Cocoa

Cocoa powder is essentially ground up roasted cocoa bean particles. It is made from the left over cakes that result after most of the cocoa butter is extracted. It is the most concentrated version of chocolate. It has pronounced astringency and bitterness. Its pH is around 5.

"Dutched" or alkalized cocoa is cocoa powder that has been treated with potassium carbonate. This alkaline substrate brings its pH to 7 or 8 and encourages astringent phenolics to form flavorless dark pigments, thus reducing the astringency, bitterness, and flavor of the cocoa. Dutched processed cocoa has a milder chocolate flavor despite its darker color.

Wacky cake

This section is a bit of a refresher on some topics we have already explored. I debated whether or not to include it (hence the lateness of these posts), but since the wacky cake raised our eyebrows, here it is. The format of this section is short and sweet, like the cake. Enjoy!

Topics include:

Cocoa
Vinegar
Baking powder and baking soda
Butter
Lukewarm water
Salt
Powdered sugar

Thoughts on cheese

I have too many rambling thoughts about cheese, so maybe it's best that I just list them:

• It is a terrible loss to the world that the world no longer enjoys cheese made in that artful tradition that evolved over thousands (thousands!) of years. Cheese, yet another casualty of war...
• That being said, I am not opposed to the use of synthetically made rennet as opposed to using the stomach of a young calf. My animal-lover self cannot justify the killing of calves that would be needed to traditionally satisfy the demand for cheese. 
• On the opposite extreme, I am disgusted by the preference to process cheese. It seems like the hot-dog version of cheese. The thing that puts me out is not so much that it exists, but that due to its low cost, it is prevalent in our society. How many times have I consumed this product without even knowing it? Yet another reason to forgo things made with products of unknown origin. 
• And since I am on an emotional rant...low fat cheese, really? When considering what manufacturers have to put into cheese to make it palatable once the fat is out, I no longer wonder why our bodies have traces of harmful pollutants. I do not want to place blame only on manufacturers though. A healthy approach to moderation would diminish the demand for these altered products that seem to scream, "eat all you want, it has only half the calories! The other half is just a bunch of anti-nutrients." How about eating half but really, really enjoying it?

Lemon cheese

As posted in Kitchen chemistry by Dr. Patti Christie, http://ocw.mit.edu/courses/special-programs/sp-287-kitchen-chemistry-spring-2009/readings/MITSP_287s09_read10_Cheese.pdf

From Cheese Making Made Easy by Ricki Carroll and Robert Carroll

This cheese has a delicate flavor of lemon. It is a moist cheese with a spreadable texture. It can be used as a spread or in cooking.

This soft cheese recipe consists of three steps: acidifying and coagulation, draining and mixing, salting and spicing.

Ingredients:

• 1 quart (4 cups) milk
• juice of 2 lemons (about 1/2 cup) or another acidifying agent; orange juice,raspberry vinegar or cider vinegar. 
• salt and herbs

Step 1 : Acidifying and coagulation

• Using a double boiler ( or a metal bowl floating in a pan of water), indirectly heat 1 quart of milk to 170 F. This will take anywhere from 15 minutes to 30 minutes. Make sure all of the milk is at least 170 F.
• Remove the milk from the heat
• Add the lemon juice and let the milk set for 15 minutes. If the milk does not set (i.e. you see the milk proteins precipitated out of solution), add more lemon juice.

Step 2: Draining

• Pour the curds into a cheesecloth-lined colander. Tie the four corners of the cheesecloth into a knot and hang bag to drain for 1 to 2 hours or until the curds have stopped draining. After the initial burst of dripping, this process can be aided by gently squeezing the curds to remove the water. Using this process, you can probably speed up the draining step to 30 minutes.
• You can save the whey. It can be used in cooking, such as baking bread. It is supposedly is a refreshing summer-time drink if it is chilled and served with mint leaves.

Step 3: Mixing, Slating and Spicing

• Take the cheese out of the cheesecloth. You may have to scrape some off the clothe
• The cheese can be lightly salted and herbs may be added if desired.
• One way to season the cheese is to make it into a log and roll it in coarsely ground pepper.
• The yield should be about 6 – 8 ounces of lemon cheese for each quart of milk

Cheese and Health

Cheese is essentially a concentrated milk, so many of the health advantages and disadvantages of milk apply to cheese. It is a rich source of protein, calcium, and energy. The main health concern derives from its high saturated fat content. However, eating cheese as part of a balanced diet is compatible with good health.

Food poisoning

People are often concerned about consuming cheeses made from raw and unpasteurized milk. Cheeses made from unpasteurized milk are required to be aged at least 60 days by law in the US. This requirement extends to imports as well. Cheese in general present a relatively low risk of food poisoning. Soft cheese has the greatest potential for growing pathogens, so even pasteurized versions should be avoided by people vulnerable to infection such as pregnant women, the elderly, and the chronically ill. Hard cheeses are inhospitable to disease microbes and seldom cause food poisoning.

Foreign molds such as Aspergillus versicolor, Penicillium viridicatum, and P. cyclopium occasionally develop on the rinds and contaminate the cheese. Though this problem is rare, it is best to discard the cheese in its entirety. 

Some people are sensitive to amines present in strongly ripened cheese. Histamine and tyramine are found in large quantities in Cheddar, blue, Swiss, and Dutch-style cheeses. Sensitive people may suffer a rise in blood pressure, headaches, and rashes.

Tooth decay

Eating cheese slows tooth decay. It appears that when cheese is eaten at the end of a meal, the calcium and phosphate from the cheese blunt the acid rise of bacteria that adhere to teeth, thus preventing tooth decay.

Process cheese and Low-fat cheese

Process cheese is an industrial version of cheese that makes use of surplus, scrap, and unripened materials. It requires the use of "melting salts" to make it fondue-like. In 1917, Kraft patented a combination of citric acid and phosphates, and a decade later presented the cheddar look-alike Velveeta to the market.

Melting salts are mixtures of sodium citrate, sodium phosphates, and sodium polyphosphates. These salts are mixed with a blend of new, partly ripened, and fully ripened cheeses. The salts  loosen the protein matrix and melt the component cheeses into a homogenous mass. The characteristics and low-cost of process cheese have made it a popular ingredient in fast-food sandwiches.

Low- and no-fat "cheese" products replace fat with various carbohydrates and proteins. These products do not melt. They soften and dry out.

Cooking with cheese

Melting cheese

At around 90°F, the milk fat melts, cheese becomes more supple, and fat beads on the surface. At higher temperatures, around 130°F/55°F for soft cheeses, 150°F/65°C for Cheddar and Swiss types, 180°F/82°C for Parmesan and pecorino, bonds holding the casein proteins together begin to break and the protein matrix collapses. Melted cheese flows as thick liquid. The moisture content dictates the melting behavior of cheese. Low moisture cheeses are more concentrated and intimately bonded, therefore, they require more enegry to melt. After continued heat, moisture evaporates and melted cheese resolidifies.

There are several cheeses that do not melt. They just get stiffer and drier. Examples include Indian paneer, Latin queso blanco, Italian ricotta, and most fresh goat cheeses. All of them are curdled primarily by acid, not rennet. Acid dissolves the calcium glue that hold casein proteins together in micelles along with the negative electrical charge. The proteins bond extensively, so when heated, water is lost first before the protein bonds break. As water boils away, the proteins become even more concentrated. Firm paneer and queso blanco can be simmered or fried like meat.

Stringiness

Melted cheese becomes stringy when mostly intact casein molecules are cross-linked together by calcium into long, fibers that can stretch. If, however, casein has been attacked extensively by enzymes, then the pieces are too small to form fibers, as is the case with well aged cheeses. These do not get stringy. The degree of cross linking is such that casein molecules are tightly bound. The molecules just break.

