It’s time for a new round of food pairing! Robert of lamiacucina is hosting TGRWT #9 and the foods to pair this time are parmesan and cocoa. I’ve previously blogged about this combination and odor activity values (OAV) are available for both parmesan and cocoa. These are the molecules that significantly impact the odor of both parmesan and cocoa:

Don’t forget to check out Chad’s roundup of TGRWT #8 where several professional chefs participated!

As a late (but just in time for the deadline) response to TGRWT #8 which was announced by Chadzilla in December last year - here is finally my write up on a recipe and a little on the background of this flavor combination which has become a classic in molecular gastronomy.

Heston Blumenthal introduced it around 2002 at The Fat Duck. It’s well worth reading what Heston wrote about this combination back then. He describes how salt can help bring out the flavor of many desserts. At one point he tried caviar and white chocolate - the effect was stunning. He then wanted to find out why this combination was so successful:

I gave some caviar and chocolate to François Benzi, who works for Firmenich, the flavourings and perfumes company based in Geneva. He was so surprised at the way that the caviar and chocolate melded together that he excused himself for half an hour while he tried to discover the reason behind the success of this union.

When he returned, the response was that both the chocolate and caviar contain high levels of amines. These are a group of proteins that have broken down from their amino acid state but not so far as to become ammonia. Amines contribute to the desirable flavours that we find in cooked meats and cheeses, among other things.

Some might object to using caviar but remember that there is no need to turn to sturgeon caviar as this species is endangered. I used caviar from Capelin which costs less than $4/€3 for a box of 50 g. As I have never tasted the “real” stuff I’m not the right person to judge about similarity or difference in aroma. And in case you also wondered about the terminology - roe is the fully ripe egg masses of fish whereas caviar refers to processed, salted roe. I decided to make a soufflé and based the recipe loosely on one of the soufflé recipes in my Larousse Gastronomique.

White chocolate soufflé with caviar
40 g white chocolate
30 g flour
1 dL milk
35 g caviar
3 eggs, separated
nutmeg

Melt chocolate on very low heat. Add 1/3 of the flour and stir, heating gently. Add a 1/3 of the milk and mix thoroughly. Add another 1/3 of the flour, then more milk and so on. Add finely ground nutmeg. Add 3 egg yolks and heat until right before the mixture sets (yeah - I admit - this is not very precise…). Then add the caviar. Beat egg whites stiff and fold them in. Pour into greased soufflé dish and bake at 220 °C for about 15 min.

Verdict: Aromas blend well together, but when eaten alone it’s perhaps a little bland. But I’m quite sure that it could be succesfully incorporated into a menu together with something acidic. The texture was nice, but the soufflé quickly falls together once it’s removed from the oven (I’ll have to post more on the chemistry of soufflés some other time - Hervé This has written a lot about this).

If you try to make this - note that white chocolate doesn’t behave excately like butter when you add the flour. It all got very thick, very fast - that’s why I started adding milk early. I also guess you have to be really careful when heating the whtie chocolate, but I didn’t do any stress tests here.

This is what the mix looks like before I folded in the egg whites.

For my first attempt at this recipe I used 20 g flour and 15 g caviar. The result was that the caviar sedimented before the soufflé had set, besides the fact that one could hardly taste the caviar at all. On my second attempt however, there was enough flour to keep the caviar suspended until the soufflé set. And one could actually also taste the caviar.

And now on to the chemistry behind:
I promised that I would come back with more information about the chemistry behind this pairing, but there isn’t very much information out there. There is one paper on aroma development in block-milk which used in the production of white chocolate. This paper lists a couple of volatiles, but only with their relative peak areas. Turning to caviar (or roe), there is a recent paper on flavor characterization of ripened cod roe, and this paper includes qualitative information about odor intensity.

Comparing the list of volatiles, the following volatiles which contribute substantially to the odor of ripened cod roe are also found in block milk (followed by odor thresholds in water, given in ppb, taken from this page):

2-butanone (50000 ppb)
2-methylbutanal (1 ppb)
3-methylbutanal (0.2-2 ppb)
pentanal (na)

Of these, the first has a high odor threshold, so it’s not likely to be an impact odorant in block-milk (and white chocolate). The methylbutanals however probably contribute to the overlapping aroma of roe and white chocolate. I didn’t find any threshold value for pentanal.

