Tag Archive for biscuits

Panko panko panko

This might be the most difficult post I’ve ever had to write. Not because of the hours involved in devising recipes, cooking them, photographing them, going through countless databases and articles in order to find some interesting food-related scientific research to write about, actually writing the post, etc. The difficulty is mainly because of the title of the paper I’m writing about:

Overcoming the urge to splurge: Influencing eating behaviour by manipulating inhibitory control.

The 5th word in the title: absolutely the worst word in the English language.

I hate it so much. Who would have thought that a single word, by virtue of the mere sound of its phonemes, could conjure up such grotesque imagery and such a visceral revulsion in a person? I don’t understand how that word isn’t onomatopoeic for the sound of vomiting. It makes me want to vomit, it sounds like the noise people make when vomiting – it would be put to good use if it were employed in that manner.

I also hate the meaning that it stands for: some sort of unjustified failure of self-control, a lapse in good judgement, a lack of consideration and deliberation. People use the word in and of itself to try to attempt to justify their unjustified behaviour, as if the fact that the behaviour has a name means that it’s legitimate. Oh I just spent $900 on an antique Royal Doulton “Bunnykins” tea set from 1954, someone (I don’t know who) might say, but it’s OK – it was a… splurge. OH MY GOD. I would prefer if people just owned up to it and said they made an impulsive, spontaneous, poorly informed decision, but hey, it felt good at the time. It would be even better if they just made an informed, thoughtful, deliberate decision after a long and critical analysis of the pros and cons, but hey – humans as a species are nothing if not impulsive and irrational.

And I should know. Well, I should know something about it, to some limited extent. One of the things I study in my PhD is the ability to control behaviour, albeit in a bit of a simplified way: I use simple computer-based tasks that test people’s ability to withhold a response that they’re used to making. So my research participants press a button as quickly as possible to indicate whether they’ve seen an X or an O flash up on the screen, but sometimes, infrequently, a red box flashes up around the X or the O and that means the participant has to withhold the response they were going to make. This is a measure of a person’s inhibitory control. The greater your inhibitory control, the less trouble you have inhibiting your response when you see that red box, and this is something that naturally varies from person to person. A pretty straight-forward task, seemingly, but incredibly important in daily life – you have to constantly evaluate your environment and change your behaviour accordingly. You don’t want to be driving through a red light because you have trouble inhibiting your foot from pressing the accelerator.

But wow – I never anticipated the potential power of this simple computer task to actually improve people’s inhibitory control in a way that might improve their eating habits. All I needed to do was chuck in some photos of things like cupcakes or chocolate and I could have been doing all my participants a huge favour (and simultaneously wrecking my actual PhD project).

This is what my task looks like:

On trials like the one in the top stream, an X or O pops up and the participant has to respond as quickly as possible to identify the letter. But on trials like the one in the bottom stream, an X or an O pops up followed a fraction of a second later by a red box, the stop-signal, which indicates to participants that they need to withhold the response they were going to make.

If I adapted my task to be like the one used in the urge to spl*rge study by Houben, this is what it would look like:

Sometimes participants might see the top stream – M&Ms flash up and they press a button to indicate that they’ve seen a food item (the alternative is that they might see something like a chair flash up and they press a button to indicate that they’ve seen a non-food item). Other times, participants might see the bottom stream – chips flash up and they go to press a button to indicate that they’ve seen a food item, but then they hear an auditory tone that tells them that they have to withhold that response that they were going to make (again, the stop-signal).

The manipulation here is that one of the 3 different food items that are displayed (chips, nuts or M&Ms) is always paired with the stop-signal, one is never paired with the stop-signal, and one is only paired with the stop-signal 50% of the time. This is to see if participants might be pairing their response inhibition with a particular type of food and perhaps through associative learning they might become better at inhibiting responses to that food in general – maybe if they’re used to inhibiting their response every time they see M&Ms, and you give them some real M&Ms, they won’t be so impulsive and eat so many of them. Maybe.

And yeah, you kind of get that. If you take a subset of participants who have particularly bad inhibitory control (they’re more than 1 standard deviation below average for inhibition speed), you can actually decrease their consumption of the food that was always paired with the stop signal, compared to the food that was paired with the stop-signal 50% of the time (the control condition). So if they were always inhibiting their response to M&Ms but not to chips, after the experiment, they’ll eat fewer M&Ms than they perhaps otherwise would.

However, you have to be careful with this one – it has the power for both good and evil. If you take a subset of participants who have particularly good inhibitory control (more than 1 standard deviation above average for inhibition speed), it seems there is a trend towards them eating more of the food that was never paired with a stop-signal compared to the food that was paired with the stop-signal 50% of the time. So they get used to responding quickly and maybe impulsively to a particular food, and when you actually give them that food after the task, they eat more of it than they perhaps otherwise would.

