MINOR EDIBLE NUTS 3


Other relatively minor edible nuts and seeds, as listed below, are also marketed commercially (Rosengarten, 1984); Sesamum indicum is not considered here as it is regarded as an oil seed. They are:
 

pili or Philippine nuts  Canarium ovatum, Burseraceae  
pumpkin, squash seeds and gourd seeds Cucurbita pepo, Cucurbitaceae  
American beechnuts Fagus grandifolia, Fagaceae  
shagbark hickory nuts Carya ovata, Juglandaceae  
butternuts or white walnuts Juglans cinerea, Juglandaceae  
soy, soja or soya beans Glycine max, Leguminosae  
water or horn chestnuts, Jesuit nuts or water calthrops Trapa natans, Trapaceae  
stone pine or parasol nuts or pignolias Pinus pinea, Pinaceae  

Pumpkin seeds, although ranked as a minor nut, are regarded as an agricultural crop and are not included here apart from the discussion regarding its effect on the marketing of other edible nuts. The inclusion of soybeans as a nut-producing plant may be considered somewhat surprising. However, Rosengarten (1984) considers that the fairly recent development of the soynut in North America as an alternative to the peanut will offer very strong competition to traditional nuts in the future. However, since it is regarded as an agricultural crop, like pumpkin seeds, it is not described in detail here although it is discussed in as far as its marketing affect other edible nuts.
 

Pili or Philippine nut: Canariumovatum, Burseraceae


"The most important of all the nuts in the world to the millions of people who depend on it for food, is the PILI NUT of the Philippines and its relatives." (Menninger, 1977.)
 

Distribution and ecology


Native of the Philippines, abundant in southern Luzon; intolerant of frost. Trial introductions under investigation in Honduras (Menninger, 1977; Rosengarten, 1984).
 

Description


Evergreen, dioecious tree to 25 m high with trunk ca. 40 cm in diameter. Leaves imparipinnate. Fruit oblong-ovoid, black; pulp thin; nuts slender, ovoid-acute, 6-7 cm long, 2-2.5 cm wide, triangular in cross-section; 1-seeded, shell thick, very hard (Menninger, 1977; Rosengarten, 1984).
 

Cultivation


Not widely cultivated on a large-scale commercial basis, production mainly from wild trees and small plantings near coconut and hemp plantations. Female trees begin to yield in sixth year with full production at 12-15 years (Rosengarten, 1984).
 

Harvesting


Yield 32 plus kg per annum (Menninger, 1977).
 

Post-harvest treatments


Pericarp removed by dipping fruits in hot water (Menninger, 1977).
 

Production and consumption/utilization


Kernels very popular in the Philippines, eaten raw or roasted and salted after first removing the seed coat. Roasted, oily kernel have a delicious flavour that is claimed superior to almonds and easily digested; used in confectionery; nutritious emulsion of the kernels occasionally used as substitute milk for infants (Menninger, 1977; Rosengarten, 1984).
 

Nutritional value


Kernel contains 71.1% fat, 11.4% protein and 8.4% carbohydrates (Rosengarten, 1984).
 

By-products and other uses


Raw nuts purgative. Seeds are source of a sweet oil suitable for culinary purposes. Oil extracted from pulp is occasionally used for cooking and as an illuminant. An odorous soft resin with the texture of honey formerly exported for the European pharmaceutical trade as Manila or Philippine gum elemi for use as an ointment for healing wounds and as a plaster; also used by Spaniards for ship repairs (Menninger, 1977; Rosengarten, 1984).
 

Marketing


Pili nuts formerly exported to USA on a fairly large scale but trade has now declined; 1 186 173 kg exported from Manila in 1913 (Menninger, 1977; Rosengarten, 1984).
 

Discussion


A promising minor nut but the thick, hard shell is hard to crack and is believed to be an obstacle for expansion. There is a need to select for shells that are thinner and easier to crack and to consider such selections for vegetative establishment in future orchards (Rosengarten, 1984). Other species (see Appendix A) should also be investigated either for development or as a genetic source for improving C. ovatum.
 