Stringiness, can be determined by how the cheese was made. Stringy cheeses are moderate in acidity, moisture, salt, and age. They are intentionally made fibrous, as is the case with mozzarella, Emmental, and Cheddar. Crumbly cheeses include Cheshire and Leicester. Caefphilly, Colby, and Jack are preferred for melted preparations. Gruyère is the choice for fondues. Italian grating cheeses, such as Parmesan, grana Padano, and pecorinos have a broken protein fabric which makes them ideal to be disperced in dishes.

When preparing cheese sauces and soups, the aim is to integrate the cheese evenly in the liquid to add richness and flavor to the dish. To avoid stringiness, lumps, and fat separation consider the following tips:

• Avoid using cheese prone to stringiness in the first place. Moist or well-aged grating cheeses blend better.
• Grate cheese finely.
• Heat the dish as little as possible after the cheese has been added. Simmer the ingredients first, cool a bit, then add the cheese.
• Minimize stirring as it can push disperesed particles together.
• Include starchy ingredients that coat proteins and fat pockets, keeping them apart. Use stablizing ingredients such as flour, cornstarch, or arrowroot.
• If the flavor permits, use wine or lemon juice.

Cheese fondue

The ingredients for fondue include an alpine cheese such as Gruyère, a tart white wine, some kirsch, and sometimes starch (for added insurance). The wine contributes water, which keeps the casein proteins moist and dilute, and tartaric acid, which pulls off the calcium and leaves casein glueless and separate. Citric acid from a lemon juice does the same thing.

When using cheese as a topping or gratin, keep in mind that too much heat dehydrates the casein fabric, toughens it, and causes the fat to separate. To avoid this, watch the dish carefully when under the broiler or in the oven, and remove as soon as the cheese melts. If you want to brown a cheese topping, pick a robust cheese such as a grating cheese.

Choosing, storing, and serving cheese

The most important thing to understand is that bulk supermarket cheeses are pale imitations to real, flavorful cheeses. To find good cheeses, buy it from a specialist. Whenever possible, buy portions that are cut to order, as precut portions may be old and their large exposed surfaces develop rancid flavors from contact with air and plastic wrap. Exposure to light also damages lipids, causes off-flavors, and bleaches the annatto in orange-dyed cheeses, turning it pink. Pregrated cheese has tremendous surface area so it looses much of its aroma and carbon dioxide, factors which contribute to the impression of staleness.
Cheese is best stored cool, not cold. It is best kept at 55-60°F/12-15° C; a temperature that extenuates the ripening conditions. It is warmer than the fridge, but cooler than ambient temperatures. The shelf life of cheese is affected by its water content. Fresh cheese with 80% water lasts a few days. Soft cheese, at 45-55% moisture, reaches its prime after a few weeks, semihard cheese at 40-45% after a few months, and hard cheese at 30-40%  moisture after a year or more.

Choose loose wrapping to preserve cheese at its best. Tight wrapping in plastic traps moisture. The restricted oxygen encourages spoilage bacterial and fungal growth. Strong volatiles like ammonia also become trapped and impregnate the cheese instead of difusing out. Whole still developing cheese should be stored unwrapped or loosely wrapped in wax paper. If a piece of cheese develops an unusual surface mold or sliminess or an unusual odor, discard it. Trimming the surface does not remove mold filaments deep in the cheese which may carry toxins and lead to food poisoning.

Cheeses should never be served direct from the refrigerator. At such low temps, milk fat is congealed and hard, the protein network is stiff, and the cheese tastes rubbery and flavorless. Cheese is best served at room temperature unless it is warmer than 80°F/26° C, at which the milk fat metls and sweats out of the cheese.

People often wonder whether the rind of certain cheeses is to be consumed. The rinds of long-aged cheeses are tough and slightly rancid, so avoid eating them. Softer cheeses have rinds that may be eaten, but doing so is a matter of taste and preference.

Making cheese

The artful transformation of milk into cheese occurs in three stages: In the first stage, lactic acid bacteria convert milk sugar into lactic acid. The second stage involves the addition of rennet and the subsequent curdling of the casein proteins and drainage of the watery whey from the concentrated curds. The third stage is ripening. Protein and fat-digesting enzymes present in the milk, from the bacteria and molds, and from the rennet work together to create the unique texture and flavor of the cheese.

Nearly all cheeses are curdled with a combination of starter bacteria acid and rennet. Acid and rennet give different curdle structures. Acid yields a fine, fragile gel; whereas rennet produces a course but robust, rubbery one. Fresh cheeses and small, surface-ripened goat cheeses begin with predominantly acid coagulation. Large semihard and hard cheeses curdle in rennet-dominant coagulation. Cheeses of moderate size and moisture have moderate content of both.

After curdling, the excess water is drained from the curds. For soft cheeses, whole curd is allowed to drain by gravity alone for many hours. The curd of future firmer cheeses is precut to increase surface area and is actively pressed to expel more moisture. Cut curd may also be cooked in its whey to 130° F/55° C to further expel whey and encourage flavor production by bacteria and enzymes. All cheese is later placed into molds and pressed to its final shape and moisture.
Salt is added to new cheese either by mixing it with the curds or applying dry salt or brine to the whole cheese. In addition to taste, salt inhibits the growth of spoilage microbes and acts as a regulator of cheese structure and the ripening process. Salt draws moisture out of the curds and firms the protein structure. Most cheeses contain 1.5 to 2% salt by weight.

Ripening, or affinage, refers to the process of bringing cheese to the point at which flavor and texture are at their best. Cheeses are said to be alive. They begin young and bland, mature into fullness of character, and eventually decay into harshness and coarseness. The length of vitality depends on the type of cheese. The cheesemaker manipulates the maturation process by controlling the temperature and humidity. Specialist cheese merchants in France are also affineurs; they buy freshly made cheese and carefully mature it in their own premises to sell at their best. Industrial producers ripen their cheeses only partly, then refrigerate them to suspend their development before shipping. This technique maximizes shelf life and stability though quality suffers greatly.

The ingredients of cheese

Milk

Cheese is concentrated milk five- to tenfold by the removal of water. The basic character of the milk defines the basic character of the cheese. Milk from cows is more neutral than others. Sheep and buffalo milk have relatively high fat and protein contents therefore make richer cheeses. Goat's milk has less casein protein, so it produces a more crumbly curd.

The cow breed also produces distinct flavors. Today most dairy comes from black and white Holstein or Friesian cows. These cows have been bred to maximize milk yields on a standarized feed. Traditional breeds, such as the Brown Swiss and others, produce a lower volume of milk but one that is richer in protein, fat, and other favorable cheese constituents.

The animal's diet also affects flavor. Today most cows are fed on a standarized diet year round. The diet is composed of silage and hay from few fodder corps such as alfalfa or maize. This feed produces neutral milk that can be made into very good cheese. However, herds allowed to graze on pastures give milk with aromatic complexities that make extraordinary cheese. Pasture cheese has traces of local climate and seasonal flavors. It is also deeper yellow color due to greater carotenoid pigments in fresh vegetation. Beware of bright orange cheeses as these have been artificially dyed.

Flavor is also affected by whether the milk used is raw or pasteurized. Pasteurization, to eliminate disease and spoilage bacteria, has been a practical necessity in industrial cheese making, which requires milk to be pooled and stored. Since 1940s, the FDA requires that any cheese made from unpasteurized milk be aged at least 60 days at a temperature above 35 degrees F/2 degrees C. In the 1950s the US also banned imports of raw-milk cheeses aged less than 60 days. This essentially means that soft cheeses made with raw milk are contraband. The French, Swiss, and Italian regulations actually forbid the use of pasteurized milk for the traditional production of cheeses such as Brie, Camembert, Comté, Emmental, Gruyère, and Parmesan. Pasteurization kills useful milk bacteria, and inactivates enzymes in the milk that work on flavor development. However, pasteurization is no guarantee of safety as milk and cheese can be contaminated in later processing. Most outbreaks in recent years have involved pasteurized products.

