Image: moolek skee/Shutterstock.comArtocarpus heterophyllus, or jackfruit, goes by many names including jak, jaca, nangka, khanun, khnor, maki mi, may mi, and mit to name a few. Although its exact origin is unknown, the fruit is likely indigenous to the Western Ghats of India and was one of the first cultivated fruits. More broadly, jackfruit has historically been a staple food in India, Myanmar, China, Malaysia, Sri Lanka, Indonesia, and the Philippines. One of the world’s largest fruits, jackfruit typically weighs about 35 pounds although it can grow significantly larger, as one in India weighed 144 pounds. The fruit rind and core are inedible, but the flesh can be cooked or served fresh. Ripened jackfruit has a strong odor, often described in colorful terms such as a mix of bananas and stinky cheese or even sweaty socks. Outdoor slicing and preparation are often recommended, followed by immediate disposal of the rinds. Nearly all parts of the jackfruit tree can be used, including the trunk, leaves, fruit, and seeds. Although the fruit if often consumed fresh, both ripe and unripe, it is often cooked, canned, or processed into ice cream, jam, jellies, or pastes. Jackfruit is also considered a meat substitute due to its high nutritional value and texture when cooked.
Types & Varieties A wide variety of species and cultivars of jackfruit are grown across Asia, the Pacific, Africa, and the United States. Since jackfruit is relatively new to the U.S. market, there is still uncertainty about optimal cultivars. Generally, jackfruit comes in two types: firm or soft. Varieties recommended in the United States include Black Gold, Dang Rasimi, Golden Nugget, Honey Gold, Kun Wi Chan, Lemon Gold, and NS1. Most have been developed overseas in Australia or Malaysia. Jackfruit’s outer skin, made up of hexagonal, conical apices, becomes greenish to brownish yellow when ripe. The flesh or pulp can range in color from amber to dark yellow or orange. Jackfruit is a compound fruit that contains between 100 and 500 seeds ranging in size from three-quarters of an inch and 1.5 inches in diameter. The seeds can be cooked and eaten, with a taste similar to chestnuts. When the tree or fruit is cut or damaged, it will ooze a very sticky, white, rubbery latex that can be used as a glue or paste. CULTIVATION An evergreen, jackfruit trees can grow up to 80 feet in height but typically only reach 30 to 40 feet in the United States. It can be direct seeded or grafted and will then produce a long taproot and grow upwards with branches eventually spreading out to create a rounded canopy. Trees grow well in tropical and subtropical environments, particularly in rich, deep soil to allow for proper root development. Before maturity, jackfruit trees do not tolerate overly wet soil conditions or temperatures below 28°F. Additionally, while jackfruit prefers ample sunlight, too much can result in sun scald. The tree will begin fruiting in the third or fourth year; fruit should reach maturity on the tree, then ripen after harvest. Mature jackfruit can be hard to identify; characteristics include skin turning from light green to yellow or brownish green, spines more spaced apart that give a little when pressed, yellowing of the last leaf on the stalk, and, if tapped, the fruit will produce a dull, almost hollow sound. Due to their large size and weight, jackfruit can be challenging to harvest. Fruit is harvested by hand, using a ladder and cutting the fruit at the stem with clippers or loppers. Many prefer to harvest between mid-morning and afternoon as the sticky latex sap will not flow as readily. Tools should be coated with vegetable oil for harvest and cutting to prevent the latex from sticking. A quality jackfruit will be of good size, well colored, rounded, and free from signs of damage or decay. Pests & Diseases As jackfruit has limited commercial production in the United States, research into pests and diseases is ongoing. Longicorn beetles when in the larval stage destroy plant stems, often leading to reduced yields. Larva from the oriental jackfruit fly can seriously affect trees and fruit, but covering the fruit in protective bags while developing can help protect fruit and control infestations. Jackfruit is vulnerable to many boring insects such as the spined oak borer, shoot borer, as well as other pests including bud weevils, spittle bugs, mealybugs, scales, thrips, and aphids. Mammals, too, often feed on and destroy fruit, especially civet cats and wild boars in some regions. Jackfruit trees are at risk of root rot if soil is overly moist for long periods, especially during flooding. Pink rot can be identified by whitish spots developing on branches, eventually expanding to encircle the branch and turning a salmon color. Stem, fruit, and male inflorescence rot can be destructive to production. These soft rots attack the tree and young fruit preventing maturity and limiting yields at harvest. Leafspot appears as darkened lesions on leaf surfaces. Other diseases that can disrupt growing and maturity include grey blight, charcoal rot, collar rot, and various types of rust.
Storage & Packaging
Although there has been little research on optimal jackfruit storage or processing, keeping the fruit cool at 52°F and 55°F with a relative humidity of 85 to 95% is recommended. Exposure to ethylene for 24 hours can aid in ripening.
References: California Rare Fruit Growers, Purdue University Extension, UC Davis Postharvest Technology Center, University of California, University of Florida/IFAS Extension, University of Hawaii.
Jackfruit Terminal Market Pricing