Jojoba: an alternative source of oil
Nomadic Holystones are constantly moving in search of water that is scarce, lies very deep, and is brackish. Lack of potable water controls the lives of the people of the region. However, there is a lot of potential to grow some drought tolerant plant of economic importance in this region. For this purpose Jojoba (Simmondsia chinensis), a perennial woody shrub, was found to be suitable. It easily acclimatises itself according to the agro-ecological conditions of Cholistan.
Jojoba grows to 1-2m tall, with a broad, dense crown. The leaves oval in shape, 2-4 cm long and 1.5-3 cm broad, thick waxy glaucous gray-green in colour. The flowers are small, greenish-yellow, with 5-6 sepals and no petals. Each plant is single-sex, either male or female, with hermaphrodites being extremely rare. The fruit is an acorn-shaped ovoid, three-angled capsule 1-2 cm long, partly enclosed at the base by sepals. The mature seed is a hard oval, dark brown in colour containing an oil (liquid wax) content of approximately 54 per cent. Leaves of the plant have a waxy cuticle that reduces moisture loss. The plant develops one or a few long tap roots (up to 40 ft) that can supply water and minerals from far below the soil surface.
The plant is grown for the liquid wax (commonly called jojoba oil) in its seeds. This oil is rare in that it is an extremely long (C36-C46) straight-chain ester wax and not a triglyceride, making jojoba and its derivative jojoba esters more similar to sebum and whale oil than to traditional vegetable oils.
Jojoba oil is easily refined to be odourless, colourless and oxidatively stable, and is often used in cosmetics as a moisturiser and as a carrier oil for specialty fragrances. It also has potential use as both a biodiesel fuel for cars and trucks, as well as a biodegradable lubricant.
The seed of the plant contains a light-gold coloured liquid wax ester, which is the primary storage lipid of the plant. This is unlike conventional oilseed crops, such as soybean, corn, olive, or peanut, which produce oils as the primary storage lipid. Jojoba wax makes up 50 per cent of the seed’s dry weight. The physical properties of the oil are: high viscosity, high flash and fire point, high dielectric constant, high stability and low volatility. Its composition is little affected by temperatures up to 570°F (300°C). The oil contains fatty acids and alcohols.
Vegetable oils have several alcohol groups on the molecule and some have forked molecules and will eventually oxidize and become rancid. Jojoba has only one alcohol group and is a straight chain molecule; therefore it is not subject to oxidising and in fact is an anti-oxidant and will never become rancid. However, the liquid ester does have the ability to self polymerise in the presence of sunlight, so it is best to keep it in brown glass bottles, in the dark, or in closed metal cans. Research is presently under way at Jojoba obispo to investigate the qualities and uses of polymerised jojoba oil.
The liquid ester is chemically almost identical to spermaceti oil which is also a pure ester found in the head of the Sperm whale. Jojoba is the ideal substitute for the Sperm whale oil which until restrictions was used for high temperature lubrication, cosmetics and as a lubricant for automatic transmissions. The ‘oil’ is a natural mimic of the oil secreted by human skin so it may be used to protect and lubricate skin and hair. It is soothing, stops multitudinous skin problems and protects against premature aging and wrinkling of the skin caused by exposure to ultraviolet radiation.
Most jojoba oil produced in the country today is sold at a high price for use in cosmetics and hair care products. As many as 300 products containing jojoba have appeared in the country in recent years. As supply of oil increases and prices decrease, more uses will become economically feasible. For example, the viscosity index of jojoba oil is much higher than that of petroleum oil; therefore, it may be used as a high temperature, high-pressure lubricant. The stability of the oil makes it attractive to the electronic and computer industries. And since it contains no cholesterol or triglycerides and is not broken down by normal metabolic pathways, it may become an important low-calorie oil for human consumption.
The oil can be used as an antifoam agent in antibiotics production and as a treatment for skin disorders. Other proposed uses include candles, plasticisers, detergents, fire retardants, transformer oil, and for the leather industry. The meal contains up to 30 per cent protein, but toxic compounds (simmondsins) make it currently hazardous as an animal feed.
