Thermoreversible No-after gelatinizing, the amylose is leached out from the original starch molecules.

Lemon Meringue PieLike many savory foods in which multiple discrete components are combined to create the dish, lemon meringue pie is the combination of three separate components: pie dough, a meringue, and a custard-like filling. We've already covered pie dough (Simple Pie Dough in in Chapter5 Chapter5) and meringues (French and Italian Meringue in in Chapter5 Chapter5), so the only thing left for making a lemon meringue pie is the filling itself. Flip to those recipes for instructions on how to make the pie dough and meringue topping.[image]To make the lemon custard, place in a saucepan off heat and whisk together: - 2 cups (500g) sugar cups (500g) sugar - cup (100g) cornstarch - teaspoon (5g) salt Add 3 cups (700g) of water, whisk together, and place over medium heat. Stir until boiling and the cornstarch has set. Remove from heat.In a separate bowl, whisk together: - 6 egg yolks Save the whites for making the meringue. Make sure not to get any egg yolk in the whites! The fats in the yolk (nonpolar) will prevent the whites from being able to form a foam when whisked.Slowly add about a quarter of the cornstarch mixture to the egg yolks while whisking continuously. This will mix the yolks into the cornstarch mixture without cooking the egg yolks (tempering). Transfer the entire egg mixture back into the saucepan, whisk in the following ingredients, and return to medium heat and cook until the eggs are set, about a minute: - 1 cup (240g) lemon juice (juice of about 4 lemons) - Zest from the lemons (optional; skip if using bottled lemon juice) Transfer the filling to a prebaked pie sh.e.l.l. Cover with Italian meringue made using the six egg whites (double the recipe in French and Italian Meringue French and Italian Meringue in in Chapter5 Chapter5, which is for three whites), and bake in a preheated oven at 375F / 190C for 10 to 15 minutes, until the meringue begins to turn brown on top. Remove and let cool for at least four hours-unless you want to serve it in soup bowls with spoons-so that the cornstarch has time to gel.[image]To create decorative peaks on the meringue, use the back of a spoon: touch the surface of the unbaked meringue and pull upward. The meringue will stick to the back of the spoon and form peaks.NoteGelling agents typically come as a powdered substance that is added to water or whatever other liquid you are working with. Upon mixing with the liquid, and typically after heating, the gelling agent rehydrates and as it cools forms a three-dimensional lattice that "traps" the rest of the liquid in suspension. By default, add your gelling agent to a cold liquid and heat that up. Adding gelling agents to hot liquid usually results in clumps because the outer layer of the powder will gel up around the rest of the powder.

Making gels: Carrageenan Carrageenan has been used in food as far back as the 15th century for thickening dairy products. Commercial ma.s.s production of carrageenan gums became feasible after World War II, and now it shows up in everything from cream cheese to dog food, where it acts as a thickener. Modernist cuisine dishes use it for the same reason, although typically to thicken liquids into gels in ways that we might not think of at first glance (beer gel, anyone?).

- Instructions for use.Mix 0.5% to 1.5% carrageenan into room-temperature liquid. Gently stir liquid to avoid trapping air bubbles into the gel; lumps are okay at this stage. (They're hard to get out unless you have a vacuum system.) Allow to rest for an hour or so; carrageenan takes a while to rehydrate. To set carrageenan, bring to a simmer either on a stovetop or in an oven. If you are working with a liquid that can't be heated, create a thicker concentration using just water, heat that, and then mix it into your dish.

- Uses.Carrageenan is used to thicken foods and to control crystal growth (e.g., in ice cream, keeping ice crystals small prevents a gritty texture). Carrageenan is commonly used in dairy (check the ingredients on your container of heavy whipping cream!) and water-based products, such as fast-food shakes (keeps ingredients in suspension and enhances mouth-feel) and ice creams (prevents aggregation of ice crystals and syneresis, the expulsion of liquid from a gel).

- Origin and chemistry.Derived from seaweed (such as Chondrus crispus Chondrus crispus-common name Irish moss), carrageenan refers to a family of molecules that all share a common shape (a linear polymer that alternates between two types of sugars). The seaweed is sundried, treated with lye, washed, and refined into a powder. Variations in the molecular structure of carrageenan cause different levels of gelification, so different effects can be achieved by using different types of carrageenan (which, helpfully, grow in different varieties of red seaweed). Kappa carrageenan (k-carrageenan) forms a stronger brittle gel, and iota carrageenan (i-carrageenan) forms a softer brittle gel.

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On the molecular level, carrageenan, when heated, untangles and loses its helical structure (left); when cooled, it reforms helices that wrap around each other and form small cl.u.s.ters (right). The small cl.u.s.ters can then form a giant three-dimensional net that traps other molecules.

Technical notes i-carrageenan k-carrageenan Gelling temperature 95149F / 3565C 95149F / 3565C Melting temperature 131185F / 5585C 131185F / 5585C Gel type Soft gel: gels in the presence of calcium ions Firm gel: gels in the presence of pota.s.sium ions Syneresis No Yes Working concentrations 0.3% to 2% 0.3% to 2%

Notes.

