The gac is a fruit native to Southeast Asia, and it grows anywhere in the region all the way from China to the North of Australia. The plant's scientific name is Momordica cochinchinensis.
The gac is not a tree but a climbing plant that develops dioecious vines. Usually the fruits are harvested from wild plants or from the ones cultivated to grow on fences and the like. In its native range, the pant can often be found on frames and gratings in rural areas, either in gardens or close to home entrances. Especially in the villages of Northern Vietnam, the fruit is traditionally found growing up on lattices. In Vietnam, gac is also known as "the heavenly fruit" because of its climbing abilities, as well as its numerous nutritional benefits. The name of the fruit itself comes from Vietnamese, where the word means "round".
When ripe, the gac fruit reaches around 13 cm in length, with a diameter of about 10 cm. The shape is round or oval and it has an intense dark orange color when fully ripe. The orange skin has small spines on its surface, which resemble thorns. The rind reaches a thickness of 2 to 3 cm when the fruit is ripe. The interior is dark red and consists of a mix of seeds and pulp. There are between 15 and 20 round seedpods, which give the interior its red color. Between them there is a cushion-like orange flesh.
The seed pods are covered in a membrane which can be converted into the so-called gac oil. This oil is very rich in lipo-carotene, an essential compound used by our body to assimilate nutrients. This is especially valuable for vitamins A, D, E and K, as well as other useful compounds that are soluble in fat.
The gac is not really a common fruit. It can be harvested once per year and is typically found in local markets, during its relatively short ripening season.
Pulp, seeds, leaves.
The gac fruit has been used in medicine since ancient times. It has been a traditional ingredient in its native range in countries like China, Indonesia, Sri Lanka, Malaysia, or the Philippines, but also in India and the Caribbean islands.
The outside layer of gac, which is covered with thorns that have a vivid red color, is toxic and must be discarded. However, the inside contents of the fruit have important health benefits. All around Southeast Asia, gac has been used as both food and medicine in almost every country of the region.
In Vietnam, the gac fruit is an important element of local cuisine and the leaves of the plant are used for cooking several traditional Vietnamese dishes as well. However, it is widely used for its nutritional content and health benefits, as a cure against several problems. The most popular medicinal use of the fruit in Vietnam is the consumption of the membrane around the seed pods, believed to improve eyesight and help moisture dry eyes.
In Chinese medicine, both ancient and modern, gac seeds are often used to treat numerous health problems. The seed even has a dedicated name in Mandarin Chinese, which can be translated as "wooden turtle seed" (mù biē zǐ).
The gac is very valuable against one of the common diseases of the modern world. Studies have revealed it can be of tremendous help to people with a high level of cholesterol in the blood, even to those who have a family history of such problems. As low as one gac fruit consumed every week appears to be enough to reduce cholesterol and keep it at a safe level.
However, the fruit is also rich in antioxidants that prevent a wide range of other heart diseases. These have been proven to especially stop the hardening of the walls of the arteries, a very dangerous condition also known as atherosclerosis. Two other compounds in the fruit, beta-carotene and lycopene, are bioactive agents that contribute to a lower risk of having a heart attack. All these benefits make gac one of the most important fruits in our natural arsenal, since cardiovascular diseases are among the top threats to our body in today's world. According to study, a healthy lifestyle and a diet that includes gac can guarantee a heart in good condition, with little risk of a fatal stroke.
At the same time, gac appears to be very useful to maintain a healthy prostate and treat BPH in men. The exact mechanism is not understood yet but it's probably because of the unusually high content of strong antioxidants.
In traditional Asian medicine, the fruit has been used as a healing and cosmetic agent in the treatment of skin diseases, scars, burns and eyesight issues. Gac juice is often prepared as a cure against heart disorders, prostate problems and as a fertility booster.
Another major medicinal use of gac is to improve vision. It has an immediate effect due to a wide range of compounds that influence eyesight, in particular beta-carotene and vitamins. Constant consumption of the fruit can prevent the onset and development of cataract and other severe eye disorders.
Gac is a very rich source of vitamins and minerals that offer an overall boost to the nervous system. These contribute to a balanced mental state and prevent depression.
