In Europe, jackfruit is often mistaken for durian. Photo: Filepic
I am now back in the UK for a short visit and was pleasantly surprised to be informed by my daughter that certain popular items in Malaysia are now big hits here.
For a start, a quarter-pound burger made with jackfruit has been voted as the “Best Vegan Supermarket Burger” in the country. And laksa restaurants are opening up faster than UK politicians can lie about Brexit (more on the subject of London laksa another time).
It was surprising to see jackfruit so popular here as it was probably the last thing I had expected. So out of curiosity, I thought it is worth investigating.
Origin
Starting with its origin, there have been claims that the jackfruit tree (known as Artocarpus heterophyllus) originated in Peninsular Malaysia and Borneo, but the reality is that it is much more likely to be a native plant from the Western Ghats of India.
There is evidence that the jackfruit was cultivated in India between 3,000 to 6,000 years ago. The plant has now migrated to other tropical regions in Africa, South America,
and islands like the Philippines.
The name jackfruit was probably derived from the Portuguese jaca, which in turn was likely to be a bastardisation of the original Indian name chakka pazham. In Bangladesh, it is the national fruit and known as kathal. The Thais call it kanun, and Malaysians refer to it as nangka.
Properties
Artocarpus heterophyllus is part of the Moraceae family of fruit-bearing trees, which means the jackfruit is related to fig and mulberry trees.
However, jackfruits are by far the largest tree-borne fruits in the world, often exceeding 30kg in weight. The Guinness World of Records lists the largest validated jackfruit to be 42.72kg with a circumference of 132cm, though there are unverified claims of jackfruits weighing over 50kg.
Jackfruit trees usually require five to seven years before producing its first harvest. But once it starts producing fruit, the output is prodigious, between 10 to 200 fruits per tree per year – around 25.71 tonnes per hectare.
The internal structure of the jackfruit itself is rather curious as it is classified as a “dicotyledonous compound fruit”. This is because the fruit is a bundled collection of ovaries of multiple flowers glued together by a strong latex adhesive secreted by laticiferous cells along the axis and core of the fruit.
The “flesh” of the jackfruit is actually the ovary casings surrounding the seeds. The texture of jackfruit flesh tends to be firm, crunchy, and sometimes a little stringy, though an over-ripe jackfruit can turn rather mushy.
Around 30% of a jackfruit by weight is the edible flesh, and jackfruits must be harvested by hand before they fall off by themselves as they would be rotten if left hanging too long on the tree.
The seeds of the jackfruit should never be eaten raw as they contain enzyme and mineral absorption inhibitors, which prevent the uptake of various minerals by the body. However, after boiling for around 40-45 mins, these inhibitors are destroyed or deactivated. I always remember how delicious boiled jackfruit seeds were when my mother prepared them.
Nowadays, it seems that they can also be roasted or baked (200ºC for 25-30 mins until brown and toasted), though I have never tried it myself. The seeds are also processed or cooked, and then ground into flour.
Note the rind and the fibrous laticiferous cells along the axis and core of the fruit are not edible as they are indigestible and may induce stomach cramps.
Jackfruit as a modern food
What makes jackfruit interesting as a modern food is its nutritional content and unusual texture, which is particularly interesting for creating meat substitutes. For such meat substitutes, the unripe jackfruit is used as it is less sweet and has less of its distinctive aroma.
The texture of chopped and cooked unripe jackfruit resembles closely the texture of meat, especially pork, and combining it with umami flavour elements and additional filler ingredients results in highly acceptable meat substitutes.
Jackfruit is used to make a very convincing substitute for pulled pork, which is strikingly usable in dishes and sandwiches or burgers; this is gaining popularity in the West. But for Asians, the jackfruit is already used extensively in curries and stir fries, especially in India.
Mature jackfruit can be included or made into various kinds of salads, desserts, ice creams, and dessicated or dehydrated into crisps.
