|Exterior and cross-sectional interior of gac|
Gac is a fruit produced by Momordica cochinchinensis, which is found throughout the Southeast Asian region from South China to Northeastern Australia, including Thailand, Laos, Myanmar, Cambodia and Vietnam.
It is commonly known as gac from the Vietnamese gấc (pronounced [ɣək˦˥]) or quả gấc (quả being a classifier for spherical objects such as fruit). It is known as mùbiēguǒ in Chinese and variously as red melon, baby jackfruit, spiny bitter gourd, sweet gourd, or cochinchin gourd in English. In Thai, it is pronounced fahk khao and taw thabu in Myanmar.
The fruit itself becomes a dark orange color upon ripening, and is typically round or oblong, maturing to a size of about 13 cm in length and 10 cm in diameter. Its exocarp, or exterior skin, is covered in small spines. Its mesocarp is dense and light-orange in color. The seeds are usually brown or black in color and are surrounded by dark red membraneous sacs.
Because it has a relatively short harvest season (which peaks in December and January), making it less abundant than other foods, gac is typically served at ceremonial or festive occasions in Vietnam, such as Tết (the Vietnamese new year) and weddings. It is most commonly prepared as a dish called xôi gấc, in which the aril and seeds of the fruit are cooked in glutinous rice, imparting both their color and flavor. More recently, the fruit has begun to be marketed outside of Asia in the form of juice dietary supplements because of its high phytonutrient content.
Propagation and Cultivation
Gac grows on dioecious vines, meaning male and female flowers are borne on separate plants. The vine is usually collected from fence climbers or from wild plants, and can be commonly seen growing on lattices at the entrances to rural homes or in gardens. The vine can grow up to 20 m in length and the bark is a pale color. It only fruits once a year, and is found seasonally in local markets.
Rooted vine cuttings are more reliable than production from seeds. Germination by seed can be difficult due to many environmental factors such as dormancy, climate, or plant age. A successful alternative method is grafting female scion material onto the main shoot of an unwanted male plant, therefore making it productive.
About 2 to 3 months after planting a momordica cochinchinensis vine, flowering typically occurs. Pollination is usually carried out by insects, but hand pollination results in a higher fruit yield. One plant can produce 30 to 60 fruits in one seasion although environmental factors can affect that.
Traditionally, gac has been used as both food and medicine in the regions in which it grows. Other than the use of its fruit and leaves for special Vietnamese culinary dishes, gac is also used for its medicinal and nutritional properties. In Vietnam, the seed membranes are said to aid in the relief of dry eyes, as well as to promote healthy vision. Similarly, in traditional Chinese medicine the seeds of gac, known in Mandarin Chinese as mù biē zǐ (Chinese: 木 鳖 子 meaning 'wooden turtle seed'), are employed for a variety of internal and external purposes.
Nutrients and phytochemicals
Typical of orange-colored plant foods, gac fruit contains carotenoids such as beta-carotene (provitamin A). Vietnamese children fed a rice dish containing beta-carotene from gac had higher blood levels of beta-carotene than those in the control group. Gac aril oil contains high levels of vitamin E. Fatty acids in the aril oil may facilitate absorption of fat-soluble nutrients, including carotenoids.
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- Media related to Momordica cochinchinensis at Wikimedia Commons