Posts Tagged ‘egg’

Khymos highlights from 2007

Monday, December 31st, 2007

Although I started blogging in August 2006, it wasn’t until 2007 that things got rollin’ so I thought I would post a “metapost” about my first whole year of blogging.

meat in plasticbag, water at 59 C

Most popular blogpost
The most popular post by far this year has been the post on how to achieve a “Perfect steak with DIY “sous vide” cooking”. This is also the post which was most commented, counting 42 comments so far. I really enjoy that this topic has become so popular. Low temperature cooking can make a huge difference in people’s cooking, yet it doesn’t require any sophisticated equipment apart from a thermometer. It’s perhaps the best example of a technical application of molecular gastronomy in a home kitchen.

formula

Most popular static page
The khymos site got a jump start in January as the static page on “How to prepare the perfect boiled egg” made it all the way up to the front page of digg.com (many readers left comments here). It’s amazing how this can drive up the traffic on a site!

hydrocolloid-recipe-collection-frontpage.jpg

Most time consuming post
The single post which took the most time to research and prepare was without doubt the one were I presented the collection of hydrocolloid recipes. I spent quite some time searching for recipes and an equal amount of time formatting and converting them all to metric units and shortening down the text. Reception has been good, and since it was published in August, it has been downloaded more than 7000 times. I hope to publish a revised edition in 2008, and I am of course always eager to hear from you, especially if you have some recipes that you think should be included.

Most fun to write
I blog because I enjoy it. But if had to chose which posts were most fun to research and to write, I think the list would include “Perfect steak with DIY “sous vide” cooking”, “Two flavour pairing case studies”, “New perspectives on whisky and water” and “First experiments with sodium alginate”.

tgrwt-1.jpg

TGRWT
The first round of the food blogging event “They go really well together” was launched in April. Since then 7 rounds have been completed with almost 90 submissions in total! I’ve had a lot of fun both preparing dishes and browsing through the round-ups. The current round is on white chocolate and caviar, and since December has been a busy month for most people (including myself), the deadline has been extended to February 1st. So if you’ve never participated before – why not try out one of the “classic” flavor pairings of molecular gastronomy?

cherry-1.jpg

DMBLGiT
I admit that I am a passionate amateur photographer, and I have submitted a couple of pictures to the monthly “Does my blog look good in this” contest. But with around 100 contributions every month, and most of them of very high quality, I haven’t had great expectations of winning. Therefore it was a pleaseant surprise that my picture of cherries (used to illustrate “Ten tips for practical molecular gastronomy, part 6”) made it all the way to the top of the August 2007 round of DMBLGiT (click to view gallery).

2008 blog forecast
One of the first things I’ll do in 2008 is to complete the series of post with “10 tips for practical molecular gastronomy” which I started in January. Apart from this I have a number of unfinished projects that only need a little more research and experimentation – so let’s hope that I can find some time for this besides my full time job and my family!

A great thing about blogging is that it allows me to interact with the readers – you. So far there are 514 comments to my 112 posts – thank you very much for taking time to comment my posts! Some of you also contact my by email, and I try my best to answer all emails, but if you haven’t heard back from me – don’t hesitate sending me a reminder to webmaster (at) khymos (dot) org!

Because of all the spam comments (67,506 so far!) it’s difficult to say something about the number of people actually visiting the site, but there’s at least a couple of hundred unique visitors every day which is very nice and encouraging. So to all my readers I just want to say Happy New Year! (and in case you missed it, go back and read “Happy New Year with the Science of Champagne!” from last year).

TGRWT #6: Applecake (with too little lavender)

Sunday, September 30th, 2007

apple-lavender-cake.jpg

In the last minutes of the TGRWT #6 I decided to make a simple apple cake and add some lavender. The cake was nice, but I could clearly have used much more lavender. This makes me curious about what experiences the rest of you have made combining apple and lavender.

