Inga edulis

Inga edulis

The ice cream bean or monkey tamarind (Inga edulis Mart. 1837) is an arboreal species belonging to the Fabaceae family.

Systematic –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Plantae,
Division Magnoliophyta,
Class Magnoliopsida,
Fabales Order,
Family Fabaceae,
Subfamily Caesalpinioideae,
Genre Inga,
Species I. edulis.
The terms are synonymous:
– Feuilleea conferta (Benth.) Kuntze;
– Feuilleea edulis (Mart.) Kuntze;
– Feuilleea scabriuscula (Benth.) Kuntze;
– Inga benthamiana Meisn.;
– Inga complanata Amshoff;
– Inga conferta Benth.;
– Inga edulis f. typica Porto;
– Inga edulis var. edulis;
– Inga edulis var. parviflora Benth.;
– Inga edulis var. parviflora Mart.;
– Inga inga (Vell.) J.W.Moore, 1934;
– Inga scabriuscula Benth.;
– Inga scabriuscula var. villosior Benth.;
– Inga uncinata Spruce;
– Inga uncinata Spruce ex Benth.;
– Inga vera Brenan;
– Inga vera Kunth;
– Inga ynga J.W.Moore;
– Mimosa inga Vell.;
– Mimosa ynga Vell..

Etymology –
The term Inga comes from the vernacular name of the Tupí people of South America.
The specific epithet edulis comes from the Latin “edulis”, i.e. edible, edible, in reference to the fruits.

Geographic Distribution and Habitat –
Inga edulis is a plant native to tropical South America (Bolivia, Brazil, Colombia, Ecuador, Guyana, French Guiana, Peru, Suriname and Venezuela); in detail it is distributed, also as a new introduction, in Cuba, while it is reported from Mexico, Central America and Northern South America. In Mexico it is distributed in the states of Campeche, Colima, Chiapas, Hidalgo, Michoacán, Morelos, Nayarit, Oaxaca, Chihuahua, Guanajuato, Guerrero, Puebla, Querétaro, Quintana Roo, Nuevo León, San Luis Potosí, Sinaloa, Tabasco, Tamaulipas and Veracruz. Present from Mexico to South America, including the Antilles and also present in Jamaica, Hispaniola, Puerto Rico and, as mentioned, Cuba.
Its natural habitat is mainly along river banks up to around 1800 m altitude, where it grows well from 0 to 1800 m altitude, preferably with an average temperature of 15 °C. In these areas it is moderately resistant to periods of drought and prefers deep, well-drained soils and requires clayey to clayey soils; it tolerates slightly acidic soils with a tendency towards neutrality.
It is common on river banks and in protected cavities. Because the plant tolerates a wide variety of soil types and has some drought resistance, it is often found associated with a wide variety of forest species. This plant grows in both tropical and subtropical climates. It is often found in very humid or humid tropical areas, where annual rainfall ranges between 1,000 and 4,000 mm, although it has also been reported to grow in arid areas.

Description –
Inga edulis is an arboreal species 4 to 30 m tall, with a diameter of 1 m, with roots which, from the information gathered from coffee growers, tend to be superficial and very divided.
It has a flattened, broad, very widespread crown with sparse foliage. If there is space it forms an open canopy that produces light shade.
The trunk is straight, the branches are long and the bark is light gray with lenticels, more or less smooth with some fine furrows; internally pink to brown in color and slightly bitter with ferruginous-tomentolated twigs, angled lenticels or ridges.
The leaves 10-18, alternate, pinnate and hairy lanceolate, deciduous, 18 to 30 cm long, petioles 0.3-2.0 cm long, round to winged, arranged in 2 divergent rows; rachis 7.0-11.0 cm long, winged, smooth margin, with both elliptical surfaces slightly hairy, leaflets 3.5-6.0 cm long and 1.5-3.5 cm wide, lanceolate to ovate, occasionally elliptical, opaque surface, from ash to yellowish brown, dense scales the main vein, opaque underside.
The inflorescence is generally made up of a few pedunculated spikes at the axils of the leaves, or frequently panicled by inserting these spikes into the subterminal nodes; the ears are mostly 6-8 cm long.
The flowers are thin, sessile or pedunculate, open flower buds, lobes that touch each other without uniting along their entire length, the flowers become yellow-green after a few hours from opening, the flowers have elongated stamens and are 5 to 7 inches long .5 cm and 7.5 to 9 cm wide, only one or two flowers open per day on each raceme, opening completely at dawn, withering during the day. The calyx is 1.0-1.8 cm long, funnel-shaped, occasionally semi-campanulate, robust and smooth stamens in an inserted stem tube.
The fruit is a slightly curved and brown pod 8.0-18.0 cm long, 1.3-2.2 cm wide, 0.8-1.3 cm thick, cylindrical, corded, spiral straight, and with 2 wide longitudinal striations, containing a white pulp, with few seeds and do not open when ripe, linear, with a sessile to attenuated base.

