Macadamia nuts are crispy, tender, creamy, fruity, queen of nuts, king of nuts.

Macadamia nuts

Macadamia fruit generally refers to macadamia nut

Macadamia nut (Latin name: Macadamia ternifolia F. Muell.) alias: Queensland chestnut, Australian walnut, Hawaiian fruit, Queensland fruit, is a kind of tree nut native to Australia. Macadamia nuts are evergreen trees and dicotyledons. The crown is tall, and the leaves are whorled, lanceolate, leathery, smooth, with spiny serrated edges. Racemes axillary, flowers beige, fruit globose, pericarp leathery, endocarp hard, seeds beige to light brown. It is suitable for growing in areas with mild, humid and low wind.

Among the many dried fruits in the world, macadamia nuts have the highest economic value and have always been known as the "king of dried fruits". Distribution: eastern Australia, New Caledonia, Sulawesi, Indonesia. In addition, macadamia nuts also have high nutritional value and medicinal value.

Morphological characteristics

Trees, 5-15 m tall. Leaves leathery, usually 3 whorled or subopposite, oblong to oblanceolate, 5-15 cm long and 2-3 (- 4.5) cm wide, apex acute to obtuse, sometimes retuse, base attenuate; lateral veins 7-12 pairs; each margin sparsely dentate ca. 10, leaves of mature trees subentire; petiole 4-15 mm long.

Racemes, axillary or subterminal, 8-15 (- 20) cm long, sparsely pubescent; flowers yellowish or white; pedicels 3-4 mm long; bracts subovate, small; perianth tube 8-11 mm long, erect, pubescent; filaments short, anthers ca. 1.5 mm, connective slightly prominent, short, obtuse; ovary and style base yellowish brown villous; disk annular, with teeth absent. Fruit globose, ca. 2.5 cm in diam., apex mucronate, pericarp 2-3 mm thick, dehiscent; seeds usually globose, seed coat bony, smooth, 2-4 (- 5) mm thick. The florescence is from April to May (Guangzhou) and the fruiting period is from July to August.

Growth habit

Macadamia nut, native to Australia, belongs to Ophthalmaceae, nut genus, evergreen tree, known as "king of dried fruit". The distribution of root system is shallow, the wind resistance is weak, the suitable temperature is 10-30 ℃, the most suitable temperature is 15-30 ℃, lower than 10 ℃ or more than 30 ℃ is disadvantageous to nut growth. When the annual rainfall is between 1000 and 2000 tons, the results are better. When the rainfall is less than 1000 tons or in arid areas, the growth is slow, the fruit becomes smaller, the development is poor, and the fruit drop is serious.

Distribution of producing area

Cultivated in Yunnan (Xishuangbanna, Lincang), Guangdong and Taiwan. It is common in botanical gardens or farms. Native to the tropical rain forests of southeastern Australia, it is now cultivated in the tropics of the world.

Cultivation techniques

Select a place

Macadamia nut is a tropical and subtropical high-grade cash crop, with strong adaptability, suitable for planting in hills or flat land below 1200 meters above sea level, requiring the maximum temperature in summer not to exceed 35 ℃, the maximum temperature in winter not less than 15 ℃, the lowest temperature not less than 0 ℃, year-round frost-free or occasional light frost, deep soil layer, rich in organic matter, good drainage, irrigation conditions when water shortage in dry season. Because the tree has a dense crown, shallow roots and no wind resistance, the orchard should choose areas where there is little strong wind all the year round and are vulnerable to typhoons. Windbreak belts should be built, and bamboo and branches should be used as supports in the young tree stage to resist wind damage.

Selection of species

Excellent varieties are characterized by exuberant plant growth, wind resistance, drought tolerance, high yield, high quality, symmetrical crown, erect and stout branches. In the peak period, the average plant yield is more than 25 kg to 50 kg, the kernel size is medium, the seed rate is 30% to 50%, and the first-class kernel accounts for about 98%. Generally, asexual bud grafting is used in planting. The seedlings were used as rootstocks, cultivated for 1 to 2 years, and then budded from November to December or March to April. The bud strips used as bud grafting were peeled around the base from January to February before bud grafting in order to facilitate the accumulation of carbohydrates, improve the survival rate of bud grafting and sprout and thrive.