The fruit can also be used as a cure against aging, besides its numerous other health benefits. It boosts the production of collagen, the main building block of the skin. This rejuvenates the skin, speeds up the healing of wounds and sunburns, as well as delays the formation of wrinkles. Gac consumption prevents stress and boosts activity inside the cells, which slows down the process of aging. Youthful appearance is preserved for a long time, due to the fruit's vitamins and minerals complex, which give our skin a healthy and youthful look.
Gac is an important addition in the diet of people with anemia, especially for women. This is due to its very high content of iron, as well as the presence of all of the other compounds that fight anemia, like vitamin C and folic acid. For this reason, those who suffer from anemia are encouraged to start eating this fruit.
The fruit can be treated like a vegetable and prepared in several ways. However, the rind can't be consumed raw. It must be blanched before cooking, afterwards its hollow center can be filled. Other popular dishes are salads or curries but it can also be fried on a stir.
In Vietnam, the fruit is mainly used to prepare xoi gac, a mix of gac with glutinous rice that gives it a spectacular orange color and a specific taste. There are also several beverages that can be prepared using gac. Another traditional use is during weddings, Tet (New Year) celebrations or other festivities, when some special dishes are prepared from gac and usually served to the guests.
Gac is a tropical plant and requires plenty of heat and rainfall in its natural range. For cultivation one has to remember that it is a dioecious vine. Unless both male and female plants are grown, they will be barren and not produce any fruits or seeds.
It is best planted in a spot with a lot of sun, although it can also grow in a shady location. In terms of elevation, it can be found from sea level to about 1100 meters of altitude. It can tolerate daily temperatures of 14°C - 35°C but it is the most productive in places with annual daytime temperatures of 20°C - 30°C.
The plant needs a lot of moisture and survives with 1,000 - 3,000mm of rainfall. However, for ideal results, rainfall must be between 1,200 - 2,500mm per year. Frost kills the plant and attempts to introduce it to colder climates have failed. As a tropical plant, it needs a good soil, rich in nutrients, with a pH in the range of 6.5 - 7 (extreme range tolerated is 6 - 7.5).
The most important beneficial compounds in gac are the so-called carotenoids. The very high content of these very strong antioxidants is obvious from the intense orange and red colors seen on both the outside and the inside of the fruit. Specifically, gac is a major source for two carotenoids: beta-carotene and lycopene.
Modern studies have revealed that Vietnamese kids have a higher level of beta-carotene in the blood than children from a control group from other parts of the world. This is because they often eat a rice dish prepared with gac and ingest massive doses of lycopene and β-carotene. These potent antioxidants are believed to provide numerous health benefits, like anticancer and provitamin A activities. Other bioactive compounds isolated from the fruit include trypsin inhibitors, phenolic compounds and flavonoids.
Besides, gac oil is very rich in vitamin E. The fatty acids contained by gac are a perfect companion to the carotenoids, since they boost their absorption, as well as that of other nutrients that are soluble in fat.
Several parts of the fruit are toxic and should never be eaten. These include the skin, the outer rind, as well as the sides, which resemble a cantaloupe due to their texture. Eating these parts doesn't have fatal consequences but can make a human sick for several days. The edible parts are the big seeds, as well as the thin, soft and oily layer of pulp that surrounds them.
Gac needs some time to grow so gardeners must be patient. Most plants will have flowers from their first year. However, the vine usually lacks the needed resistance to support a fruit, so these can be harvested and eaten only after two years.
Gac is a purely seasonal fruit and it only ripens once every year. It has a maturing time of about five months, from the flower stage until they are fully ripe and ready for harvest. It can be extremely productive, with a single vine having between 30 and 60 fruits every year. However, this depends on a lot of factors like the soil, the climate and the age of the vine.
The harvest period generally lasts about two months. In Vietnam, it already matures and produces fruits 8 months after it was planted. The short harvest season and the fact that it only happens once per year makes gac a rather special and rare fruit, the Vietnamese usually consume it during festivals, celebrations and other special occasions.
For the same reasons, gac is quite rare and obscure in the rest of the world. It can't be harvested and exported while green, like bananas and other popular fruits. Because it can only be picked when ripe, it doesn't last long on the shelves and its short harvesting season makes it unsuitable for large-scale commercial production. Gac is a real exotic fruit, which can be found and eaten in its native area.