Cultivation –
Inga edulis is a plant that grows in an area that extends from Central America to South America and varies from dry subtropical to humid tropical conditions. It can be found at altitudes from sea level up to 2200 m. It grows best when the average annual daytime temperature is between 23 and 30°C. However, it can tolerate 18–35 °C. During the dormant period, mature trees can survive at -2 °C while young plants die at 0 °C. Preferred annual precipitation ranges from 1200 to 2500 mm, but 640 to 4000 mm of annual precipitation can also be tolerated.
Inga edulis can be grown on a very variable range of soil conditions. It prefers a soil pH of 5 to 6.5, but can also grow in strongly acidic soils down to a pH of 4.5 or in moderately alkaline conditions down to pH 8.
Because this plant’s natural habitat includes the edges of large rivers such as the Amazon, thickets below the high water line, and wooded swamps, it tolerates temporarily waterlogged soil for 2-3 months of the year. However, it can also tolerate drought seasons of up to 6 months. It can also handle heavy terrain or slopes quite well. In terms of soil fertility, Inga edulis is not only unpretentious, but has the potential to improve soil quality. Being a legume, it can compensate for nutrient-depleted soils by fixing nitrogen with its root nodules. Ammonium and nitrates in soil typically result in reduced nodulation. Inga edulis is an exception, as its nodules increase in size when ammonium levels are at 5 mM. Nitrate on the other hand did not benefit Inga edulis and continued to exhibit properties that prevented nodulation. In addition to nitrogen, Inga edulis has been reported to significantly increase extractable phosphorus content in soil and thus further improve degraded soils.
The plant is grown in agroforestry systems in its Neotropical dispersal area. This form of cultivation, often associated with coffee or cocoa culture, has been widely known since pre-Columbian times.
Trees propagated from seedlings can start fruiting when they are just two years old and can flower and fruit all year round, plus the tree responds well to coppice.
It is also reported that it is a very variable species, the forms with pods of the best quality are rarely found in Central America, where it is very likely that all the trees are relics of ancient cultivations.
Furthermore, Inga edulis appears to be very resistant to parasites and diseases. Minor damage can result from fungal attacks in the seedling stage. Mature Inga edulis can be defoliated by lepidopteran larvae. Additionally, fruit fly larvae often damage the seed head. In Ecuador, Inga edulis is particularly susceptible to mistletoe infestations.
The plant reproduces easily by seed which has a short germination period, about two weeks, germination occurs in two, three days, sometimes in the same legume. Fruiting can begin, in the best cultivation conditions, in the second year after sowing.
Seed germination is quite simple as the seeds often germinate already in the pod. Direct sowing of seeds is possible, but planting seedlings already at a certain height can reduce competition with weeds and therefore increase growth. Additionally, inoculation with rhizobia and mycorrhizal fungi in depleted soils is recommended to promote growth. These inoculants can easily be produced by collecting soil, nodules and fine roots from mature, nodulated stands of Inga edulis.