Apple cake (with too little lavender)
100 g butter
170 g sugar
rind of 1/2 lemon
4 eggs (~210 g)
275 g flour
1 t baking powder
1 dL milk (or cream)
ca. 20 lavender leaves
3-4 apples, thinly sliced
3-4 t sugar

Mix butter and sugar. Add eggs and lemon rind. Mix flour and baking powder and add to the rest. Stir in milk and add lavender. I used leaves for the batter and ca. 15 to decorate the top. Pour batter into greased pan. Insert apple slices. Sprinkle with sugar. Bake at 175 °C for 45-55 min until golden. Cool. Serve with whipped cream.

Two flavour pairing case studies

Saturday, May 5th, 2007

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:

coffee-chocolate-oav.jpg
(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.

parmesan-cocoa-oav.jpg

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:

  • 5-methyl furfural (found naturally in all three, used for coffee and garlic)
  • benzothiazole (found naturally in cocoa, used in all three)
  • 2-furfuryl mercaptan (found naturally in coffee, used in coffee, garlic cocoa)
  • isovaleraldehyde (found naturally in coffee and cocoa, used in all three)
  • ethyl methyl sulfide (found naturally in coffee and cocoa, used in coffee and garlic)
  • bis(2-methyl-3-furyl) disulfide (used in all three)
  • butyraldehyde (found naturally in all three)
  • S-(methyl thio) butyrate (used in all three)
  • isopropyl mercaptan (found naturally in garlic, used in coffee and cocoa)
  • 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.

    intensity-vs-concentration.jpg

    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.

    Dyeing eggs for the easter holiday

    Thursday, April 5th, 2007

    About.com has a nice guide on how to color eggs, and the list of colors is quite impressive (click for instructions):

    Lavender
    Small Quantity of Purple Grape Juice
    Violet Blossoms plus 2 tsp Lemon Juice

    Violet Blue
    Violet Blossoms
    Small Quantity of Red Onions Skins (boiled)

    Blue
    Canned Blueberries
    Red Cabbage Leaves (boiled)
    Purple Grape Juice

    Green
    Spinach Leaves (boiled)
    Liquid Chlorophyll

    Greenish Yellow
    Yellow Delicious Apple Peels (boiled)

    Yellow
    Orange or Lemon Peels (boiled)
    Carrot Tops (boiled)
    Celery Seed (boiled)
    Ground Cumin (boiled)
    Ground Turmeric (boiled)

    Brown
    Strong Coffee
    Instant Coffee
    Black Walnut Shells (boiled)

    Orange
    Yellow Onion Skins (boiled)

    Pink
    Beets
    Cranberries or Juice
    Raspberries
    Red Grape Juice
    Juice from Pickled Beets

    Red
    Lots of Red Onions Skins (boiled)

    More information about the chemistry behind can be found in the article “Chemistry in the dyeing of eggs” (Journal of Chemical Education, 1987, 291). The article discusses anionic dyes with sulfonate groups. These bond to the cuticle (protein) covering the egg shell forming salt linkages as shown (illustrated using FD&C yellow no. 6):

    egg-colouring.jpg

    By lowering the pH (for example by adding vinegar), more amino groups in the proteins covering the egg shell are protonated and thus available for formation of the salt linkages with the anionic dyes.

    Practical molecular gastronomy, part 4

    Saturday, March 17th, 2007


    (Photo by vintage_patrisha at flickr.com)

    4. Learn how to control the texture of food

    Taste and flavour normally get more attention when food is discussed, but the texture of food is equally important and our tongue is very sensitive, not only to taste and temperature, but also to the texture of food. The texture of food determines it’s mouthfeel and it is related to many physical properties of the food. Wikipedia lists the following aspects of mouthfeel (click to see the full description of each aspect) which can be useful when analyzing food:

    Adhesiveness, Bounce/Springiness, Chewiness, Coarseness, Cohesiveness, Denseness, Dryness, Fracturability, Graininess, Gumminess, Hardness, Heaviness, Moisture absorption, Moisture release, Mouthcoating, Roughness, Slipperiness, Smoothness, Uniformity, Uniformity of chew, Uniformity of bite, Viscosity, Wetness

    I will barely scratch the surface of how texture can be controlled by highlighting a couple of topics and point you to further resources. Hopefully it will spark your interest and give some new ideas for you to play with in the kitchen. Those interested in a comprehensive review of food texture are referred to the CRC handbooks on food texture (volume 1: semi-solid foods, volume 2: solid foods).

