Jojoba oil is unproven in wide-scale commercial practice, but it offers the chemical industry a new basic raw material that in the near future will be produced in bulk. Liquid waxes have never before been available to industry from a cultivated plant. It seems likely that, with the first significant supplies becoming available, industrial chemists will soon uncover many new and wide-ranging uses for this unique natural product.
Jojoba oil and its derivatives seem to have potential for uses in products as diverse as cosmetics, pharmaceuticals, lubricants, foods, electrical insulators, foam-control agents, high-pressure lubricants, heating oils, plasticizers, fire retardants, and transformer oils. Moreover, jojoba oil is also a source of long-chain alcohols and acids with double bonds in slightly different positions from those in other natural fatty acids.
As already noted, jojoba oil's boiling point is high - a desirable feature in many applications. In addition, the oil has thermal stability and high smoke, flash, and fire points. The decomposition point is 600°F (315°C).
On the other hand, the freezing point (45°-51°F; 7°-10.6°C) is also high, and this may limit the oil's uses. For instance, the freezing point may be too high for some lubricant or food uses where the oil could solidify in cold weather or in refrigerated products.
Until the early 1970s, sperm-whale oil was a common ingredient in high-quality lubricants. It was used notably in vehicle differentials and transmissions, in hydraulic fluids that need a low coefficient of friction, and in cutting and drawing oils. The high-pressure lubricants used worldwide - for example, those in most automobile transmissions - commonly contained 5-25 percent sperm oil. In some of these, unmodified sperm oil was used, but more often it was sulfurized; sometimes it was epoxidized, chlorinated, or phosphorylated before being added to the lubricant base stock.
The enactment of legislation to preserve the sperm whale banned all these uses. However, jojoba oil's composition and physical properties are close enough to those of sperm oil to ensure its suitability as a substitute. In principle, it, too, could end up in most of the vehicle transmissions used around the world. Its oiliness and surface-wetting properties are particularly promising for extreme-pressure/extreme-temperature gear oils and greases. Its wetting properties mean reduced wear and its nondrying characteristics prevent gumming and tackiness.
Sulfurized jojoba oil in general lubricants. Laboratory tests have demonstrated that jojoba can match the exceptional lubricating qualities of sperm oil. (Source: H. Gisser)
Actually, jojoba oil has several advantages over sperm oil:
· It has a mild, pleasant odor, with no fishy
· It contains no triglycerides (sperm oil contains about 30 percent).
· It requires little or no purification.
· It can absorb larger amounts of sulfur, giving better lubrication per unit weight.
· It does not darken significantly on sulfurization.
· The highly sulfurized oil is liquid, whereas mineral oil must be added to keep sulfurized sperm oil liquid.
· It is a renewable vegetable product that can be produced without destroying an endangered species.
Incorporating sulfur or sulfur-containing compounds enormously enhances the lubrication qualities. Extensive evaluations have shown that sulfurized jojoba oil has properties equivalent to or much better than sulfurized sperm oil in lubricant applications. Under extreme pressure it is at least as good at improving the antiwear properties and load-carrying capacity of both naphthenic and bright-stock base oils. In some tests, when small amounts of sulfurized jojoba oil were added to lubricants, the performance improved so much that it exceeded the limits of the testing machine.
Sulfurized oil in cutting-tool lubricant. Bench tests have shown that adding sulfurized jojoba oil to a base oil dramatically improves the life and cutting speed of machine tools. (Source: J. Messina)
When, in addition to sulfur, a molecule such as phosphorus, chlorine, or bromine is incorporated into the jojoba molecule, a synergistic action occurs and an even better lubricant additive is obtained. Sulfurchlorinating jojoba oil particularly enhances the wear properties, while sulfurbrominating it improves the load-carrying capacity.(J. Wisniak and H. Benajahu, U.S. Patent 4.130.495 (1978))
Jojoba oil's main limitation as an ingredient in lubricants is its high pour point. Below 50°F (10°C) the oil solidifies. Thus, as of now, jojoba is likely to be most useful in lubricants for use at high temperatures.
Factices and Adhesives
Vegetable oils react with sulfur chloride to form materials known as factices, which are used in manufacturing varnishes, adhesives, printing ink, and flooring materials.