Pumpkin, squash or gourd seeds: Cucurbita pepo, Cucurbitaceae

 

Discussion


Widely eaten as a dessert nut in Asia either raw or roasted, fried in deep fat and salted or made into a confection and becoming increasingly important as a health food in the Western World.

The seeds of other widely cultivated pumpkins and squashes are also eaten, including the cold tolerant winter Cucurbita maxima, the cold intolerant C. mixta and the humid tolerant C. moschata, as well as the watermelon, Citrullus lanatus (Purseglove, 1987).

According to FAO (1994) the world production of pumpkins and squashes has risen steadily from 5.7 million tonnes in 1979-81 to 8 million tonnes in 1993, with the largest production from Asia with 3.5 million tonnes. The proportion grown for their edible seed, however, is not known but is believed to be increasing.
 

American beechnut: Fagus grandifolia, Fagaceae

 

Distribution and ecology


Eastern USA, from the Allegheny mountains south to Florida and Texas, especially at higher elevations; calcareous soils preferred (Howes, 1948; Menninger, 1977; Rosengarten, 1984).
 

Description


Slow-growing tree, with a life span of 400 years or more (Rosengarten, 1984). Deciduous, up to 25 m tall and trunk up to 1 m in diameter. Leaves simple, ovate-acute, around 7.5 cm long, margins serrated. Fruit a woody burr; seeds 2-3, triangular, ca.0.75-3.7 cm wide (Rosengarten, 1984). Woody capsules dehisce on ripening and nuts fall to the ground in autumn; they soon spoil unless collected and dried (Howes, 1948; Menninger, 1977; Rosengarten, 1984).
 

Cultivation


No information available.
 

Harvesting


No information available.
 

Post-harvest treatments


None given apart from drying.
 

Production and consumption/utilization


Beechnuts gathered from the wild eaten fresh, dried or roasted, usually sweet but the flavour varies from tree to tree; much appreciated by native Americans.
 

Nutritional value


Beechnuts contain ca. 15% fat, 19.4% protein, 20.3% carbohydrates and have an energy value of 1 169 calories per kilogram (Rosengarten, 1984).
 

By-products and other uses


Timber is good, dark to reddish brown, strong, heavy and hard; excellent for furniture and flooring, also used for clothpegs. A good ornamental tree for landscaping (Rosengarten, 1984).
 

Marketing


Although liked, little potential for food and feed; the oil potential has not been developed as in Europe with F. sylvatica.
 

Discussion


Neglected as a source of edible nuts, with little attempt to develop suitable cultivars. This may be due to the small size of the nut and variability in flavour, the frequent presence of blind nuts, the irregularity of bearing and difficulty of harvesting (Rosengarten, 1984).
 

Shagbark hickory nut: Carya ovata, Juglandaceae

 

Distribution and ecology


Distribution covers southeastern Canada and eastern USA west to the Mississippi except for Florida and the coastal plains of the southern states; prefers the upland plains (Howes, 1984; Menninger, 1977; Rosengarten, 1984).
 

Description


Deciduous tree up to more than 30 m tall with trunk up to 60 cm in diameter, bark exfoliating in long narrow plates but remaining attached by the middle, trunk clear of branches to half its height, with small, open crown. Leaves imparipinnate, 5 leaflets. Nut enveloped in an outer, green and fleshy husk, becoming black, dry and splitting open at maturity; nut ellipsoidal, somewhat flattened laterally, with four prominent longitudinal ridges (sutures of the valves), ca. 2.5 cm long, shell thin but hard, light tan; kernel deeply divided into 2 halves, longitudinally ridged (Menninger, 1977).
 

Cultivation


Occasional trees preserved when land is cleared (Menninger, 1977). Trees difficult to transplant, slow-growing, late-bearing and low-yielding. Seedling trees yield at ca. 15 years, grafted trees produce much earlier. Interspecific hybrids readily occur. Those between C. ovata or C. laciniosa and C. illinoinensis are known as hicans (Rosengarten, 1984).
 

Harvesting


Harvested largely from the wild, from hedgerows and wood margins where the branches are free to spread. Solitary trees tend to have higher yields and better developed nuts than trees growing close together (Howes, 1948).
 

