**Taxonomy and Naming:**
– The specific epithet julianettii honors naturalist Amedeo Giulianetti.
– Karuka is a loanword from Tok Pisin.
– The tree is sometimes called karuga or karuka nut pandanus.
– Karuka can refer to Pandanus julianettii and P. brosimos.
– P. julianettii is sometimes termed planted karuka in discussions of multiple species.
**Description and Cultivars:**
– The tree is dioecious with male trees uncommon.
– It reaches 10–30 meters in height with a grey trunk.
– There are up to 45 cultivars of karuka with different kernel shapes.
– Tabuna and Henga are important cultivars.
– Some cultivars are edible raw.
**Distribution and Cultural Significance:**
– Giulianetti’s type specimens were collected from Vanapa, British New Guinea.
– Karuka is an important regional food crop in New Guinea.
– Nearly 2 million people in PNG rely on karuka as a food source.
– Demand for karuka is high in the New Guinea Highlands.
– In PNG’s Central Province, a rugby league team is named Karukas.
**Nutritional Value and Human Use:**
– Karuka nuts have high energy content (540-700 kcal per 100g).
– They are rich in carbohydrates, dietary fiber, and fats.
– Karuka kernels are consumed raw, roasted, or smoked.
– Karuka oil extracted from nuts is rich in oleic acid and Vitamin E.
– Karuka nuts are more nutritious than coconuts and are popular in the local diet.
**Ecology, Pests, and Diseases:**
– Karuka fruit production occurs in February, with a secondary season in July.
– Pollination by humans is possible.
– Fungal pests of karuka include leaf spot and black leaf mold.
– Longhorn grasshoppers are significant insect pests.
– Measures like using platforms on tree trunks help protect against pests.
The karuka (Pandanus julianettii, also called karuka nut and Pandanus nut) is a species of tree in the screwpine family (Pandanaceae) and an important regional food crop in New Guinea. The nuts are more nutritious than coconuts, and are so popular that villagers in the highlands will move their entire households closer to trees for the harvest season.
| Karuka | |
|---|---|
| |
| Pandanus julianettii fruit cluster | |
Scientific classification 
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Pandanales |
| Family: | Pandanaceae |
| Genus: | Pandanus |
| Subgenus: | Pandanus subg. Lophostigma |
| Section: | Pandanus sect. Karuka |
| Species: | P. julianettii
|
| Binomial name | |
| Pandanus julianettii | |
| Synonyms | |
| |
 | |
| Nutritional value per 100 g | |
|---|---|
| Energy | 2,259–2,929 kJ (540–700 kcal) |
28-33.5 g | |
| Sugars | 5 g |
| Dietary fiber | 9.2-25 g |
35.6-47 g | |
| Saturated | 18 g |
| Trans | 0 |
11.9-18 g | |
| Tryptophan | 102-136 mg |
| Threonine | 435-482 mg |
| Isoleucine | 503-555 mg |
| Leucine | 904-993 mg |
| Lysine | 426-526 mg |
| Methionine | 272-279 mg |
| Cystine | 204-234 mg |
| Phenylalanine | 571-613 mg |
| Tyrosine | 408-438 mg |
| Valine | 745-832 mg |
| Arginine | 1238-1329 mg |
| Histidine | 293-336 mg |
| Alanine | 585-642 mg |
| Aspartic acid | 1064-1197 mg |
| Glutamic acid | 2285-2453 mg |
| Glycine | 638-701 mg |
| Proline | 530-613 mg |
| Serine | 545-584 mg |
| Vitamins | Quantity %DV† |
| Vitamin A | 2 IU |
| Vitamin C | 7% 6.40 mg |
| Vitamin E | 3% 0.46 mg |
| Minerals | Quantity %DV† |
| Calcium | 62% 97-460 mg |
| Iron | 2328% 419 mg |
| Phosphorus | 191% 220-360 mg |
| Potassium | 10% 300.22 mg |
| Sodium | 3% 71.21 mg |
| Other constituents | Quantity |
| Water | 9% |
| Cholesterol | 0 |
| †Percentages estimated using US recommendations for adults, except for potassium, which is estimated based on expert recommendation from the National Academies. Source: | |
| Nutritional value per 100 g | |
|---|---|
| Dietary fiber | 5.3 g |
0.43 g | |
8.5 g | |
| Threonine | 289 mg |
| Isoleucine | 281 mg |
| Leucine | 485 mg |
| Lysine | 196 mg |
| Methionine | 170 mg |
| Phenylalanine | 315 mg |
| Tyrosine | 323 mg |
| Valine | 340 mg |
| Arginine | 255 mg |
| Histidine | 162 mg |
| Alanine | 391 mg |
| Aspartic acid | 672 mg |
| Glutamic acid | 748 mg |
| Glycine | 459 mg |
| Proline | 196 mg |
| Serine | 315 mg |
| Minerals | Quantity %DV† |
| Calcium | 9% 120 mg |
| Phosphorus | 11% 140 mg |
| Other constituents | Quantity |
| Cholesterol | 0 |
| †Percentages estimated using US recommendations for adults, except for potassium, which is estimated based on expert recommendation from the National Academies. Source: | |