Sulfurchlorinating jojoba oil produces an array of products ranging from oils to rubbery solids. Each has its own qualities and properties. A sulfur content of up to 4 percent produces a flowing, reddish-yellow liquid with the same pleasant odor as raw jojoba oil itself. Higher sulfur content increases the factice's viscosity and darkens its color to brown. When the sulfur content exceeds 9 percent, the factice becomes elastic and takes on the properties of a contact adhesive. This array of products, with widely differing viscosities and properties, offers an open field for product development and research. The sulfurchlorination process is simple and inexpensive and can easily be performed at room temperature.
Unusual Acids and Alcohols
Jojoba oil could become a source of mono-unsaturated alcohols and acids with chain lengths of 22 and 24 carbons. They can be isolated in unusual molecular purity. In principle, these acids and alcohols could be used as intermediates in the preparation of disinfectants, surfactants, detergents, lubricants, driers, emulsifiers, resins, plasticizers, protective coatings, fibers, and corrosion inhibitors. They might also prove valuable as bases for creams, ointments, antifoams for industrial use, and numerous other products. They have longer chain lengths than those currently available, and this makes possible a new range of materials with subtly changed properties.
Olive oil, beeswax, and fats are traditional cosmetics bases, but jojoba has important aesthetic and technical qualities that could also make it a widespread basic cosmetics ingredient. Indeed, in recent trials, cosmetics researchers have found that refined jojoba oil was superior to all alternatives. It has no resins, tars, glycerides, alkaloids, glucosides, or low-molecular-weight fatty acids. And, because of its stability toward rancidity and its pleasant feel on the skin, it could become a standard oil-phase base for the cosmetics industry.
Jojoba oil has already been widely used in cosmetics in the United States and Europe. As many as 300 products have appeared in United States markets alone. But most of these have used jojoba oil only for its novelty value, not for its fundamental qualities. Such health and beauty care products have been successful largely because jojoba oil is easily substituted for other oils.
But manufacturers are now coming to realize that the oil has high aesthetic qualities, better stability than even mineral oil, and lacks the problems of conventional triglyceride oils. (Information from H. Libby)
Among the varied products already being sold are shampoos, hair conditioners, hair sprays, facial oils, body oils, bath oils, hand lotions, moisturizers, suntan lotions, make-up removers, shaving creams, lipsticks and lip glosses, vanishing creams, cleansing creams, and skin fresheners.
A Japanese cosmetic company (Koei Perfumery, Tokyo) has reported the absence of any acute toxicity in laboratory studies and clinical tests carried out with jojoba and jojoba-based cosmetics over a period of almost 10 years. No acute toxicity nor eye irritation resulted from use. Indeed, only 3 out of 46 persons, chosen for their susceptibility to dermatological problems, showed even slight irritation. Similar favorable results have been reported in toxicity studies conducted in the United States.
Skin seems to absorb jojoba oil within a few minutes, and transdermal penetration is suspected, although not yet proved. A preliminary investigation at the University of Michigan suggested that it penetrates the outer skin via hair follicles and accumulates within the keratin layer beneath. Neither triglycerides nor lanolin had this ability; the characteristic was unique to jojoba. Thus, jojoba oil promises not only to help make skin supple and smooth, but perhaps to carry medications into the skin as well.(Information from K. McLatchey.)
Preparation of Pharmaceuticals
Sperm oil has long been valued for controlling foam in industrial fermentations. It has excellent antifoam properties and is barely metabolized by the microbial cultures. Comparative tests have shown that jojoba oil could also be an excellent antifoam agent, at least for the production of penicillin G and cephalosporin. In fact, in a couple of experiments, the yield of penicillin unexpectedly increased by more than 20 percent when jojoba oil was substituted for sperm oil. The results have been so satisfying that industry sources have indicated they would switch entirely to jojoba if sufficient supplies could be assured.(Information from S. G. Pathak.) More research is needed to settle the matter, however, because experiments in Israel found that jojoba oil was ineffective in foam control in other applications.(Information from J. Wisniak.)
