The document discusses baking science and technology, including the baking process, events that occur during baking, and types of ovens. The main points are: 1. Baking involves at least 11 events like fats melting, gases forming, microorganisms dying, and starches gelatinizing. 2. Types of ovens include direct gas fired ovens, radiating cyclotherm ovens, indirect convection ovens, direct convection ovens, and hybrid ovens. Each oven has different applications. 3. Impingement ovens and thermal oil ovens provide advantages like shorter cooking times and ability to handle high moisture doughs respectively.

2. Baking Science and Technology
Presenting To: Dr Shabir Ahmad
Presenting By: Umm e Habiba
Sobia Akbar

3. Content
Baking Process &Types of Ovens
• Fat melt, Gases form & expand
• Microorganisms die, Sugar dissolves
• Egg and gluten protein coagulate
• Starches gelatinize, Gases evaporate
• Caramilization & millard browning occur on
crust
• Enzymes are inactivated
• Changes occur to nutrients, Pectin breaks down
• Direct Gas fired oven
• Radiating cyclotherm oven
• Indirect convection oven
• Direct convection oven
• Hybrid oven
• Impingement oven
• Thermal oil oven

4. Baking Process
• Baking is a method of cooking that uses dry heat in an enclosed space.
• Typically done in an oven, baking occurs when heat makes contact with
dough or batter and causes the starches in the dish to change form.
• This results in the development of a firm, browned surface due to the
Maillard reaction, and a soft inside as a result of moisture getting trapped
within the baked good.
• An enclosed space is necessary for baking in order to uniformly distribute
heat, resulting in evenly cooked baked goods.

5. Baking
• During baking: – Heat is slowly conducted from the outside in. – Heat
transforms batter/dough from a foam that traps air bubbles to a porous
sponge.
• Term sponge is used whether product has a springy, spongy texture
• Crumb, or grain, of baked goods consists of air cells surrounded by porous
cell walls.

6. Baking involves at least eleven events
• Events occur concurrently and influence each other.
• Many would never occur at room temperature; heat is required.
• Several have no upper limit; they continue for as long as baked good is in
oven.
• Examples: protein coagulation, starch gelatinization, evaporation of gases.

7. 1. Fats Melt
• Most melt between 90º and 130ºF (30º–55ºC).
• Results in: Increased volume, or rise: trapped steam and air expand.
• The later fats melt, the more rise.
• Increased tenderness: melted fats coat structure builders.
• The sooner fats melt, often the more tenderness. Example: oil and pie pastry
dough.
• Thinned batters and doughs. Example: high-fat cookie dough and spread.

8. 2. Gases Form and Expand
• Starts at room temperature; continues until about 170ºF (75ºC).
• Three most important leavening gases: air, steam, carbon dioxide.
• Results in: Increased volume or rise: expanding gases push on cell walls.
Example: Oven spring
• Increased tenderness: expanding gases thin cells walls, making them easier
to bite.

9. 3. Microorganisms Die
• Microorganisms include: yeast, mold, bacteria, viruses.
• Most die at 135 –140ºF (55–60ºC).
• Depends on microorganism and amount of sugar or salt.
• Results in: Fermentation stopping.
• Safer food, since pathogenic bacteria are killed.
• Examples of pathogens: Salmonella bacteria, hepatitis virus.

10. 4. Sugar Dissolves
• Heat of oven dissolves sugar that did not dissolve during mixing.
• Results in: Moistening, tenderizing, browning, sweetening.
• That is, sugar now acts like sugar.
• Thinned batters and doughs.
• Dissolved sugar pulls water from driers.
• Other solutes that dissolve during baking include acid salts in baking powder

11. 5. Egg and Gluten Proteins Coagulate
• Starts at 140 –160ºF (60–70ºC).
• Egg proteins: Unfold (denature) and bond, forming a network of stretched-
out clusters of egg proteins.
• Heat dries out and stiffens the proteins.
• Results in formation of rigid structure that sets the final size and shape of
baked goods.

12. 6. Starches Gelatinize
• Starts at 120 –140ºF (50–60ºC).
• Starch granules, tightly-packed with starch molecules, swell and soften.
• Results in: Thickening of batter/dough.
• Formation of rigid structure that sets the final size and shape of baked goods.
• Besides heat, water is required.
• Bread dough vs. cookie dough

13. 7. Gases Evaporate
• Starts at about 160ºF (72ºC).
• Rigid cell walls rupture from pressure of expanding gases; gases escape.
• Results in: Formation of dry, hard (white) crust.
• Weight loss.
• Aroma loss.

14. 8. Caramelization and Maillard Browning Occur
on Crust.
• Begins at 300ºF (150ºC) and above.
• Temperature of crust rises only after water evaporation slows.
• Caramelization: breakdown of sugars.
• Maillard browning: breakdown of sugars and proteins together.
• Results in: Brown color, Baked flavors.