Poor solubility in sugary solutions Interacts well with starches Insoluble in salty solutions Interacts well with nongelling polysaccharides (e.g., gums like locust bean gum) Thermoreversible Yes Yes

Gelled Milk with Iota and Kappa CarrageenanThis isn't, in and of itself, a tasty recipe (add some chocolate, though, and you've got something close to commercial prepackaged food). Still, it will give you a good sense of what adding a gelling agent does to a liquid and provides a good comparison between soft and brittle gels.Flexible brittle versionIn a saucepan, whisk to combine and then bring to a boil: - 1 teaspoon (1.5g) iota carrageenan - 3.5 oz (100 ml) milk Pour into a gla.s.s, ice cube tray, or mold and chill in the fridge until set (about 10 minutes).Firm brittle versionAgain in a saucepan, whisk to combine and then bring to a boil: - 1 teaspoon (1.5g) kappa carrageenan - 3.5 oz (100 ml) milk Pour into a second gla.s.s, ice cube tray, or mold and chill in the fridge until set.Notes - Try modifying the recipe by adding 1 teaspoon (4g) of sugar, subst.i.tuting some cream for a portion of the milk, popping the mixture into a microwave for a minute to set it, and pouring it into a ramekin that has a thin layer of jam or jelly and toasted sliced almonds on the bottom. Once gelled, invert the set gel onto a plate for something roughly approximating a flan-style custard.

- Since the carrageenan is thermoreversible (once gelled, it can still be melted), you can take a block of food gelled with kappa carrageenan, slice it into cubes, and do silly things like serve it with coffee or tea (one lump or two?).

- You can take a firm brittle gel and break up the structure using a whisk to create things like thick chocolate pudding.[image]

Making gels: Agar Agar-sometimes called agar-agar agar-agar-is perhaps the oldest of all the food additives commonly used in industry, but has only recently become known in western cuisines, mostly as a vegetarian subst.i.tute for gelatin. First used by the j.a.panese in the firm, jelly-type desserts that they're known for, such as mizuyokan mizuyokan, agar has a history stretching back many centuries.

When it comes to playing with food additives, agar is one of the simplest to work with. You can add it to just about any liquid to create a firm gel-a 2% concentration in, say, a cup of Earl Grey tea will make it firmer than Jell-O-and it sets quickly at room temperature. It comes in two general varieties: flakes or powder. The powdered form is easier to work with (just add to liquid and heat). When working with the flake variety, presoak it for at least five minutes and make sure to cook long enough so that it breaks down fully.

- Instructions for use.Dissolve 0.5% to 2% agar by weight in cold liquid and whisk to combine. Bring liquid to a boil. As with carrageenan, you can create a thicker concentrate and add that to a target liquid if the target liquid can't be boiled. Compared to carrageenan, agar has a broader range of substances in which it will work, but it requires a higher temperature to set.

- Use.Agar is a gelling agent, used in industry in lieu of gelatin in products such as jellies, candies, cheeses, and glazes. Since agar is vegetarian, it's a good subst.i.tute in dishes that traditionally call for gelatin, which is derived from animal skins and bones. Agar has a slight taste, though, so it works best with strongly flavored dishes.

- Origin and chemistry.Derived from seaweed. Like carrageenan, agar is a seaweed-derived polysaccharide used to thicken foods and create gels. When heated above 185F / 85C, the galactose in agar melts, and upon cooling below 90104F / 3240C it forms a double-helix structure. (The exact gelling temperature depends on the concentration of agar.)During gelling, the endpoints of the double helices are able to bond to each other. Agar has a large hysteresis; that is, the temperature at which it converts back to a gel is much lower than the temperature at which that gel melts back to a liquid, which means that you can warm the set gel up to a moderately warm temperature and have it remain solid. For more information on the chemistry of agar, see http://www.cybercolloids.net/library/agar/properties.php.

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Agar at the molecular level. When heated, the molecule relaxes into a relatively straight molecule (upper left) that upon cooling forms a double helix with another agar molecule (center). The ends of these double helices can bond with other agar double helices (upper right), forming a 3D mesh (left).

Technical notes Gelling temperature 90104F / 3240C Melting temperature 185F / 85C.

Hysteresis 140F / 60C.

Gel Type Brittle Syneresis Yes Concentrations 0.5%2% Synergisms Works well with sucrose

Notes.

