Stretchy ice-cream

This year is the "Year of Chemistry" and in August we also have "Wellington on a Plate" - so to celebrate both, the Chemistry Department of Victoria University invited Kent Kirshenbaum from New York University to present a couple of lectures this week on Chemical Gastronomy. Kent has founded a group in the States called Experimental Cuisine, which aims to understand the chemical and physical process of cooking, and is on a mad-cap adventure to find alternatives to traditional ingredients.  For example, pavlova without egg whites?! The idea is that chefs can learn a thing or two from chemists, and likewise chemists could learn a thing or two from chefs. Good stuff.

Kitchen chemistry is hot news right now - Kent said it was listed number 5 in Time's Top 10 list for 2010, wedged in between global warming and stopping terrorism! Certainly we've been enjoying our cooking shows on TV the past few years, learning how to make mango caviar using sodium alginate (the ions form a bridging link, pulling the polymers together), and learning that by precisely cooking an egg at 62.5 degrees C (in a water bath which looks suspiciously like the one in my old molecular biology lab) the cooked yolks are supple enough to be rolled out like pastry. Hmmn, that gives me a few ideas... If you want to read some more on this subject, and try some experiments yourself, check out  Cooking for Geeks by Jeff Potter and Molecular Gastronomy by Herve This.

But what interested me the most in Kent's talk was the prospect of making my very own stretchy ice-cream from none-other-than one of my all-time favourite plants, Amorphophallus konjac! Traditional stretchy ice-cream, or Salep Dondurma as it's known in Istanbul, is made from milk sweetened and flavoured with mastic, an aromatic resin, and thickened with salep, the powdered bulbs of wild orchids. Not just any orchid, but orchids from the Anatolian mountains - Orchis mascula or Orchis militaris - which look a little like a Hyacinth in flower. The orchid bulb contains a mucilaginous carbohydrate called glucomannan which, when dissolved in milk, binds up and blocks the movement of water molecules, thickening the milk. "Salep" is an Arabic word for "fox testicle", presumably referring to the shape of the orchids bulb (I am unable to confirm the likeness due to the general shortage of Vulpes vulpes in New Zealand). Salep is becoming expensive and hard to source, as the orchids are becoming increasingly scarce in the wild. But good news! there are other botanical sources of glucomannans which can do the job.  Enter again my dear Amorphophallus...

I've had this plant for over twenty years now. It comes up every spring time, forms this luscious green canopy with a leopard-spotted trunk, always attracts lots of attention and comments, and then dies back at the start of the winter to it's underground corm. When the plant has stored up enough energy, it flowers - an enormous black/purple arum flower on a stalk, which stinks like a dead hedgehog... Mine has only flowered twice in twenty years - and it goes outside when it does! Each year the big corm creates lots of new little corms, so eventually I had a small forest in my pot, and I have given tens of them away over the years. Kew Gardens have a giant species - Amorphophallus titanum - standing about 3m tall with a trunk about 15-20cm in diameter. I will try and find my photo of it and post it here.

 

Amorphophallus in flower - phew

Amorphophallus titanum, at Kew Gardens in London.

Anyway, back to the stretchy ice-cream.... Amorphophallus konjac also has a high glucomannan content, and can apparently be used as an alternative for salep. Konjac flour looks to be readily available in Japan, and is used for all sorts of things. But I'm wondering, in the spirit of having a botanical picnic, if I can just dry a corm or two out and process the flour myself at home?


Should you wish to try it too, here is the recipe for Konjac Dondurma
2 grams mastic (optional)
8 grams konjac flour
1.6 L whole milk
410 grams sugar

The corms

2 Litres of liquid nitrogen (for cooling. You could probably cool the ice cream in the usual, less dramatic, way. Maybe an ice cream maker would work too?).

I'll let you know how mine turns out.

Wonderful breadfruit!

If you've never heard of breadfruit before you must definitely read up on this wonderful plant, it's story is fascinating! Artocarpus altilis is the scientific name. It grows as a medium to large tree, with fabulously large deltoid leathery leaves and large green ovoid fruit. The fruit are very dense in carbohydrates, vitamins and minerals - and can be cooked in many different ways, similar to potatoes. It was the food that fueled the Polynesian migrations across the Pacific - from west to east - with the canoe people taking fruit for food on the way, and little plants to start off new plantations in their newly-discovered islands. Closely related varieties which are seeded exist in New Guinea - and then from west to east, progressively, the varieties have fewer seeds until they are completely seedless in Samoa and Tahiti. Did seedlessness occur because the Polynesians selected for seedlessness, or was it a consequence of them propagating the plants from sprouts from the base of the tree (vegetative propagation)?