15. 9. Enzymes are Inactivated
• By about 160 –180ºF (70–80ºC).
• Below this temperature, rising oven temperatures increase enzyme activity.
• Enzymes are: Proteins, Biological catalysts; they speed up chemical reactions.
• Denatured by heat.
• Example: amylase.

16. 10.Changes Occur to Nutrients
• Examples of nutrients: proteins, fats, carbohydrates, vitamins, minerals.
• Results in: Proteins and starches becoming more digestible.
• Destruction of certain vitamins (Vitamin C and thiamin).

17. 11.Pectin Breaks Down
• Pectin holds fruits together.
• Dissolves when heated.
• Results in softened fruit.

18. Types of Ovens

19. Direct gas fired oven
• The direct gas fired oven is used for those products that require great
heating power.
• They can burn natural gas or LPG.
• in each zone, the heat at top and bottom can be independently set by
regulating the two combustion air fans which control the volume of gas fed
to the burners.
• Each zone is managed by a suitable automatic humidity extraction system.

20. Example applications for direct gas-fired ovens
• Pizzas
• Flatbreads
• Pita bread
• Bread, Rolls, Bagels
• Biscuits, Cookies
• Crackers

21. Radiating -cyclotherm oven
• The indirect radiating oven – also known as a cyclotherm oven –transfers the
heat to the product by radiation.
• Each zone consists of a set of tubes at the top and at the bottom of the baking
conveyor, through which the hot air, that has been previously heated by a
burner, flows.
• At the end of each baking zone the hot gases are collected by a plenum and
return by a blowing fan to the burner, where they are heated up again to the
working temperature and sent back to the tube circuit.
• The heating system is therefore completely independent, and the products of
combustion in fact never come in contact with the dough being baked.
• Each zone is managed by a suitable automatic humidity extraction system.

22. Indirect convection oven
• In the indirect convection oven the air is heated up by passing through a
dedicated heat exchanger: the dough under baking never comes in contact
with the products of combustion.
• This type of heating is suitable for baking more delicate products.
• Its baking chamber is constituted by a plenum duct positioned on the top
and bottom of the baking conveyor where hot air is gently blown out of
properly designed slats and comes in contact with the dough.
• The heat transfer is mainly by convection and it has a pronounced drying
effect on the dough.
• Each zone is managed by a suitable automatic humidity extraction system.

23. Example applications for indirect convection
ovens
• Bread
• Rolls
• Cakes
• Confectionary

24. Direct convection oven
• In those cases where the fuel available is natural gas and the reduction of the
baking time is a necessity, the direct convection oven is the right choice.
• Its baking chamber is constituted by a plenum
duct positioned on the top and bottom of the baking conveyor where hot gases
are gently blown out of properly designed slats and come in contact with the
dough.
• The heat transfer is mainly by convection and it has a pronounced drying effect
on the dough.
• Each zone is managed by a suitable automatic humidity extraction system.

25. Hybrid oven
• An hybrid oven is divided into sections with different types of heating
systems; depending on the type of product and its baking requirement.
• Cracker and hard sweet biscuits are usually baked in a hybrid oven with a
direct gas fired section, followed by the direct convection system.
• A cyclotherm section followed by indirect convection is usually used when
rotary moulded and wire-cut products are to be baked.

26. Impingement ovens
• Impingement ovens are indirect-fired baking solutions, which means that no
combustion products share the baking chamber with the food products.
• Like traditional ovens, impingement ovens surround products with radiant heat,
but they also use pressurized jets of hot air to penetrate the product.
• This design significantly shortens the cooking time by heating product from the
inside as well as from the outside.
• Impingement ovens are best for products that need to be cooked quickly but are
also relatively sturdy — fragile doughs and batters don’t stand up well to the
jets of hot air.

27. Example applications for impingement ovens
• Pizzas, Calzones
• Flatbreads, Empanadas
• Bread, Breadsticks
• Cakes, Cookies
• Pastries, Muffins, Pies
• Macaroons
• Granola

28. Thermal oil ovens
• Thermal oil ovens provide the gentle heat transfer necessary to create
artisan-style products at an industrial scale.
• These ovens are hugely popular in Europe and are gaining traction in the
United States because of their ability to handle high moisture doughs and
produce artisan-style crusts.
• Thermal oil ovens also have a high thermal capacity, providing precise
temperature control.

29. Example applications for thermal oil ovens
• Freestanding products
• Artisan- and rustic-style products
• Bread, Rolls, Pies
• Pita bread, Bagels
• Pretzels, Pastries

30. Reference
• https://www.masterclass.com/articles/baking-101-5-baking-techniques-plus-
how-to-build-a-perfectly-stocked-home-bakery
• Pdf: chapter 3 Overview of the baking process-how baking works
• https://www.naegele-inc.com/2020/06/25/features-and-types-of-industrial-
baking-ovens
• cat_ Ovens_rev13GEA_MEDIA_min.pdf