    What determines the texture of food?
    Put very simple, it’s the relative amounts of air, liquid and solids that determines the texture of food. This is complicated by the fact that liquids have different viscosities. Furthermore the air, liquid and solid ratio is not necessarily constant. A liquid can solidify or evaporate, solids can melt or dissolve, and air bubbles can escape during cooking or storage. An elegant but quite abstract way of describing the complicated mixtures of air, liquids and solids found in food, is to use the CDS formalism (CDS = complex disperse systems), introduced by Hervé This.


    (Photo by Subspace at flickr.com)

    How can texture be controlled and changed?
    Texture can be controlled by temperature, pH, air/liquid/solid ratio, osmosis, hydrocolloids and emulsifiers – to mention a few. Here’s some examples:

  • Heating induces a change in the structure of proteins referred to as coagulation or denaturation. Typical examples are the boiling of eggs and the cooking of meat. When proteins denature they contract and become firmer. There are several helpful tables relating the doneness of different meats to temperature.
  • At around 70 °C (160 °F) collagen, the connective tissue in meat, turns into gelatin. As a result the meat becomes more tender, which is desireable in stews and other slow cooked meats.
  • Heat causes air/gas to expand and water to evaporate to give a foamy/airy texture. For example, experiments have shown that it is mainly the evaporation of water that causes a soufflé to rise.
  • Heat will cause certain hydrocolloids to solidify (for exaple methyl cellulose) whereas it will cause others to melt (such as gelatin).
  • Brining meat can greatly improve it’s texture and juicyness. This is done by immersing the meat in a 3-6% salt solution from anyhere between a few hours to two days before cooking.
  • Frozen water in the form of tiny ice crystals are important for the smooth texture of sorbets and ice cream. Ice cream that has been partly melted and frozen again will grow larger ice crystals that impart a coarser texture to the ice cream.
  • Acidic solutions (low pH) can cause proteins to denature. This allows fish to be cooked without the use of any heat. An example is the use of lime juice in ceviche.
  • Emulsifiers, thickeners and gelling agents have almost become synonymous with molecular gastronomy for many. They can greatly alter the texture of foods and typically only a very small amount is required. Where gelatin was the only gelling agent videly available to cooks in Europe and America only a decade ago, this has changed with the advent of many internet suppliers of speciality ingredients.
  • Cooking under vacuum can create new and exciting textures. First of all it’s a way of removing excess water without having to raise the temperature all the way up to 100 °C. When the water is removed, this will create pockets of air in the food, and when the pressure is released, the liquid surrounding the food that is prepared will rush in and fill these pockets. There is a commercially available vacuum cooker, but a DIY version can be made from a pressure cooker and a vacuum pump.

  • (Photo by Trinity at flickr.com)