One group of compounds which was not mentioned in the paper on cod roe odor from 2004, but which was mentioned in a Russian paper from 1967 are amines (Golovnya: “Gas-chromatographic analysis of amines in volatile substances of salmon caviar”). Considering the fact that trimethylamine has a threshold in the range of 0.37-1.06 ppb, and that trimethylamine is found in block-milk suggests that it might contribute significantly to the odor of both white chocolate and roe. I guess the reason trimethylamine (and the whole range of other, closely related amines) is not found in the odor analysis in the 2004 paper has to do with the analytical method used.

The fact that amines are crucial is further supported by the Guardian article I quoted from in the beginning where Heston Blumenthal describes how he turned to François Benzi, a flavor chemist at Firmenich, to find out why white chocolate and caviar is such a good match. Benzi concludes that it is due to the presence of similar amines in white chocolate and caviar.

The long awaited website on foodpairings has now been launched, and they’ve also registred the corresponding blogspot name (which isn’t online yet as of today). The beautiful photos, great design and easy maneuvering makes it an excellent place to start if you are looking for some new and perhaps surprising combinations of foods. The foods are grouped into categories such as cocoa (?), dairy, fruits, meat, sea food and vegetables. One of the vegetables listed is cauliflower, and clicking it reveals that the topic of TGRWT #7 (caramelized cauliflower and cocoa) is one of several possible combinations. This is how it is displayed (an important detail is that the shorter the distance between the names, the more flavours they have in common):

(click to open the full picture from the foodpairing.be site)

As an added bonus interchangeable herbs and spices are also listed. This is how it works:

A food product has a specific flavour because of a combination of different flavours. Like basil taste like basil because of the combination of linalool, estragol, …. So if I want to reconstruct the basil flavour without using any basil, you have to search for a combination of other food products where one contains linalool (like coriander), one contains estragol (like tarragon),… So I can reconstruct basil by combining coriander, tarragon, cloves, laurel. The way to use it is to take from each branch of the plot one product and make a combination of those food products.

It should be noted that the proximity of the foods in the diagrams is based on the number of volatile compounds they have in common, not the actual key odorants. As I have elaborated on previously, pairings like these should preferably be based on odor activity values (OAV). Or to put it differently, if the volatiles shared by two foods are not the ones that actually contribute to the overall flavor, there is no reason to expect that they go well together from a chemical perspective (which is not to say that they won’t match, only that if they do, it is for some other reason). This is a limitation both of the foodpairing site, but of course also of the food blogging event They Go Really Well Together (or TGRWT) which I have initiated. Having said this, I still believe that the foodpairing site is an excellent place to start, especially if you like to improvise in the kitchen. I sincerely believe that the site will spark the creativity both of professional and amateur cooks (just like TGRWT already has)! I should add that the website is set up by the people behind Food for Design, so no wonder it looks so good!

Amrita of Le Petite Boulanger has announced the foods to pair for the fifth round: chocolate and meat! And in case you didn’t notice, Dennis has written an excellent summary of the mustard-mint recipes of round four.

I was not able to figure out which odorants actually formed the basis for the mustard-mint pairing (and perhaps there is none… as I’ve touched upon before, some of the data is hard to come at so it’s difficult to check all the entries of my compiled list). At M’s blog however you can find more info on the cold receptors which are triggered by both mint and mustard.

Fortunately data for chocolate and meat is available: odor activity values for cocoa and flavour dilution values for boiled beef and roasted beef. All flavour compounds were ranked and compounds given the same color coding as before. As you can see, there is considerable overlap between chocolate and meat.

(click to enlarge)

And here’s what the molecules that are found both in cocoa and beef look like. Notice that this pairing is dominated by furanones and pyrazines. The molecules are ranked according the the odor activity values in cocoa.

