the 67 species of sunflower and the only one grown commercially for oilseed production. A member of the family Compositae, the sunflower, is related to daisies, asters, marigolds, and dandelions. Although sunflower stems may reach heights of 5 m and have heads as large as 0.75 m in diameter (34), they typically are 1-3 m high with heads 0.3 m in diameter. The diameter of the stem is 3-6 cm. The head is actually a composite of 1,000-4,000 little flowers (florets) and will produce several hundred seeds. The head of the sunflower is heliotropic, ie, it turns to face the sun, until the majority of the flowers are fertilized, then it remains facing east. The easterly exposure minimizes the plant's temperature, which helps the seeds to set (9). The seed, more properly called an achene, is oblong and flatfish, about 1.0-2.5 cm long, 0.75-1.5 cm wide, and 0.3-0.75 cm thick.

Origin and Cultivation. Sunflower seeds have been found at several archaeological sites in Mexico and southern and western United States. Although evidence exists of early precontact native Americans gathering wild sun flowers and making meal from the seeds, there is no evidence that they cultivated the plant. Even though corn, squash, and beans were cultivated, the prolific nature of wild sunflowers may have obviated the need to cultivate them. Around the 1500s, several native American nations were cultivating sunflower, although not nearly as much as they were cultivating corn. This is reasonable because corn is one of the best food plants known to humans.

The sunflower, like many other indigenous American plants, was taken back to Europe by early explorers. The first study of the sunflower, written by a Belgian herbalist (35), was published in 1568, and by 1616 sunflowers were common in England. Europeans did not at first know the uses for sunflower. In 1783 it was reported that not only are the seeds an excellent poultry feed but are also easily expressed to yield a good-quality oil. When sunflowers spread to Russia in the 1800s, the seeds became immensely popular there as a food source. This was because, during the forty days before Easter and the forty days before Christmas, the Russian Orthodox Church observed strict dietary guidelines. Almost all foods rich in oil were not to be eaten during these periods. Because the sunflower had only recently entered the country, it was not one of the prohibited foods. The people took advantage of this loophole and Russia became the foremost producer of sunflowers.

Although important in Europe, sunflowers were little cultivated by early American settlers. American seed companies did not offer sunflower seeds until Russian varieties were introduced in the 1880s. Even then, they never achieved great popularity. Only recently has the sunflower become an important oil crop in the United States. Ironically, even though the sunflower originated in the western hemisphere, USSR-cultivated varieties are the ones used almost exclusively throughout the world. Sunflower is commercially produced in warm to temperate regions. It grows well in the 20-28°C range. The former USSR is the major producer of sunflowers, although in recent years it has gained popularity in many countries. In the United States it is grown mainly in Minnesota and North Dakota.

Composition and Use. The oil content of the seed can vary from a low of 24%, caused by adverse growing conditions, to a high of 65% for experimental strains. The commercial seed typically contains about 40% oil. Its protein content is usually between 15 and 20% (Table 1). Probably the oldest use of sunflower seeds is in whole form as human food. In the former USSR they are eaten as commonly as peanuts are in the United States. In recent years, whole sunflower seeds have become increasingly popular in the United States because of the general increased interest of health food conscious consumers in whole grains and dietary fiber. Most of the commercial production of sunflower seeds goes into the manufacture of oil and animal feed. Because of its relatively high iodine number (ca 130) sunflower is considered a semidrying oil. As such, it can be used in the formulation of paints and for other industrial uses. It is, however, much more popular as a food and is considered by some as desirable a salad oil as olive. It is also used in cooking, frying, and in the manufacture of margarine and shortening. The meal left after oil removal is usually used as animal feed. In Canada and the former

USSR the hulls are pressed into logs and used as fuel. The hulls are used in the manufacture of ethanol and furfural, as plywood filler, and in the production of yeast.

Homemade Pet Food Secrets

Homemade Pet Food Secrets

It is a well known fact that homemade food is always a healthier option for pets when compared to the market packed food. The increasing hazards to the health of the pets have made pet owners stick to containment of commercial pet food. The basic fundamentals of health for human beings are applicable for pets also.

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