The plant is best suited for areas that are frost-free. When temperatures drop below 20°F, flowers and terminal portions of young branches of most jojoba plants are damaged. During early seedling development, excessive cold may kill an entire plantation. Frost may not damage taller plants to the same degree, but it can reduce yield. Jojoba is very tolerant to high temperatures. Natural stands of jojoba occur in areas that receive three to 18 inches of precipitation annually. Irrigation has produced more luxuriant vegetative growth, but it is not known whether this increased growth results in higher seed yield.
The plant requires the most water during late winter and early spring. Most wild jojoba populations occur on coarse, light or medium textured soils with good drainage and good water infiltration. Plantation on heavy soil results in later blooming, slower growth and more fungal diseases problems.
The plant can be grown by direct seeding or by transplanting seedlings to the field. Many growers here prefer direct seeding because it is less expensive, faster and requires less hand labour. Seed can be germinated in vermiculite or sand at about 80°F. Emergence occurs in 15 to 20 days, and the seedlings are ready for transplanting when they are 6 -12 inch tall (8 to 10 weeks). Propagation from clones or from tissue culture is a more rapid method of varietal improvement.
The pant is usually mono sexual. Female flowers are small, pale green and commonly solitary or in clusters at the nodes. Male flowers are yellow, larger, and occur in clusters. Pollination occurs via wind or insect. The fruit is a green capsule, which encloses up to three seeds, when ripe, the capsule splits and reveals the seed, which is brown, wrinkled and about the size of a small olive. Seed production is generally limited until the fourth year of growth.
Little information is available on the response of cultivated jojoba to lime or fertiliser applications. Jojoba grows wild on soils of marginal fertility with soil pH ranging from 5 to 8. The soils that jojoba is adapted to in the semiarid regions of Cholistan is generally slightly alkaline and has native high potassium levels. Yield trials conducted in Arid Zone Research Institute, Bahawalpur, have not shown any improvement in vegetative growth with the addition of nitrogen or phosphorus, therefore no additional N or P2O5 fertilisers are recommended.
Weeds must be controlled early in the establishment of the plantation. Weed control prior to planting and/or cultivation between rows during growth is needed until the plant is large enough to shade competing plants. No herbicides are registered for use on jojoba in Pakistan. On poorly drained soil, the plant is susceptible to fungal wilts, including Verticillium, Fusarium, Pithium and Phytopthora. More than 100 species of insects have been identified on jojoba, but few cause known economic damage. Infestations of spider mites, grasshoppers, and thrips may result in yield losses. Fences may be necessary to eliminate browsing by wild animals who find the plant very palatable. This has been a major factor in the distribution of jojoba.
All seeds on a jojoba shrub do not mature at the same time, and more than one harvest may be necessary. Most jojoba is currently harvested by hand. Over-the-row fruit and berry harvesting equipment is adaptable to jojoba harvesting. Jojoba seed that has been dried to around 10 per cent moisture and protected from pest damage will keep for several years. The plant generally does not produce an economically useful yield until the fourth or fifth year after planting. Seed yields in natural stands of jojoba range from a few seeds to as much as 30 lb of clean, dry seed per plant. Production of seed varies greatly from plant to plant in a stand and from year to year for a particular plant.
Currently, the average yield of commercial jojoba plantations is less than 300 lb/acre. Plantations that were established with selected higher yielding clones are capable of producing up to 800 lb/acre.
Crop improvement programmes at Jojoba Research Station and Arid Zone Research Institute, Bahawalpur, are actively researching consistent productivity. Low yields and frost damage have resulted in financial losses for many farmers and investors.
Successful long-term production of jojoba depends on improved yield and a strong market. Industry is typically hesitant to invest in new technology involving an agriculturally produced resource until a steady and continued supply of that resource can be demonstrated.
The value of jojoba oil as an alternative industrial oil with multiple applications and as a replacement for non-renewable fossil petroleum has been demonstrated.