Cream chargers containing 8 g of nitrous oxide each (N₂O) to be used with an iSi whipper for whipping cream, making foams/espumas or pressurized infusions.

A little more than a week ago Dave Arnold posted a great, new technique: pressure infusion using a conventional iSi whipper! Just think of it – the whipper has been around for decades, and years a go Ferran Adrià pioneered it’s use for espumas. Several have suggested it’s use for carbonation of fruit. But no one had thought of utilizing the whipper for infusions – until August 11th when Dave Arnold of Cooking issues posted the results of his experiments in “Infusion Profusion: Game-Changing Fast ‘N Cheap Technique”. The first blogger to pick up the technique and post about it on August 12th was Linda of playing with fire and water who termed it a revolutionary technique. A couple of days later, on August 17th Aki and Alex of Ideas in food posted a combined pressurized infusion of basil and marination of mozzarella. And then on August 20th James of Jim Seven describes his results comparing conventional cold brewed coffee to cold pressure brewed coffee. It’s really fascinating how fast the idea spread, and it illustrates the benefits of an open and sharing approach to food innovations.
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For TGRWT #2 I made banana marshmallows with parsley. The texture came out nice, but the initially fresh parsley flavour had become grassy/hay-like over night. The litterature I referred to last time suggested that the off-flavour is produced by oxidation of unsaturated fatty acids or polyenes. There are several strategies to avoid this. The first would be not to mince the parsley as finely as I did last time to avoid exposure to the air’s oxygen. If the oxidation is enzymatic, blanching would be helpful. And it would also be worthwhile to see if addition of lemon juice (vitamin C and citric acid, are both antioxidants) would have any effect (however, on second thought this would be strange since parsley already has a lot of vitamin C!). Mirko Junge commented last time that freeze dried parsley would possibly retain more of the freshness and he most generously provided me with several samples of freeze dried parsley. I decided to proceed with the following six types of parsley for my marshmallows:

1. fresh parsley leaves, chopped to pieces of about 2-3 mm (picture above, left)
2. parsley leaves, blanched for 30 sec, chopped to pieces of about 2-3 mm
3. parsley leaves, sprinkled with lemon jucie, chopped to pieces of about 2-3 mm
4. parsley leaves, blached for 30 sec, sprinkled with lemon juice, chopped to pieces of about 2-3 mm
5. freeze dried parsley from Goutess (picture above, right)
6. plain, dried parsley from my local store (picture above, front)

I used the same recipe as last time, but split the whipped sugar-gelatin-banana mixture into six different bowls before mixing with the parsley. I used approximately 0.6-0.8 g of fresh parsley for each of the entries 1-4. I tried to estimate the amount of dried parsley to use by eye, comparing with the amount of fresh leaves. The amount of dried parsley used was less than 0.1 g, so my balance was not of much help. The picture below might give you an idea.

Six different types of parsley were prepared immediately prior to mixing with the marshmallow base to minimize oxidation.

If the term ‘parallel cooking’ has not been invented yet, this might be good time to introduce it.

I let the marhsmallows set between two sheets of greased parchment paper.

Blind tasting of banana parsley marshmallows.

My wife helped me do a blind tasting to avoid any bias. The six marshmallow samples were each associated with a three digit code and presented on a plate to the taster. We both did two rounds each (A1/A2 and B1/B2) and the results are summarised in the table below. The scoring only describes the parsley flavour unless otherwise noted.

Legend:
5 fresh parsley, strong
4 fresh parsley, weak
2 grassy/hay-like parsley, weak
1 grassy/hay-like parsley, strong
0 neither fresh nor grassy, weak overall
- disagreeable
* banana dominates

I was quite surprised once I had decoded the score sheets. Fresh parsley cut into relatively large pieces gave a parsley flavour without any hints of grassy or hay-like off flavours! Blanching or treatment with lemon juice were both detrimental to the parsley flavour, and even more so when combined. The variation observed for could be a result of an uneven distribution of the parsley in the marshmallow (increased parsley flavour if you happen to chew a leaf). The freeze dried parsley didn’t do very well compared with fresh parsley, but outperformed the dried parsley from my local store which didn’t have much flavour at all. Both samples of dried parsley however were dominated by a grassy/hay-like flavour. I should add that the grassy/hay-like flavour in itself is not especially disagreeable, but it does not go very well together with the banana.

The result is interesting and perhaps a little counter intuitive. Generally one would say that a larger surface area (= finely chopped) would enhance the flavour release. This experiment however shows that this is not universally true, especially if the flavours can be oxidized. So next time you make banana parsley marshmallows remember that less chopping gives better parsley flavour.