It’s time for the third round of the They go really well together food blogging event (TGRWT #3). Ingredients to pair this time are strawberry and coriander (coriander sativum, also known as cilantro in North America). You can use fresh leaves, whole seeds or ground seeds - it’s all your choice. Deadline is July 1st, so there’s still a couple of weekends left for you to do some experimental cooking. This round is hosted by Evelin at Bounteous bites, so check out her post with instructions on how to participate! She will also post a round-up in due time. And in case you’ve missed it, Tara has posted the round-up of TGRWT #2 featuring banana and parsley.

The first place I saw this combination mentioned at eGullet in a post by Heston Blumenthal. Six impact odorants have been identified for strawberry juice:

(Z)-3-hexenal (green)
2,5-dimethyl-4-hydroxy-3(2H)-furanone (caramel-like, sweet)
methyl butanoate (fruity)
ethyl butanoate (fruity)
methyl 2-methylpropanoate (fruity)
2,3-butanedione (buttery)

The paper “Character-impact aroma components of coriander (Coriandrum sativum) herb” by Cadwallader et al. (couldn’t find any link for this) presented at the 5th Chemical Congress of North America lists (Z)-3-hexenal (green/cut-grass) as an impact odorants based on AEDA (aroma extraction dilution analysis), so there is at least one overlap between the impact odorants of strawberry and coriander (shown below). Please let me know if you should find odor activity values (OAV) for the volatile compounds in coriander. A search at The Good Scents Company also gives many hits for strawberry and coriander.

If you have a hard time finding inspiration for this round, how about Mousses de fraises à la coriandre, Cupcake, Strawberry grapefruit dressing, Strawberry salsa or Strawberry spring rolls?

Good luck!

It’s time for the second round of the They go really well together food blogging event (hereafter referred to as TGRWT #2). Ingredients to pair this time are banana and parsley, which should be an easy match compared to last round with coffee, chocolate and garlic. Deadline is June 1st, so there’s still a couple of weekends left for you to do some experimental cooking. The event and round-up is hosted by Tara over at Should you eat that, so check out her post with instructions on how to participate!

I’ve tried to track down the origin of this pairing. First place I saw it mentioned was by Heston Blumenthal at eGullet, and in an interview with The Independent Heston explains how he discovered it:

He gives an example of this creative process in action. “I was cooking rabbit stew for the kids last summer in France, lifted the lid and threw in chopped parsley and got a smell of banana.” Which prompted him to pair banana with parsley, and banana with tarragon. “It worked really well.”

I have found odour activity values (OAV) for parsley, but not for banana. A search at The good scents company reavels that (Z)-3-hexen-1-yl formate and linalool are present in both banana and parsley. When comparing the OAV data of parsley with a search for banana only at The good scents company oct-1-en-3-one and (Z)-hex-3-enyl acetate were also found. Please post a comment if you have more data on the volatile compounds of this pairing and their OAV values.

In previous posts and comments I have suggested that flavour pairings based on key odorants could be explored by looking at odor activity values (= ratio of volatile compound to it’s threshold). If two foods share one or more key odorants, chances are that they will go well together. It is also reasonable to assume that the more key odorants are shared, the more similar the flavours will be and the more likely it is that the foods will blend well and match each other.

Having initiated the TGRWT event I figured I should try to see if there was any OAV data available for coffee, chocolate and garlic. I was lucky to find OAVs for coffee (both arabica and robusta beans) and cocoa. To compare coffee and cocoa I sorted the flavour compounds in a descending order based on the OAV, keeping only the 20 first compounds. I turned out that 7 out of 20 key odorants in coffee and cocoa are shared, corresponding to 28/25% and 39% respectively of the total “odor activity” (= sum of OAV of top 20 odorants). Here’s the whole list:

(I hope the authors stuck to the IUPAC naming conventions as I did not take the time to check if synonyms were present in the compounds lists)

To compare this with a random pairing I search for more OAVs and found data for parmigiano reggiano and mango, so I repeated the excercise. Among the 20 odorants with the highest OAVs respectively for coffee and mango there was no overlap. A neglibile overlap was found between cocoa and mango: one odorant (linalool) was present in both with OAVs corresponding to 0.03% and 0.05% of the “odor activity” respectively. The fact that there is no overlap between coffee or cocoa and mango does not imply that they don’t go well together, only that their key odorants don’t match. Parmigiano reggiano and cocoa however had a lot in common, as seen from the table below. In fact 6 out of 20 key odorants, representing 36% and 89% of the “odor activity” for parmigiano reggiano and cocoa respectively.

