Does ascorbic acid enhance the dough’s rise and help it rise higher? Check out this article for insights on its baking power.
Ascorbic acid, also known as vitamin C, is a vital nutrient found in various citrus fruits and vegetables. Apart from being an essential dietary requirement, it is frequently used as a flour improver in yeast-leavened baked goods.
Origin and Discovery of Ascorbic Acid
The discovery of ascorbic acid dates back to the late 1920s when Albert Von Szent Györgyi first identified it. He was later awarded the Nobel Prize in 1937 for his contribution to this field. Initially, ascorbic acid was used to treat scurvy caused by the lack of fresh fruits and vegetables in the diet. Later in 1935, Jorgensen developed the concept of using ascorbic acid as a flour improver or dough conditioner. At very low doses, it significantly increased bread volume.
Function of Ascorbic Acid in Bread Dough
As a flour improver, one significant function of ascorbic acid is to stabilize the gluten protein network. This stabilization results in a higher loaf volume and a finer, more uniform crumb structure. Unlike traditional oxidizing agents such as potassium bromate, azodicarbonamide (ADA), and calcium peroxide, ascorbic acid depends on external factors such as the presence of oxygen and naturally occurring cereal grain enzymes to function as an oxidizing agent.
Function of Ascorbic Acid in Food Systems
Ascorbic acid is a potent reducing agent and an antioxidant with significant benefits in food systems. However, in the presence of oxygen gas and ascorbic acid oxidase (an enzyme found naturally in wheat flour), ascorbic acid gets converted to its oxidized form. The oxidized form has the potential to participate in oxidation reactions during flour-water mixing, such as SH/SS interchange between cysteine residues of gluten-forming proteins. The oxidation of thiol groups promotes the formation of disulphide bonds between proteins, leading to gluten cross-linking and polymerization (gluten strengthening effect).
Gluten Strengthening Effects of Ascorbic Acid
- Higher gas retention capacity of dough
- Greater elasticity of dough
- Higher dough tolerance to over-proofing and over-mixing
- Higher water absorption of flour to obtain equivalent dough rheology after mixing
- Diminished dough viscous behaviour
- Higher dough resistance to deformation
- Enhanced oven spring during baking
The strengthening of gluten can result in several positive consequences in breadmaking, such as higher gas retention capacity of dough, greater elasticity of dough, higher dough tolerance to over-proofing and over-mixing, higher water absorption of flour to obtain equivalent dough rheology after mixing, diminished dough viscous behavior, higher dough resistance to deformation, and enhanced oven spring during baking.
Commercial Production of Ascorbic Acid
Although fruits and vegetables are natural sources of ascorbic acid, most of the ascorbic acid used in the food industry is synthesized from carbon sources such as glucose or molasses. This is achieved using a combination of microbial fermentations and chemical methods.
Application of Ascorbic Acid in Breadmaking
Ascorbic acid is a white granular powder that is commonly used in bread and buns at levels up to 150 ppm (based on flour weight). The exact amount of AA dosed depends on several factors, such as the protein level of flour, breadmaking system used (e.g., sponge and dough, no-time dough, Chorleywood bread process), bake test results, scaling weight/pan volume ratio, amount of other oxidizing agents (e.g., ascorbic acid for ADA or bromate replacement), and amount of bran, whole grains, and fruit inclusions in the formulation (whole wheat and multigrain bread require higher amounts of AA).
Factors That Affect the Oxidizing Potential of Ascorbic Acid
Several factors can affect the oxidizing potential of ascorbic acid, such as the amount and enzyme activity of ascorbate oxidase in flour, the amount of atmospheric oxygen during mixing, and competition with yeast and glucose oxidase for air (oxygen).
Regulation of Ascorbic Acid in Breadmaking
According to the U.S. FDA, ascorbic acid is a permitted dough conditioner and flour improver up to a maximum of 200 parts per million (based on flour weight). In the UK and European Union, AA is allowed in all flour and breads except wholemeal up to a maximum of 200 ppm.
Assuming we are working with untreated flour that has no ascorbic acid already added to it, 0.02 to 0.2 grams ascorbic acid per kilogram of flour can be added to improve dough strength. The ideal dosage is about 0.05 to 0.07 grams (50-70 parts per million) of Vitamin C per kilogram of flour.
Lemon’s vitamin C content vary greatly across varieties or even individual fruit but to get an idea 100g raw lemon juice contains approx 38mg ascorbic acid according to USDA. Which basically means a gentle squeeze of lemon will provide plenty enough ascorbic acid for any of our homemade dough.