Breadfruit tree in Samoa

When Joseph Banks accompanied Captain Cook on the Transit of Venus voyage to Tahiti in 1769, he was floored by breadfruit! In England, carbohydrates were hard-won through cultivation of the land (to grow potatoes and wheat), while here in the Pacific they only need be plucked from the trees! On his return to England he convinced the King that breadfruit would be extremely useful in the Caribbean Islands, providing food for the slaves working in the sugarcane plantations - and the botanical ark (alias the Bounty) was sent forth with Sir William Bligh as Captain, Fletcher Christian and crew to obtain the breadfruit tree and bring it back to England. Did you know that the seedless breadfruit was the root cause of the infamous mutiny of the Bounty? Polynesians had perfected the art of rooting these cuttings, but it apparently took the crew of the Bounty many months to achieve success - by which time, the crew had fallen in love with  local Tahitian beauties and were a little reluctant to pull-anchor and sail back to England. Their subsequent mutiny and voyage to Pitcairn Island, where they burnt the boat and thus stranded themselves there (there are no trees on Pitcairn worthy enough to build canoes or boats, so they were totally stuck there) is, as they say, history.

Larger fruited variety.

I've just got back to Wellington from a trip to Samoa to see these trees up-close and personal, and give them a good old hug. I was expecting that each family would have a tree in their garden - but I was not expecting to see as many trees as I did, they were absolutely everywhere! The most common variety had round to ovid fruit, but there seemed to be a fair amount of variation in tree size, leaf shape and fruit numbers/characteristics.

Fugalei Market in Apia, Samoa

The Fugalei market in Apai had the most incredible variety of fruit and vegetables - but I did not see any uncooked breadfruit of these common varieties for sale, possibly because every family has a tree so why buy them? (Breadfruit are called ulu in Samoa). I did however find some breadfruit crisps (which were delicious), and a completely different variety of breadfruit which was huge. It probably weighed 3 kilograms - and I can't imagine how these would be supported by a tree's branches! My Samoan host, Lele, told me this variety is called Aveloloa, which is a bit cheeky in Samoa because it refers to its appearance not unlike a large-woman's breast. Lele self-consciously giggled when she told me the name, and then told me it is traditionally used to make a dish called Taufolo. First the fruit is baked whole in an umu (oven), which is covered with coconut fibres. When the fruit is cooked, it is peeled then mashed and formed into balls. A dipping sauce is then made with coconut cream and sugar, heated with a hot stone from the umu and the Taufolo are dipped into this. Sounds fabulous! Lele's husband Sau prepared an umu-cooked breadfruit for me for my last night on Savai'i island, with coconut cream to dip it into. It was absolutely delicious - it's texture was much softer and creamier than potato.

Me with a large breadfruit variety called Aveloloa at the Fugalei Market in Apia.

In the 1980s, the botanist Dr. Diane Ragone went all through the Pacific collecting different breadfruit varieties and has set up a collection at The Breadfruit Institute, at the National Tropical Botanical Gardens in Hawai'i. She has worked tirelessly to promote this fruit for food security in developing nations, and has worked with a German biotech company who have successfully managed to initiate the plants in tissue culture. A New Zealand company in Auckland is one of only a few worldwide who have managed to micro-propagate the tissue cultures and initiate whole plantlets and I have great hopes that this wonderful plant will soon be propagated en masse to be sent to developing nations in Haiti, Honduras, Caribbean and African nations - so that families and local communities are able to produce food in abundance, much like I saw in Samoa!

Marvellous baobabs!

I don't usually "do" favourite things because I just have such a hard time trying to decide between all the possibilities. But I am decidedly decided on trees - my favourite is most definitely the Baobab. Without equal, it is the most magnificent and grotesque tree you could ever hope to encounter. Swollen trunks, leafless  in the dry season, the trees in Dr Seuss books have nothing on the Baobab!All hands in the air like they just don't care.

This tree is growing in Derby, Australia.