Rennet

At least 2,500 years ago, shepherds began using pieces of the first stomach of a young calf, lamb, or goat to curdle milk for cheese. Later, people made a brine extract from the stomach. This was, conceivably, the first semipurified enzyme. Modern methods allow for the production of that same enzyme, chymosin, to be produced in a bacterium, a mold, and a yeast. Most cheese today uses this engineered "vegetable rennets." In Europe, rennet from a calf stomach is required for traditional cheese making.

Traditional rennet is made from the fourth stomach or abomasum of a milk-fed calf less than 30 days old, before chymosin is replaced by other protein-digesting enzymes. Chymosin is unlike other enzymes because it attacks only one milk protein at just one point. It targets the negatively charged kappa-casein that repels individual casein particles from each other. Thus, chymosin allows the casein particles to bond and form a continuous solid gel which is better known as the curd.
Acidity alone reduces the zeta potential and causes milk to curdle, so why rennet? Acid disperses casein proteins and their calcium glue before it allows the proteins to come together. Some casein and most of the calcium are lost in the whey. In addition, the acidity required to curdle milk is so high that some of the flavor-producing enzymes work very slowly or not at all. The curd produced is weak and brittle. By contrast, rennet leaves the casein micelle proteins intact and causes them to bond into a firm, elastic curd.

Microbes

A handful of modern cheese is made with purified cultures, but mostly it is made using a portion of the previous batch's starter.

Starter bacteria consists of lactic acid bacteria which initially acidify the milk, persist in the drained curd, and generate much of the flavor during the ripening process of semihard and hard cheeses such as Cheddar, Gouda, and Parmesan. The numbers of starter bacteria drop dramatically during cheesemaking, but their enzymes continue to work for months. There are two broad groups of starters: Lactococci (mesophilic) and Lactobacilli and Streptococci (thermophilic). Most cheeses are acidified by the mesophilic group, while the few that undergo a cooking step, such as mozzarella and the Italian hard cheeses, are acidified by the thermophilic group.

In addition, there are other microbes that give some cheeses their characteristic looks and flavors:

• The Propionibacteria- Propionibacter shermanii is the hole maker, important in Swiss starters. It produces carbon dioxide gas that makes up the holes in cheese.
• The Smear Bacteria-Brevibacterium linens gives some strong cheeses their characteristic stink, such as Münster, Epoisses, Limburger.
• Molds, especially Penicillium, require oxygen to grow, can tolerate drier conditions than bacteria, and produce powerful protein- and fat-digesting enzymes that improve the texture and flavor of certain cheeses.
• Blue molds include Penicillium roqueforti, which gives Roquefort cheese its veins of blue; and P. glaucum, which colors the interior of Stilton and Gorgonzola.
• White molds include P. camemberti, which contributes to the creamy texture of Camembert, Brie, and Neufchâtel.

History of cheese

Cheesemaking dates back 5,000 years. It is believed to have originated from warm central Asia and the Middle East, as people learned to preserve naturally curdled milk by draining off the watery whey and salting the concentrated curds. There is physical evidence of cheesemaking in Egyptian pots dating to 2300 BCE.

Eventually, the custom moved West and North into Europe. In those cooler regions, people produced many variations of curds that resulted from milder treatments and time. The cheese became alive with different microorganisms. The ancient Columella notes cheese making practices in Europe in his Rei rusticae ("On Rustic Matters") about 65 CE. By the Middle Ages, cheesemaking techniques developed independently in the large feudal estates and monasteries. They suited local conditions and markets. Small, soft cheeses were mostly eaten locally. Large hard cheeses required milk from many animals so cooperatives developed. Gruyère fruiteries began around 1200 CE. Hard cheese was transported long distances and kept indefinitely. The independent producers resulted in a wide variety of cheese. By the 18th century, cheese was considered a stape food, "white meat" for the poor and an integral course in a multicourse feasts for the rich. The golden age of cheese was probably in the late 19th century to the early 20th century when the art was fully matured and railroad transportation made cheese widely available still at its best.
Sadly, industrialization and war brought the demise of traditional cheesemaking. Cheese and butter factories were born in the US, a country with no cheesemaking tradition. By the end of the Civil War there were hundreds of "associated dairies" that manufactured cheese for many farms. Pharmacies, and later pharmaceutical companies, began mass-producing rennet. At the turn of the century, scientists in Denmark, the US, and France standarized cheese making by introducing pure microbial cultures for curdling and ripening cheese. Cheesemaking no longer benefited from the complex flora found in individual farms. According to Harold McGee, in On Food and Cooking, "the crowning blow to cheese diversity and quality was World War II" (p. 54). Dairying in continental Europe was devastated. In the prolongued recovery, factory production of cheese was favored for its economies of scale and regulation. Cheese became inexpensive and standarized. Since then, most of the cheese in Europe and the US is factory made. In 1973, France instituted a certification program for cheese made by traditional methods. Still, less than 20% of French cheese today qualifies for that certification. In the US, most of the market is flooded with factory "process" cheese, made from a mixture of aged and fresh cheeses blended with emulsifiers and repasteurized. "Natural" cheese, though still almost exclusively factory-made, is not as widely consumed.

In the 21st century, cheese consumption is at its highest world wide. However, it has become an industrial product with little resemblance to the age-old art. McGee expresses that "industrial cheese is...a simplified food that could be and is made anywhere, and that tastes of nowhere in particular" (On Food and Cooking, p.54).

In the recent years, there has been a revival of tradition and quality. In the US, artisan cheese is starting to claim a small portion of the market share. What once was considered white meat for the poor, now is a pricey treat for the urban middle class.

Cheese

This week the topic is all about cheese. Sections include:

History of cheese
Components of cheese
Making cheese
Cooking and storing cheese

Hope you join me!

Thoughts on beans and other legumes

When I was growing up, my family always had real Chinese soy sauce. It might have been the only true remnant of our not-so-distant Chinese ancestry. I am not sure who, but someone would travel to Mexico City and buy it from the Chinese market. So it never occurred to me that there would be anything different until we moved to the US and all that was available was Kikkoman soy sauce. This type of soy sauce was watery, milder, and had a funny taste. At the time I thought that it had to do with commercialization and price. Real Chinese soy sauce was obviously much better, so how come all the Chinese restaurants served Kikkoman?

In reading for this lesson, I came to the conclusion that the Kikkoman soy sauce is indeed made after the Japanese soy sauce model which includes a mixture of soybeans and wheat. I grew up on Chinese soy sauce made solely from soybeans, so my palate appreciated the difference. I often wonder whether Americans are afraid of robust flavor because most "ethnic" foods available tend to be milder than the original. Funny enough, my parents never conceded to the Japanese style, and since have found a store in Atlanta that sells real Chinese soy sauce.

On a different, though slightly related note, growing up I never conceived the idea of eating beans from a can. Mexicans are known for eating beans, therefore, Mexicans cook beans. They have these big pots made out of clay in which traditionally beans are cooked. I ought to get one the next time I travel down there. My mom still makes really good beans even without the pot. Before I moved out, I asked my mom to show me how to make some of my favorite dishes. She never said how tricky it was to cook beans. She simply told me to pre-soak and cook on low for a couple of hours. Well, my first attempts turned out to be a mess of gigantic, undercooked beans. I guess my mom did not account for the change in altitude. So after many years of somewhat eradicating my Mexican diet, maybe I should give beans another try. After all, one  really just needs to pre-soak and cook on low for a few hours...

