Chemistry in Bread-baking

Chemistry in Bread-baking

AJ Gordon and Hannah Shiflett

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01

Yeast Breads

Typcal Ingredients

• Warm water (105-115 degrees fareinheit if using active dry yeast)
• Yeast
• Sugar
• Salt
• Oil
• Flour

The Two Main types of Yeast for bread-making

What is yeast? - Single celled eukaryotic organisms in the fungus kingdom. - Usually found in the wild in sugary environments like flower nectar or fruit - While there are over 1500 species of yeast, Saccharomyces cerevisiae is typically used for bread, known as "Baker's Yeast."

Instant Yeast

Active Dry Yeast

What is difference between Instant and Active Dry yeast? - Granule size -Refining process -Baking (proofing) process

Yeast Chemistry

How does yeast leaven, or make bread rise? - Water brings out naturally occuring enzymes in from flour - Amylase breaks down long polysacharides in the flour - Yeast ferments simple sugars - CO2 creates gas bubbles and alcohol burns off Why knead dough? - Kneading induces aerobic fermentation and reproduction - C6O12H6 + 6O2 -> 6H20 + 6CO2

Other Processes

Mailliard reaction

Gluten Formation

When the surface temperature of the bread reaches around 165oF, the Maillard Effect occurs. Sugar corbonyl groups react with amino acides to produce Melanoidins which cause the change in color and smell.

Water allows gliadin and glutenin proteins to bind. Kneading dough allows gluten to develop, allowing for a stretchy dough that is able to rise.

02

Quick breads

Leavening Agent: a substance causing expansion of doughs and batters by the release of gases within such mixtures, producing baked products with porous structure.

• Baking Soda (Sodium Hydrogencarbonate = NaHCO3)
1. The agent reacts with moisture, heat, and an added acid through acid and base reactions
2. Carbon dioxide bubbles are produced
3. Creates volume and lightens the texture

• Baking Powder (NaHCO3 + Tartaric Acids + Cornstarch)

1. The agent reacts with moisture and heat through decomposition and acid/base reactions
1. 2 NaHCO3 (s) -> Na2CO3 (s) + CO2 (g) + H2O
2. Carbon dioxide bubbles are produced and expand during heating, causing batter to rise
3. Creates volume and lightens the texture

Typical Ingredients

sour cream

Eggs

butter

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Sugar

Flour

Salt

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04

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Bread!

More Mixing

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Mixing

Filling Pans

Future Implications

References

https://www.britannica.com/topic/leavening-agent https://datasciencemilan.org/what-is-baking-powder-s-scientific-name.html https://freescience.info/the-science-of-eggs-in-baking-structure-moisture-and-binding/ https://pastryteamusa.com/the-golden-ingredient-the-science-of-using-butter-in-baking/ https://www.homecookingtech.com/the-secret-ingredient-how-sour-cream-elevates-your-baked-goods-to-the-next-level/ https://modernistcuisine.com/mbah/the-science-behind-each-stage-of-the-bread-making-process/ https://www.ragus.co.uk/how-sugar-provides-structure-in-baking-ragus/ https://bakingscience.co.uk/the-science-of-adding-salt-to-baking-as-a-flavour-enhancer/ https://www.britannica.com/science/yeast-fungus https://modernistcuisine.com/mbah/the-science-behind-each-stage-of-the-bread-making-process/ https://source.colostate.edu/what-every-new-baker-should-know-about-the-yeast-all-around-us/ https://tastesbetterfromscratch.com/bread-recipe/

Bon appetit!

Enjoy our bread :)

Salt

• Promotes protein bonding, strengthening the gluten network through ionic interactions
• Tightens gluten strands to trap air
• Dough can stretch without tearing
• Prevents overproofing by slowing down the yeast fermentation
• Affects the flavor and texture
• Enhances savory (umami) and sweetness tones while suppressing bitterness
• Acts as a preservative
• Reduces water and prevents microbial growth

• 1.5% to 2% of the flour weight
• Sodium ions drive the perception of saltiness

Eggs

• Yolks:
• Full of fat and proteins
• Facilitate emulsification (mixing of two immiscible liquids--water and oil)
• Provide rich and velvet-like texture
• Whites:
• Full of water and proteins
• Create structure and leavening
• Trap air and provide lightness and moisture

Butter

80-82% fat, 16-17.5% water, 1.5% salt (in salted varieties), 1% milk solids (vitamins, minerals, and lactose)

• Fat content contributes to tenderness (coats flour particles and inhibits gluten formation), flakiness (water evaporates and creates steam), and moisture
• Rich, creamy flavor and aroma through the Maillard reaction and caramelization
• Provides a light, airy texture through the creaming method and steam leavening

• Other factors like temperature, cutting in, creaming, and types of butter affect its role

Sour Cream

Lactic acid-producing bacteria + cream, pH 4.0-4.5

• High fat content tenderizes gluten by clinging to the flour, making the product softer and moister (shortening)
• Acidity activates the reaction with baking soda to produce the needed carbon dioxide gas for the product to rise
• Adds a rich, creamy texture and a tangy balance to the sweetness of the other ingredients

Sugar

• Reduces the formation of gluten strands and starch gelatinization by slowing down protein coagulation
• Softens the texture and enhances moisture retention
• Hygroscopic/humectant
• Supports volume and leavening and stabilizes egg mixtures
• Binds to water molecules to create a thickened syrup that stabilizes the protein network

Flour

• Starch Damage:
• Milled -> ~12% damaged starch granules
• Brings out enzymes like amylase and starch molecules with amylose and amylopectin

• Affects the amount of water needed, mixing time, and crust browning
• Starch gelatinization
• Protein Content:
• Glutenin + gliadin + water = gluten
• Gives structure and ability to hold gas bubbles
• Creates lots of long chains that are elastic and extesible to trap air

• Amylase: breaks down amylose and amylopectin to make food for yeast
• Pentosanase: breaks down pentosan to allow the dough to absorb water
• Protease: makes the dough extensible
• Lipoxidase: breaks down lipids to change crumb color