During the rainy season, they soak a huge amount of water into spongy fibers in their massive trunks and roots. They don't grown annual rings like other trees, so while it's generally assumed they live for more than 2000 years, it's impossible to tell.  The upper part of the trunk is often hollow and no doubt used as shelter by nomadic peoples and stock over the ages. In the early pioneering days in the Kimberley, the Boabs (as they are known in Australia) even had gates fitted to the openings in the trunk and were used as prisons! Imagine that?


There is 1 species in Australia, 6 in Madagascar and 1 in the African savannah - proof (if we ever needed more) of the existence of the great southern super-continent Gondwana. I was wishfully thinking I'd like to attend the World Botanical Congress  in Melbourne in late July, and most especially the eight day trek across the Kimberley  from Broome to Kununurra. I've always wanted to go on a guided trek through this bit of Australia - it is home to some of the most spectacular, ancient and diverse flora and fauna in Australia, and it's also smack in the middle of Boab country. Alas at ~NZ$5,000 for the trek, it was a bit too pricey for me at this stage (and has actually been cancelled now), so for now I will just marvel these trees from afar and plan for my adventure another day. A day when I can get up-close in person to a few trees, give them a great big hug and tell them they really are my favourites.

Poroporo update

The poroporo experiment has not been a complete disaster, but you'd have to ignore a few setbacks to agree with me on this point.
The summer was actually quite a hot and dry one this year, which makes a nice change for Wellingtonians, but was not ideal for the garden! I assumed poroporo was weedy enough in it's tendencies to battle on regardless, and so did not make special effort to water them through the really dry periods and they suffered a bit. At one stage I thought they had been attacked by psyllids containing the Solanaceous Liberibacter bacterium, but the brown lesions and wilting were most likely symptomatic of the dry conditions and physiological suffering which attends this. Thank goodness there are no laws against the mistreatment of plants!

We expanded our menagerie in late summer to include two gold-laced Wyandotte hens, whose favourite "in-between-meal" snack seems to be poroporo leaves. And even though the plants behind the chicken coop are now bereft of leaves to a height of one metre, chicken max headroom, this doesn't seem to have set the plants back too much. Indeed, they are no further behind the other poroporo along the back fence which haven't received such close inspection by their Galliform neighbours. There are few flowers, however, which means scant fruit.

I must admit here to being a bit chicken myself. The plant in the front garden, which is now very well established, has been producing ripe fruit for months. Not just ripe but exceedingly ripe, ripe to the point where the skins split open and they fall to the ground and rot. At any point I could intervene in this cycle of life and actually try one, but it took me until yesterday to bolster enough courage to actually do so. And I did. And as a fruit it is quite indifferent. Full of seeds, the orange flesh tastes something like a guava. Actually not unlike the taste of a pepino. I am not convinced they would make good jam. All seedy like raspberry but without the delicious flavour. Jelly perhaps. Cooking the fruit to a mush and straining over night in a jelly bag, and then boiling the next day with sugar to setting point (if there is enough pectin in the fruit) - but I'd need half a kilo of fruit to make a single jar I would think, which looks unlikely this year.

And besides, the first aim of the experiment was science. How long would it take to increase fruit size under selection for larger fruit? I have to own now, having seen the fruit under macroscope, that this is most certainly not going to be a commercial enterprise!

Solanum aviculare - n=23

So following on from last week, where I found out that the chemical oryzalin could be used to accelerate plant breeding by doubling chromosomes - I was attempting to find out whether I needed to obtain a Growsafe certificate in order to obtain the hazardous chemical. Well it turns out that one of my work colleagues happened to be a GrowSafe Instructor in a former incarnation, and most likely has some Surfluran herbicide in his garden shed. So he may just give me a little bit, and then I can try soaking some poroporo seeds in different dilutions this coming season to see if I can double the ploidy. Maybe polyploidy could be a good cheats way to get bigger fruit, faster!

Also today I came across a 1954 paper by Baylis in the Transactions and Proceedings of the Royal Society of New Zealand 1868-1961 which discusses ploidy in Solanum aviculare (poroporo) and S. laciniatum, and guess what? S. aviculare has exactly the same number of chromosomes as humans (n = 23)!! The other New Zealand Solanum, S. laciniatum, has twice the number of chromosomes as poroporo (n = 46). This ensures their genetic isolation. Apparently most Solanaceae have only 12 chromosomes, so this is an example where polyploidy has already occurred (allopolyploidy). Baylis makes the comment that S. laciniatum pollen is larger, its flowers, seeds and stone-cell masses (in the fruit pulp) are larger, and it has deeper corolla colour than poroporo. So this means that if I were to create a straight doubling of chromosomes using oryzalin, to obtain a tetraploid poroporo, it would probably just resemble S. laciniatum. The two aren't cross-breedable back to a triploid (46 crossed with 23, divided by 2 is an odd number, so no going there). I wonder what the maximum number of chromosomes a plant can have? Is 92 a bit excessive, do you think? What about an octoploid (n=92 crossed back with a triploid n = 46 to obtain a pentaploid n=69?). I'm not sure how this would work....