The low protein and fat content of jackfruit is ideal for people who want a healthier diet, particularly if its other nutritional elements are considered. The jackfruit contains significant amounts of ascorbic acid, pyridoxine, riboflavin, thiamine, folic acid, magnesium and phosphorus.
It contains an unusually wide spectrum of amino acids such as tryptophan, threonine, isoleucine, leucine, lysine, methionine, phenylalanine, valine and histidine, which are important for healthy body functions.
In summary, there appears to be very few disadvantages of using the jackfruit as a modern food and a lot of undeniable advantages. So this may be another impetus to the adoption of modern foods made with natural ingredients such as the jackfruit.
To understand what modern foods are, go read A Modern Food Story - Part 3.
Confusion with the durian
In the West, many people still confuse the jackfruit with durian. This may be because they both look like big, spiky, green fruits from a distance. But the more discerning will realise their mistake once they get close enough to smell the fruits.
The jackfruit has a sweet aroma, a mix of bubble gum with a hint of fish sauce, whereas durian tends to evoke the full-on disgust reaction when encountering a bucket of rotten fruit mixed with dog poo.
Anthony Bourdain once said the aroma of durian is “indescribable, something you will either love or despise. Your breath will smell as if you’d been French-kissing your dead grandmother.”
Nevertheless, I admit that durian is still my all-time favourite fruit and my abiding regret is that only frozen, odourless Thai durians are available in Europe. They are vile and tasteless compared to the Musang King, Red Prawn, D101 and D24 varieties available in Kuala Lumpur when I was working there.
Still, it is curious why durians invoke such strong reactions in novices. I came across a 2012 German Research Centre for Food Chemistry study into a durian species often grown in Thailand called Durio zibethinus (or Monthong) where they performed an aroma extract dilution analysis.
In the fruit, they found 44 active odorants including some highly active compounds (with an indication of the aroma of each): hydrogen sulfide (rotten egg), acetaldehyde (sickly fruity), methanethiol (rotten cabbage), ethanethiol (rotten onion), 3-methylbut-2-ene-1-thiol (skunky) and propane-1-thiol (an indescribable rotten stink).
Interestingly, three complex compounds which were completely unknown to chemists previously were found in durian: 1-(propylsulfanyl)ethanethiol, 1-{[1-(methylsulfanyl)ethyl]-sulfanyl}ethanethiol, and 1-{[1-(ethylsulfanyl)ethyl]sulfanyl}ethanethiol.
But they also found other attractive odorants such as ethyl (2S)-2-methylbutanoate (fruity), ethyl cinnamate (honey), 1-(ethylsulfanyl)ethanethiol (roasted onion), 2(5)-ethyl-4-hydroxy-5(2)-methylfuran-3(2H)-one (caramel), ethyl 2-methylpropanoate (fruity), ethyl butanoate (fruity), 1-(methylsulfanyl)-ethanethiol (roasted onion), 1-(ethylsulfanyl)propane-1-thiol (roasted onion), etc.
The study concluded that the researchers did not know which odorants were the most disgusting to uninitiated people. It may be one, a few, or it may be many compounds operating in combination.
It does not attempt to explain why many people actually find the aroma of the durian so attractive. Maybe they had lost interest by the end, after all that smelling in the laboratory.
Anyway, there are 400 known species of durians and one suspects the German research centre is not too keen to investigate the other 399 species.
There is one other curiosity about the durian, which may validate a Malaysian old wives’ tale. The University of Tsukuba in Japan tested the effect of durian extract on aldehyde dehydrogenases (ALDH), the important enzymes involved in the liver’s metabolism of blood alcohol.
Probably due to the high sulphur content, the durian extract inhibited the effect of ALDH by up to 70%, thus leaving much of the toxic blood acetaldehyde unprocessed for longer in the body. (For the gory details, you can refer to A cure for hangovers.)
I once had half a bottle of vodka after some durians and felt awful the next day. Until I came across the research paper today, I never understood why. At least, now you know.