The degree of overlap between parmesan and cocoa is in fact better than for coffee and chocolate when judging by the percentages (albeit with one less odorant), so this pairing will certainly be included in a future TGRWT event! A quick google search revealed that chef Masaharu Morimoto has come up with a recipe combining cocoa and parmesan:

Chocolate Carbonara with Parmigiano Reggiano Cream

Chocolate Pasta:
1 pound all-purpose flour
4 eggs
½ cup cocoa powder
1 Tablespoon olive oil

Pasta Sauce:
2 cups cream
4 egg yolks
½ cup sugar
½ cup Parmigiano Reggiano

For the Chocolate Pasta:
Sift flour and cocoa powder together and knead in the eggs and olive oil for 15 minutes. Rest for another fifteen minutes then roll and cut in a pasta machine. Heat up a pot of lightly salted water and boil pasta until al dente.

For the Pasta Sauce:
In a medium sauce pot scald the cream. In a separate bowl, whisk together egg yolks, Parmigiano Reggiano, and sugar. Temper this mixture into the hot cream and bring to a light simmer, whisking constantly to prevent curdling.

Unfortunately I couldn’t find any OAVs for garlic, so I haven’t been able to verify the triple pairing forming the basis for TGRWT #1. The claim was that coffee has dimethyl sulfide in common with garlic, and methyl pyrazine in common with chocolate. The table above confirms that coffee and chocolate have several methyl pyrazines in common, but dimethylsulfide is not among the 20 key odorants in coffee. This puzzles me, but there could of course be other volatile compounds that garlic shares with coffee. There should also be quite a difference between raw garlic (not to mention between whole, crushed and possibly even minced) and roasted garlic. If I overlooked something (or perhaps a paper with OAVs for garlic), please drop me an email about this. The OAVs of garlic could easily be calculated if data on volatile compounds in garlic and threshold concentrations are available.

I did a search on coffee, cocoa and garlic on The Good Scents Company website as described previously and found the following compounds either naturally occuring or used for recreating the aroma of coffee, cocoa and garlic:

So there are obviously similarities similarities between coffee, chocolate and garlic, but the question is whether these compounds are key odorants or not.

It’s only fair enough to add that the concept of odor activity values has it’s limitations. Some are related to matrix effects, because thresholds are not necessarily recorded in a matrix mimicking the food product. Possible synergies between flavour compounds are disregarded (examples are known where sub-threshold concentrations are detected in the presence of other volatile compounds). Also, the underlying assumption that the odor intensity increases linearily is not quite correct. The typical intensity vs. concentration curve is more ‘S’ shaped with an expansive, linear and compressive region as shown below. At low concentrations (expansive region) synergism (also known as hyperadditivity or mutual enhancement) is observed. At high concentrations (compressive region) antagonism (or subadditivity or mutual suppresion) is observed. This means that a high OAV overestimates and a low OAV underestimates the impact of the individual compounds. This also means that the odor activity percentages calculated for the pairings above should be take with a pinch of salt. In between these extremes normal additivities are observed.

Even though OAVs are not phsychophysical measures of the perceived odor intensity, they compare quite well with models that take different aspects of sensing into accout. The validity of the found OAV can also be tested by a recombination of the flavour compounds to see how good it imitates the original product studied. I can recommend the freely downloadable article “Evaluation of the Key Odorants of Foods by Dilution Experiments, Aroma Models and Omission” (DOI: 10.1093/chemse/26.5.533) for those interested in reading more about the science.

Despite the drawbacks and limitations I think OAVs can and will be helpful when studying the flavour pairing hypothesis.

Tips: You can read more about OAVs in books which are (partly) available through Google books.