  • Green leaf vegetables such as lettuce loose water upon storage. As the pressure inside the cells drops, the leaf becomes softer. By immersing the leaves in cold water for 15-30 min, thanks to osmosis, water will enter into the cells again. As the pressure increases, the leaves become crisper.
  • Air bubbles can greatly modify textures, and foams really are ubiquitious (which becomes obvious if you read the book “Universal foam – from cappuccino to the cosmos”). Ferran Adria’s espumas have become very popular, as has his recent invention, the Espesso. Air bubbles are also very important for the texture of ice cream, in fact ice cream is nearly 50% air (just consider the fact that ice cream is sold by volume, not by weight!).
  • A very recent addition to the modern kitchen pantry is the enzyme transglutaminase. The enzyme acts like a meat glue and Chadzilla has nice blog post on his transglutaminase experiments.
  • There are also enzymatic counterparts of transglutaminase available: proteolytic enzymes also known as proteases. You can find them in pineapple (bromelain/bromelin), papaya (papain), figs (ficin) and kiwi (actinidin) – and they are capable of degrading proteins and muscle tissue. Despite this, they have only found limited use in marinades, as their action can be difficult to control (as Nicholas Kurti experienced, look for the “But the crackling is superb” link).
  • When mixing flour and water, glutenin and gliadin react to form gluten which gives bread it’s elasticity and plasticity. Addition of 1-2% salt to bread tightens the gluten network and increases the volume of the finished loaf. Similarly, addition of 1% oil to the dough (after the first kneading) can further increase the volume. Larger amounts of fat added before kneading will interfere with the formation of long gluten strands, hence the name shortening.
  • The no-knead bread that recently hoovered around in the blogosphere challenges the conventional wisdom that bread needs kneading to get a good texture.
  • Once bread is baked, the staling process starts. Staling does not necessarily involve loss of water from the bread and is caused by crystallisation (or retrogradation) of starch. In this process water molecules are trapped. The process proceeds fastest at 14 °C, but is halted below -5 °C. This is the reason why bread should be stored at room temperature. The staling process can be slowed down by addition of an emulsifier such as lecithin which is abundant in egg yolk.
  • A way of turning high fat foods and oils into powders is by the use of tapioca maltodextrin. Hungry in Hogtown has shown how Nutella can be turned into a powder.
  • *

    Check out my previous blogpost for an overview of the tips for practical molecular gastronomy. The collection of books (favorite, molecular gastronomy, aroma/taste, reference/technique, food chemistry) and links (webresources, people/chefs/blogs, institutions, articles, audio/video) at khymos.org might also be of interest.

    Egg white foam + microwave = Vauquelin

    Sunday, February 4th, 2007

    By beating air into an egg white you can increase it’s volume by a factor of approximately 8. Hervé This has shown that water is the limiting component. By adding more water you can significantly increase the volume. Addition of sugar further stabilises the foam by increasing the viscosity of the water. A very simple dessert kan be made by whisking egg whites with sugar and berries of your choice. In Norway we refer to this as “Troll cream”. There’s more on this over at eriks-food-ucation.blogspot.com. An interesting question for you to ponder upon is in what order egg whites, berries and sugar should be mixed to maximize the volume!

    But there is more to such a foam than trolls! For the following experiment, use one eggwhite and a berry syrup of your choice – I used a blueberry syrup (approximately 1,5 dL). Start by whisking the egg white. Add the syrup slowly over 5-10 min while constantly whisking. Observe how the volume increases dramatically. When I did the experiment I got roughly 2 L of foam (which corresponds to a 40-50 fold increase in volume). Make sure you use a clean bowl, preferably one of metal as fats and oil cling very well to plastic bowls.

    vauquelin-1.jpg

    Now comes the fun part: Put some of the egg white foam onto a plate and place it in a microwave oven to make the proteins set! Hervé This described this in a recent article and decided to name this dish “Vauquelin” after the french pharmacist and chemist Louis Nicolas Vauquelin. It does take some experimentation to find a proper combination of the power setting and the time needed for the Vauquelin to set. If you overdo it, the foam will just collapse. I used the 360W setting and 4 seconds for the Vaquelin in the picture below.

    vauquelin-2.jpg

    Cutting through the Vauquelin with a knife leaves a trace which does not refill.

    vauquelin-4.jpg

    Scooping out with a spoon also gives you an impression of the texture.

    vauquelin-3.jpg

    Instead of blueberry syrup you can try other liquids. Hervé This suggests orange juice or cranberry juice (both require addition of sugar). Liquours also work fine (although my experimentation suggests that the volume increases somewhat less), but remember to add sugar as this stabilises the foam and rounds of the taste.