Post-harvest treatments


Nuts can be readily stored for 2-3 years with little or no deterioration (Howes, 1948).

Production and consumption/utilization


Nuts are delicious, considered the sweetest of the hickories, eaten by native Americans either dried and pounded into flour, boiled as a soup; source of a cooking oil (also used as a hair dressing); also pounded shells and kernels mixed in water for a nourishing beverage known as pawcohiccora or hickory milk (Menninger, 1977; Rosengarten, 1984).
 

Nutritional value


On a moisture-free basis the kernels contain 9.8% carbohydrates, 72.7% fat and 13.7% protein (Melville, 1947).
 

By-products and other uses


The tough, elastic wood ideal for tool handles and agricultural implements, and also a good fuelwood. Hicans often are attractive ornamental trees (Rosengarten, 1984).
 

Marketing


A neglected, minor nut, not commercially important. The relative high proportion of shell compared with other better-known nuts probably restricts long-distance marketing prospects; sold in the local markets and occasionally sold in England (Howes, 1948; Menninger, 1977; Rosengarten, 1984).
 

Discussion


A more marketable nut with higher proportion of kernel to shell is required. Considerable research will be required before any hybrid hican clones could be developed for commercial nut production (Howes, 1948; Rosengarten, 1984). Presumably any commercial development will follow that of the pecan.
 

Butternut or white walnut: Juglans cinerea, Juglandaceae

 

Distribution and ecology


Eastern North America, from New Brunswick to Manitoba south; butternut represents the most northern and cold resistant member of the family (Rosengarten, 1984).
 

Description


A deciduous tree to 18 m tall, with a trunk up to 1 m in diameter. Leaves imparipinnate with 11-17, glutinous leaflets. Fruits oblong-cylindrical, ca. 6.5 cm long and 3 cm in diameter, apex acute, surface rough, shell bony and thick, 1 kernel (Howes, 1948; Rosengarten, 1984).
 

Cultivation


Superior cultivars available for grafting but not commercialized (Howes, 1948).
 

Harvesting


No information given, presumably as for Juglans regia.
 

Post-harvest treatments


No information given, presumably as for Juglans regia.
 

Production and consumption/utilization


Immature fruit makes an excellent pickle. Kernels are highly esteemed and used by native Americans, eaten raw, ground to flour for baking or to thicken their pottage; seed oil also used for cooking, and dressing hair (Menninger, 1977; Rosengarten, 1984).
 

Nutritional value


Nuts are highly nutritious with 23.7% protein, 61.2% fat and an energy value of ca. 1 360 calories per kg. The protein value is one of the highest in edible nuts (Rosengarten, 1984).
 

By-products and other uses


Oil from nut used medicinally by the Narragansett native Americans. The boiled or distilled hairy, sticky indumentum of young twigs, leaves, buds and fruits are source of a light brown dye. Close-grained, satiny wood, known as white walnut, used for furniture, boats and carving. Grown as a shade tree (Menninger, 1977; Rosengarten, 1984).
 

Marketing


Butternuts are highly regarded by those that know them but are largely unknown by the present generation. Market is mainly limited to home consumption, primarily in southern Canada and New England (Menninger, 1977; Rosengarten, 1984).
 

Discussion


Despite the delectable flavour of the nuts, its reputation for being slow-growing and short-lived, its susceptibility to butternut dieback from the fungus Melanconis juglandis, difficulties with propagating cultivars plus the nut being hard to crack, limit the potential for commercial expansion (Rosengarten, 1984).
 

Soy, soja or soya bean: Glycine max, Leguminosae subfamily Papilionoideae

 

Discussion


The soynut industry is a fairly recent development in USA. The seeds are processed to resemble nuts in appearance, flavour and utilization. With a crunchy texture, low moisture content, absence of cholesterol and twice the protein content of tree nuts together with all-year round availability and low price, they are an ideal health food. With only 2% moisture, they have a shelf life of 6-8 months. Their price is competitive with peanuts and, since the soynuts occupy ca. 30% more volume than the same weight of peanuts, their price per unit of volume is even more economical. Their major disadvantages are that their flavour is not to everyone's taste and, unlike many other nuts, they cannot be sliced for use in the confectionery trade. The less expensive, readily available and highly nutritious soynuts undoubtedly offer strong future competition to traditional tree nuts and peanuts. The percentage of the crop used for soynuts is small but not known (Rosengarten, 1984).
 