Tannic acid inhibits gel formation (tannic acid is what causes overbrewed tea to taste bad; berries also contain tannins) Thermoreversible Yes

Chocolate Panna CottaAgar can be used to provide firmness, as this example shows. In a saucepan, whisk together and gently simmer (below boiling-just until small bubbles form on surface) for one minute: - 3 oz (100g) milk - 3 oz (100g) heavy cream - pod vanilla bean, sliced lengthwise and sc.r.a.ped - 8 teaspoons (20g) powdered sugar - 1 teaspoon (2g) agar powder Turn off heat, remove vanilla bean pod, and add, briefly stir, and let rest: - 3.5 oz (100g) bittersweet chocolate, chopped into fine pieces to a.s.sist in rapid melting After a minute, add and whisk to thoroughly combine: - 2 eggs yolks (reserve whites for some other recipe) Pour mixture into gla.s.ses, bowl, or molds and store in fridge. The gel will set in as little as 15 minutes, depending upon the size of the mold and how long it takes the mousse to drop below agar's setting point (around 90F / 32C).Notes - The agar provides a firmness that creates a stronger mousse than that created when using gelatin, so you should plan to use this mousse in applications where firmness is a desired trait.

- This chocolate mousse, while good by itself, really works better as a component in a dish. Example uses: roll a ball of the mousse in toasted nuts to create a truffle-like confection, spread a layer of the mousse into a prebaked pie crust and top with raspberries and whipped cream, or smear a thin layer of the mousse in the bottom of a bowl and place a small scoop of vanilla ice cream and some fresh fruit on top.

- When working with a vanilla bean, use a spoon or the edge of a knife to sc.r.a.pe the seeds from the pod, and add both pod and seeds to your mixture. Sc.r.a.ping the bean helps get the vanilla into the mixture more quickly.

Rum Screwdriver GelIn a small mixing bowl, measure out: - 8 teaspoons (40g) rum In a saucepan, whisk to combine, and bring to a boil and hold for an additional minute: - 10 teaspoons (50g) orange juice - cup (40g) sugar - 1 teaspoon (2g) agar powder Pour the hot liquid into the small mixing bowl, and stir thoroughly to combine. Transfer mixture to a gla.s.s, ice cube tray, or other food mold and store in fridge for 30 minutes or until set.Notes - Yes, these are basically rapid-setting Jell-O shots. Using agar allows for a higher percentage of alcohol-you can gel rum by itself if careful-but make sure to leave enough juice in for flavor.

- Play with subst.i.tutions. You can replace the rum and orange juice with fluids such as Malibu and coconut milk.

Making gels: Sodium alginate The gels covered so far are all h.o.m.ogenous h.o.m.ogenous, in the sense that they are incorporated into the entire liquid and then set with heat. Alginate, however, sets via a chemical reaction with calcium, not heat, which allows for an interesting application: setting just part of the liquid by localized exposure to calcium.

This is done by adding sodium alginate to one liquid and calcium to a second liquid and then exposing the two liquids to each other. The sodium alginate dissolves in water, freeing up the alginate, which sets in the presence of calcium ions, which will only occur where the two liquids touch. Imagine a large drop of sodium alginatefilled liquid: the outside of the drop sets once it has a chance to gel with the a.s.sistance of the calcium ions, while the center of the drop remains liquid. It's from this application that the technique called spherification spherification is derived. is derived.

- Instructions for use.Add 1.0% to 1.5% sodium alginate into your liquid (use water for your first attempt). Let the liquid rest for two hours or so to hydrate fully. It will be lumpy at first; don't stir or agitate the liquid, as doing so will trap air bubbles in the mixture.It's probably easiest to add the sodium alginate a day in advance and let it hydrate in the fridge overnight.In a separate water bath, dissolve calcium chloride to create a 0.67% solution (about 1g calcium chloride to 150g water).Carefully drip or spoon some of your sodium alginate liquid into the calcium bath and let it rest for 30 seconds or so. (You can use a large "syringe" dripper or turkey baster to create uniformly sized drops.) If your shape floats, use a fork or spoon to flip it over, so that all sides of it are exposed to the calcium bath. Remove from bath, dip into another bowl of just water to rinse off any remaining calcium, and play.Sodium alginate gels firm up over the span of a few hours, so you'll need to make these near when you intend to serve them.If your sodium alginate sets without exposure to the calcium bath, use filtered or distilled water. Hard water is high in calcium, which can trigger the gelling reaction.

- Uses.The food industry uses alginate as a thickener and emulsifier. Since it readily absorbs water, it easily thickens fillings and drinks and is used to stabilize ice creams. It's also used in manufacturing a.s.sembled foods; for example, some pimento-stuffed olives are actually stuffed with a pimento paste that contains sodium alginate. The olives are pitted, injected with the paste, and then set in a bath with calcium ions to gel the paste.

- Origin and chemistry.Derived from the cell walls of brown algae, which are made of cellulose and algin. Alginates are block copolymers composed of repeating units of mannopyranosyluronic and gulopyranosyluronic acids. Based on the sequence of the two acids, different regions of an alginate molecule can take on one of three shapes: ribbon-line, buckled shape, and irregular coils. Of the three shapes, the buckled shape regions can bind together via any divalent cation. (A cation is just an ion that's positively charged, i.e., missing electrons. Divalent Divalent simply means having a valence of two, so a simply means having a valence of two, so a divalent cation divalent cation is any ion or molecule that is missing two electrons.) is any ion or molecule that is missing two electrons.) [image]

Alginate does not normally bind together (left), but with the a.s.sistance of calcium ions is able to form a 3D mesh (right).