Hearty three-bean chili

As posted on Kitchen Chemistry, by Dr. Patti Christie, from Cooking Light Annual Cookbook, 1996.
http://ocw.mit.edu/courses/special-programs/sp-287-kitchen-chemistry-spring-2009/readings/MITSP_287s09_read09_Chili.pdf

Ingredients:

1 teaspoon vegetable oil
2 cups chopped onion
3 cloves garlic, minced
2 tablespoons chili powder
1 1/2 tablespoons ground cumin
1/2 teaspoon salt
1 (28 oz) can ground tomatoes
2 (15 oz) cans black beans, drained
1 (15 oz) pinto beans, drained
1 (14.5 oz) can broth, vegetable or beef
1/2 cup water
1 large green pepper, cut into 1-inch pieces
1 large sweet red pepper, cut into 1-inch pieces
1/2 cup nonfat sour cream
1/3 cup diced green pepper
1/3 cup diced sweet red pepper

Method:

1. Open the cans of the beans upside down and dump into colander. Opening the cans upside down enables all of the beans to be removed from the can without the use of a spatula. Rinse the beans under running water to remove excess salt.
2. Heat oil in a large Dutch oven over medium-high heat until hot
3. Add onion and garlic; sauté 5 minutes or until onion is tender
4. Stir in chili powder, cumin and salt; sauté 1 minute
5. Add tomato and next 7 ingredients
6. Bring to a boil; cover, reduce heat and simmer 30 minutes, stirring occasionally
7. Ladle chili into individual bowls, and top each serving with 1 tablespoon sour cream
8. Sprinkle diced pepper evenly over each serving

Yield: 12 servings of 1.5 cups each.

Fermented soybean products

Fermented soy products include sufu, miso, soy sauce, tempeh, and natto.  

Fermented bean curd or sufu (tou fu ru, fu ru) is the vegetarian equivalent to mold-ripened milk cheeses.

Most fermented soybean products suffer a two-stage fermentation process where to start, dormant green spores of Aspergillus molds are mixed with cooked grains or soybeans, and kept well aerated and moist. The spores germinate and produce digestive enzymes that break down the beans/grains. After two days, the enzymes are at their peak. The mixture, called chhü in China and koji in Japan, is immersed in salt brine and more cooked soybeans. In this oxygen-poor brine, the molds die, but their enzymes continue to work. To end, anaerobic, salt-tolerant lactic-acid bacteria and yeasts grow in the brine and contribute their own flavorful by-products to the mixture.

Traditionally miso making allows the mixture to ferment for months to years at a warm temperature. Browning reactions generate deeper layers of color and flavor. Modern, industrial production cuts the fermentation and aging from months to weeks, and compensates the resulting lack of color and flavor with additives.

Soy sauce in the West is mostly Japanese soy sauce, which includes an even mixture of soybeans and wheat. The starch from the wheat gives it a characteristic sweetness, higher alcohol content, lighter flavor and color. 

Chinese soy sauce and Japanese tamari are almost exclusively made from soybeans. It is darker in color and richer in flavor due to the higher concentration of soybean amino acids. 

“Chemical” soy sauce is a non-fermented approximation of soy sauce that uses defatted soy meal left over from soybean oil production and is hydrolyzed with concentrated hydrochloric acid. The mixture is neutralized with sodium carbonate and later flavored and colored with corn syrup, caramel, water, and salt. To make it more palatable, it is blended with some portion of genuine fermented soy sauce. To ensure buying genuine soy sauce, avoid labels containing added flavorings and color.

Tempeh originated from Indonesia and is a perishable main ingredient, not a preserved condiment. It is made by cooking the whole soybeans, placed in thin layers, and fermented with a mold. The mold forms hyphae that binds the beans together and digests proteins and fats that turns it into flavorful bits. Fresh tempeh develops a nutty, almost meaty flavor when sliced and fried.

Natto, like tempeh is a perishable product. It is notably alkaline and develops a sticky, slippery slime that can be drawn with the tip of a chopstick into threads up to 3 ft/1 m long. It is made from whole cooked beans and inoculated with a culture of Bacillus bacteria and held at warm temperatures for 20 hrs. Its stringiness derives from long chains of glutamic acid and long branched chains of sucrose.

Palatable soybean forms (non-fermented)

• A few legumes are parched in dry heat to create a crisp texture. Peanuts are the most commonly roasted legumes, but soybeans and chickpeas are also roasted.
• Fresh soybeans are more palatable before they fully mature. Fresh soybeans, Japanese edamame, or Chinese mao dou are special varieties harvested at 80% maturity. They have lower levels of gassy and antinutritional substances.  The beans are sweet, crisp, and green. They are boiled for a few minutes in salted water. Green soybeans are around 15% protein and 10% oil.
• Soy milk has become a popular alternative to cow’s milk, though it must be fortified with calcium to make it an adequate substitute.
• The traditional method of making soy milk involves soaking the beans until soft, grinding them, and either sieving out the solids and cooking the milk (China) or cooking the slurry, then sieving out the solids (Japan). This process produces milk with a strong soy flavor.
• Modern method minimizes enzyme action and soy flavor. The dry beans are soaked, then either cooked quickly at 180-212 degrees F/80-100 degrees C before grinding, or grinding them at that temperature. 
• Bean curd or Tofu is curdled soy milk, a concentrated mass of protein and oil formed by coagulating the dissolved proteins with salts. Invented in China around 2,000 years ago, the Chinese have traditionally coagulated with calcium sulfate. The Japanese and coastal regions of China coagulate it with nigari, a mixture of magnesium and calcium salts that are left over after sodium chloride is crystallized from seawater.
• To make it, soy milk is cooled to 175 degrees F/78 degrees C, and then coagulated with salts. The curd is pressed to form a continuous mass. Commercially, it is cut in blocks and pasteurized.
• Freezing bean curd is a useful application as it concentrates the proteins. Once thawed, the liquid leaks out, and leaves a spongy network that is ready to absorb other flavors. It also develops a chewier, meatier texture.

Soybeans and health

In On Food and Cooking, Harold McGee describes the soybean as

“exceptionally nutritious, with double the protein content of other legumes, a near ideal balance of amino acids, a rich endowment of oil, and a number of minor constituents that may contribute to long-term health.” page 493.

Soybeans contain storage forms of isoflavones. These are phenolic compounds are liberated by intestinal bacteria as phytoestrogens, a form that resembles the hormone estrogen. Boiled whole beans contain the most isoflavones. Some research suggests that they may slow bone loss, prostate cancer, and heart disease, but due to their hormone-like effects on the body, soybeans can worsen pre-existing breast cancer. This process is not completely understood.

Soy beans are also a rich source of saponins, which are soap-like defensive compounds that are both, water- and fat-soluble. Soy saponins bind cholesterol so that the body can’t absorb it efficiently. Furthermore, soybeans have phytosterols, chemical relatives of cholesterol, which also interfere with cholesterol absorbtion.

For all their goodness, soybeans are at the same time, unappealing. They contain abundant antinutritional factors, fiber, and oligosaccharides. They contain negligible amounts of starch. Their texture tends to remain firm. To make them more appealing, the Chinese and others have developed ways to alter their taste, such as via extraction of the protein and fermentation.

Common legumes (not including peanuts)

Fava or Broad Beans – Vicia faba – are the largest legume. They originated in Asia and are believed the earliest domesticated plant. Evidence of cultivation found in Mediterranean sites date back to 3000 BCE. Today, China is the world’s largest producer.

People who have an inherited G6PD deficiency should not consume fava beans as they can develop a hemolytic reaction called “favism.”  Fava beans contain two unusual amino-acid relatives, vicine and convicine, which are oxidants that become toxic to people with an inadequate supply of glutathione, as are people with G6PD deficiency. Favism is found most commonly in the southern Mediterranean and Middle East. In areas where malaria has been historically endemic, G6PD deficiency appears to have been a result of natural selection, as it suppresses the growth of the malaria parasite in red blood cells.

Chickpea/Garbanzo is native of southwest Asia. Two main varieties are available: desi and kabuli. Desi are small, thick, tough seed coat, and dark. These are mainly grown in Asia, Iran, Ethiopia, and Mexico. The kabuli type is most common in the Middle East and Mediterranean. It is larger, cream-colored, with a light seed coat. Chickpeas have 5% oil by weight compared to 1-2% of other legumes.

Hummus is a chickpea paste usually flavored with garlic, paprika, and lemon. Chickpeas are the most important legume in India.

Common bean is native of southwestern Mexico, and most widely consumed in Latin America. The common bean has developed hundreds of varieties. Large varieties originally from the Andes, include kidney, cranberry, large red, and white. Smaller-seeded Central American types include pinto, black, small red, and white.

