Episode 5 Bang Goes the Theory

Welcome to Bang Goes The Theory, bringing you the science

behind the headlines and tackling the issues

that impact all of our lives.

The discovery of horse meat in beef products earlier this year

has prompted some serious investigations.

It's also been a veritable feast for the headline-writers.

On the whole, it's a story of deceit.

Someone somewhere in the supply chain

passing food off for something that it isn't.

And it has brought up a lot of questions about the food industry,

making us all think more about what we're eating

and where it comes from. But for answers,

you need to look at the facts, and that's where the science comes in.

So tonight we're lifting the lid on food technology.

Coming up, I investigate the invisible tricks

used to keep our food fresh.

Whoa! Look at that!

Maggie finds out how science can add gourmet flavour

to bland food.

It's really got a nasty aroma, but it's required.

You need to have it there to give you that nice fried steak aroma.

And Liz discovers the weird things added to our food to keep it looking good.

And what you get is this almost soapy material.

And what this is designed to do

is kind of the same thing that the egg does.

That's Bang Goes The Theory on processed food.

Recent news reports have really made us question what's in our food.

I'm not that concerned about eating horse,

but I am concerned about the labelling issue. So if you buy something that says 100% beef,

that's what you expect it to be. So there's definitely a trust issue there.

The general public are fed up with being conned now.

And they feel conned by the food manufacturers.

They're making a lot of money.

Absolutely shocked, because if they can do that to food,

they could put other things into food that we're not aware of.

When it came to exposing the horse meat fraud,

the forensic weapon in the limelight was DNA analysis.

Without this technology,

identifying minced horse meat in food would have been impossible.

But the horse meat scandal is small

in comparison to what goes on with fish.

The Food Standards Agency has revealed that one in ten fish dishes

are not quite what they seem.

So I'm making my own mystery fish pie

to find out how they're investigated.

Quality fish simply isn't cheap any more.

And food manufacturers have been substituting

fish like prime North Atlantic cod, for example,

in ready meals like fish pies

for cheaper alternatives,

and that's where DNA analysis comes in.

DNA testing for fish is so advanced

that it can identify over 1,000 different species.

So, in theory, it should be virtually impossible

for a rogue species to make it into a dish.

But is it?

OK, so in this pie are several different types of fish,

all bought on the high street,

one of which is a rogue species that's often substituted for cod.

The question is, will DNA analysis

be able to identify all six species correctly?

We've sent our pie to one of the top fish genetics labs in the country

at Bangor University.

OK, so, Mark, here we have the mystery fish pie.

The first stage of their analysis

is to extract and clean the fish meat.

The fish DNA is extracted using ethanol.

Then a specific gene that's present in all fish

is pinpointed, and using PCR, a sort of molecular photocopier,

millions of copies of this genetic bar code are made.

By reading that bar code, they can identify the exact species of fish.

Maggie has gone to Bangor

to get the results from Professor Gary Carvalho,

who runs the lab.

I can't wait to find out whether you've identified the fish in our pie.

Those mystery fish. Neither can I!

I'm even more anxious than you are.

OK, well, based on what we could see in terms of the colour

and the texture of the chunks in the fish pie,

we actually think we have six different species of fish.

And that gets the first big tick, because, as you see on our fish chart,

there are six species.

But have you correctly identified them?

When we get the data back, we have a trace of the sequences.

-So that's one fish there?

-This is the trace from one fish.

Essentially, the DNA is an alphabet of just basically four letters

and it's the combination and the order of those letters

that collectively will tell us specific species.

And over a third of fish species have now been bar-coded

and they are in the reference database.

So it means we can take our mystery unknown sequences,

drop them into the database

and then search for a match.

So what it is telling us, with a very high level of certainty,

it's telling us that the first piece of tissue that we extracted DNA from

belongs to Atlantic salmon.

-Ta-da!

-We have an Atlantic salmon.

Very good! Very good.

The other fish that we've identified

are trout...

Excellent.

And the third fish

we thought was cod.

-Cod.

-And the fourth fish

was haddock.

-OK.

-It is a very tense game.

There's no massive prize, sadly, at the end of this!

I feel as if there should be.