There you go – if for some reason you desperately want to improve your ability to resist a particular food (have you had to take out a personal loan to finance your Valrhona habit?), all you have to do is spend a few thousands dollars on a computer and some task-programming software like E-Prime or Presentation, spend days or possibly weeks learning how to program a response inhibition task containing photos of the food you want to resist and voilà – if you’ve got poor inhibitory control to start with, you might be better at resisting that food, at least immediately after doing that task. Who knows how long-lasting the effects are? Actually, that would be an interesting study to do.

In the meantime, here are some maple syrup and panko biscuits. For those who don’ t know, panko are Japanese breadcrumbs. Panko’s potential for use in sweet recipes was first brought to my attention by the Chuao Chocolatier panko chocolate bar I tried in San Francisco – I found the bar kind of disappointing because try as I might I could not detect the panko flavour, but I believed it could still work well if done differently, which is why I came up with these biscuits. They’re delightfully crunchy and the panko gives them a nice wheaty flavour and trust me, you do not want to inhibit your eating of them.

Recipe for maple syrup & panko biscuits…

Srs nurrosiense tiem

Have you ever been walking down the street when you stopped dead in your tracks and thought “OH GOD OH GOD HOW DO I TASTE THINGS?!! HOW DOES MY BRAIN LET ME TASTE SALTY PRETZELS UNNNGHHHH OH GOD I DON’T KNOW FFFFFFFFFFFFFWHAT DO I DO?”. I bet you have. I haven’t, but that’s because I do know (in a very rough approximation), although I imagine that if I didn’t know, I would be shrieking and my eyes would be bulging out of their sockets and I would possibly be convulsing in the middle of a road somewhere. Such is life.

So that’s it. It’s neuroscience time. None of this namby-pamby psychology stuff with people reading lists of words and acting ever so slightly differently as a result. We’re getting on a little nano-rocket and riding into the neuron metropolis. I’m a neuroscientist and I’m bringing my A-game. Are you? Yes? Is it folded up in your backpack? Ok.

Right then. After your tastebuds have detected food and the basic information about the food has been transmitted along nerves to the more fancy parts of the brain, what does the brain do? How do the actual neurons in the brain respond, and what sort of information do they respond to?

I’m going to concentrate on just one part of the brain for now – the primary taste cortex, consisting of sections called the insula and the frontal operculum. This primary taste cortex is place where the brain starts to integrate all the different bits of information about food. After this complex processing has begun, the primary taste cortex interacts with a huge range of other brain areas that are involved in the processing and perception of vision, smell and touch (not surprising, given the multisensory experience that is eating).

The other senses also have primary cortices where this sort of processing of sensory information goes on at a higher level, and taste perception shows some striking similarities to perception in the other senses.

For instance, in the primary visual cortex, there are neurons that only fire when you see very particular things. For example, there are neurons that fire in response to a vertical line in your field of vision (the side of house, a flagpole, etc) but don’t fire or decrease their firing below normal in response to a horizontal line (the horizon, the top of a desk, etc), and likewise, there are some neurons that only fire in response to horizontal lines and they’re not so responsive when presented with vertical lines. Neurons can be very specifically tuned and only respond to a very distinct stimulus, or they can be more general and fire in response to a range of stimuli. The same is the case in the primary taste cortex.

In the primary taste cortex, neurons respond to lots of different properties of food. Verhagen and colleagues looked at neurons in the primary taste cortex and how these neurons fired in response to food of varying taste, temperature, grittiness, viscosity and fat texture. They found that neurons can have a very specific profile of stimuli that they actually fire in response to.

Viscosity
53% of the neurons tested fired in response to the thickness or viscosity of food. When the researchers tested different viscosities (using carboxymethylcellulose), some neurons fired more in response to very thick consistencies whereas others fired in response to a runnier consistency.

Grittiness
8% of the neurons tested responded to grittiness as a consistency. So I guess these neurons will be firing like mad if you eat porridge with sand in it.

Fat
Another 8% of neurons tested actually responded to fat, but they identified fat by its texture, not by any chemical method. The researchers figured this out because the same neurons fired in response to non-fat oils that had the same texture as the fats tested.

Temperature
35% of neurons tested responded to the temperature of whatever was in the mouth. The researchers used water at different temperatures (10°C for a chilled drink, 42°C for a warm drink, 37°C for body temperature and 23°C for room temperature) and some neurons fired more in response to particular temperatures than others.

Capsaicin
6% of the neurons tested responded to capsaicin, the hot compound of chilli peppers. The interesting thing here is that these neurons didn’t respond to the warmest water temperature (42°C). So even though capsaicin is experienced as heat, it didn’t result in firing of the neurons that had fired to a warm liquid. However, it turns out that 42°C might have just been an unlucky temperature to choose as the upper limit in the experiment, as capsaicin’s hot effect is achieved through a particular type of receptor that only responds to temperatures greater than… 43°C. So if a hotter liquid had also been used in the experiment, then maybe neurons would have been found that fired in response to the hot liquid and capsaicin.