Popping bean or nuña is cultivated in the high Andes. It can be popped in 3-4 min of high dry heat (i.e. microwave). It does not expand as much as popcorn as it remains fairly dense, with powdery texture and nutty flavor.

Lima bean originated from Peru (named for its capital of Lima). It was introduced to Africa via the slave trade, where today they remain the main legume in the African tropics. Some wild types contain potentially toxic quantities of cyanide, so they must be cooked thoroughly to be safe. Commercial varieties are cyanide-free.

Tepary beans are native of the American southwest, and are unusually tolerant of heat and water stress. They are rich in protein, iron, calcium, and fiber. Tepary have a distinctive sweet flavor.

Lentil is probably the oldest cultivated legume. Native of Southwest Asia, there are two groups: large flat (>5mm across) and small rounded (<5mm). Large are most commonly grown. Varieties include brown, red, or green seed coats. Their flat shape and thin seed coats allows water to penetrate easily, thus they cook quickly, in  one hour or less.

Peas are a cool climate legume. Historically, peas have been an important protein source in Europe, especially around the Middle Ages, from when the following children’s rhyme came: “Pease porridge hot, Pease porridge cold, Pease porridge in the pot, Nine days old.”

There are two main varieties: smooth and wrinkly. Smooth makes for dried and split peas. Wrinkly has higher sugar content, and are usually eaten immature as a green vegetable.

Black-eyed pea/cowpea is not really a pea, but an African relative of the mung bean, brought to the southern US with the slave trade. It has a characteristic eye-like anthocyanin pigmentation around the hilum.

The pigeon pea is distant relative of the common bean. It is native to India. It has tough, reddish brown seed coat.

The “Grams” include several small seeded, quick-cooking beans. The green gram or mung beans are native to India, and widely grown in China. Grams also include the rice bean and the African bambara groundnut.

The azuki bean is an East Asian species of deep maroon color. It is mainly cultivated in Korea, China, and Japan. Azuki are a favorite sprouting seed, and are candied in Japan.

Lupins are mostly found in Italy. They are unusual because they contain no starch and 30-40% protein, 5-10% oil, and up to 50% soluble, but indigestible carbohydrates. They require special processing as many have toxic alkaloids. L. mutabilis is grown in the Andes and has a protein content approaching 50% of the dry seed weight.

Soybeans are the most versatile legume. Domesticated in China more than 3,000 years ago, the soybean spread widely as a staple food throughout Asia encouraged by the vegetarian doctrine of Buddhism. It only became known to the West until after the 19^th century. Today the US supplies half of the world production. However, most US soybeans feed livestock, not people, and much is processed for manufacturing purposes.

A note on hard beans

“Hard-seed” beans occur when temperatures are high, but humidity and water supply are low during the growing season. The outer seed coat gets very water-resistant. Hard-seed beans are smaller than normal and can be picked out before cooking.

“Hard-to-cook” beans are normal when harvested, but become resistant to softening when they are stored for a prolonged time (months) at warm temperatures in high humidity. This results from changes in the bean cell walls and interiors, including the denaturation of storage proteins and the formation of a water-resistant coating around the starch granules. There is no way to reverse these changes and no way of spotting them before cooking. Once cooked, they are smaller than normal and can be picked out.

Presoaking

Presoaking the dried beans in water can reduce the cooking time by more than 25%.

Heat penetrates a dry seed faster than water. If cooked directly from the dry state, much of the cooking time is spent waiting for water to get to the center. Meanwhile, the outer portions of the bean overcook and become fragile. Presoaking helps by allowing the water to reach the center first, before the heat cooks them.  

Soaking times depend on temperature. It is helpful to blanch the beans for 1.5 minutes in boiling water and then allowed to soak in the cooling water for two or three hours. Blanching rapidly hydrates the seed coat that controls water movement. If soaked in cool water, it takes 10-12 hrs before beans double in size.

Salt and baking soda speed cooking. Salt concentration at 1% (10g/l or 2 tsp/qt) speeds cooking greatly. Sodium displaces magnesium from the cell wall pectins and makes them more easily dissolved. Baking soda at 0.5% (1 tsp/qt) can reduce cooking time by 75%. It also contains sodium and its alkalinity facilitates the dissolving of cell-wall hemicelluloses. These additions, however, have an effect on the taste and texture of the cooked beans. Baking soda can give a slippery mouth feel and soapy taste. Salt reduces the swelling and gelation of starch granules within the beans, so the texture is mealy instead of creamy.

Cooking legumes

Fresh shell beans cook fairly quickly, in 10-30 min. Peas, lima beans, cranberry beans, and soybeans (edamame) are the legumes most commonly eaten fresh. Whole dried beans and peas take one to two hours to cook. Their larger size and water intake affect cooking time. Initially, water can only enter through the beans through the hilum, the little pore on the curved back of the bean. After 30-60 minutes, the seed coat has fully hydrated and expanded so that water flowing can pass across the entire seed coat surface, though the rate of flow is still limited.

The liquid in which legumes are cooked greatly affects both, the quality of the cooked beans and the time it takes to cook them. The greater the volume of cooking water, the more color, flavor, and nutrients are leached out of the beans, and the more they are diluted. Beans are best cooked in just enough water to soak up and to cook in.

Take into account the following:

• Boiling water speeds cooking, but damages seed coats and cause the beans to disintegrate.
• Temperatures below boiling (180-200 degrees F/80-93 degrees C) are gentler and better maintain bean structure.  
• Hard water with high levels of calcium or magnesium reinforces the bean cell walls, so cooking takes longer and may prevent the beans from softening fully.
• Acidity slows the dissolving of the cell wall pectins and hemicelluloses, so it slows the softening process but it helps maintain structure.
• Alkalinity does the reverse; it enhances the softening process.
• Sugar reinforces cell-wall structure and slows the swelling of the starch granules. It also helps maintain structure.
• Salt in the water slows the rate at which the beans absorb water, but it does get absorbed eventually. If beans are pre-soaked in salted water, they cook much faster.
• High altitude lowers the boiling point, so cooking dry beans is prolonged.

Note: ingredients such as molasses, which are somewhat acidic and rich in sugar and calcium, and acidic tomatoes can preserve bean structure during long cooking and reheating, such as in baked beans.

Legumes and flatulence

Many legumes contain large amounts of indigestible carbohydrates, such as oligosaccharides and cell-wall cements. The human body cannot break down these carbohydrates; therefore, they pass through the stomach in their complex form. Resident, symbiotic bacteria in the intestine break them down into absorbable forms. The increased growth and metabolism of the intestinal bacteria cause a sudden increase in gas production. 

Cooks can help minimize flatulence by manipulating legumes before consumption. Prolonged cooking helps break down much of the oligosaccharides and cell-wall cements into digestible single sugars. Oligosaccharides are also broken down during germination and fermentation, so sprouts, miso, soy sauce, and extracts like bean curd are less offensive than whole beans.

Legume structure and composition

Legume seeds consist of an embryonic plant surrounded by a protective seed coat. The embryo is made up of two large storage leaves, the cotyledons, and a tiny stem. The cotyledons are a transformed endosperm that provide the bulk of nourishment. The seed coat is interrupted at the hilum, a small depression where the seed is attached to the pod. It is through the hilum that the legume absorbs water.

Most beans and peas are mainly protein and starch, except soybeans and peanuts which have large contents of oil (between 25% and 50% respectively).

The colors of beans and peas are determined mainly by anthocyanin pigments in the seed coat. Solid reds and blacks survive cooking, while mottled patterns become washed out when their pigments leak into adjacent non-pigmented areas and into the cooking water. Color intensity is best preserved by cooking the beans in just enough water to keep them covered. It is best to add water only as needed to keep them barely covered.

Importance of legumes

Legumes have a high content of protein, two to three times that of wheat and rice. Their protein develops from a symbiotic relationship with species of the Rhizobium bacteria, which invade the roots of legume plants and convert nitrogen in the air into a form that is directly usable by the plant to make amino acids.