Jojoba oil may have potential as a treatment for skin disorders. At the Ben-Gurion University Hospital in Beer-Sheva, Israel, 35 patients with severe acne were treated with cream containing jojoba oil. Doctors conducting the test report that the patients found it pleasant to use, and it seemed to ease their conditions in all cases. There were no side effects, and it restored a natural shine to skin. However, although it slowed down the acne outbreaks, it did not stop the eruption of new pustules.(Information from B.Mosovich)
Jojoba oil seems to have promise for use as an antifoaming agent in fermentation processes. Shown are the results of a set of experiments on the formation of oral penicillin. Various vegetable oils were used in various concentrations to break the foam in the fermentation flasks, and the penicillin production was measured against that resulting when sperm oil was the antifoam.Because sperm oil has long been the standard antifoam used by the pharmaceutical industry, it was surprising that substituting jojoba oil increased the penicillin yields dramatically. If such findings hold up in production scale, the increased yield would be a financial boon to the pharmaceutical industry. (Information from S. G. Pathak)
At the same university, 27 patients with psoriasis were also treated with jojoba oil-based creams. These, too, were well accepted and some noticeable improvement in skin condition was recorded. Psoriasis medicines today are either unpleasant black mixtures of coal tar and mineral oil or expensive steroids with unpleasant side effects, so this may prove to be a promising line of research.
Dermatological research suggests that jojoba oil may help reduce inflammation (Information from K.McLatchey). And in Israel, 40 volunteers in a laboratory used a jojoba cream for sunburn and chapped hands. There were no allergic reactions and the users reported getting relief.
TABLE 4 : Comparison Between Hydrogenated Jojoba Oil , Beeswax , and Carnauba
Jojoba oil's use as a possible cooking oil has often been speculated about. It has desirable culinary properties. It is stable, bland tasting, and has no unpleasant texture. Its unusual chemical structure could make it resistant to hydrolysis by the digestive enzymes that hydrolyze most fats. Thus, the oil would be digested much less than conventional lipids, perhaps making it healthful, low-calorie food oil. (The undigested portion is eliminated in the feces.)
The Nestle Company in Switzerland has shown that laboratory rats have no dislike for, or reluctance to eat, jojoba oil. The rats ate the same amount of food as the control. It lowered their body weights and the animals were lean at the end:
These results indicate that jojoba oil may well be marketable as an edible oil for dieters. Much costly research will be needed, however, to prove its effectiveness and safety, and official acceptance from regulatory agencies will be necessary as well.
Other Uses of Jojoba Oil
Jojoba oil is highly resistant to rancidity, and this characteristic suggests that products requiring a stable vegetable oil may create an important market opportunity. Possibilities include carriers for pesticides and plant hormones, water-evaporation retardants, products for sizing and waterproofing, and formulations for softening leather, paints, and adhesives.
The oil also has important potential as an additive to some plastics. It is crystallographically almost identical to, and miscible in all proportions with, low-density polyethylene.
Jojoba in Foods
When jojoba oil was administered in a single dose to rats, about 50 percent of it was absorbed, the rest being excreted in the feces. When jojoba oil was incorporated in the diets of rats at levels of 6 percent and 12 percent, its digestibility was about 40 percent. The rats showed a good tolerance to, and had no reluctance to eat, jojoba oil. At the 12-percent dietary level, they ate the same amount of food as the controls, but their body-weight gain was slightly lower and they were much leaner at the end: fat made up 7.6 percent of their body weight compared with 13 percent for the controls. At the 6-percent dietary level, they ate more food than the controls but maintained a comparable body weight.
The digested jojoba oil appears not to be accumulated in significant amounts in the body tissues. In vitro experiments show that the liver metabolizes it. One of the potential hazards of using jojoba oil in foods is that about 13 percent of its fatty acids are close to erucic acid in composition. Since this acid might contribute to heart disease, the hearts were examined histopathologically. Jojoba oil induced no lesions under the given experimental conditions.
A subchronic toxicity study was carried out to evaluate the safety of jojoba oil. The oil, fed to rats over a 2-month period, was incorporated into basal diet at 0.5, 5.0, and 10.0 percent (w/w) level. At weeks 4 and 13 of the experiment, transaminase and alkaline phosphatase levels increased in the plasma. This may indicate some liver damage, but no pathological lesions were found in the liver or other organs of the animals.
These results indicate that jojoba oil may have potential as an
edible low-calorie oil for dieters, but before a wide application of jojoba oil
in foods can be envisaged, safety aspects should be investigated
Nestle Products Technical Assistance Orbe, Switzerland.
Hot jojoba oil readily dissolves polyethylene. The jojoba becomes microencapsulated and, over a period of days, diffuses out. This appears to be a fruitful area for research and product development.(Information from T. Miwa.) Researchers have also suggested that jojoba oil should be examined as a potential polyethylene expander and as a lubricant for extrusion and molding.
Reacting jojoba oil with chlorine and bromine produces liquid derivatives that may be useful as solvents or as plasticizers for polymers. Of particular interest are bromo-derivatives, which may have fire-retardant characteristics.