Gel "Noodles" and DotsThis is really just a quick experiment to ill.u.s.trate how to work with sodium alginate.[image]Create a 1% solution of sodium alginate and water. Add food coloring so that you can see the mixture as you work with it. Using a squeeze bottle, pipe out a strand into a bowl containing a 0.67% solution of calcium chloride in water.Try making drops and other shapes as well. One food trend that's still making the rounds is mini "caviar." The small drops of set sodium alginate liquids have a similar texture and feel as caviar but with the flavor of whatever liquid you use.Once you've played with this using water, try using other liquids. Jolt Cola? Cherry juice? Keep in mind that liquids that are high in calcium or very acidic will cause the alginate solution to gel up on its own.[image]

Spherification in shapes Since sodium alginate sets via a chemical reaction, not a thermal one, you can freeze a liquid into a mold and then thaw it in a calcium bath to cause it to partially maintain its shape. The final shape won't retain the crisp edges of the original frozen shape-it'll swell and bloat out slightly-but you'll still get a distinctive shape.

NoteNote that straight-up lime juice won't work, because the alginate will precipitate out in the presence of strong acids. If you're willing to experiment further, try using sodium citrate to adjust the pH.

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Try freezing the liquid in a mold before setting the sodium alginate to get more complicated shapes.

Mozzarella spheres What happens if you want to use sodium alginate in a food that already contains calcium? Depending upon the amount of calcium in the food, adding the sodium alginate straight to it would cause the liquid to set, giving you something similar to a brittle gel.

Swapping the chemicals-adding the calcium chloride to the food and setting it in a sodium alginate bath-doesn't work; calcium chloride is nasty-tasting. Luckily, it's the calcium that's needed for the gelling reaction, not the offensive-tasting chloride, so any compound that's food-safe and able to donate calcium ions will work; calcium lactate happens to fit the bill. This technique is called reverse spherification reverse spherification.

To create mozzarella spheres, mix 2 parts mozzarella cheese with 1 part heavy cream under low heat. Add around 1.0% of calcium lactate to this liquid and then set it in a water/sodium alginate solution of 0.5% to 0.67% concentration.