Taste
And of course, a fair few neurons responded to taste. 56% of neurons tested responded to taste, which was tested using blackcurrant juice (for sweetness), table salt (for saltiness), weak hydrochloric acid (for sourness), quinine (for bitterness) and MSG (for umami).

Now, these neurons didn’t always just fire preferentially for taste or temperature or viscosity or whatever — about half of them fired in response to combinations of these classes of stimuli. For example, 23% of them fired in response to both taste and temperature. A couple of them fired in response to taste and temperature and viscosity and fat. So there was overlap between the groups of neurons involved in responding to the different properties of the food, which allows for a much more complex and nuanced representation of food in the brain.

The interesting thing was that these neurons in the primary taste cortex did not fire in response to odor or the sight of food. This tells us that it isn’t until a later stage that taste information and visual and olfactory information get integrated. And that is indeed what the pathways of sensation in the brain tell us (as seen in the diagram below that I hastily knocked together). It’s rather complicated but hey, that’s the brain for you:

So don’t worry about understanding this whole mess (simply stand back and appreciate the complexity of that soft lumpy thing inside your skull). Just know that arrows indicate the flow of information, and blunt-ended lines indicate an inhibitory effect where the flow of information is dampened. And you can see that in the pink taste pathway, by the time information has gotten to the primary taste cortex from the taste receptors in the tongue, it hasn’t interacted with any of the other pathways. But in the next step, when information flows into the orbitofrontal cortex and amygdala, it has its first chance to interact with information from the other sensory modalities, vision (green), smell (gold) and touch (blue).

The orbitofrontal cortex is also the part of the brain responsible for the representation of the palatability and pleasantness of food, which means that how enjoyable food is probably results from an interplay of visual, taste, olfactory and touch factors. So no matter how delicious that pie tastes, if it happens to look like horse manure then the orbitofrontal cortex just isn’t going to assign as much of a pleasant experience to it.

So there you go. The basics of how the brain processes taste. But as is always the case, it’s a whole lot more complicated than that. When Verhagen and colleagues were looking at the firing properties of neurons in the primary taste cortex, they only reported on the neurons that responded to at least one of the stimuli in the experiment, whether it be a particular taste or viscosity, the presence of grittiness or fat, water of a particular temperature, and so on. In all, they tested 29 different stimuli to see if neurons fired in response. They found 62 neurons that did this. They found 1,060 that didn’t.

What are these other 1,060 neurons doing? What are the other hundreds of thousands of neurons that weren’t tested in the primary taste cortex doing? What do they respond to? What’s their job?

The science continues!

And in the meantime, while you wait, have a HobNob shake. It’s based on the recipe for the Max Brenner cookie shake, lord among shakes that it is. It looks good, it tastes good, it smells good and… well I guess it has a good texture, in the scheme of things. Your orbitofrontal cortex is going to assign awesomeness to this via the striatum so hard.

Read on for the recipe for a HobNob shake.

Taste in the face

There’s no art
to find the mind’s construction in the face.

Macbeth, Act 1 Scene 4

I might be going out on a limb when I suggest that Shakespeare probably wasn’t a neuroscientist. I’m sure I can find some Shakespeare conspiracy theorists to tell me how wrong I am and that Christopher Marlowe was also a talented geneticist in between writing Shakespeare’s work, but for that line in Macbeth to suggest that our faces do not betray our thoughts and feelings and intentions indicates clearly that Shakespeare had a very poor understanding of modern social neuroscience research between the 1970s and 2010. How embarrassing for him.

These are “Old Fashioned” snickerdoodles, based on the sweet and bitter taste combination of the Old Fashioned cocktail. (This recipe is from the book The Boozy Baker, which Dan bestowed upon me after returning from a social cognition workshop via NYC and San Francisco — thanks, Dan!) One interesting bit of research looking and both sweet and bitter tastes found some very intriguing results about how our faces react to those tastes, and also how changing our emotional state changes our ability to perceive tastes. Who would have thought — eating is tied in with feelings! (Hi to all the other emotional eaters out there. Let’s have a piece of cake to celebrate how interesting neuroscience research is!)

In a study by Greimel et al., researchers video-recorded people’s facial expressions as they were drinking either a sweet chocolate drink, a bitter quinine drink, or a bitter-sweet carbonated drink. (The chocolate drink was Müllermilch Schoko and the carbonated drink was Schweppes Bitter Lemon, if you’re planning on replicating this experiment in the comfort of your own home or laboratory.) The researchers later watched these videos and scored a range of particular facial movements (brow lower, lip press, upper lip raise, etc.) to see what people did with their faces when they tasted a bitter or sweet taste.