Customs and Traditions –
Inga edulis is known by various common names; among these are: ice cream bean, monkey tamarind (English); pois doux (French); anga, ingá, inga-cipó, ingá de macaco, maingá de metro, ingá macarrão, inga-rabo-de-mico (Portuguese – Brazil); chalaite, cuajiniquil, guaba, guaba de bejuco, guaba mecate, guaba chillillo, guama, guamo san Antonio, guamo santafereño, guava, guava machete, guavo-bejuco, inga cipo, jiniquil, pacae, pacay (Spanish); affenschwanz-inga, essbare inga (German).
The edible fruit is very popular in South America, where it is commonly harvested from the wild and often also cultivated.
The fruits are often sold in local markets and the tree is also widely used, especially in Central America, to provide shade on coffee, tea and cocoa plantations and also around homes.
It also has a fair ornamental value due to its expanded and rather dense foliage.
The pulp surrounding the seed, sweet and with a vanilla flavour, is consumed fresh, but a juice can be obtained from it which is sometimes used to prepare an alcoholic drink.
The seeds, eaten cooked as a vegetable or roasted, are very popular in their places of origin.
The leaves and seeds, with their high protein content, are also used as fodder for livestock.
Locally the wood is used as fuel and building material.
Finally, the seeds and leaves are used in traditional medicine as astringents in intestinal diseases and as antirheumatics.
The plant, historically, is widely cultivated, especially by indigenous Amazonians, for shade, food, wood, medicine and the production of the alcoholic drink cachiri.
From an ecological point of view, this plant is in symbiosis with ants (e.g. Pheidoles spp.), which obtain nectar from extrafloral nectaries. In return the ants will patrol the Inga plant to protect it from herbivores. There are some insects such as Riodinid caterpillars that excrete sugary honeydew from their tentacled nectaries. The ants will form a symbiosis with the caterpillars by letting them feed on the tree and obtaining sugary honeydew from them.
The plant, as mentioned, can also form symbiotic relationships in which atmospheric nitrogen can be fixed by rhizobial bacteria and mycorrhizae as other legumes do. Investigations have shown that Inga edulis establishes a mutualistic relationship with the Bradyrhizobium bacterial strain.
As regards its state of conservation, there seems to be a certain variability between the origins of this species, at least in the size and shape of the leaves, in the shape of the crown, etc. It is assumed that there are differences in tolerance to different soils, including acidity, humidity, etc., but there is not yet sufficient data to recommend varieties or provenances.
Other uses include agroforestry uses.
The species is commonly planted as a shade tree on coffee and cocoa plantations, as it grows rapidly, fixes atmospheric nitrogen, has a well-spread canopy and produces large quantities of leaves that cover the ground and contribute significant quantities of organic matter to the soil .
In test experiments on cultivated slopes, mulching this tree reduced soil erosion to levels almost equal to those of secondary forests.
Leaf litter is rich in nitrogen, lignin and polyphenols. It is slow to decompose, but provides long-term storage of organic nitrogen and effective weed control. Weed biomass decreased considerably in all agroforestry trials with this species, much more than with other legume species. Existing studies are too new to ascertain whether the species can maintain or improve soil fertility in acidic sites in the long term, but the results so far are promising.
Cuttings and leaves are also used as mulch and fodder for animals.
Despite its rapid growth and significant soil improvement potential in agroforestry systems, Inga edulis has not been the subject of any genetic improvement program. However, it has been shown that the plant shows strong introgression with Inga ingoides in the contact areas of the species. This could enable the selection of hybrids via interspecific hybridization to further increase the yield and flood tolerance of the crop.
Regarding the uses of the wood, it is reported that the heartwood is light brown with dark streaks; the sapwood is pale yellow or almost white. The texture is coarse; the grain from straight to twisted; the shine is medium; there is no characteristic taste or aroma. The wood is not very heavy; difficult to moderately difficult. It is said to be very durable, even in water.
It is easy to cut, is slightly woolly and tends to split during drying. It is mainly used to make packing cases, and above all to make poles, and is also used as fuel. It is a popular source of firewood, the wood has a high calorific value and burns producing little smoke.

Preparation Method –
Inga edulis is a plant that is used in many fields, from edible to medicinal, agroforestry and for various materials.
In edible use, the pulp surrounding the seeds of the pod is white, translucent and gelatinous, with a sweet and fragrant flavour. It is highly appreciated in Ecuador, some forms have a light cinnamon flavour. The taste is described as similar to vanilla ice cream. Some varieties also possess a light cinnamon flavor.
In Colombia arils are also used to prepare an alcoholic drink called cachiri for the festival of the same name. Indigenous women chew the arils and spit the mixture into a tub, where it is left to ferment. The fruit ripens quickly and can only be stored for three or four days, limiting potential export opportunities. However, refrigeration can extend the shelf life to about three weeks.
The seeds are edible only cooked and have a flavor similar to that of chickpeas.
The plant is widely used in the folk medicine of South American natives. Decoctions of the leaves, bark, or root are commonly used as treatments for diarrhea, arthritis, and rheumatism.
The chopped and boiled leaves are ingested to relieve coughs or applied to sores on the lips, probably caused by herpes. Several studies have investigated Inga edulis as a source of polyphenols for use as antioxidants and have shown promising results. However, further studies are needed to test and develop medical applications.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora d’Italia, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Photo source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/1364117/original.JPG
– https://upload.wikimedia.org/wikipedia/commons/5/54/Inga_edulis_Taub57.png

Attention: Pharmaceutical applications and food uses are indicated for informational purposes only, they do not represent in any way a medical prescription; we therefore decline any responsibility for their use for healing, aesthetic or food purposes.