Ann Barrett on Texture[image]PHOTO USED BY PERMISSION OF ANN BARRETTAnn Barrett is a food engineer specializing in food textures. She works for the Combat Feeding Directorate of the U.S. Army Natick Soldier Research, Development and Engineering Center (NSRDEC).What does a food engineer do?It's like applied chemical engineering but for food. The training focuses on how to process food and how to preserve food, looking at food as material. I happen to have a specialty in food texture or food rheology; rheology means how something flows or deforms. My PhD topic was on the fracturability of crunchy food. How do you measure crunchiness or fracturability, and how do you quant.i.tatively describe the way a food fails? When you chew a food and it breaks apart, can you describe that quant.i.tatively and then relate that to the physical structure of the food?Tell me a little bit about the NSRDEC.There are several RDECs (research, development, and engineering centers) throughout the country. NSRDEC is focused on everything the soldier needs for survival or sustenance, aside from weaponry: food, clothing, shelters, and parachutes. The food part is largely driven by the fact that the military is potentially deployed in every kind of physical environment, so we need a wide range of foods to support soldiers operating in a wide range of situations. They have large depots of rations, and that drives a very long shelf-life requirement. Most of the food that we make needs to be shelf-stable for three years at 80F / 26.7C. That is not to say that the soldier will always eat something that's three years old, but they definitely might. That drives a lot of the research here; foods that are shelf-stable but also good, that the soldiers will want to eat.It must be really interesting to work with the constraints that you've got while trying to preserve flavor and texture. How do you go about doing that?Well, it's often one part experience or knowledge combined with two parts trial and error. There's a lot of bench-top development here. Most of my experience has been in processing and engineering a.n.a.lysis of food, but I do have a project now where we're trying to develop flavors for sandwich fillings. All flavors are chemicals, so you can replicate a natural flavor by knowing what the chemistry is.For example, we're working on a peanut b.u.t.ter filling for sandwiches. We're trying to make a chocolate peanut b.u.t.ter flavor, a bit like Nutella. We have the peanut b.u.t.ter formula, and we've been looking at adding cocoa and at different chocolate flavors. We put three into storage to see how they would work, and two of them came out just okay, and one of them was delicious. When you're developing something, you have to look at a number of different ingredients to see what works. There will be changes in both the flavor and texture of a food during long-term storage. Flavors tend to become less intense, or off-flavors might develop. Texture can degrade by moisture equilibrating, say in a sandwich, or by staling. There are a mult.i.tude of flavors that are commercially available, and also a mult.i.tude of ingredients that will adjust texture-for example, starches and gums for liquid or semi-solid foods, enzymes and dough conditioners for breads. So during development you need to optimize a formula to make sure the food is good after you make it and also good after storage.Even with all the hard science, you still have some degree of, well, "Let's just try it and see what happens?"Oh, absolutely. You make a product up for a project, sample it, store it, and then sample it again. Everything is actually tasted here, and as a matter of fact, part of our duties is to go over and partic.i.p.ate in the sensory panels because the food scientists here, the nutritionists, the dieticians, are all considered expert tasters. The first thing we do is make our product on the bench and then put it into a box that's 120F / 49C for four weeks. Those conditions approximate a longer period of time at a lower temperature; it's just a quick test to see if quality holds up. If the product holds up, next is 100F / 38C for six months; that's supposed to approximate the quality you would get at three years at 80F / 26.7C. Then you have to check that it's microbiologically stable, so it goes to the microbiologist for clearance, and then you can ask people to come and evaluate it. We rate the appearance, aroma, flavor, texture, and the overall quality.How does the science of food texture work into enjoyment of food?There are expected textural properties of whatever food category you're dealing with. Sauces are supposed to be creamy; meats are supposed to be at least somewhat fibrous; bread and cake are supposed to be soft and spongy; cereals and crackers are supposed to be crunchy. When texture deviates from what's expected, the food quality is poor. If you are going to measure and to optimize the texture of a product, you need to pinpoint the exact sensory properties you want.For example, for liquids, flowability or viscosity is the defining physical and measurable characteristic. There are "thin" liquids and "thick" liquids, and you can often change thin to thick by adding hydrocolloids or thermal treatment. Solid foods come in many different textural types. There are elastic solids that spring back after deformation (Jell-O); there are plastic solids that don't (peanut b.u.t.ter). Then besides "solid" solids there are also porous solids-think bread, cake, puffed cereal, extruded snacks such as cheese puffs. Porous foods have the structure of sponges, and like a wet versus a dry sponge, they can be elastic or brittle.Somebody cooking in the kitchen is actually manipulating these things both physically and chemically?Yes, that's exactly what cooking is. Take cooking an egg. The protein alb.u.min will denature with heat, causing molecular crosslinking and solidification. Another example is kneading bread dough, which is a mechanical rather than a thermal process that makes the gluten molecules link up; that gluten network is what allows the bread to rise because a structure is developed that will hold gas liberated by yeast. And of course, every time you use cornstarch or flour to thicken a gravy or sauce, you're employing a physico-chemical process. Heat and moisture will make the starch granules absorb water and swell and then bleed out individual starch polymers, which are like threads attached to the granules. The starch polymers then entangle, creating an interconnected structure that builds viscosity. That's why your gravy gets thick.GravyFlour (roux method)Create a simple roux by melting 2 tablespoons (25g) of b.u.t.ter in a saucepan and then adding 2 tablespoons (17g) of flour. Stir while cooking over low heat until the roux sets and begins to turn light brown, about two to three minutes.Add 1 to 1 cups broth or stock; whisk to combine. Simmer over low heat for several minutes, until the gravy has reached your desired thickness. If the gravy remains too thin, add more flour. (To prevent clumping, create a slurry by mixing flour with cold water, and add that.) If the gravy becomes too thick, add more liquid.CornstarchCreate a cornstarch paste by mixing 2 tablespoons (16g) cornstarch with cup (60g) cold water.In a saucepan, heat up 1 to 1 cups broth or stock. Add the cornstarch and simmer for 8 to 10 minutes to cook the cornstarch. If the gravy remains too thin, add more cornstarch paste. If the gravy becomes too thick, add more liquid.Notes - You can use the drippings from roasted meats, such as turkey or chicken, to bring more flavor to the gravy. If using flour, subst.i.tute the fat in the drippings for the b.u.t.ter. If you're searing a piece of meat, use the same pan for making the gravy, deglazing it with a few tablespoons of wine, vermouth, Madeira, or port to loosen up the fond fond that will have formed on the surface of the pan. that will have formed on the surface of the pan.

- Try sauteing some mushrooms and adding them into the gravy as well. Or, if you're cooking a turkey, slow-cook the turkey neck a day in advance and pull off the meat and add it into the gravy as well.

Making Things Melt in Weird Ways: Methylcellulose and Maltodextrin At a high level, making gels is about transforming liquids into solids. In addition to creating gels, though, modern food additives can be used to alter other properties of foods, and another area of play in the modernist kitchen is that of melting. How can we make things change state in unexpected ways?

"Melts" as it cools: Methylcellulose Methylcellulose has the unusual property of getting thicker when heated (thermo-gelling in chem-speak). Take jam: when heated, it loses its gel structure (the pectin melts), causing it to flow out of things like jam-filled pastries. Adding methylcellulose prevents this by causing the jam to "gel" into a solid under heat. And since methylcellulose is thermoreversible, upon cooling after baking, the jam returns to its normal consistency. in chem-speak). Take jam: when heated, it loses its gel structure (the pectin melts), causing it to flow out of things like jam-filled pastries. Adding methylcellulose prevents this by causing the jam to "gel" into a solid under heat. And since methylcellulose is thermoreversible, upon cooling after baking, the jam returns to its normal consistency.

