Q: Why is “creaming” an important technique for quality-shortened cakes?
Melanie, via e-mail

A: Creaming is a process of working the fat and sugar to incorporate air bubbles and results in a heavy foam. Ideally, the air bubbles are uniform, small and surrounded by fat. These bits of fat are then dispersed throughout the liquid batter. The air bubbles contribute to the leavening of the cake and subsequent increase in volume, serving as cells where steam and carbon dioxide can collect and expand during baking.

Ideal thickness of croissant dough

Q: To what thickness should croissant dough be sheeted?
C.D., Alma, Mich.

A: I have great success when sheeting croissant dough to 0.15 ins. or 3.5 to 4 mm.

Q: What is the difference between alkalized and non-alkalized processed cocoa powder? Do we need to make any changes when interchanging them?
R.P., Chicago

A: Dutch process cocoa powder is alkalized and other cocoa powders are non-alkalized. If your formula calls for Dutch process cocoa and you don't have any, you can use non-alkalized cocoa, but you must add a smidge of baking soda to even out the alkalinity and keep the cake from being coarse and dry. And vice versa-if you are baking a cake and it calls for regular cocoa and all you have is Dutch-processed cocoa, just leave out any baking soda in the formula. I would not recommend doing this on a regular basis, and use the above tip only in emergencies.

Q: What is the difference between an essence and an extract?
Bernard, via e-mail

A: An extract is a concentrated mixture of ethyl alcohol and flavoring oils, such as vanilla, lemon, almond, etc., and is made by distilling, steeping and pressing foods. An essence is a concentrated liquid usually made from an herb, spice or flower and used as a flavoring or aromatic. Essence also is the French word for a concentrated stock.

Q: We want to produce breads fortified with both soluble and insoluble fiber. How do we do this?
Geralyn, via e-mail

A: While breads with high levels of insoluble dietary fiber have been on the market for some time, some obstacles exist to developing breads that are fortified with both soluble and insoluble fiber. Several new gum blends have made it possible to create such a fiber-enhanced product. Used to replace up to 20 percent of the flour in bread dough, these products can deliver about 0.15 oz./4 g of soluble dietary fiber per slice (1.75 ozs./50 g). Some of these gum blends are specially designed to behave like bread flour when used with vital wheat gluten and do not interfere with gluten development and strength. These gums are cold water soluble, kosher and have a typical usage level of 1 percent to 20 percent as replacement of flour.

Prolonging oil life

Q: How can we prolong our frying oils' useful life?
Scott, via e-mail

A: The longer oil is heated, the more quickly it decomposes. Avoid preheating the oil any longer than necessary. If you're frying more than one batch, quickly add each new batch, unless time is needed to recover back to the desired frying temperature. Turn off the heat as soon as you have removed the last batch from the oil. Shake off loosely attached crumbs from food before adding it to the oil. Loose crumbs and other particles scorch quickly and will pollute any oil. Use a small strainer or slotted spoon to remove as many impurities as possible. When the oil has cooled enough that it is safe to handle, strain it through paper towels, coffee filters or cheesecloth into its original empty container. Do not mix it with unused oil. Store the oil, tightly sealed, in a cool, dark place or in the refrigerator. The oil may cloud in the refrigerator, but it should become clear again at room temperature with no ill effects.

Q: What is the definition of high-ratio cake flour?
M.C., Washington, D.C.

A: High-ratio cake flour is soft wheat flour with a protein content within the range of 7 percent to 9 percent, and is treated to render it particularly suitable for the production of high-ratio cakes. It is finely ground and chlorinated to a pH value of 5.2 or lower.

Q: What are pregelatinized flours, and what is their functionality?
B.T., Miami

A: Pregelatinized flours are substances with high water absorption ability that are also called stabilizers. Guar flour and carob gum are two of the best known pregelatinized flours. Pregelatinized flours are essentially used in improvers for interrupted fermentation. In this case, the part of free water in the dough is reduced, which means when the product is frozen, less crystals can be formed. These crystals lead to a deterioration of the gluten membranes and thereby to a deterioration of the product. Carob gum is extracted from the seeds of the carob tree that is found in Mediterranean countries. Guar gum is extracted from a type of bean that grows in India. The kernels of these beans are ground into flour.

Q: Recently we came across a formula that called for curled wheat. Can you tell us what this is?
Chris, via e-mail

A: Curled wheat is ground whole wheat containing about 11 percent protein that has been mixed with moisture and an edible acid to produce dough. The heated dough is then extruded through a die under particular conditions-from high to low pressure zones-to provide a high protein expanded curled wheat product which can be used as an ingredient.

Q: While reading the ingredient label of margarine, I wondered at the meaning of the E-numbers? Do you have an idea?
Michael, via e-mail

A: All food additives have E-numbers. The E stands for Europe. The E-numbers have been introduced in order to be able to clearly define the additives on an international level, because the names for the additives vary from country to country. Moreover, the E-number indicates the food additive is on the list of admissible additives, and therefore is not detrimental to health. Some examples are:

E 170 Acidulant calcium carbonate

E 263 Acidulant calcium acetate

E 300 Flour improver L-ascorbic acid (vitamin C)

E 322 Emulsifier lecithin

E 341 Acidulant calcium phosphate

E 410 Thickener carob gum

E 412 Thickener guar gum

E 450 Acidulant diphosphate

E 471 Emulsifier mono- and diglycerides of edible fatty acids

E 472e Emulsifier DATEM (diacetyl tartaric acid ester)

Q: We produce our signature banana bread almost every week. We buy bananas in bulk, and were hoping you knew a trick to lengthen the life of the bananas.
Nina, via e-mail

A: I place bananas in plastic grocery bags. Push out the air from the bag, and close it tightly. I have stored bananas up to five weeks in the refrigerator this way without the skins turning dark or the flavor deteriorating quickly. One thing taking place is that the ethylene gas is still active but greatly slowed by the chill of the refrigerator. They still continue to ripen, but as a much slower rate. The bags shield the bananas from dehydration and oxygen.

Q: Is there an economical substitute for marzipan?
Gary, via e-mail

A: Persipan is an economical substitute for marzipan. Raw persipan paste is manufactured through the same process as marzipan, and consists of debittered apricot kernels and sugar. The moisture content does not exceed 20 percent, and a maximum of 35 percent sugar is added. Apart from this, the paste contains 0.5 percent potato starch, which is added to comply with food legislation. Persipan for forming is made by blending raw persipan with sugar. Up to one-and-one-half parts sugar may be added to one part raw persipan. It is recommended to add up to 5 percent glucose syrup and 5 percent sorbitol syrup, but these additions must be deducted from the sugar amount. Labeling is required.

Klaus Tenbergen is certified as a Master Baker in Germany, South Africa and the United States. He is currently an assistant professor at California State University in Fresno, teaching classes in Culinology®-the blending of culinary arts and the science of food. For more information, call 559/278-2164 or contact Klaus Tenbergen at ktenbergen@csufresno.edu.