As a vegetable source of protein, legumes have been highly prized throughout history. No other food item has been so notably honored. Each of the four major legumes known to Rome lent its name to a prominent Roman family: Fabius (fava bean), Lentulus (lentil), Piso (pea), and Cicero (chick pea).

Legumes have been domesticated for thousands of years. Some date back to 3000 BCE. Today they make up staple ingredients in many food cultures.

Beans and other legumes

This week the topics are all about legumes. Topics include:

Legume overview
Common legumes
Cooking beans
Soybeans
Soybean products

Hope you join me!

Thoughts on Jams and Jellies

One of the draws of learning about what we eat is coming to understand the origin of foodstuff. I had no idea that gelatin came from animal sources. It made me realize how hard it is to adopt a vegan lifestyle. I truly respect people that do because it takes an enormous amount of effort and awareness to know where products come from and even more discipline to not be a consumer.

That said, I am once again blown away at the ingenuity of the human species. It is remarkable the stuff that people eat and how resourcefulness (i.e. using every bit of an animal/plant) has transformed food. The natural world provides us with so many delicious fruits and vegetables, it is interesting that our palates have craved for more and more diverse ways of consuming them.

On a side note, as I read about pectin and gel-formation, I could not help to reference in my brain that scene from Little Women when Meg is distressed and at her worst presentation when her husband comes home:

John: "My dearest girl, what is the matter?"
Meg: "Oh, John, I am so tired and hot and cross and worried! I've been at it till I'm all worn out. Do come and help me or I shall die!"
John: "What worries you dear? Has anything dreadful happened?"
Meg: "Yes,"
John: "Tell me quick, then. Don't cry. I can bear anything better than that. Out with it, love."
Meg: "The...The jelly won't jell and I don't know what to do!"

(text adapted from Little Women by Louisa M. Alcott, 1869.)

It made me laugh. Poor Meg did not know about pectin, sugar, and acid...

Berry Jam

As noted on Kitchen Chemistry by Dr. Patti Christie

Strawberry or other Berry Jam

From Certo package insert

Ingredients:  

• 4 cups crushed fruit (this is about 2 quarts of fresh fruit or 2.5 pounds of frozen, thawed fruit)
• 7 cup white sugar
• 1 pouch of liquid Certo

Method:
 

• Start the dishwasher with the jam jars. The best jars are the Mason Jars with the lid, glass jar and screw bands. To achieve the best seal, it is best to put the jam into a hot glass jar, so time the dishwasher accordingly.
• Prepare fruit. For berries, crush the fruit with a potato masher to the desired chunkiness.
• Measure the exact amount of prepared fruit into a 6 or 8 quart saucepan. It is best to use a pot in which the fruit does not go above about one quarter of the depth to prevent the jam from boiling over
• Stir sugar into fruit
• Bring mixture to full rolling boil ( a boil that does not stop bubbling when stirred) on high heat stirring constantly
• Stir in Certo quickly. Return to full rolling boil and boil exactly 1 minute stirring constantly. Remove from heat. Skim off any foam with a spoon.
• Using a 2 cup measuring cup, ladle quickly into prepared jars, filling to within 1/8 inch of tops. Wipe jar rims and threads. Cover with flat lids, then screw bands tightly.
• Invert jars for 5 minutes, then turn upright.
• After jars cool, check seals by pressing middle of lid with finger. If lid springs back, lid is not sealed and refrigeration is necessary.
• Let stand at room temperature 24 hours. Store unopened jams in a cool dark place up to 1 year. Refrigerate opened jams up to 3 weeks.
• Yield is about 8 cups of jam

Tips in making a fruit preserve

Cook the fruit to extract the pectin. This preliminary cooking should be brief and as gentle as possible since heat and acid eventually break pectin chains. If a clear jelly is desired, the cooked fruit is strained to remove solid particles and cell debris.

Add sugar and supplemental pectin if needed. Bring the mixture to a rapid boil to concentrate the ingredients. Continue to boil until the mix reaches a temperature of 217-221 degrees F/103 - 105 degrees C at sea level. If not at sea level, adjust the temperature by lowering 2 degrees F/1 degree C per every 1000 ft/305 m elevation. At the noted temperature, the sugar concentration reaches around 65%.

Use a wide pot with a large surface area for evaporation and more gentle cooking.

Add acid in the late stages of cooking to avoid breaking the pectin molecules.

Test the readiness of the mix by placing a drop on a cold spoon and see whether it gels.

Pour into sterilized jars. The mix sets as it cools below 180 degrees F/80 degrees C. It sets most rapidly at warm room temperature (around 86 degrees F/ 30 degrees C), and continous to get firmer with time.

Failure of the mix to set can be attributed to inadequate amounts of good-quality pectin, prolonged cooking that damages the pectin, or inadequate amounts of acid. To remedy, addition of commercial liquid pectin and cream of tartar or lemon juice, and a brief reboiling should work. Too much acid causes weeping of fluid from an overfirm gel.

Uncooked and unsweeted preserves can be made by using concentrated pectin. "Freezer" jams are made by loading crushed fruit with concentrated pectin and sugar and allowed to set for a day. They are preserved in the refrigerator or freezer. Low-calorie and low-sugar jams are made by adding a modified pectin that uses cross-linking calcium to gel instead of sugar. The sugar is replaced by artificial sweeteners.

High and low pectin fruit

Preserves can be made from all kinds of fruit, though some fruits are low in pectin and have to be mixed with either fruits high in pectin or commercial pectin to get a good gel.

Fruits high in pectin include: quince, apples, citrus fruits, cranberries, currants, gooseberries, plums, and grapes.

Fruits low in pectin include: apricots, most berries, cherries, peaches, pears, and pineapple.

Pectin gels

Pectin is a polysaccharide naturally contained in the cell walls of plants. Coupled with sugar and acid, pectin is what transforms cooked fruits into jams and jellies.

Brief history

The Ancient Greeks discovered that fruit cooked with honey developed a texture unlike any of its counterparts. By the 7th century there were several recipes for making delicate jellies made by boiling the juice of a quince with honey (quince is especially rich in pectin). The introduction of the sugar cane from Asia transformed jelly production. Unlike honey, sugar did not have excess moisture that needed to be evaporated. The Arab world used sugar to make fruit preserves through the Middle Ages, and took them to Europe in the 13th century. Still, sugar jams and jellies did not become common until after the 19th century, when sugar became cheaply available.

Transforming a jelly

Pectin, sugar, and acid are needed to make a fruit preserve, jam, or jelly. When fruit is cut up and heated near the boil, the pectin chains come off of the cell walls and dissolve into the released cell fluids and added water. Pectin molecules have the ability to bond with each other and form a meshwork that gives the jam a gel-like texture. However, pectin cannot accomplish this alone. When in solution, pectin molecules obtain a negative electrical charge that repels them from each other and they are too dilute to form a continuous network. To form the gel, sugar is added to absorb water molecules away from pectin, leaving the long chains exposed for bonding. In addition, boiling concentrates the pectin molecules as excessive water evaporates. Finally, acid provides the needed H+ that neutralize the negative electrical charge of pectin and allows the chains to come in close-enough proximity to bond.  The ideal conditions for pectin gelation are: a pectin concentration of 0.5 - 1.0%; a sugar concentration of 60 -65%; and a pH between 2.8 - 3.5, about the acidity of orange juice.

Types of starch

Grain starches have some common characteristics:

• granules are medium sized
• contain significant amounts of lipids and protein
• have increased structureal stability and thus require higher temperatures to gelate
• have distinct "cereal" flavor
• contain a high proportion of moderately long amylose, so they thicken and congeal quickly

Examples:

• Wheat flour is only 75% starch, which makes it a less efficient thickener than cornstarch or potatoe starch. It adds a distinct wheat flavor to the sauce. Common rule of thumb is to add 1.5 times as much flour as starch.
• Cornstarch is practically pure starch. It is an efficient thickener, but it absorbs odors and develops flavors during processing.
• Rice starch have the smallest granule size and produce a fine texture. It is seldom available in Western markets.  