NoteHollywood uses methylcellulose to make slime. Add a bit of yellow and green food dye, and you've got yourself Ghostbusters Ghostbusters-style slime. To get good consistency, whisk it vigorously to trap air bubbles into the mixture.

Methylcellulose has been used in some modernist cuisine dishes for its thermo-gelling effects. One famous example is "Hot Ice Cream" in which the "ice" cream is actually hot cream that's been set with methylcellulose. As it cools to room temperature, it melts.

- Instructions for use.Dissolve methylcellulose into hot water (above 122F / 50C) and then whisk while cooling down. Mixing it directly in cold water can be difficult because the powder will clump up as it comes into contact with water. In hot water, though, the powder doesn't absorb any water, allowing it to be uniformly mixed. It's easiest to stir in 1.0% to 2.0% (by weight) into your liquid and let it rest overnight in the fridge to dissolve fully. You can then experiment with setting the liquid. Try baking a small dollop of it, or dropping it by the ice cream scoopful into a pan of simmering water.

- Uses.Commercial applications use it to prevent "bake-out" of fillings in baked goods. Methylcellulose also has high surface activity, meaning that it acts as an emulsifier by keeping oil and water from separating, so it is also used in low-oil and no-oil dressings and to lower oil absorption in fried foods.

NoteMethylcellulose increases surface tension-well, actually, "interfacial tension" because "surface" refers to a two-dimensional shape-which is why it works as an emulsifier.

- Origin and chemistry.Methylcellulose is made by chemically modifying cellulose (via etherification of the hydroxyl groups). There can be great variation between types and derivatives of methylcellulose, in terms of thickness (viscosity), gelling temperature (122194F / 5090C), and strength of gel (ranging from firm to soft). If you're having problems getting your methylcellulose to set, check the specifications of the type you have. See Linda Anctil's primer at http://www.playingwithfireandwater.com/foodplay/2008/03/methylcellulose.html for additional details. for additional details.

[image]

When cold (on left), water molecules are able to form water cl.u.s.ters around the methylcellulose molecule. With sufficient heat-around 122F / 50C-the water cl.u.s.ters are destroyed and the methylcellulose is able to form crosslinks, resulting in a stable gel at higher temperatures.

Hot MarshmallowsThese marshmallows remain firm when hot, but melt as they cool. This recipe is adapted from a recipe by Linda Anctil ( (http://www.playingwithfireandwater.com).In a saucepan, bring to a boil: - 2 cups (500g) water - 1 cup (200g) sugar Let cool, and then whisk in: - 10g methylcellulose (use a scale to ensure an accurate measurement) - 1 teaspoon (5g) vanilla extract Let rest in fridge until thick, around two hours. Once thick, whisk until light and foamy. Transfer to a 9 9 / 20 cm 20 cm baking pan lined with parchment paper. Bake for five to eight minutes at 300F / 150C, until set. The marshmallows should feel dry to the touch and not at all sticky. Remove from oven, cut into desired shapes, and coat with powdered sugar.[image]Two marshmallows on a plate of powdered sugar.[image]Two marshmallows after being coated with powdered sugar while still hot.[image]Same marshmallows after cooling for a few minutes.[image]When working with gels, you can quickly cool the hot liquid by whisking it while running cold water over the outside of the pan. The water will flow along the bottom of the pan.

"Melts" in your mouth: Maltodextrin Maltodextrin-a starch-dissolves in water, but not fat. In manufacturing, it's spray-dried and agglomerated, which creates a powder that's very porous on the microscopic level. Because of this structure, maltodextrin is able soak up fatty substances (they won't cause it to dissolve), making maltodextrin useful for working with fats when designing food. It also absorbs water, so is used as an emulsifier and thickener, as well as a fat subst.i.tute: once hydrated, it literally sticks around, mimicking the viscosity and texture of fats.

Since it comes as a white powder, you can also use maltodextrin to turn fatty liquids and solids such as olive oil and peanut b.u.t.ter into powder. Because maltodextrin traps oils but dissolves in water, the resulting powder dissolves in your mouth, effectively "melting" back into the original ingredient and releasing its flavor. Since maltodextrin itself is generally flavorless (only slightly sweet), it does not substantially alter the flavor of the product that is being "powderized."

In addition to the novelty and surprise of, say, a powder dusting on top of fish melting into olive oil in your mouth, powders can carry flavors over into applications that require the ingredients to be effectively "dry." Think of chocolate truffles rolled in chopped nuts: in addition to providing flavor and texture contrast, the chopped nuts provide a convenient "wrapper" around the chocolate to allow you to pick up the truffle and eat it, without the chocolate ganache melting on to your fingers. Powdered products can be used to coat the outsides of foods in much the same way that chopped nuts are used to coat the outside of truffles.