Two to go.

OK.

Now, with the other two, we had difficulties in terms of

-the quality of the sequence.

-OK.

So, one of them we actually thought was not a very good-quality sequence.

Visually, when we took it from the pie,

it looked to us like it could be catfish.

Vietnamese catfish, otherwise known as river cobbler.

But we had it sequenced alongside all of our other samples,

and it came back as a bacterium.

So it can actually, of course, indicate poorly stored fish.

When we think about Vietnam, it's a long distance away,

and the likelihood is of course

that for part of that, or periods of that,

the fish may have been stored above freezing for quite some time.

Well, let's just see if you're correct.

And it is indeed river cobbler.

And of course, this was at the heart of the scandal in fish and chip shops, wasn't it?

Yes, indeed.

River cobbler has been a major culprit actually

of substitution across the world.

Once it's been stored for a period of time,

the white flesh can look something like cod or...

And, of course, it is I think quite readily substituted.

And in our red herring pie,

this was the fish that we wondered whether or not you would spot.

It was quite evident to us, or very likely to be a catfish,

so something we could readily recognise.

The identity of the last species wasn't clear from the first analysis,

but a routine second test did confirm the result.

The quality of the sequence is not up to our usual standard,

but we do have pretty high certainty

that it was monkfish,

based on re-sequencing it more than once.

A re-test also confirmed the river cobbler,

complete with bacterial contamination,

giving Dr Carvalho an impressive six out of six.

We see all these fish on the board here. They're clearly identifiable, easy to distinguish,

but once fish have been processed and filleted,

often prepared in a variety of ways,

it becomes increasingly difficult

to be absolutely certain that what is on the label is what is inside the packet.

Technology like this doesn't just benefit consumers.

It's also helping to tackle illegal fishing

and protect vulnerable fish stocks,

because Professor Carvalho has pioneered a system

that can even pinpoint where certain species were caught.

From this year, all fish and fish products

which is eaten within the EU

will have to be labelled not only with the species,

but whether it's wild or farmed,

and it will have to state exactly where it's been caught.

And with these advances in fish forensics,

it's going to get harder and harder

for the fraudsters to slip through the net.

Thank you very much. Cheers.

So, that's good news for fish eaters,

but you do have to wonder why this technology wasn't used

to avoid the horse meat scandal.

But the thing is, fish testing is very different to meat testing.

In meat testing, you're looking specifically for cross-contamination

with other farmed meats, so you're looking for the DNA of lamb and beef

and pork and poultry,

but not for the DNA of horse.

It was only after a tip-off that they went looking for it,

and unfortunately found it.

But food fakery is only one of the things that worries consumers.

Just look at the produce, and if I think it looks good, I'll buy it.

Spraying your fruit with this or that to make it keep its shine and everything else,

so, yeah, I'm sure there's all sorts of unsavoury practices going on.

One of the tricks of the trade

is to package food in strange atmospheres.

So what's that all about?

Meat is actually packaged quite often in an atmosphere very rich in oxygen -

far more oxygen than we're used to breathing.

Blow this out.

It leaps into flame very easily.

Whoa! Look at that!

Now, the reason for this is for cosmetics.

Just as blood turns a brighter red with oxygen,

so does muscle.

And so, by flooding it with oxygen,

the kind of muscle in there

gets to look much redder than it would normally.

And we think that's the one to buy.

But pre-packaged salads could be the total opposite.

They're packed in atmospheres with very little oxygen.

I'll show you what I mean.

Light this...

and I plunge it into a little...

basket of salad...

It will not stay alight.

And that's because there's no oxygen in there, really.

And so the things that would normally cause the food to rot and decay

can't thrive, so the food stays fresh a lot longer.

We all want to buy fruit and veg at the peak of perfection.

But there's a fine balance between ripe and rotten.

And getting that right is all about another gas -

ethylene.

This is the same gas that plants use to make flowers open,

leaves change colour and drop off in the autumn.

Because ethylene's regarded as dangerous,

it's difficult to get.

So I'm going to make my own,

starting with ethanol.

I need to heat the ethanol in order to vaporise it

and break it down into water and ethylene gas.

