Why is the Oven Relevant?

Why is the oven related?

An oven is an important processing step within the baking business for several reasons:

1. It is the workhorse of the bakery. 4. It gives a vital kill step that prevents pathogens from thriving within the product. 3. Baking within the oven is the step that imparts the final characteristics to the merchandise (e.g., shelf life, taste, texture, shade, aroma). The manufacturing output of a bakery is normally managed by the capacity of the oven.2
2. Heat and mass transfer phenomena both happen simultaneously inside this piece of equipment, triggering physicochemical and biochemical modifications within the product.

Origin

The basic oven mannequin, with stone ground and dome construction, has been round for many years. The decrease section formed the firebox during which items of dried wooden and charcoal were burned. The higher part, accessible from the highest, was the baking chamber.3 It was the Egyptians who initially utilized a handcrafted oven cavity made from clay.

Several centuries later, the Roman Empire began to create more refined ovens with higher baking quality and better effectivity ovens. Brick and stone ovens have been constructed contained in the bakery’s premises, with thermostable supplies for the baking chamber, and different excessive-temperature-resistant materials to insulate the oven and keep the heat atmosphere for prolonged time frames. These ovens were powered by burning wooden straight inside the heating chamber, removing the ashes, after which putting the dough/batter items inside for baking.3

Forms of ovens

Depending on their mode of operation and heat switch mechanism, ovens may be labeled as both batch or steady equipment and as utilizing either direct or indirect heat alternate.

The type of oven that suits a bakery’s operation may be a perform of production capability, product specs, floor space, obtainable energy sources, operation efficiencies, development materials, and maintenance needs.1

These are the common kind of commercial ovens:

1. Direct-fired oven (DFO)

DFOs place combusting gasoline (energy supply) inside the baking chamber to heat the air and the products. The heat switch in a direct gasoline-fired oven is primarily carried out by radiation from the flames (ribbon burners placed above and below the oven band), prime, base and walls of the baking chamber. Direct-fired ovens are very environment friendly because they convert many of the gasoline to heat and course of the merchandise, and this lowers gasoline consumption and working prices.Four

2. Oblique-fired oven (IFO)

IFOs indirectly heat the baking chamber by utilizing exchangers. This oven is appropriate for delicate bakery merchandise (e.g., cakes, pastries) because the byproducts of combustion stay contained in the heat exchanger structure and do not come into direct contact with the dough pieces. This eliminates the chance of contamination and of impregnation of off-odors in the products.

This type of oven is less often used these days due to its restricted power for heat switch and vitality effectivity (amount of gas burned in a given time versus water loss (evaporated moisture) of the merchandise during baking).4

3. Electric oven

Electric ovens have construction options much like those of DFOs, and function equally by way of heat transfer mechanism to bake the merchandise. This sort of oven uses electrical resistances instead of the normal gasoline burners of DFOs.Four

Electric-fired ovens have limited use in the baking industry due to their energy consumption and prices per kWh. Additionally they face scale-up challenges that require further analysis and industry software.

4. Peel brick oven

The peel brick oven was considered one of the first constructed baking units in human history. Coal and wood are used as gas (combustion source).5 It consists of a large brick material chamber. The chamber is connected to a refractory tile floor that holds the dough pieces.

Because of their building options (insulation capacity of supplies and thickness of the walls), these ovens are in a position to steadily switch radiant heat to the merchandise, and also maintain excessive temperatures contained in the baking chamber for prolonged periods of time. The ovens are operated manually and require special skills from the baker.5

5. Rack oven

A rack oven is a batch vertical oven into which racks filled with sheet pans could be wheeled for baking. Some items make use of electric or gasoline sources, and place fans inside the baking chamber (generation of convection drying) to hurry up baking occasions and to develop special options in the merchandise. This unit can hold eight to 20 sheet pans per baking cycle.

This oven is appropriate for retail operations due to its flooring space economic system, and medium to lengthy baking cycle occasions. The products are baked upon buyer order, and are sometimes offered immediately (unpackaged) for speedy consumption.2 These ovens usually have programmable (saved) recipes so that the operator can change baking time and temperature, intensity of air ventilation, and steam impingement frequency.

