You’ve probably seen Citric acid in cake listed on ingredient label of a soda can or a package of snacks—and it sounds like a substance that belongs in a chemistry lab rather than a kitchen. True, the citrus-derived powder is used as a preservative and emulsifier.
Many cut fruits, like apples or avocado, tend to oxidize and go brown after sitting out for a while. You’ve likely heard of squeezing lemon or lime onto fruit to prevent oxidization—but Citric acid in cake is a next-level trick that’s beloved by food stylists. Rhoda, Epi’s food director, says, “If I want to keep produce like apples and avocados looking really fresh for camera, I make a mixture of citric acid and water and brush it on the cut sides of the fruit so they don’t brown.”
Acidic ingredients play an important role in cake baking. They add and enhance flavors as well as contribute to leavening and tenderization of cakes. Batter acidity can come from a wide variety of sources including vinegar, lemon juice, chocolate, buttermilk, coffee, brown sugar, fruits and vegetables to name a few. While acid is most definitely a baker’s friend, it can also be a source of frustration if it interferes with the molecular integrity of a cake. To gain a better grasp on acid ingredients, I decided to take a look at how increasing the acidity of a cake recipe affected the final outcome.
Before we dive into cake experimentation, it helps to know what acids are and
how they play a role in baking chemistry. Acidic ingredients are those which
give off hydrogen ions (H+) when they are dissolved in water. These newly
released hydrogen ions are now free to interact with other molecules in
solution. Here are the major alterations to baked goods caused by acid:
1. Protein alteration- Hydrogen ions disrupt the bonds that keep proteins
folded into a specific shape and cause them to unravel. This undoing can
beneficially tenderize or, in excess, cause problems with the structure of the
cake.
2. Starch modification- Acids cause starches to breakdown and gel at a lower
temperature. This can cause cake to set more quickly but with less structural
support.
3. Acidic ingredients interfere with the reactions that cause browning in baked
foods.
Alkaline/basic ingredients readily accept free-floating hydrogen ions and in
effect neutralize acids by chemically reacting with the hydrogen they provide.
Baking soda is an example of an alkaline ingredient. When baking soda reacts with
an acid such as lemon juice or buttermilk the neutralizing reaction releases
carbon dioxide as a byproduct. This carbon dioxide contributes to leavening in
baked goods. Unlike its savory cousin, though, citric acid is so much more than
a seasoning; it’s also a food-safe pH adjuster. Adding the smallest pinch to
cake batter or biscuit dough enhances the leavening power of baking soda; it
also slows oxidation significantly, so it’ll keep your fruit salad or guacamole
from browning too quickly. Basically, whenever you need an acid that’s stronger
than vinegar but still safe to eat, citric acid is there to help.
The sourness of these acidic items is very well taken care of, by any alkaline
constituent. For example – baking soda which is widely used as an alkaline
ingredient to neutralise the acidic effect and to give the cake a perfectly
sweet taste.
Among other such acidic ingredients would fall lemon juice, chocolate and
buttermilk which perfectly blends in, thereby making the cake dough soft and
fluffy. Buttermilk is one of the acidic components which gives any bakery item
an unseemingly taste but also blends well along with any of the leaveners. A
nice frothy, foamy taste and texture is given rise due to the release of carbon
dioxide when an acidic chemically bonds with alkaline ingredients. But, as
mentioned prior, proportions need to be taken care of. Any ingredients in
excess portion would spoil the cake mixture.
Applications of citric acid and other acidic substances play an important role in cake production. Because it is added to the cake as a flavoring and preservative and helps the texture of the cake. Citric acid prevents fruits such as apples and avocados from turning brown and helps keep them fresh. Citric acid is a safe pH regulator for food that you can use for cooking.