What I've collected here should now be pure ethylene gas.

It certainly smells pretty fruity.

And it's phenomenally flammable.

It's harmless to humans, and to fruit, it's a ripening hormone.

I'm adding a quick blast of ethylene here,

just like they do to kick-start ripening

before bananas are delivered to the shops.

From then on, it produces its own and continues the process.

So the timing is critical,

or your banana will end up too ripe too soon.

For fruit distributors like this one,

getting ethylene levels right is crucial.

Working with it as opposed to railing against it

has enabled suppliers to time their fruit and veg deliveries

to near perfection.

Apples are relatively easy to store.

Cold storage does most of the job,

but they're kept separately so their ethylene production

doesn't affect more sensitive fruits.

But pears we want to be much juicier.

They are taken right to the brink of ripeness before packing,

but then held there as long as possible

by these little white patches -

ethylene absorbers -

which mop up the gas inside the packet.

So, when I buy them, should I keep them in the packet that you delivered them,

with their little ethylene absorption patch, and then they'll last longer?

That's exactly what you should do, really.

Just before you want to eat them, about an hour or so,

take them out of the cold fridge, put them on the side.

The temperature changes to room temperature,

and you'll get an enjoyable experience.

For the perfect avocado experience,

the whole process gets much more complicated.

This machine actually checks out every single avocado.

They're kind of tapped and listened to

to find out what they're like inside,

then they're photographed from many angles to find out what they're like on the outside.

And then, from that, a computer deduces

exactly what state each one's in

and whether it's supposed to be eaten in two days

or whether it'll be perfect in a week or ten days.

Avocados don't even ripen at all until they're picked.

But from then on, it's a tricky balancing act

to store them en masse, but also ensure they all get ready together.

It's a combination of temperature control

and these large ethylene absorption pads.

And basically, what this is doing is absorbing the ethylene

from the ones that are ripening quicker than the others.

So it's basically shutting them ones down

in terms of their speed of maturity,

allowing the ones that are less mature to catch up, and so hopefully,

you end up with a much more even sample.

Visiting this packing factory has made me realise

that different kinds of fruit are all speaking the same language.

And it's called ethylene.

And these avocados have to be kept separate

from the apples and pears, to stop them talking to each other,

to stop one releasing ethylene

and telling the others to start ripening and start changing rapidly.

And these things here...

they're almost like kind of mufflers

that absorb the ethylene

to stop them communicating with each other.

It's really about understanding the biology of what we eat

in order to keep it fresher for longer,

so we can get more out of it and hopefully produce less waste.

Which has to be a good thing.

Still to come tonight,

Maggie discovers how scientists can fool us with flavours.

But first, I'm taking a look at the additives

that seem to be in so much of our food.

If you take a look at the list of ingredients in a lot of the stuff that you buy,

chances are there's a whole bunch of things

you've probably never even heard of.

So what are they,

and why do they feature so heavily in foods like these?

-Can I rummage around and have a look at what you might have?

-Yes.

Let me see these. Listen to this.

"Flavourings, colours, E104, E122, E110..."

-Any idea what they are and what they're for?

-No.

When you read a label, you need to be in the pharmacy industry

to understand all the chemicals and other bits and pieces.

"E471, E920,

"emulsifiers and calcium propionate." Any ideas?

No.

-Dextrose - do you know what dextrose is?

-No.

-Do you know what "stabiliser E451" is?

-No.

Why would you want to put stabiliser in chicken? What would it be for? Do you know?

Er...again, I haven't the faintest idea.

The truth is, additives go hand-in-hand with processed food,

which is pretty much everything that isn't a raw ingredient.

A really good example of how additives

can be fairly obvious in foods is salad dressings.

Now, first up, if I make my own at home,

all I'm going to put in is a bit of olive oil

and vinegar.

And then I always bung in a bit of mustard.

And then just give it a good stir.

And that does the job.

No additives needed.

Now, oil and vinegar

don't mix,

but the mustard in my dressing... A - tastes really good,

but B - it acts as an emulsifier.

And what means is there's a chemical in the mustard

that bridges the gap between oil molecules and vinegar molecules

that essentially repel each other

and essentially makes my dressing into an emulsion.