Tuber and root starches come from moist underground storage organs and have the following characteristics:

• larger granules that retain more water molecules
• cook faster
• release starch at lower temperatures
• contain less amylose, but the amylose chains are four times longer than cereal starches
• readily gelate
• do not require precooking to improve flavor

Examples:

• Potato starch has very large granules and very long amylose chains. Stringiness and initial graininess in the sauces are notable. However, the granules are fragile and fragment easily. It is unusual in that it contains a large number of phosphate groups that carry a weak electric charge and cause the chains to repel each other. This repulsion keeps starch chains evenly dispersed in a sauce and prevents them from congealing when cool.
• Tapioca is derived from the tropical plant casava (aka manioc). It does not develop any strong aromas and it is prized for its neutral flavor. It is mostly used in puddings.
• Arrowroot starch has smaller granules than potato or tapioca starches. Its gelation temperature is higher, more comparable to that of cornstarch.

There are also a number of modified starches available. Plant breeders have developed "waxy" varieties of corn that contain little or no amylose and nearly all amylopectin. Waxy starches make sauces and gels that resist congealing. Manufacturers have also used physical and chemical treatments to produce starches that readily absorb cold water or disperse in liquids without cooking. They have also added cross-linking chains, made them fat-soluble, and have given them other qualities that make them more effective emulsion stabilizers. Such starches are listed as "modified starch."

Starch

Starch is made up of thousands of glucose molecules linked up together. There are two structures of starch molecules: amylose and amylopectin. Amylose molecules are long and straight; amylopectin molecules are short and branched. Of the two, amylose is a more effective thickener than amylopectin as its long chains tangle with each other more readily and slow the motion of other molecules in the surrounding fluid.

When starch is mixed into cold water, its granules only absorb a limited amount of water and sink. Nothing happens. When starch is mixed into hot water, however, the granules absorb large amounts of water and swell up. As they do so, weak regions of the granules become disrupted; stronger regions lose their organized structure and become water-containing meshworks of long molecules. In other words, the granules become individual gels. A cloudy suspension of granules becomes more translucent as individual starch molecules become less packed and no longer deflect as many rays of light.

The temperature at which starch begins to behave in this manner is called the gelation range, usually around 120-140 degrees F/50-60 degrees C. 

Thickening of a sauce/dish with starch occurs as the granules become so saturated with water that they begin to leak amylose and amylopectin molecules into the surrounding liquid. The long amylose molecules form a fishnet of sorts that entraps pockets of water and blocks the movement of the swollen starch granules.

After reaching its thickest consistency, the starch-water mixture begins to thin out again. As more amylose leaks into the water, the starch granules break or otherwise become smaller. Heating close to boiling point, vigorous stirring, continued heating long after thickening, and addition of an acid accelerate the thinning process.

The cooling that follows allows amylose molecules to form stable bonds and water molecules settle in the pockets between the starch chains. As a result, the sauce/liquid gets thicker. If the temperature drops low enough, the starch particles begin to congeal. It is important to judge the consistency of a sauce/dish at serving temperatures, not at cooking temperatures. The best way to predict the final texture of a sauce is to pour a spoonful into a cool dish and sample it.

Other gelling agents

• Carrageenan is a high-molecular weight polysaccharide obtained from red algae and has long been used in China and Ireland. It is a common food additive used as a stabilizer or emulsifier.
• Alginates come from brown seaweeds. They only form gels in the presence of calcium. They are the preferred emulsifiers for ice cream and other dairy products.
• Gellan is an industrial discovery. It is a polysaccharide produced as a fermentation product of the bacteria Sphingomonas elodea. Gellan forms a gel in the presence of salts and/or acids. Gellan is extremely versatile as it forms gels in textures ranging from hard and brittle to fluid. It is used in cosmetics and air-freshners as well as a common additive in food.

From pudding to Petri Dish

In the late 19th century, Lina Hesse, the American wife of a German scientist, recalled the advise of friends who had lived in Asia and made agar jellies and puddings that stayed solid despite the summer heat. Her husband relayed the message to his boss, microbiologist Robert Koch, who then used agar to isolate the causative agent of tuberculosis, Mycobacterium tuberculosis.

Agar gels are used as an invaluable tool in the microbiology laboratory. Scientists make agars containing various nutrients that help grow and differentiate bacteria. Agar is helpful to microbiologists because

• very few bacteria can digest the agar carbohydrates, so agar gels remain intact and bacteria colonies separate. Bacteria readily digest the proteins in gelatin and many liquify the gel.
• Agar gels remain solid at the ideal growth temperature for most bacteria, around 100 degrees F/38 degrees C. Gelatin melts at this temperature.

Agar

Agar is a mixture of several different carbohydrates and other materials extracted from red algae. Today it is manufactured primarily by boiling the seaweeds, filtering the liquid, and freeze-drying it in strands. Solid agar pieces can be consumed raw in salads; it can be used in many sauces as a thickening agent; or used to gel flavorful mixtures of fruit juices and sugar, stews, meats, and vegetables. Agar is consumed as a jellied sweet in Japan.

Agar forms gels at much lower concentrations than gelatin. Where commercial gelatin concentration is usually >3%, agar concentrations work well under 1% by weight. The jelly is somewhat opaque, as opposed to the clear gelatin, and it has a more crumbly texture. Formed agar melts at 185 degrees F/85 degrees C, therefore it does not have the "melt-in-your-mouth" quality of gelatin. Agar gels must be chewed. The higher melting point is often desirable for cool treats that do not melt in the summer heat as well as hot dishes.

From liquid to solid

When a gelatin solution is hot, the proteins molecules are in constant, forceful movement. As the solution cools, the molecules move more gently. The proteins form regions with helical association, i.e. they coil. A meshwork of gelatin molecules begins to form as these regions bind and align themselves. Liquid becomes trapped in the interstices of the meshwork, preventing a noticeable flow. The liquid becomes a solid gel.

Gelatin

Gelatin is a pure protein derivative that contains no fat, carbohydrates, or cholesterol and is free of all preservatives. It is most widely known for its setting qualities as a thickening and emulsifying agent in culinary uses. However, gelatin is also useful in other food processing, pharmaceuticals, photography, paper production, and other fields.

Gelatin is produced from the partial hydrolysis of collagen found in mammals. It is produced from the connective tissues, bones, and skins of animals, most commonly cows and pigs. The animal tissues undergo a process which includes cleaning, roasting, treating with acid/alkali, and boiling before gelatin is ready to be extracted. Solid gelatin is separated from its liquid components and pressed into sheets. Depending on its final purpose, it is pulverized and mixed with flavorings, colorings, sweeteners, and other additives.

Here is the chemical structure of gelatin:



taken from: http://www.madehow.com/Volume-5/Gelatin.html

The chemical structure of gelatin gives it its versatility. It is water-soluble and forms digestible gels and films that are strong and flexible. It is transparent and has no flavor/color.

The exact history of gelatin is not documented. As it is a byproduct of animal parts, it is likely that its discovery dates back hundreds of years. Up to the 19th century, gelatin production was arduous and time consuming. In the 1840s a salesman named Charles B. Knox started packaging sheets of gelatin and selling it door to door. Peter Cooper, who had made a fortune in the manufacture of glue (a similar process to that of gelatin) received the first patent for a gelatin dessert in 1845.

In 1897, Pearl B. Wait, a cough medicine manufacturer, developed a fruit-flavored gelatin. His wife named his product Jell-O. Wait sold the rights to the process to the Genesee Food Company, for $450. In 1902, after an aggressive advertising campaign in Ladies Home Journal magazine generated enormous interest. Today, 400 million packages of Jello-O are produced each year. Over a million packages are purchased or eaten each day.