- Instructions for use.Add powder slowly to your liquid fat for a ratio of about 60% fat, 40% maltodextrin by weight. You can pa.s.s the results through a sieve to change the texture from breadcrumb-like to a finer powder.

- Uses.Industry commonly uses maltodextrin as a filler to thicken liquids (e.g., the liquid in canned fruits) and as a way to carry flavors in prepackaged foods such as flavored chips and crackers. Since it traps fats, any fat-soluble substances can be "wicked up" with maltodextrin and then more easily incorporated into a product. For experimental dishes, you can use maltodextrin to create powders that can be sprinkled on the plate as garnish or as a way of transforming something that's normally liquid into a solid.

- Origin and chemistry.Derived from starches such as corn, wheat, or tapioca. Tapioca maltodextrin seems to be most commonly used in modernist cooking. Maltodextrin is made by cooking down the starches and running the resulting hydrolyzed starches through a spray-dryer. Chemically, maltodextrin is a sweet polysaccharide composed of typically between 3 and 20 glucose units linked together.When it comes to understanding how maltodextrin soaks up oils, imagine it being like sand at the beach. The sand doesn't actually bond with the water, but it's still wicking up the liquid in the s.p.a.ce between the granules due to capillary action. When working with either sand or maltodextrin, with the right amount of liquid, the powder clumps up and becomes workable. Because maltodextrin is water soluble, however, water would dissolve the starch granules. And, luckily, maltodextrin can soak up a lot more oil per volume than sand can soak up water, making it useful for conveying flavors in a nonliquid form.

Powdered Brown b.u.t.terWhisking any fat such as browned b.u.t.ter (upper left) with maltodextrin (center right) creates a powdered form (bottom) that can be used to create a surprising texture as the powder "melts" back into browned b.u.t.ter when placed in the mouth. Try using this browned b.u.t.ter powder as a garnish on top of or alongside fish, or making a version with peanut b.u.t.ter and sprinkling on desserts.[image]In a skillet, melt: - 4 tablespoons (60g) salted b.u.t.ter Once melted, continue to heat until all the water has boiled off. The b.u.t.ter solids will start to brown. Once the b.u.t.ter has completely browned and achieved a nutty, toasted aroma, remove from heat and allow to cool for a minute or two.In a small mixing bowl, measure out: - cup (40g) maltodextrin While whisking the maltodextrin, slowly dribble in the browned b.u.t.ter until a wet sandlike consistency is reached.[image]Notes - Stir slowly at the beginning because maltodextrin is light and will easily aerosolize. The ratio between maltodextrin and the food will vary. If your result is more like toothpaste, add more maltodextrin.

- If the resulting powder is still too clumpy, you might be able to dry it carefully by transferring the powder to a frying pan and applying low heat for a few minutes. This will help dry out any dampness present from room humidity. It will also partially cook the food item, which might not work for powders containing items such as white chocolate.

- For a finer texture, try pa.s.sing the powder through a sieve or strainer using the back of a spoon.

- Try adding a bit of lemon juice to the brown b.u.t.ter, after it has cooled but before mixing it with the maltodextrin.

- Additional flavors to try: peanut b.u.t.ter, almond b.u.t.ter, coconut oil (virgin/unrefined), caramel, white chocolate, Nutella, olive oil, foie gras, bacon fat (cook some bacon and save the fat drippings-this is called rendering rendering). You don't need to heat the fats first, but it might take a bit of working to get the maltodextrin to combine. For liquid fats (olive oil), you will need to use roughly 2 parts maltodextrin to 1 part fat: 50g olive oil, 100g maltodextrin.[image]

Making Foams: Lecithin Foams are another area of play in modernist cuisine. If you ever happen to be served a dish that has a "foam" component-say, cod served on a bed of rice with a "carrot" foam or uni uni (sea urchin) in a sh.e.l.l with green apple foam, it was probably created by adding a stabilizer such as lecithin or methylcellulose to a liquid and then whipping or pureeing it. (Foams can also be created using cream whippers as described in (sea urchin) in a sh.e.l.l with green apple foam, it was probably created by adding a stabilizer such as lecithin or methylcellulose to a liquid and then whipping or pureeing it. (Foams can also be created using cream whippers as described in Cream Whippers (a.k.a. "iSi Whippers") Cream Whippers (a.k.a. "iSi Whippers") in in Chapter7 Chapter7.) While perhaps a little too trendy, it's a clever way to introduce a flavor to a dish without adding much body.

- Instructions for use.Add about 1% to 2% lecithin to your liquid (by weight, i.e., 1g lecithin per 100g liquid) and use an immersion blender to froth the liquid. Hold the immersion blender up and at a slight angle so that the blades are in contact with both the liquid and air.

- Uses.As an emulsifier, lecithin can be used to create stable flavored foams. It's also used as an antispattering agent in margarines, an emulsifier in chocolate (to reduce the viscosity of the melted chocolate during manufacturing), and as an active ingredient in nonstick food sprays.