But that doesn't last very long.

Now, as my salad dressing settles,

you can see all the different components -

the oil and the vinegar separating

and also all the mustard seeds have settled

to the bottom.

But if I show you an equivalent salad dressing

that comes from a shop...

There's no separation whatsoever

and all the seeds are suspended throughout.

It looks very different.

But I need just one secret ingredient to get my DIY dressing bottle-ready.

Now, this is E415, or xanthan gum.

It's a very popular additive - it's used in hundreds of salad dressings and sauces.

And it comes from this little bacteria,

Xanthomonas campestris,

and it's what causes the black spots on broccoli and cabbage.

And it uses this gum-like substance

that it secretes to attach to the leaves of the vegetables.

But when that gum is dried out,

it looks like this.

And if I add

a little bit to my dressing and stir...

Look at that already.

I can notice a bit of a difference.

The gum further emulsifies the dressing,

but also surrounds the molecules of oil and vinegar,

stabilising the mixture so that the oil and vinegar can't separate back out.

But xanthan is also a thickener.

It's also made my dressing a lot more viscous

and that means that all the mustard seeds

are now sort of permanently suspended

in my dressing, and suddenly...

these two don't look that dissimilar any more.

Because it's so thick, I can even water it down.

Which not only makes it cheaper to produce,

it also gives you a fraction of the calories per teaspoon.

Xanthan is just one of hundreds of additives used in our food.

Chemistry professor Andrea Sella

is going to show me some

of the most commonly used additives

in mass-produced food

like this Victoria sponge cake.

OK, so what are the challenges

you have to face when you're making cakes on a mass scale?

One of the things you're going to have to worry about is shelf life.

Now, we know that if we leave a cake lying around,

it's going to dry out.

So, for example, there are things called humectants.

These are really edible moisturisers.

A good example of this would be glucose syrup.

Humectants like glucose and glycerin

keep the cake moist, but also stop mould growing

and extend the shelf life.

But mass-produced foods also need to be consistent.

If you think about when you bake at home,

you know, one cake will always be very slightly different from the next.

And a big producer cannot afford that.

Every single cake must come out completely identical.

So what they really need is control.

And this is where emulsifiers come in.

What you get is this slightly sort of...

gloppy, soapy material.

It feels a bit like Vaseline as well.

It certainly feels odd.

And what this is designed to do

is kind of the same thing as the egg does

when you bake a cake,

and that is to control the bubbles within...within your cake.

-But much more than the eggs do?

-And it provides much finer control,

much more careful control.

In fact, what it really does is to ensure

that we will get a consistent structure to the bubbles inside our cake.

So, additives definitely serve a very useful purpose

in the food industry, and when it comes to safety,

of course questions will be raised every now and again.

But every additive that features in our food has been rigorously tested.

And indeed, the "E" in every E number

simply means that the additive has passed European safety testing.

Thanks to the additives in processed foods,

more often than not,

what you're tasting isn't quite what you're eating.

I've come to the University of Reading

to find out how scientists manage to give plain food gourmet flavour.

-So, Maggie, how do you like your steak?

-I'm a medium rare kind of person.

-Excellent.

I'm glad to hear it, because I like...

Today Dr Jane Parker is cooking up a prime pan-fried steak

to show me what makes it so deliciously meaty.

If you are a meat eater, there is nothing like that moment

when the steak goes in the pan and then all...

You start to get aromas coming up already. It doesn't take very long

-till you get that aroma coming off.

-Yes.

And what's happening on the other side is it's starting to go brown.

The basic flavour of food comes from its taste -

bitter, sweet, sour, salty and, if it's meat, umami.

But far more important for flavour

is the food's aroma.

So, yeah, you can stick your nose in and smell that aroma coming off.

So Jane's first step is to identify

the signature components of gourmet steak aroma.

She puts the pieces of steak into a gas chromatograph,

which collects the aroma,

before separating out and measuring every component,

displaying the results on a graph.

Each peak is a single component

that's come from the aroma that's come off the steak.

-Probably at least 100.

-I would say a couple of hundred, easily.

But you could go up to 600 if you looked at absolutely everything that was there.