Jojoba oil may also have promise in the treatment of wastewater and the recovery of rare metals. It has been used experimentally in Israel to recover radioactive metals from nuclear wastewater as well as to remove toxic heavy metals from industrial wastewater. Reportedly, it worked with high efficiency.(Information from J. Wisniak.)
Uses of Jojoba Wax
If it is priced competitively, jojoba wax appears to have commercial potential for substituting for several waxes that are now widely used. Hard waxes of this type are incorporated into floor finishes, carbon paper, coatings, masks, and sizings, as well as polishes for furniture, shoes, and automobiles. They are also employed to raise the melting point, gloss, and hardness of waxes used in paper, textiles, insulation, batteries, candles, matches, soaps, salves, crayons, and chalk. They are used to coat fruits and vegetables to retard shrinkage, reduce spoilage, minimize the effects of aging, and retain flavor. In the United States, some candy is also treated in this way so it doesn't melt in the hand. One hard wax, spermaceti, was once used by bakeries as a release agent and lubricant. Moreover, both spermaceti and beeswax have been used as carriers for medicines. Already, small amounts of jojoba wax are being purchased by U.S. cosmetics manufacturers as a substitute for Japan wax, a hard wax used especially in mascara.
Wax-in-water emulsions have been prepared from hydrogenated jojoba wax. The wax emulsified easily, and the prepared emulsion showed no sign of water separation - an indication of good stability - after more than one month (Information from T. Miwa. The emulsifying agents were 4 percent stearic acid and 2 percent triethanolamine, and the amount of wax was 30 percent in water).
This, combined with the excellent hardness of the hydrogenated product, should enhance its desirability in a variety of applications.
Hydrogenated jojoba oil buffs well and leaves a coat hard enough for use in both solvent- and emulsion-type floor waxes. One test, however, indicated that jojoba wax tends to crystallize out from an oil or solvent. To overcome this tendency, it can be blended with petroleum waxes to form gels that are unlikely to crystallize.
Jojoba wax has a high dielectric constant, an important property for use in insulators.
TABLE 5 Hardness of Hydrogenated Jojoba Wax and Several Other Vegetable Waxes
Hydrogenated jojoba oil
(a) Brinel Hardness Number at 25°C, 4.3 kg load for 60 sec on 10.0 mm diameter steel ball.
SOURCE: T. K. Miwa
Household paraffin wax is hardened appreciably by the addition of jojoba wax. The paraffin's opalescent appearance changes to a creamy white, giving jojoba wax important potential markets in candlemaking. It is combustible, smokeless, and has a low ash content. It makes a brittle, unsatisfactory candle when used alone, but it blends well with other waxes to produce a high-quality product. The melting point is high enough that candles do not drip around the edges or melt during storage in warm climates.
Because of its crystallinity, jojoba wax appears unsatisfactory as a mold-release agent or as a plug for making molded objects; as the molten wax cools and solidifies it develops too many fracture lines. However, a small amount of additive (such as another wax) destroys the crystallinity and could be a way to overcome this limitation.
Partially hydrogenating jojoba oil, as previously noted, produces a range of soft white waxes whose properties are as yet unknown, but they may have good prospects in lipstick and cosmetics manufacture.
The meal that remains after the oil has been extracted is a potentially valuable by-product. It could be of particular interest for feeding livestock because such feeds are often scarce in arid areas where the plant is grown. It contains about 30 percent protein as well as carbohydrate and fiber. Of the essential amino acids in its protein, the lysine content is good, but the methionine content is poor.
However, using jojoba meal in animal feeds is very uncertain at present because of an unusual toxic factor. The meal contains four compounds (collectively known as simmondsins) that animals find unpalatable. These are potentially hazardous because they contain cyano groups.
Of the different methods used to substantially decrease or eliminate simmondsins, fermentation using the bacterium of sweet (acidophilous) milk currently seems to be the most effective. The bacterium grows well on jojoba meal, and, after three weeks at room temperature, converts it to a palatable, nutritious feed. The resulting fermented meal is high in protein and is suitable for livestock, especially ruminants. In practice, the actual detoxification can be done by a process resembling the ensilage methods already used on many of the world's farms.(Information from A. Verbiscar)
Before jojoba meal can be accepted as a livestock feed, it must be shown that hazardous compounds cannot be transmitted to milk, meat, and eggs. In the United States, pertinent requirements of the Food and Drug Administration will have to be met.