Gac Fruit

Gac fruit is a perennial tropical vine that requires a long, hot growing season and is dioecious, meaning separate male and female plants are needed for fruit production. Plant both sexes from root cuttings or seeds, spacing plants 8-10 feet apart along a sturdy fence or trellis system. Vines can grow 30-50 feet in a single season in tropical conditions. In temperate climates, grow in large containers in a heated greenhouse or against a warm south-facing wall.

Provide consistent moisture but excellent drainage, as gac fruit is susceptible to root rot in waterlogged conditions. The vines grow vigorously from tuberous roots that can survive mild winters and resprout in spring in zones 9-10. Apply balanced fertilizer monthly during the growing season and increase potassium when flowering begins. Train vines along overhead structures for easy fruit harvesting.

Hand pollination significantly increases fruit set. Transfer pollen from male flowers to female flowers early in the morning when flowers are freshly opened. Each vine can produce 30-60 fruits per season in ideal conditions. Fruits take approximately 4-5 months from pollination to full maturity, changing from green to bright orange-red. In areas with short growing seasons, start tubers indoors 2 months before the last frost.

Gac fruit (Momordica cochinchinensis) is native to the tropical regions of Southeast Asia, ranging from southern China through Vietnam, Laos, Cambodia, Thailand, and into northeastern India and Bangladesh. The plant grows wild in forests and along riverbanks, climbing over trees and shrubs with its vigorous tendrils. Its species name 'cochinchinensis' refers to Cochinchina, the historic name for southern Vietnam, where the fruit has been cultivated and revered for centuries.

In Vietnam, gac holds a uniquely important cultural position. Xoi gac, the brilliant red-orange sticky rice coloured and flavoured with gac aril, is considered essential at Tet (Lunar New Year) celebrations, weddings, and other auspicious occasions. The vivid red colour symbolises luck, prosperity, and happiness in Vietnamese culture. Historical records suggest gac has been cultivated in Vietnam for at least 500 years, and it is mentioned in traditional Vietnamese medical texts as a remedy for eye ailments, dry skin, and childhood nutritional deficiencies.

In traditional Chinese medicine, gac seeds (known as 'mu bie zi') have been used for over a thousand years, primarily as a topical treatment for skin conditions, wounds, and swelling. The fruit flesh and arils gained prominence as a food only in the last few centuries as their extraordinary nutritional properties became better understood. In recent decades, scientific analysis revealed that gac arils contain the highest known concentrations of beta-carotene and lycopene of any fruit or vegetable, sparking intense international interest. Today, gac is cultivated commercially in Vietnam, Thailand, and Australia, and gac-derived supplements, oils, and powders are exported worldwide. Despite this growing global awareness, gac remains largely unknown outside of Southeast Asian communities, making it one of the great undiscovered superfruits of the tropical world.

Gac fruit requires well-drained, fertile soil rich in organic matter with a pH of 6.0-7.0. The tuberous root system needs loose, deep soil to develop properly. Amend planting areas with generous compost and ensure drainage is excellent. Apply balanced fertilizer monthly and increase potassium and phosphorus during flowering and fruiting. In containers, use a rich potting mix with added perlite for drainage. Avoid high-nitrogen fertilizers which promote excessive vine growth at the expense of fruit production.

Harvest gac fruit when the skin turns from green to bright orange-red and the spines soften slightly, typically 4-5 months after pollination. The fruit should give slightly when pressed. Cut from the vine with a sharp knife, wearing gloves as the spines can irritate skin. Open fruits carefully to access the bright red aril (seed membrane) that surrounds the seeds, which is the primary edible and most nutritious part. Each fruit yields approximately 2-4 tablespoons of aril. Handle cut fruits over a bowl as the aril stains surfaces intensely.

Whole gac fruit stores at room temperature for 1-2 weeks or refrigerated for up to a month. Once opened, the aril should be used immediately or frozen for long-term storage. Frozen aril maintains its nutritional value and color for up to 12 months. The aril can be oil-extracted to make gac oil, which is extremely rich in beta-carotene and lycopene and stores refrigerated for months. Seeds can be dried and stored for planting. In Vietnamese tradition, aril is mixed with glutinous rice and cooked immediately for the bright red ceremonial dish xoi gac.

Gac fruit is most famous for xoi gac, the brilliant red glutinous rice prepared for Vietnamese Tet (New Year) celebrations and weddings. The aril is mixed into the rice before cooking, imparting both color and a mildly sweet, nutty flavor. Gac oil extracted from the aril is used as a natural food colorant and nutritional supplement due to its extraordinarily high beta-carotene and lycopene content. In India, young fruits of the related variety (kakrol) are sliced and stir-fried as a vegetable. Seeds are roasted and eaten in some regions.