There's one somewhere here that is a very interesting compound.

People describe it as rotting drains, rotting vegetables,

rotten eggs. It's really got a nasty aroma,

but it's required. You need to have it there

to give you that nice fried steak aroma.

Where do you start when you're trying to recreate something

which can almost con our taste buds into thinking,

"Mmm, delicious meaty flavour"?

Well, the first thing you need to do is work out

which of the peaks are important,

which compounds are actually giving you the aromas that you need.

But giving a delicious flavour to processed food

is more complicated than just adding those aroma compounds.

In something like a steak,

there are specific natural chemicals which react together during cooking,

each combination generating a different aroma.

Those precursor chemicals build up in meat as it matures,

producing an even stronger reaction in the pan.

And that's what gives a quality steak

its rich, gourmet aroma.

It's called the Maillard reaction,

and it gives all cooked foods their signature aroma.

-This is a real art, isn't it?

-Oh, it is.

You need the science, you need the chemistry,

to understand how the flavours are generated.

But there's an awful lot of art in it as well.

You need to have a good nose to be able to create an aroma that's convincing.

One man who can do that

is Dr David Baines.

He's worked out which of the precursor chemicals in a steak

are responsible for those signature aroma peaks.

To reproduce that natural flavour,

he just mixes those chemicals and cooks them.

First, a dash of natural ribose powder.

This is a key sugar in meat.

Next, some cysteine.

This is the powerhouse. This produces hydrogen sulphide.

Then a pinch of glutamic acid,

a natural monosodium glutamate or MSG

and some ribonucleotides.

The ribonucleotides

and the glutamate are what give us...

umami.

-And that's the fifth...

-The fifth taste, yes.

Sweet, sour, bitter, salty, umami.

A dollop of yeast extract adds body.

And it won't work without the water.

At this stage, the mixture has very little flavour,

but that will all change after half an hour in a pressure cooker.

Now, it may seem very artificial,

but this lab flavour could be safer than the real thing.

When you cook a piece of meat,

you do get some substances formed

that have been linked to cancer.

They're formed from a precursor called creatine.

I don't use creatine, so they're not going to be formed.

As you do with a normal pressure cooker...

Finally, it's time to check the results.

I can smell it already.

And here we have it. You see the colour formation's taken place.

Ooh!

I'm not sure whether that's pleasant or not.

That has to be the beefiest beef I have ever smelt.

# Gravy

# On my mashed potatoes give me Gravy... #

Now for the test.

We've taken some bland, pre-sliced beef

with none of the flavour of a prime pan-fried steak

and we're going to see if a few drops of David's potion

can give it a flavour makeover.

Add gravy to each sample, but only those with a blue flag

get gravy containing the flavouring.

Well, they say the proof of the pudding is in the eating, so let's put it to the test.

Excuse me. Do you have a moment to help us with a taste test?

Our guinea pigs are students from the University of Reading.

I asked them which tastes meatier - red or blue?

Red, I think.

I think blue.

Tell me which one is the meatiest.

-Definitely this one, the blue one.

-Really?

-The first one's more meaty.

-So the first one much meatier?

The blue one's really strong, like super-strong,

whereas the red one's quite watery, I find. Not much taste.

80% of the people we asked

thought our enhanced beef was tastier.

-The blue one.

-The blue one. And how did that taste in your mouth compared to the red one?

It's just got more flavour.

In our experiment, we were only using flavourings to make bland meat taste meatier.

But they can also help us in the search

to find new sustainable sources of protein.

Whether it's from meat grown in a test tube,

insects

or mycoprotein,

lab-made flavours could transform alternative sources of protein

into something much more pleasing to the palate.

One thing's for sure - food technology involves a broad and fascinating range of science,

and it is to a great extent driven by the need to keep costs down,

reduce waste and meet customer demand.

Absolutely. And the important thing

is to arm yourself with as much information as possible

so you can decide what you want to eat and what you don't.

-We'll see you next time. Bye.

-Goodbye.

Visit bbc.co.uk for another one of my web exclusives.

And you can follow the links to the Open University

for more information on food importing and the global supply chain.

Subtitles by Red Bee Media Ltd