Water or horn chestnut, jesuit nut or water calthrop: Trapa natans, Trapaceae

 

Distribution and ecology


A standing water, aquatic species with a wide and discontinuous range through Europe, Asia and Africa. It is naturalized in northern America and Australia with var. natans distributed through Europe, Asia and North Africa and var. bispinosa ranging from India eastward to China and Japan and widely scattered in tropical Africa. A var. africana is endemic to Lake Victoria (Brenan, 1963).
 

Description


Annual aquatic herb with a rosette of floating leaves and submerged, paired but not opposite, pinnatisect and leaf-like adventitious roots. Fruit a 1-seeded, top-shaped drupe; pericarp soon disappearing; endocarp very hard, ca. 3-5 cm across, variously 2-4 horned, the horns 1-1.8 cm long, derived from the persistent sepals (Brenan, 1963).
 

Cultivation


In India fruit is broadcast in 30-69 cm deep nursery ponds and pressed into the mud, transplanted at the 4-5-leaf stage and replanted when 4-5 months old. Lateral pruning is carried out to accelerate flowering and fruiting. In China, according to Menninger (1977), the water chestnut is cultivated in running water. A soft, thin-skinned, sweeter cultivar known as Kota Sudhar has been selected in Kashmir which ripens 20 days earlier and yields up to 6 200 kg per ha compared to 4 800 kg per ha for other cultivars (CSIR, 1976).
 

Harvesting


Nuts are gathered or scooped up from the depths in small nets; in China nuts are collected in autumn by people in boats seeking ripe fruits as they pull themselves through the surface vegetation. Depending on the weather harvesting in India commences some time during September to December (–February), initially harvesting every 15 days and eventually daily. Average yields range from 1 760 to 4 440 kg per ha, with a good crop yielding 13 200 kg (Hedrick, 1972; CSIR, 1976; Menninger, 1977; Rosengarten, 1984).
 

Post-harvest treatments


Removal of the hard endocarp to yield the edible, starchy, white seed (Menninger, 1977).
 

Production and consumption/ utilization


Nuts are eaten raw, boiled, fried. preserved in honey and sugar, candied or ground into flour for making bread. A staple food for as much as five months of the year in Kashmir, where the starchy kernels are eaten raw (cv. Kota Sudhar), or cooked as a porridge (Howes, 1948; Hedrick, 1972; CSIR , 1976; Menninger, 1977; Rosengarten, 1984).
 

Nutritional value


Kernels are not particularly nutritious compared to other nuts, they contain ca. 70% moisture, 4.7% protein, 0.3% fat, 0.6% fibre and 3% protein (CSIR, 1976; Rosengarten, 1984).
 

By-products and other uses


Hard fruits (endocarp) are strung into necklaces (Menninger, 1977).
 

Marketing


Formerly widely eaten in southern Europe but its use has declined although still used in the Loire region of France and parts of Italy; still an important food in Asia where it is sold in the local markets. It has been introduced into North America and is naturalized in some areas, however, it is doubtful if it will become commercially important (Menninger, 1977; Rosengarten, 1984; Bianchini et al., 1988).
 

Discussion


Little appreciated in the western world but obviously an important crop in Asia and its use should perhaps be encouraged in the lakes of East Africa.
 

Stone or parasol pine nut or pignolia: Pinuspinea, Pinaceae

 

Distribution and ecology


Northern Mediterranean region and Portugal; altitudes up to 1 000 m. Locally cultivated (Tutin et al., 1964; Menninger, 1977).
 

Description


Evergreen, needle-leaved tree to 30 m, crown umbrella-shaped. Leaves borne in pairs, 10-20 cm long. Male and female reproductive structures, strobili, borne separately on the tree. Seeds borne in cones 8-14 cm x 10 cm, maturing in the third year; seeds 15-20 mm x 7-11 mm, wing less than 1 mm, caducous (Tutin et al., 1964; Menninger, 1977).
 