Colonization

Planting should avoid dry, rainy and high temperature seasons and be planted in the early or late rainy season to facilitate plant growth. The planting density varies with soil conditions and variety types. In Guangxi, the row spacing is 4 m × 5 m, 33 plants per mu and more than 25 plants per mu, while Yunnan advocates that the row spacing varies according to varieties, with row spacing of 4 m × 7 m, 4 m × 8 m and 4 m × 9 m, and planting 18 to 24 plants per mu. The specification of digging hole is 0.8 × 0.8 × 0.6 (m). Most macadamia nuts have a high degree of self-sterility, so planting varieties should be crossed (different varieties should be interlaced and cross-planted), and at least two varieties should be matched in a piece of land.

Young tree management

The seedlings should be watered frequently after planting to keep the soil moist; after 2 months, fertilization should be carried out according to the growth of the seedlings, and the principle is to apply frequently and thinly, mainly with water and fertilizer; fertilization management can be carried out after the seedlings are mature for the first time. The seedlings were naturally formed without pruning 3 years before planting, except for the exuberant growth of terminal buds and the need to cut off low-hanging branches.

Put into production tree management

Macadamia nuts entered the production period in 4-5 years, and the tree consumption was large, so the green pressing was carried out every year combined with clearing the garden in winter, and 20-30kg per plant, 0.5 kg phosphate fertilizer, 0.5 kg lime per plant, and 0.5-1.2 compound fertilizer per plant in May. The amount of fertilizer increased with the increase of tree age. In the aspect of pruning, it is mainly to retract the long branches and cut off the low-hanging branches, while thinning the dense branches and disease and insect branches to keep the tree ventilated and transparent.

Matters needing attention

The management of macadamia nuts is extremely sensitive to water, and there should be no shortage of water from flowering to ripening, especially during the period of accumulation of fruit oil, which will seriously reduce the quality and yield of nuts. When young leaves wilt and mature leaf tips lose luster, it is a sign of water shortage and should be irrigated in time.

Main value

nutritive value

Macadamia nuts are considered to be one of the best table nuts in the world. They contain a high amount of oil, so they are very fattening.

Macadamia nuts are nutritious and contain 70-79% oil, especially rich in unsaturated fatty acids, mainly oleic acid and palmitic acid. The ratio of unsaturated fatty acids to saturated fatty acids in the kernels of smooth-shelled macadamia nuts is 6.2, and the crude shell species is 4.8%. Protein 9%, but also rich in calcium, phosphorus, iron, vitamin B1, B2 and eight essential amino acids.

Macadamia nuts are crisp, tender and delicious, with a unique creamy flavor. They are the best edible nuts in the world. They are known as "queen of dried fruits" and "king of nuts in the world". Their flavor and taste are much better than cashew nuts.

Medicinal value

Atherosclerosis, cardiovascular disease:

Atherosclerosis is one of the most common diseases in industrialized countries. The occurrence of atherosclerosis is closely related to eating habits. Macadamia nut oil, a natural vegetable oil high in monounsaturated fatty acids, not only does not contain cholesterol, but also reduces the content of LDL cholesterol (bad cholesterol) in the blood, while maintaining or even increasing the content of HDL cholesterol (good cholesterol). This two-way regulation of killing two birds with one stone is not available to other fats. This is why macadamia nut oil can prevent heart disease.

Macadamia nut oil has been medically proved to be very effective in lowering blood pressure. In a study conducted abroad in 1996, 16 women with high blood pressure agreed to switch to macadamia nut oil within a month. As a result, their average blood pressure dropped from 161 to 85, and both diastolic and systolic blood pressure decreased by almost 10 mm Hg.

Long-term consumption of macadamia nut oil, people's blood lipids will be controlled in a healthy state. Due to the biphasic regulation of macadamia nut oil on blood lipids, it can effectively reduce blood viscosity, prevent atherosclerosis and effectively protect the cardio-cerebrovascular system. The latest research suggests that macadamia nut oil can prevent thrombosis and control blood pressure.

Diabetes:

Macadamia nuts are rich in monounsaturated fatty acids, which can lower blood pressure, regulate and control blood sugar levels, and improve lipid metabolism in patients with diabetes, which is the best source of fat supplement for diabetics. Macadamia nuts are rich in antioxidants, can limit the peroxidation process in patients with diabetes. The famous American doctor Jean Carper said: "oleic acid can lower blood pressure, balance blood lipids and blood sugar, and make it normal." For diabetics who are difficult to see a doctor often, it is easier to stick to diet therapy.