Some additional reading: "Species of this group in Australia are S. aviculare, S. capsiciforme, S. laciniatum, S. linearifolium, S. simile, S. symonii and S. vescum. The 8th species, S. multivenosum, is found in the highlands of New Guinea.
For a treatment of the group as a whole see D.E.Symon (1994). Kangaroo Apples. Solanum sect. Archaeosolanum. (D.E.Symon: State Herbarium of South Australia)."

Solanum laciniatum

Revenge to the killer caterpillars...

Brassicas are high-maintenance. I mean you can plant out a whole patch of silver beet everything runs smoothly, but Brassicas... oh boy, do they ever need some protecting from those infernal cabbage whites!
They're fine in the garden for the winter sowings because the white's simply aren't around. But from late Spring onwards it's virtually impossible to get your kales, cabbages, and broccoli through to harvest without some form of protection.

I don't like to use chemicals, like Derris dust. I would be OK with genetically modified Brassica's, transformed with a Bt gene to express itself in the young plants (killing newly emerged caterpillars at their first wee nibble), but in New Zealand I might be alone on this one. Certainly GE Free NZ and Soil & Health wouldn't share my feelings that these plants would be totally OK to human health and the environment! A good old-fashioned cloche could do the job, or caging the plants in a frame covered in bird-netting to keep the butterflies from unloading their round cargo on the young plants.

Must build something like this for next year.

For this season I've employed another method, which involves hand-plucking caterpillars and feeding them to the chickens.... not terribly effective in preventing damage, but revenge is a dish best served wriggly...

Truffles via Agrobacterium rhizogenes - of course!

I have been musing on how one would go about getting truffle fruiting bodies to form on agar plates, in vitro, and came across a section in Ian Hall's latest book (Taming the Truffle: the history, lore, and science of the ultimate mushroom, co-authored with Gordon Brown and Alessandra Zambonelli) which describes a technique for doing just this.

It would be fair to say I've had a wee obsession with truffles ever since I read The Black Truffle (also by Ian Hall) in my university years. Truffle oils are definitely more in my budget than the real thing, so I can only imagine what they might taste like.  But as to growing them myself - then the whole delightful venture takes on an appearance mid-way between science and magic! The first truffiere set up in New Zealand was in my home town Gisborne, and produced truffles within 5 years of planting. This is really fast - many more truffieres have been planted around the country which are still waiting on their first treasure.

Growing truffles on agar plates is quite possibly a holy grail - ingeniously dispensing of the need to inoculate roots of living trees with the fungus, and all of the orchard set-up and ongoing management.  Instead, infected root is produced using transformed roots which are able to grow without an attached shoot. This kind of system has also been used for arbuscular mycorrhizal fungi, and is described by Varda Kagan-Zur (2006) and colleagues. Derooted rockrose (Cistus incanus) seedlings are inoculated with Agrobacterium rhizogenes, a bacterium that carries the Ri (root-inducing) plasmid which induces root galls on some trees. The roots then produce thin, delicate hairy roots 8-11 days after inoculation, and can be transferred individually to liquid culture medium containing antibiotics.

The inoculated roots are then grown on a solid culture medium containing lower concentrations of antibiotics and nitrates, and transferred to solid media capable of supporting the endomycorrhizal association.   A piece of agar containing actively growing perigord black truffle hyphae is placed in the middle of a bunch of hairy roots growing on solid medium and voila! after 3 months, mycorrhizae forms in the elongated roots, and about 2 months later, short, club-like root forms can be observed. These are then further encouraged to produce truffles, probably even in a commercial way.

Heck of a lot easier than asking a sow to give it up once she's sniffed one out too!!

IAPB - Plant Biotech meeting

I'm just back from Hanmer Springs, where I attended the 19th New Zealand branch meeting for the International Association for Plant Biotechnology. Just loved it! There were some really great presentations on tissue culture, plant developments and new technologies in plant breeding, and Hanmer Springs is the most incredibly scenic place.