Cultivation


Grown in pine groves. Unlike some species of Pinus, it does not hybridize readily with other species. A thin-shelled form is known in Italy where it is possible to break the shell with the fingers (Howes, 1948; Menninger, 1977; Rosengarten, 1984).
 

Harvesting


Green cones are harvested by pickers armed with long hooked poles and piled into heaps to dry in the sun in order that the cone scales may open and loosen the seeds. The harvest can last from autumn to spring without any problems as the nuts store very well in their cones on the tree (Menninger, 1977; Rosengarten, 1984).
 

Post-harvest treatments


Nuts are extracted by beating the cones by hand or thrashed mechanically. The seeds are then dried before passing through a milling machine to separate the kernel from its hard outer covering. The kernels and shells are then sorted by sifting, after which the testa is removed from the kernel. Kernels are graded according to size (Menninger, 1977; Rosengarten, 1984).
 

Production and consumption/ utilization


Pinus pinea is the largest producer of pine nuts commercially; known as pignolias (English), pignons (France), piñones (Spain) or pinoli (Italy). Both the large and small, superior, unblemished, shelled kernels are packed for export. Pine nuts may be eaten whole, either raw or roasted; the shell cracked by the teeth and spat out; usually marketed without their shells. Nuts may be made into flour for cakes, pressed into sweetmeats and used to garnish pastries, etc. (Menninger, 1977; Rosengarten, 1984).
 

Nutritional value


Pine nuts contain 47.4% fat, 11.6% carbohydrates, 31.1% protein, 4.3% ash, 0.9% fibre and an energy value of 556 Kcal. per 100 kg (Farris, 1983).
 

By-products and other uses


Broken nuts are source of oil used for making soap. It is also a source of timber. Cultivated as an ornamental tree (Menninger, 1977; Rosengarten, 1984).
 

Marketing


Figures for world production are not available. In USA, between 1976 and 1980 an annual average of ca. US$ 800 000 worth of pine nuts were imported of which 41% were pignolias from Portugal and 27% from Spain while China supplied 26% from P. koraiensis. The imported nuts from P. pinea rank second to macadamia nuts as being the most costly, while the Chinese pine nuts are less expensive and inferior to those from Europe. They are becoming increasingly important in the American market. The unspecified uneven supply of indigenous pine nuts in USA certainly favours the more reliable importations (Rosengarten, 1984; Prescott-Allen and Prescott-Allen, 1986).
 

Discussion


The other species of Pinus with edible seeds have been largely neglected due to establishment of P. pinea as the prime source of pine nuts for the past 2 000 or more years. The Colorado pine, P. edulis, is an additional important source of pine nuts in USA, while those of P. sabiniana, a relatively little known species from California, have been demonstrated as having very similar nutritional properties to pine nuts from P. pinea and, if developed, could be a strong contender for the pine nut market (Farris, 1983; Prescott-Allen and Prescott-Allen, 1986). Doubtless further research will reveal other possible species for commercial plantations with high-yielding cultivars throughout North America and elsewhere.
 

Figures:


Fig 11. Canarium ovatum. 1: branch with leaves and flowers. 2: fruit

Fig 12. Fagus grandifolia. 1: branch with leaves and flowers.

Fig 13. Carya ovata. 1: twig 2: fruit and cross section of fruit.

Fig 14. Juglans cinerea

Fig 15. Trapa natans ver. africana. 1: floating leaves and submerged adventitious roots 2: floating leaf 3: marginal part of leaf, lower side 4: nodes 5: nodes showing first stage of adventitious roots 6:  nodes showing developed adventitious roots 7: flowers 8: longitudinal section of flower 9: two sepals 10: petal 11: stamen 12: anther 13: ovary and disc 14: ovary and calyx 15: endocarp 16: apex.

Fig 16: Pinus pinea 1: branch with mature cones 2: male inflorescence 3: female inflorescences 4: scale 5: winged seed.