    Chocolate sauerkraut cake

    Sunday, January 14th, 2007

    After giving a presentation about molecular gastronomy I was asked if I had ever heard about a chocolate cake baked with sauerkraut. I admitted that this was new for me, but that I would be very interested in the recipe. Could it be that this is a new flavor/flavour pairing? Remember, the hypothesis is: if the major volatile molecules of two foods are the same, they might taste (and smell) nice when eaten together. Perhaps there’s some one out there with access to a headspace gas chromatographer that could check this out? Or perhaps someone who has access to the Volatile Compounds in Foods database could do a quick search? If you’re unfamilier with such flavor pairings, another nice pairing with chocolate is the one with caramelized cauliflower and chocolate jelly.

    I did get the recipe and it turned out that it was from a cookbook called “Food that really schmecks” by Edna Staebler. The book is a collection of recipes from the Mennonite community in Ontario. Many Mennonites came from Germany, hence the word “schmecks” in the title which is German (zu schmecken = to taste). According to the cookbook, leftover sauerkraut makes the cake moist and delicious – which I can certainly confirm! And the strange things is you can’t really taste the sauerkraut. Here is the recipe (the way I made it):

    Sauerkraut chocolate cake
    170 g butter (ca. 3/4 cup)
    300 g white sugar – less than the 1 1/2 cups in the original recipe
    3 large eggs
    1 teaspoon vanilla (either essence or vanilla flavored sugar)
    2.5 dL water (= 1 cup)
    6 dL flour (= 2 1/2 cup)
    1.3 dL unsweetened cocoa (= 1/2 cup)
    1 teaspoon baking powder
    1 teaspoon soda (sauerkraut is sour, therefore the recipe calls for soda!)
    1/2 teaspoon salt
    330 g drained  sauerkraut (1 1/2 cup) – more than in the original recipe

    Mix butter and sugar. Add eggs, water and dry ingredients. Stir in the sauerkraut and pour batter into greased pan. Bake at 350 F/180 C for 30-50 minutes.

    chocolate-sauerkraut-cake

    The cake was a little too moist in the center when I made it and could have needed a couple more minutes in the oven. Make sure you check if it’s all set by inserting a wooden match or a knitting pin in the center of the cake!

    Interestingly, the cookbook “Food that really schmecks” was recently presented in the blog Cream Puffs in Venice, with the following statement attached: “There is no haute cuisine or molecular gastronomy to be found here”. But chocolate and sauerkraut might turn out to be another flavor pairing based on sound chemical reasoning.

    Update: Read the followup on this post with more about chocolate and caraway (the main spice in sauerkraut)

    TGIF: Molecular gastronomy with a twist

    Friday, November 17th, 2006

    Heston Blumenthal was recently featured in “Private Eye”, a british satire magazine (found via Aidan Brooks). They included the following recipe for boiled eggs:

    heston blumensilly

    A further discussion of boiled eggs from the perspective of molecular gastronomy is found here.

    Perfect eggs?

    Sunday, October 22nd, 2006

    I just came across this fancy egg boiler. It’s designed by Simon Rhymes and bears the name BEM. The egg is cooked in about 6 minutes by the heat from 4 halogen light bulbs with a total output of 500 W.

    bem.jpg

    It sure looks fancy, but I doubt that these eggs can rival the texture of those prepared by the low temperature methods I have described. The reason for this is that the halogen lamps heat up the eggs above the temperature required for the white and the yolk to set. This gives the white a rubbery texture. And even though the BEM has a timer, you still have to figure out (by experimenting?) for how long to cook your eggs…

    I think the best part is the cutting ring with a 125 g mass which is raised and dropped to create a crack around the top of the egg. But there is no need to buy the BEM, because a similar egg cracker can be bought separately here for instance! You place the cup on top of the egg, raise the steel ball and drop it. The energy is transferred to the egg, creating a perfectly circular crack. This is actually very neat!

    clack-egg-punch.jpg