I mentally refreshed some of the techniques I used during my time as a Research Associate at AgResearch many years back - using plasmid vectors and restriction enzymes to clone DNA, and PCR to check whether all the pieces went together in the right order. Someone asked a very good question in one talk about whether concatemers were formed, and I knew what they were talking about! My AgResearch work used electroporation techniques to then get the plasmids into E. coli and Mycobacterium bovis (or bovine Tb). But plant transformation uses completely different techniques of course - neither of which I have tried yet. The biolistic guns methods look especially cool - perhaps science would appeal more to school kids if they got to see some of these guns shooting DNA-covered pellets into plants to transform them!  The 007 approach to modern day science!

Another presenter showed how oryzalin can double the somatic chromosome number in plants, from diploid 2n to the tetraploid in Sandersonia, which completely altered the plant's architecture. These were then crossed back with the 2n to obtain an infertile triploid which looked pretty marvelous. I wondered whether this might be a good option for increasing fruit size in my poroporo? Oryzalin is apparently found in the herbicide surfluran, which apparently cannot be bought over the shop counter. I might need to obtain my GrowSafe certificate in order to buy it and use it, so I'll investigate this a bit further.

Another brilliant presentation was the production of mature stigma-like structures from saffron in vitro (on agar plates basically), which release an exudate containing compounds associated with the saffron taste (picrocrocin), aroma (safranal) and colour (crocins) in very pure form.

Another talk discussed the potential for removing viruses, phytoplasmas and bacteria through cryotherapy (a two-step cooling process getting down to temps of -35 to -40 degrees Celcius), where ice nucleation crystals kill the pathogens. This could be useful! And another brilliant talk on micrografting in apples to reduce the breeding time - now that the apple genome has been sequenced and a huge deal of work has been done in mapping the genes and QTLs.

Very inspiring to get among plant scientists again and have a jolly good geek out, and of course enjoy the wonderful surroundings of Hanmer, the hot springs, sunshine and beautiful scenery!

Where have all the sheep gone?

I was talking with a sheep farmer in the Wairarapa last month who has Gotland/merino crossbreeds.  I bought some carded fleece, which had been combed so all the fibres are aligned in one direction, ready for spinning into knitting yarn. I paid $30 a kilo. Jane told me that a wool merchant offered her $17 for the whole fleece! Seeing as a full-grown sheep produces about 5kg of useable fleece, that price seems like daylight robbery and must barely cover the cost of animal husbandry and shearing.

They say that New Zealand was built on the sheep's back. When I was a wee lass in the 70s there were 60 million sheep dotted all over the New Zealand landscape. But the latest figures from MAF show the number has dropped to 32 million. Tourists must be wondering what we've done with them all "Did we eat them?!" 

Wool may have been relegated to the back seat in the era of modern and synthetic fibres, and cheap carpets and clothing are so readily available. But even with this decline, New Zealand still produces 30% of the world's strong wool clip.  In the UK, the value of British fleece to farmers has dropped by about a third in  the past 10 years, so farmers there have started a Campaign for Wool. It's an initiative backed by HRH Prince of Wales who is concerned that British Sheep Farmers have not been getting a fair price for fleece.
“The sad truth is that around the world farmers are leaving sheep production because the price they get for their wool is below the costs of actually shearing it”, he said. The aim of the campaign is to encourage people to buy more British wool, not only for handicrafts such as knitting and crochet, but also to encourage the public to buy British wool clothing as well as larger ticket items such as carpets, and even house insulation.

Wool Partners International, chaired by Theresa Gattung, is a commercial group set up to reinvigorate New Zealand's strong wool industry. Strong wool is wool of 28.5 microns or coarser, and is mostly used for carpets. The wool comes froms breeds like the Romney. Theresa thinks wool shold be a marketer's dream. In New Zealand, we produce the volume and quality needed by markets, backed by an excellent reputation for animal welfare and ethics, and fair employment rules. And of course wool is a sustainable product (totally renewable!). Wool Partners International are hoping to recreate the success of the fine-wool industry in New Zealand, emulating companies like New Zealand Merino Ltd which was formed in the mid to late 1990s to market merino. The company works directly with the clothing manufacturer Icebreaker in New Zealand and SmartWool in the United States, making a range of active outdoor clothing.  Theresa thinks that wool's time has come - again – big time.  I hope so.  Buy wool - wear wool!