In a not highly surprising result, sweet and bitter tastes elicited different facial expressions. Bitter tastes warranted brow lowering and lip raising just prior to swallowing, then brow lowering and mouth opening after swallowing, and on the odd occasion, a smile, presumably by the people cynically amused by their unfortunate situation of having to drink something gross like quinine. Sweet tastes reliably resulted in lip sucking before swallowing, lip wiping after swallowing, and of course, smiling (including the Duchenne smile, which is when you smile with your eyes as well as your mouth — yes, it has a name!).

So the specifics are interesting but overall, none of this is all that surprising — we all make the faces too and we’ve all seen other people make the faces. But the other thing the researchers did was that after people had tasted all the different drinks, they were shown one of two movie clips. One group was shown a clip that was intended to make them feel happy, whereas the other group was shown a clip that was intended to make them feel sad. Then — they tasted the different drinks again.

And what did this show? It showed that changing someone’s emotional state makes them perceive tastes differently. More specifically, people who had watched the happy clip then found the sweet chocolate drink even sweeter and more pleasant. People who had watched the sad clip then found the sweet chocolate drink less sweet and less pleasant. How nice this chocolate drink tasted was dependent on whether the person was a bit happier or a bit sadder.

This was not the case, however, for the bitter-tasting drink. Watching the happy movie clip or the sad movie clip didn’t change people’s ratings of how bitter or unpleasant the drink was. A potential explanation of this is that sugary sweetness plays with the neural wiring of our emotions a bit more because the brain wants to reward us for seeking out energy-rich sugar by giving us a pleasant, hedonic experience after we eat something sweet. Bitterness, on the other hand, doesn’t really need that kind of emotional involvement. It might play a role in telling us what foods to avoid, since bitterness can be associated with toxins in the things that our ancestors might have been jamming in their mouths to see if they were any good for eating — but if something is bad for us, and it tastes bitter when we eat it, and then we get physically sick from it, that association between the bitter taste and physical sickness is an association that doesn’t need more subtle emotional prompting from the brain to make us realise to not eat the bitter berries next time or we’ll end up with our stomach contents on our feet. Bitterness also doesn’t reliably tell us much about nutritional value of food. So if we want to learn to avoid something that could potentially kill us, probably better to not just have our brains’ perception of that bad taste be susceptible to our emotional state (and probably better to have a more emphatic response to bad food, rather than our brains just making us a feel a little bit sad after eating something potentially deadly).

So the next time you’re on a hedonic quest for enjoyment through the wonders of cake, chocolate, ice-cream, whatever, pre-emptively enhance your experience by watching something heart-warming or hilarious. If you wish to adhere to the rigours of scientific research, you can even use the exact movie clip used in the experiment in elicit the happy state. It’s this one.

References
Greimel et al. (2006). Facial and affective reactions to tastes and their modulation by sadness and joy. Physiology & Behavior, 89, 261-269.

Recipe for “Old Fashioned” snickerdoodles under the cut.

Cocoa nib biscuits with vodka-soaked cranberries

Still going with the cocoa nibs I got at L.A. Burdick when I was in New York (since they’re kind of difficult to get here in Australia, alas!), because they’re pretty amazing and I want to find the perfect way to showcase them. My experiments so far have shown that they’re best with something that isn’t too sweet (I put them in custard biscuits which are very similar to melting moments biscuits, and wasn’t overjoyed with the results because the sweetness really took away from the nibs) or something that isn’t too chocolately (I put them in chocolate biscuits and it was kind of pointless because then you only really get the typical sweet chocolate taste and it overwhelms the more savoury chocolate flavour of the nibs, which in retrospect seems kind of obvious).

So next on the list for experimenting with were oat biscuits and they have been by far the best for showcasing the nibs, with the right amount of sweetness and a flavour that complements the nibs perfectly. I also decided to add dried cranberries so that their tartness offset the sweetness a little bit further, and then I thought the whole thing seemed kind of rustic, so I soaked the cranberries in vodka as if these biscuits were some sort of Polish peasant recipe (ideally I would have used dried cherries to make it a bit more believable but alas, I didn’t have any, and I don’t know what Polish peasants are doing with cocoa nibs anyway but let’s just pretend).

For the recipe, I just used this oat biscuit recipe but when adding the flour, I also added a tablespoon of sifted Dutch processed cocoa powder. I replaced the glacé cherries and raisins with cranberries (100g dried cranberries which were soaked overnight in vodka, then pressed in a sieve to remove the excess liquid, which is worth reclaiming since you’ll get about 90% of it back and it’ll be a bright pinkish-red and good for use in other recipes) and replaced the chocolate with 100g of cocoa nibs. Nice.