A while back I saw Evelin’s post on how to make marshmallows for Valentine’s day, and I knew immediately that I would like to give it a try. With TGRWT #2 coming up (that’s the second round of the food blogging event “they go really well together”), I thought I’d make marshmallows with a banana parsley twist. I figured that the banana flavour should fit very well with the soft and airy, yet elastic texture of marshmallows. And I was very curious to find out how the parsley would fit in!

Marshmallows were originally made using egg whites and the sap of the root of the marshmallow plant which were cooked with sugar and whipped into a foam. Today the marshmallow sap and egg white have been replaced by gelatin which is a protein produced from collagen in the connective tissue of animals. Proteins are good at stabilising foams (see previous post on how to make a Vauqelin). Addition of sugar increases the viscosity which stabilizes the foam even more. In marshmallows this is taken to an extreme. A large amount of gelatin is added to a concentrated solution of sugar (and corn syrup). This mixture is whipped for about 10 minutes to incorporate air and to break up larger air bubbles into smaller ones.

The first challenge was to find a suitable recipe. There are recipes that call for sugar only whereas others call for sugar and corn syrup (this recipe also gives a hint on how to substitute fruit purree for water). Corn syrup is added to prevent crystallization. Also some recipes use egg whites which are said to give a lighter texture. I decided to go for a simple recipe and used only sugar. I would also need to substitute mashed bananas for some of the water. Addition of parsley shouldn’t need any special adjustments of the recipe. I ended up with a recipe which is more or less a mixture of all these.

If you’re unsure about the process of how to make marshmallows, Cooking for Engineers has a detailed step-by-step description with pictures. The pictures at the end of this post should also give you an idea of what the texture is like. If you’re still lost, check out this video (the first in a series of six) on how to make mango marshmallows.

Banana marshmallows with parsley
65 g water
200 g sugar
10 g gelatin, bloomed in plenty of water
65 g banana, mashed
parsley (see comment below on why it shouldn’t be finely chopped)

Bring water and sugar to boil while stirring. Remove from heat when temperature reaches 110-115 °C (230-240 F). Add bloomed gelatin sheets and mashed bananas. Whip for 10 minutes (much longer than you think!). Add parsley to taste. Grease a pan, sprinkle with powdered sugar and spread mixture in pan. When set, invert pan on a surface dusted with plenty of powdered sugar and starch. Cut up in desired pieces and coat every cut surface with powdered sugar and starch.

What about the taste? I tasted the mixture before it set and was surprised by how well the banana and parsley blended together. To be honest, it tasted really nice! The next day however, after I had cut the marshmallows into squares, they tasted quite different. The parsley aroma had changed significantly and was more reminiscent of hay, so I was quite disappointed. The banana flavour was still intact, but I felt it was somewhat weaker than in the fresh mixture. Nevertheless, some guests I served it to reached out for both a second and a third piece of my banana marshmallows with parsley, so they couldn’t have been that bad after all. Perhaps it had to do with the texture which was really, really nice!

It turns out that the hay like off flavour of parsley is well known and described in the litterature! See for instance “Hay-like off-flavour of dry parsley” or “Evaluation of the effect of drying on aroma of parsley by free choice profiling”. The molecule responsible for the hay-like off flavour is 3-methyl-2,4-nonanedione. And apparently vacuum-microwave drying of parsley gives less hay flavour.

It is suggested that the hay like off flavour is formed by oxidation of unsaturated fatty acids or polyenes. As a consequence, I would suggest not to chop the parsley (or at least leave large pieces intact) to limit the exposure to oxygen. After parsley has been added, the mixture should be mixed carefully to keep the leaves intact. I used finely chopped parsley when I made the marshmallows in order to increase the release of volatile compounds from the parsley, and I think this is the main reason why I got the hay like off flavour.

Whip until you get a thick, creamy texture.

Spread in a pan greased with butter/fat and sprinkled with powdered sugar.

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.

If two different foods share one or more volatile molecules, chances are they can taste pretty nice when eaten together. A further discussion of the science behind can be found here. I justed wanted to share a picture of the simplest possible way this can be done. White chocolate/black caviar (top left – this is one of Heston Blumenthals signature combinations!), strawberries and coriander leafs, pineapple and blue cheese, and banana and parsley. Definitely very strange, but when eaten together, the tastes more or less blend together. Convince yourself and try this at home!

Any readers with fantasy to create exciting dishes based on such flavor pairings? Suggestions and links are welcome!