Tumors, cancers:

Among people who regularly eat Hawaiian oil, the incidence of various cancers is very low, especially breast cancer and cancers of the gastrointestinal system are significantly lower than other populations. The incidence of lung cancer in the Mediterranean is 50% lower than in the United States due to consumption of Hawaiian nut oil. Macadamia nut oil has been found to reduce the rate at which ketone derivatives of carcinogens form tumors in the intestine. The protective effect of macadamia nut oil is related to its rich in monounsaturated fatty acids, antioxidants and other trace elements. They cooperate with each other and enhance the protective effect. Macadamia nut oil intake (accompanied by vegetables and fruits) is particularly important in anti-tumor foods.

Breast cancer research reports that women who eat macadamia nuts a day can reduce the risk of cancer by 25%, and if they use macadamia nut oil instead of other cooking oils, they can reduce cancer by 50%. Studies have shown that women who consume more monounsaturated fatty acids are significantly less likely to develop breast cancer. The researchers suggest that people should replace polyunsaturated fatty acids with monounsaturated fatty acids, that is, macadamia nut oil instead of other edible oils, to reduce the risk of breast cancer.

Bowel cancer researchers in another study confirmed that B-sitosterol is a plant fat found in macadamia nut oil that blocks the growth of prostate cancer cells. A recent study shows that macadamia nut oil can prevent bowel cancer, and macadamia nut oil reacts with stomach acid to prevent the attack of colorectal cancer and rectal cancer.

Rheumatoid arthritis:

Rheumatoid arthritis is a chronic infectious joint inflammation. People who do not eat macadamia nut oil are 2.5 times more likely to develop rheumatoid arthritis than those who eat macadamia nut oil for a long time. At the same time, it was found that vitamin E, rich in macadamia nut oil, could play a "beneficial role as a similar inhibitor". When the body consumes saturated fatty acids, they break down to produce hormones that promote inflammation, while when the unsaturated fatty acids in macadamia nuts are consumed, they break down to produce hormones that inhibit inflammation. Therefore, long-term consumption of Hawaiian nut oil can prevent rheumatoid arthritis.

Skin:

Among the many ingredients of macadamia nut oil, carotene and chlorophyll give macadamia nut oil a unique golden yellow and green color, while chlorophyll plays a metabolic role, promotes cell growth, accelerates wound healing, and helps to nourish and beautify the skin. reduce wrinkles. Macadamia nut oil is also an excellent natural medicine for the treatment of skin diseases. According to the principle of dermatology for external use, three dosage forms made from macadamia nut oil are effective in the treatment of 5 types and 15 kinds of exudative dermatitis and ulcers. Because macadamia nut oil contains polyphenols and lipopolysaccharide, macadamia nut oil also has the function of radiation protection, so macadamia nuts are often used to make food for astronauts. Regular computer users regard it as a good product for health care and skin care.

Anti-aging:

Aging is closely related to peroxidation in the human body. Human life is like a burning candle. The more intense the oxidation burns, the shorter the life span.

Macadamia nut oil contains a lot of antioxidants, low content of saturated fatty acids, rich in monounsaturated fatty acids, polyunsaturated fatty acids are abundant but not excessive.

At the same time, the ratio of essential fatty acids ω 3 to ω 6 is very ideal. When the ratio of essential fatty acids ω 3 to ω 6 is 1: 4, it is difficult for various diseases to invade the human body.

Osteoporosis is another serious problem among the elderly.

Macadamia nut oil has a very positive effect in preventing this disease.

The more macadamia nut oil consumed, the better the mineralization of bones.

Macadamia nut oil is rich in oleic acid to promote the absorption of calcium, phosphorus, zinc and other minerals, and increase bone mineral density.

Macadamia nut oil is necessary for the human body at all stages from growth and development to adulthood and can prevent the loss of calcium.

In old age, people's digestion and absorption capacity will decline, and the absorption of nutrients, especially vitamins and minerals, will become very poor.

Macadamia nut oil also has excellent characteristics in digestion and absorption, and has the effect of mild laxative (to eliminate constipation).

Economic value

Macadamia nut has a good market prospect, good ecological and economic benefits. It is a kind of edible nut with high oil content, rich nutrition and unique flavor.

The global market demand for macadamia nuts is more than 400000 tons, but because of its strong selectivity to natural conditions such as light, heat, water and wind, and a long investment cycle, the global planting area is only 40, 000 hectares. The planting area is mainly in Hawaii and Australia, with an annual output of less than 30, 000 tons. Therefore, the development of macadamia nut cultivation has great market potential and broad market prospects.