14 March 2020 | New Scientist | 51VIRUSOWY/ALAMYSam Wong is social media
editor at New Scientist.
Follow him @samwong1Science of cooking online
All projects are posted at
newscientist.com/cooking Email: [email protected]The back pages
GARLIC can be big and fiery or
soft and mellow. Understanding
the chemistry of its flavour can
help us amplify or tame it.
If you sniff a bulb of garlic,
it doesn’t have a strong smell.
But if you bite into raw garlic,
it will produce a pungent aroma
and a burning sensation in your
mouth. This is garlic’s chemical
defence, evolved to deter animals
from eating the plant.
It is caused by a chemical called
allicin, which activates the same
pain-sensing receptors that
respond to the capsaicin in chilli
peppers. Allicin isn’t present in
garlic until its cells are damaged
and stores containing an enzyme
called alliinase break open. The
enzyme acts on alliin, a derivative
of the amino acid cysteine, to
produce allicin.
Allicin has antibacterial
and antifungal properties as it
inhibits enzymes called cysteine
proteases, which pathogens use
to invade the tissues of their hosts.
This is possibly why garlic has
been touted as a medicine for
thousands of years – Hippocrates
recommended it for wound
healing, for example.
Garlic becomes less fiery
when you cook it, because
alliinase is inactivated, stopping
allicin production. Allicin is also
unstable, quickly reacting to form
other odorous compounds. Some
of these can persist in the mouth
for hours after eating garlic,
giving rise to garlic breath. If this
happens, eating an apple or salad
can help, as enzymes found in
many raw fruits and vegetablesconvert these compounds into
odourless molecules.
When we mince or chop garlic,
we damage lots of cells. When we
leave its cloves intact and cook
them slowly, it becomes sweet and
mellow instead. Here are two ways
to prepare garlic that bring out
different sides of its personality.
First, the fiery one: a Lebanese
garlic sauce called toum. Peel two
bulbs’ worth of garlic (roughly
120 grams) and blend in a food
processor with half a teaspoon of
salt. With the blade still running,
slowly add 125 millilitres of
vegetable oil, then a tablespoon
of lemon juice. Repeat until you
have added 500 ml of oil and four
tablespoons of lemon juice in total.
The result should be smoothand mayonnaise-like. Garlic
contains emulsifiers that coat
droplets of fat, allowing them
to become suspended in water,
but the oil must be added very
slowly to make it work. If the
emulsion breaks, add an egg
white to the mixture and
blend again. Toum is a perfect
accompaniment to grilled meat,
roasted vegetables or falafel.
Garlic confit is a great way
to appreciate its mellower side.
Peel two bulbs’ worth of garlic
and cover them with olive oil in
a small saucepan. Cook over a very
low heat for 45 minutes to an hour,
until soft. Keep the cloves in the oil
in a jar in the fridge. Mash them
on toast, add to salads or eat them
with pretty much anything. ❚Understand garlic’s chemistry and you can add sweetness
or fire to your food, says Sam WongPuzzles
Quick crossword,
a river challenge
and the quiz p52Feedback
Thou shalt not troll
and no bad apples:
the week in weird p53Almost the last word
Squirrel antics and
what eats foxes:
readers respond p54The Q&A
Urbasi Sinha on
quantum physics
in a cornfield p56Twisteddoodles
for New Scientist
A cartoonist’s take
on the world p53Sam Wong is social media
editor at New Scientist.
Follow him @samwong1Science of cooking Week 11
Bring out the best in garlic
Science of cooking online
All projects are posted at
newscientist.com/cooking Email: [email protected]What you need
Garlic
Vegetable oil
Salt
Lemon
For next week
Plain flour
Salt
Vegetable oil
Next week
Noodles: get to grips
with gluten for silky,
hand-pulled noodles