Gelatin has also had a long presence in other fields. There is documentation of the use of gelatin in paper making as early as the 14th century. In the 1870s, gelatin became a substitute for wet collodion in photography. It was used to coat dry photographic plates, marking the beginning of modern photographic methods. Today, most shells of pharmaceutical capsules are made of gelatin. Glues, paper, cosmetics, soft drinks, and many other things also contain gelatin.

Jams and Jellies

This week is another quick and easy subject. The topics include:

Gelatin jellies
Carbohydrate jellies
Thickeners
Sugar preserves

Hope you join me!

Thoughts on Meringues

The topics of eggs and foams are two of which I knew very little.  I read a lot about eggs that I did not publish on posts due to highly politized views on chickens, living conditions, chickens as biological factories, animal rights, and egg economics. Though fascinating, the material is beyond the scope of this blog. If any of these topics piques your interest, I encourage you to research further.

On the posts published, I found some of the figures outstanding:

• Some factories house up to 1 million egg-laying hens, and handle upwards of a million eggs daily.
• A hen expends 3% of her body weight to produce an egg.
• Hens produce around 250 eggs a year in the US.
• There are close to 300 million egg-laying hens in the US (and about 300 million people!)

In relation to foams, they have intrigued me since childhood. I remember wondering whether they were a solid or a liquid, and what made them so. Even now, as a scientist, I find them incredibly fascinating. To think that I can visualize proteins unfolding from their tightly bound structure by simply whisking away an egg white. How tightly packed they are to increase the volume eight-fold!

In terms of techniques, I haven't had much experience making meringues or mousses, but I recently made some macaroons that are similar. I use a pretty efficient stand up mixer, so I did not have any trouble getting stiff peaks, but I imagine that a lot of the trouble with such treats comes down to inefficient beating. It takes a while. If you attempt it by hand, it takes a long, long time. I read somewhere, "whip until both your arms get tired, then ask your neighbor to whip until her arms get tired too, and then some more." Just don't let it get dry or all your efforts have been in vain.

Mile-High Lemon Meringue Tarts

From Women's Day, February 1, 2001, page 124 as posted by Dr. Patti Christie on: http://ocw.mit.edu/courses/special-programs/sp-287-kitchen-chemistry-spring-2009/readings/MITSP_287s09_read07_meringue.pdf

Ingredients:

Lemon filling

• 2/3 cup white sugar
• 2 tbps cornstarch
• 2/3 cup water
• yolks from 2 large eggs (reserve whites for meringue)
• 1/3 cup fresh lemon juice (from 1-2 lemons)
• 1 tbsp grated lemon peel (from 1 lemon)
• 1 tbsp butter
• 1 pkg (4 oz) ready-to-serve graham cracker crusts (6/pkg)

Meringue

• Egg whites from 4 large eggs
• 1/2 tsp Cider vinegar
• 1/2 tsp vanilla extract
• 1/2 cup sugar

Method:

Lemon filling

1. Whisk sugar and cornstarch in the top bowl of a double boiler to mix.
2. Whisk in water, egg yolks and lemon juice until smooth.
3. Place bowl over double boiler, stirring often with the whisk.
4. Boil, stirring constantly, 1 minute or until filling is translucent and thick.
5. Remove from heat. Add lemon peel and butter; stir until butter melts.
6. Pour 1/2 cup into each cracker crust and place on a rimmed baking sheet

Meringue

1. Heat oven to 350 degrees F.
2. Beat egg whites, vinegar and vanilla in a medium metal or copper bowl with a whisk until soft peaks form when whisk is lifted.
3. Gradually beat in sugar, 1 tbsp. at a time, increasing whisking speed and beating well after each addition until sugar dissolves.
4. Beat 2 minutes longer or until stiff peaks form when beaters are lifted.
5. Mound Meringue high on each tart, spread to edge of crust , then swirl with back of a teaspoon.
6. Bake 20 minutes or until meringue is browned an instant-read thermometer inserted in center of meringue registers 160 degrees F.
7. Cool completely on a wire rack, then refrigerate at least 2 hours or up to 8.
8. If you wish to share one, use a small sharp knife dipped in cold water to cut through the meringue smoothly.

A note on cold mousses

An egg foam can also be used as scaffolding for cold mousses and cold soufflés. The foam is stabilized when cold congeals fats and gelatin protein. Chocolate mousse is a prime example. Egg yolks are combined with melted chocolate and finely ground sugar and heated to around 100 degrees F/38 degrees C. The mixture is then combined with 3 or 4 times its volume in stiffly beaten egg whites. The cocoa solids and sugar absorbs much of the moisture from the egg whites and the bubble walls are reinforced. The mousse is spooned into dishes and refrigerated for several hours. As the mousse cools down, the cocoa butter congeals into a rigid solid.

Troubleshooting meringues

Meringues have a reputation for being troublesome. Keep in mind the following things:

• Under- or overbeaten foams leak syrup into unsightly beads and puddles.
• Undissolved sugar is undercooked syrup that has come to room temperature. If the sugar has not been completely dissolved, residual crystals attract water and create pockets of concentrated syrup (beads).  These meringues have a gritty texture.
• Too high an oven temperature squeezes wter from the coagulating proteins faster than it evaporates, producing syrup beads. It can also cause the foam to rise and crack, and turn its surface yellow.
• Weeping of syrup is caused by either undercooking a foam bottom in a hot oven and cold base, or overcooking the foam bottom in a moderate oven and hot base. To prevent weeping, cover the pie base with a layer of crumbs before adding the meringue topping and include starch or gelatin in the foam to help it retain moisture.
• Humidity is bad for meringues. Their sugary surface absorbs moisture from the air and gets sticky. Transfer dried meringues directly from the oven to an airtight container and serve immediately after removing from container.

Meringues

A meringue is a sweetened egg foam that generally stands on its own. Meringues obtain their stiffness and stability from sugar and heat. They are often baked slowly at low oven temperatures of 200 degrees F/93 degrees C. When browned in a hot oven or under a broiler, the surface gets crisp while the interior remains moist.

Meringues have a lot of sugar. The proportion of sugar to egg white ranges from 1:1 to 2:1. The higher, a 67% sugar content, is typical of jams. At this concentration, sugar reaches its water solubility at room temperature. Granulated sugar does not dissolve completely in a hard meringue. It leaves a gritty texture and weeping syrup drops. Confectioner's sugar or premade syrup are better suited for meringue use.

There are two main categories of meringues: uncooked and cooked.

Uncooked meringues are the simplest and most common. They vary in purpose and firmness based on the timing of the cook's addition of sugar. The lightest meringues are obtained by folding in the sugar only after the foam is formed. The sugar dissolves into the bubble walls and adds bulk and cohesiveness. These meringues are suitable for a spread pie topping or folding into a mousse or chiffon mix. If the sugar is beaten into the foam as it forms, it noticeably tightens the foam texture. These meringues get stiffer and can be shaped. Some cooks reverse the technique by beating the eggs gradually into the sugar. This process takes longer but a cook can form a foam in autopilot as it demans little attention. The resulting meringues are denser and less brittle. Therefore, the earlier the sugar is added, the firmer and finer the meringue.

Cooked meringues are more complex and are generally more dense. Heat incorporates the sugar better in the meringue and stabilizes the protein network into a solid structure. There are two basic cooked meringues:

• The Italian meringue is a syrup-cooked meringue. Sugar is made into a syrup first by heating sugar and water to 240 degrees F/115 degrees C. The whites are whipped to stiff peaks and then the syrup is streamed into the foam and beaten. The result is a fluffy, fine-textured, stiff foam. It can be used to decorate pastries or blend into batters and creams. Note: The heat from the hot syrup is not enough to kill salmonella as much of its heat gets lost to the bowl, whisk, and air.
• The Swiss meringue (similar to the French meringue cuite) is prepared by heating eggs, acid, and sugar in a hot bath and then beaten into a stiff foam. This preparation pausterizes the egg whites before forming the foam. This meringue can be refrigerated for several days and is usually pipped into decorative shapes.