- Origin and chemistry.Lecithin is typically derived from soya beans as a byproduct of creating soy-based vegetable oil. Lecithin is extracted from hulled, cooked soya beans by crushing the beans and then mechanically separating out (via extraction, filtration, and washing) crude lecithin. The crude lecithin is then either enzymatically modified or extracted with solvents (e.g., de-oiling with acetone or fractionating via alcohol). Lecithin can also be derived from animal sources, such as eggs and animal proteins, but animal-derived lecithin is much more expensive than plant-derived lecithin, so it is less common.

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Lecithin molecules have polar and non-polar regions that are most stable when one side is exposed to a polar substance and the other side to a nonpolar substance. See the sidebar The Chemistry of Emulsifiers The Chemistry of Emulsifiers for a description of how lecithin stabilizes foams. for a description of how lecithin stabilizes foams.

Fruit Juice FoamIn a large mixing bowl or other similarly large and flat container, blend with an immersion blender: - cup (100g) water - cup (100g) juice, such as carrot, lime, or cranberry - 1 teaspoon (3g) lecithin (powder)

Notes.

- Hold the immersion blender such that it is partly out of the liquid. You want to allow it to siphon air into the mixture.

- Allow foam to rest for a minute after blending, so that the resulting foam that you spoon off is more stable.

- Try other liquids, such as coffee or beet juice. Lecithin works best at around a 12% concentration (2g lecithin per 100g of liquid).[image]Lecithin can be used to make a large-bubble foam that is surprisingly stable for long periods of time.

The Chemistry of EmulsifiersYou might be wondering why oil and water are able to "mix" in the presence of an emulsifying agent, after the earlier discussion about polar (e.g., water) versus non-polar (e.g., oil) molecules not being able to mix. An emulsifier has a hydrophilic/lipophilic structure: part of the molecule is polar and thus "likes" the water, and part of the molecule is nonpolar and "likes" the oil. Emulsifiers concentrate at the boundary between water and oil because of the charge structure of the molecules.Adding an emulsifier keeps foods from separating by providing a barrier between droplets of oil. Think of it like a skin around the oil droplets that prevents different droplets from touching and coalescing. Emulsifiers reduce the chance that oil droplets will aggregate by increasing what chemists call interfacial tension interfacial tension. The oil and water don't actually mix; they're just held apart at the microscopic level.Emulsifiers stabilize foams by increasing their kinetic stability-i.e., the amount of energy needed to get the foam to transition from one state to another is higher. Take the foam of a bubble bath as an example: the soap acts as an emulsifier, creating a foam of air and water. Water doesn't normally hold on to air bubbles, but with the soap (the emulsifier), the interfacial tension between the air and water goes way, way up, so it takes more energy to disrupt the system. The more energy it takes, the more kinetically stable the foam is, and the longer it'll last.Take a look at the following two photographs to see what a difference an emulsifier can make (and see http://www.cookingforgeeks.com/book/lecithin/ for a video demonstration). for a video demonstration).[image]A photo under a light microscope of a half-water, half-oil solution. (The slide is pressing the oil droplets flat.)[image]The same mixture with 1% lecithin added. The droplets are stable and do not coalesce into larger drops.

Anti-Sugar: Lactisole This one is unusual. Unlike the modern additives covered so far, which have essentially focused on either trapping liquids in a gel structure or changing the physical state of food, "anti-sugar" is an additive used to modify a flavor sensation: it reduces the sensation of sweetness. (And no, mixing sugar and anti-sugar does not result in more energy being released than eating just plain sugar.) One of the challenges facing the food industry is the need to maximize shelf stability and storage potential while maintaining acceptable flavor and texture. Sugar is used in confections and sweets not just for its sweetness, but also as a preservative: because sugar "latches" on to water, it reduces the amount of water available in a food product for bacterial growth. Think back to the FAT TOM rule from Chapter4 Chapter4: bacterial growth is inhibited by reducing the water activity (the "M" in FAT TOM is for moisture), and because sugar is hygroscopic, adding sugar reduces the freely available water. But more sugar means increased sweetness, so the other flavors in foods can end up being masked with a cloying, overly sweet taste.

In the mid-1990s, Domino Sugar researched chemical modifiers that would reduce the perception of sweetness. The compound lactisole-a carboxylic acid salt-happens to do just that: add it to your foods at a concentration of around 100 parts per million (ppm), and goodbye sweet sensation, as it interferes with your taste buds (the TAS1R3 sweet protein receptor, for you bio geeks). Unlike traditional methods of dampening sweetness in a dish (i.e., adding bitter or sour ingredients), lactisole works by inhibiting the sensation of sweetness on the tongue, so it does not impact perception of saltiness, bitterness, or sourness. Sadly, you can't add it to foods to remove the calories from sugar.

Domino sells a product called Super Envision that is a blend of mostly sucrose, some maltodextrin, and "artificial flavor" at 10,000 ppm. It's meant to be used at around a 1% concentration in the final product, so the 10,000 ppm becomes 100 ppm. (Gee, I wonder if that "artificial flavor" could be lactisole?) [image]