6. Reel oven (also referred to as revolving tray oven)

A reel oven is an oven wherein trays or shelves are placed on platforms rotating on a central horizontal axis. A high baking chamber is required to accommodate the reel structure, thereby saving floor area. Reel ovens are normally instantly fired with gas or electricity, with the heating source located centrally across the floor of the chamber. One of these oven is usually designed for retail bakeries or baking plants with small-scale manufacturing.6

Reel ovens often do not generate uniform distribution of heat switch as a result of their revolving nature and interfering construction for radiant heat transfer. Products positioned on sheet pans or trays constantly rotating might current uneven coloring or poor remaining moisture distribution.

7. Conveyorized oven (also known as traveling tray oven)

Conveyorized ovens change the reel ovens idea with two parallel countless conveying chains that carry trays of products through the size of the baking chamber, so the dough items regularly enter and go away the oven.5 Their fundamental advantages are simplicity of design, and uniformity of baking because the merchandise journey the same path via the baking chamber. A motor drive instantly controls band velocity, thereby figuring out baking cycle time.

Conveyorized ovens may be single-lap or double-lap. In single-lap ovens, the trays containing the merchandise travel a single go (back and forth). The trays in a double-lap oven travel by four heat zones as an alternative of the 2 zones of the single-lap oven.5

8. Tunnel oven

Tunnel ovens are steady mode operation baking units, and are commonly utilized in large-scale bakeries. This unit typically has an extended baking chamber (normally more than eighty meters in size), which goes from one aspect (loading level) to another (unloading level) in a straight conveying band. The conveyor band material may be constructed of wire mesh or carbon steel sheets.

Tunnel ovens are generally powered by fuels such as pure gas (used for baking), and electricity (for powering air circulation and conveying system). The baking chamber may be divided into a number of baking zones. This makes the appliance of a temperature sequence doable, which provides the baker more flexibility in baking conditions and more complexity for controlling baking parameters.7

9. Hybrid oven

Hybrid ovens mix the three modes of heat switch and take advantage of their synergistic effect on merchandise.4

The sort of oven often requires a excessive diploma of automation since its construction, management techniques, and vitality sources are too complex to be manipulated manually.

Maintenance of ovens

Oven maintenance focuses on two major targets:

1. Stop food security hazards (physical, biological, and chemical) from occurring by decreasing the probability of overseas material contamination, below-processing, and contamination with lubricants. 2. Prevent mechanical, electrical, and thermal gear failures that could negatively influence normal oven operation; and increase downtime, which could trigger significant economic losses. These hazards might pose a food safety threat to customers, not to say the loss of an excellent reputation and money.

Inspection and maintenance of equipment and calibration of measuring and instrumentation devices are important for clean oven operation. Particular consideration should be paid to: welded components, drive chains and belts, motors and drives, steam strains and fittings, air strains and fittings, seals and gaskets in piping, bearings, conveyor belts, bands, temperature indicators and controllers, in-line humidity meters and humidity exhaust systems, electrical management systems, and followers (axial or centrifugal).8

References

1. Manley, D. “Biscuit Baking.” Manley’s Technology of Biscuits, Crackers and Cookies, 4th ed., Woodhead Publishing Restricted, 2011, p. 328.
7. Conforti, F. D. “Industrial Preparation and Baking of Cakes.” Bakery Merchandise Science and Know-how, 2nd ed., John Wiley & Sons, Ltd, 2014, pp. 73-90.
5. Stear, C. A. “Types of Oven and Oven Design.” Handbook of Breadmaking Expertise, Elsevier Science Publishers LTD, 1990, pp. The Story of Bread. 3, Elsevier Ltd., 2016, p. 602-791.
6. Walker, C. E. “Grain-Based Products and Their Processing: Oven Applied sciences.” Encyclopedia of Food Grains, 2nd ed., vol. 45.
3. Sheppard, R., and E. Newton. Routledge & Paul, 1957, pp. 485.
2. Gisslen, W. “Baking and Pastry Gear.” Skilled Baking, seventh ed., John Wiley & Sons, Inc., 2017, p. 582-583.
8. Davidson, I. “Appendix 2: Oven Upkeep.” Biscuit Baking Expertise: Processing and Engineering Guide, 2nd ed., Elsevier Inc. 107-120.
4. Davidson, I. “Oven Designs.” Biscuit Baking Know-how: Processing and Engineering Handbook, 2nd ed., Elsevier Inc. , 2016, pp.